Remove Bizware Vector2/3/4 and Matrix4 in favor of System.Numerics's implementation

Many many cleanups in BizwareGL and DisplayManager and GDI+ code

src/BizHawk.Bizware.BizwareGL/Art.cs

@@ -5,7 +5,7 @@ namespace BizHawk.Bizware.BizwareGL
 	/// </summary>
 	public class Art
 	{
-		//bleh, didnt mean to have this here, but I need it now
+		// bleh, didnt mean to have this here, but I need it now
 		public Art(Texture2d tex)
 		{
 			BaseTexture = tex;

src/BizHawk.Bizware.BizwareGL/ArtManager.cs

@@ -1,6 +1,7 @@
 using System;
 using System.IO;
 using System.Collections.Generic;
+using System.Linq;
 
 namespace BizHawk.Bizware.BizwareGL
 {
@@ -18,7 +19,7 @@ namespace BizHawk.Bizware.BizwareGL
 
 		public void Dispose()
 		{
-			//todo
+			// todo
 		}
 
 		/// <summary>
@@ -27,7 +28,11 @@ namespace BizHawk.Bizware.BizwareGL
 		public void Open()
 		{
 			AssertIsOpen(false);
-			if (IsClosedForever) throw new InvalidOperationException($"{nameof(ArtManager)} instance has been closed forever!");
+			if (IsClosedForever)
+			{
+				throw new InvalidOperationException($"{nameof(ArtManager)} instance has been closed forever!");
+			}
+
 			IsOpened = true;
 		}
 
@@ -52,7 +57,7 @@ namespace BizHawk.Bizware.BizwareGL
 		{
 			AssertIsOpen(true);
 
-			Art a = new Art(this);
+			var a = new Art(this);
 			ArtLooseTextureAssociation.Add((a, tex));
 			ManagedArts.Add(a);
 
@@ -72,16 +77,16 @@ namespace BizHawk.Bizware.BizwareGL
 
 			// first, cleanup old stuff
 			foreach (var tex in ManagedTextures)
+			{
 				tex.Dispose();
+			}
 			ManagedTextures.Clear();
 
 			// prepare input for atlas process and perform atlas
 			// add 2 extra pixels for padding on all sides
-			var atlasItems = new List<TexAtlas.RectItem>();
-			foreach (var kvp in ArtLooseTextureAssociation)
-			{
-				atlasItems.Add(new TexAtlas.RectItem(kvp.Bitmap.Width + 2, kvp.Bitmap.Height + 2, kvp));
-			}
+			var atlasItems = ArtLooseTextureAssociation
+				.Select(kvp => new TexAtlas.RectItem(kvp.Bitmap.Width + 2, kvp.Bitmap.Height + 2, kvp))
+				.ToList();
 			var results = TexAtlas.PackAtlas(atlasItems);
 
 			// this isn't supported yet:
@@ -89,27 +94,28 @@ namespace BizHawk.Bizware.BizwareGL
 				throw new InvalidOperationException("Art files too big for atlas");
 
 			// prepare the output buffer
-			BitmapBuffer bmpResult = new BitmapBuffer(results[0].Size);
+			var bmpResult = new BitmapBuffer(results[0].Size);
 
 			//for each item, copy it into the output buffer and set the tex parameters on them
-			for (int i = 0; i < atlasItems.Count; i++)
+			for (var i = 0; i < atlasItems.Count; i++)
 			{
 				var item = results[0].Items[i];
 				var (art, bitmap) = ((Art, BitmapBuffer)) item.Item;
-				int w = bitmap.Width;
-				int h = bitmap.Height;
-				int dx = item.X + 1;
-				int dy = item.Y + 1;
-				for (int y = 0; y < h; y++)
-					for (int x = 0; x < w; x++)
+				var w = bitmap.Width;
+				var h = bitmap.Height;
+				var dx = item.X + 1;
+				var dy = item.Y + 1;
+				for (var y = 0; y < h; y++)
+				{
+					for (var x = 0; x < w; x++)
 					{
-						int pixel = bitmap.GetPixel(x, y);
+						var pixel = bitmap.GetPixel(x, y);
 						bmpResult.SetPixel(x+dx,y+dy,pixel);
 					}
+				}
 
-				var myDestBitmap = bmpResult;
-				float myDestWidth = (float)myDestBitmap.Width;
-				float myDestHeight = (float)myDestBitmap.Height;
+				var myDestWidth = (float)bmpResult.Width;
+				var myDestHeight = (float)bmpResult.Height;
 
 				art.u0 = dx / myDestWidth;
 				art.v0 = dy / myDestHeight;
@@ -138,7 +144,13 @@ namespace BizHawk.Bizware.BizwareGL
 		/// <summary>
 		/// Throws an exception if the instance is not open
 		/// </summary>
-		private void AssertIsOpen(bool state) { if (IsOpened != state) throw new InvalidOperationException($"{nameof(ArtManager)} instance is not open!"); }
+		private void AssertIsOpen(bool state)
+		{
+			if (IsOpened != state)
+			{
+				throw new InvalidOperationException($"{nameof(ArtManager)} instance is not open!");
+			}
+		}
 
 		public IGL Owner { get; }
 
@@ -153,11 +165,11 @@ namespace BizHawk.Bizware.BizwareGL
 		/// <summary>
 		/// Physical texture resources, which exist after this ArtManager has been closed
 		/// </summary>
-		private readonly List<Texture2d> ManagedTextures = new List<Texture2d>();
+		private readonly List<Texture2d> ManagedTextures = new();
 
 		/// <summary>
 		/// All the Arts managed by this instance
 		/// </summary>
-		private readonly List<Art> ManagedArts = new List<Art>();
+		private readonly List<Art> ManagedArts = new();
 	}
 }

src/BizHawk.Bizware.BizwareGL/BitmapBuffer.cs

@@ -1,15 +1,14 @@
-//TODO - introduce Trim for ArtManager
-//TODO - add a small buffer reuse manager.. small images can be stored in larger buffers which we happen to have held. use a timer to wait to free it until some time has passed
+// TODO - introduce Trim for ArtManager
+// TODO - add a small buffer reuse manager.. small images can be stored in larger buffers which we happen to have held. use a timer to wait to free it until some time has passed
 
 using System;
 using System.Diagnostics;
-using System.Runtime.InteropServices;
-using System.Drawing.Imaging;
 using System.Drawing;
+using System.Drawing.Drawing2D;
+using System.Drawing.Imaging;
+using System.Runtime.InteropServices;
 using System.IO;
 
-using sd = System.Drawing;
-
 namespace BizHawk.Bizware.BizwareGL
 {
 	/// <summary>
@@ -28,7 +27,7 @@ namespace BizHawk.Bizware.BizwareGL
 		/// </summary>
 		public bool HasAlpha = true;
 
-		public Size Size => new Size(Width, Height);
+		public Size Size => new(Width, Height);
 
 		private readonly Bitmap WrappedBitmap;
 		private GCHandle CurrLockHandle;
@@ -48,7 +47,7 @@ namespace BizHawk.Bizware.BizwareGL
 			}
 
 			CurrLockHandle = GCHandle.Alloc(Pixels, GCHandleType.Pinned);
-			CurrLock = new BitmapData
+			CurrLock = new()
 			{
 				Height = Height,
 				Width = Width,
@@ -82,16 +81,15 @@ namespace BizHawk.Bizware.BizwareGL
 
 		public void YFlip()
 		{
-			//TODO - could be faster
+			// TODO - could be faster
 			var bmpdata = LockBits();
-			int[] newPixels = new int[Width * Height];
-			int todo = Width * Height;
-			int* s = (int*)bmpdata.Scan0.ToPointer();
+			var newPixels = new int[Width * Height];
+			var s = (int*)bmpdata.Scan0.ToPointer();
 			fixed (int* d = newPixels)
 			{
 				for (int y = 0, si = 0, di = (Height - 1) * Width; y < Height; y++)
 				{
-					for (int x = 0; x < Width; x++, si++, di++)
+					for (var x = 0; x < Width; x++, si++, di++)
 					{
 						d[di] = s[si];
 					}
@@ -110,16 +108,15 @@ namespace BizHawk.Bizware.BizwareGL
 		public void Normalize(bool yflip)
 		{
 			var bmpdata = LockBits();
-			int[] newPixels = new int[Width * Height];
-			int todo = Width*Height;
-			int* s = (int*)bmpdata.Scan0.ToPointer();
+			var newPixels = new int[Width * Height];
+			var s = (int*)bmpdata.Scan0.ToPointer();
 			fixed (int* d = newPixels)
 			{
 				if (yflip)
 				{
 					for (int y = 0, si = 0, di = (Height - 1) * Width; y < Height; y++)
 					{
-						for (int x = 0; x < Width; x++, si++, di++)
+						for (var x = 0; x < Width; x++, si++, di++)
 						{
 							d[di] = s[si] | unchecked((int)0xFF000000);
 						}
@@ -130,7 +127,7 @@ namespace BizHawk.Bizware.BizwareGL
 				{
 					for (int y = 0, i=0; y < Height; y++)
 					{
-						for (int x = 0; x < Width; x++, i++)
+						for (var x = 0; x < Width; x++, i++)
 						{
 							d[i] = s[i] | unchecked((int)0xFF000000);
 						}
@@ -143,11 +140,19 @@ namespace BizHawk.Bizware.BizwareGL
 			Pixels = newPixels;
 		}
 
-		public int GetPixel(int x, int y) { return Pixels[Width * y + x]; }
-		public void SetPixel(int x, int y, int value) { Pixels[Width * y + x] = value; }
+		public int GetPixel(int x, int y)
+		{
+			return Pixels[Width * y + x];
+		}
+
+		public void SetPixel(int x, int y, int value)
+		{
+			Pixels[Width * y + x] = value;
+		}
+
 		public Color GetPixelAsColor(int x, int y)
 		{
-			int c = Pixels[Width * y + x];
+			var c = Pixels[Width * y + x];
 			return Color.FromArgb(c);
 		}
 
@@ -157,11 +162,15 @@ namespace BizHawk.Bizware.BizwareGL
 		public void Alphafy(int tcol)
 		{
 			for (int y = 0, idx = 0; y < Height; y++)
-				for (int x = 0; x < Width; x++, idx++)
+			{
+				for (var x = 0; x < Width; x++, idx++)
 				{
 					if (Pixels[idx] == tcol)
+					{
 						Pixels[idx] = 0;
+					}
 				}
+			}
 		}
 
 		/// <summary>
@@ -177,15 +186,16 @@ namespace BizHawk.Bizware.BizwareGL
 		/// </summary>
 		public BitmapBuffer Trim(out int xofs, out int yofs)
 		{
-			int minx = int.MaxValue;
-			int maxx = int.MinValue;
-			int miny = int.MaxValue;
-			int maxy = int.MinValue;
-			for (int y = 0; y < Height; y++)
-				for (int x = 0; x < Width; x++)
+			var minx = int.MaxValue;
+			var maxx = int.MinValue;
+			var miny = int.MaxValue;
+			var maxy = int.MinValue;
+			for (var y = 0; y < Height; y++)
+			{
+				for (var x = 0; x < Width; x++)
 				{
-					int pixel = GetPixel(x, y);
-					int a = (pixel >> 24) & 0xFF;
+					var pixel = GetPixel(x, y);
+					var a = (pixel >> 24) & 0xFF;
 					if (a != 0)
 					{
 						minx = Math.Min(minx, x);
@@ -194,21 +204,24 @@ namespace BizHawk.Bizware.BizwareGL
 						maxy = Math.Max(maxy, y);
 					}
 				}
+			}
 
 			if (minx == int.MaxValue || maxx == int.MinValue || miny == int.MaxValue || minx == int.MinValue)
 			{
 				xofs = yofs = 0;
-				return new BitmapBuffer(0, 0);
+				return new(0, 0);
 			}
 
-			int w = maxx - minx + 1;
-			int h = maxy - miny + 1;
-			BitmapBuffer bbRet = new BitmapBuffer(w, h);
-			for (int y = 0; y < h; y++)
-				for (int x = 0; x < w; x++)
+			var w = maxx - minx + 1;
+			var h = maxy - miny + 1;
+			var bbRet = new BitmapBuffer(w, h);
+			for (var y = 0; y < h; y++)
+			{
+				for (var x = 0; x < w; x++)
 				{
 					bbRet.SetPixel(x, y, GetPixel(x + minx, y + miny));
 				}
+			}
 
 			xofs = minx;
 			yofs = miny;
@@ -220,15 +233,18 @@ namespace BizHawk.Bizware.BizwareGL
 		/// </summary>
 		public void Pad()
 		{
-			int widthRound = NextHigher(Width);
-			int heightRound = NextHigher(Height);
+			var widthRound = NextHigher(Width);
+			var heightRound = NextHigher(Height);
 			if (widthRound == Width && heightRound == Height) return;
-			int[] NewPixels = new int[heightRound * widthRound];
+			var NewPixels = new int[heightRound * widthRound];
 
 			for (int y = 0, sptr = 0, dptr = 0; y < Height; y++)
 			{
-				for (int x = 0; x < Width; x++)
+				for (var x = 0; x < Width; x++)
+				{
 					NewPixels[dptr++] = Pixels[sptr++];
+				}
+
 				dptr += (widthRound - Width);
 			}
 
@@ -265,10 +281,12 @@ namespace BizHawk.Bizware.BizwareGL
 				Height = bitmap.Height;
 				WrappedBitmap = bitmap;
 			}
-			else LoadInternal(null, bitmap, options);
+			else
+			{
+				LoadInternal(null, bitmap, options);
+			}
 		}
 
-
 		/// <summary>
 		/// Initializes a BitmapBuffer --WRAPPED-- from the supplied parameters, which should definitely have a stride==width and be in the standard color format
 		/// </summary>
@@ -290,82 +308,89 @@ namespace BizHawk.Bizware.BizwareGL
 
 		private void LoadInternal(Stream stream, Bitmap bitmap, BitmapLoadOptions options)
 		{
-			bool cleanup = options.CleanupAlpha0;
-			bool needsPad = true;
+			var cleanup = options.CleanupAlpha0;
+			var needsPad = true;
 
 			var colorKey24bpp = options.ColorKey24bpp;
-			using (Bitmap loadedBmp = bitmap == null ? new Bitmap(stream) : null) //sneaky!
+			using (var loadedBmp = bitmap == null ? new Bitmap(stream) : null) // sneaky!
 			{
-				Bitmap bmp = loadedBmp;
-				if (bmp == null)
-					bmp = bitmap;
+				var bmp = loadedBmp ?? bitmap;
 
-				//if we have a 24bpp image and a colorkey callback, the callback can choose a colorkey color and we'll use that
+				// if we have a 24bpp image and a colorkey callback, the callback can choose a colorkey color and we'll use that
 				if (bmp.PixelFormat == PixelFormat.Format24bppRgb && colorKey24bpp != null)
 				{
-					int colorKey = colorKey24bpp(bmp);
-					int w = bmp.Width;
-					int h = bmp.Height;
+					var colorKey = colorKey24bpp(bmp);
+					var w = bmp.Width;
+					var h = bmp.Height;
 					InitSize(w, h);
-					BitmapData bmpdata = bmp.LockBits(new Rectangle(0, 0, w, h), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
-					Color[] palette = bmp.Palette.Entries;
-					int* ptr = (int*)bmpdata.Scan0.ToPointer();
-					int stride = bmpdata.Stride;
+					var bmpdata = bmp.LockBits(new(0, 0, w, h), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
+					var ptr = (int*)bmpdata.Scan0.ToPointer();
 					fixed (int* pPtr = &Pixels[0])
 					{
 						for (int idx = 0, y = 0; y < h; y++)
-							for (int x = 0; x < w; x++)
+						{
+							for (var x = 0; x < w; x++)
 							{
-								int srcPixel = ptr[idx];
+								var srcPixel = ptr[idx];
 								if (srcPixel == colorKey)
+								{
 									srcPixel = 0;
+								}
+
 								pPtr[idx++] = srcPixel;
 							}
+						}
 					}
 
 					bmp.UnlockBits(bmpdata);
 				}
-				if (bmp.PixelFormat == PixelFormat.Format8bppIndexed || bmp.PixelFormat == PixelFormat.Format4bppIndexed)
+				if (bmp.PixelFormat is PixelFormat.Format8bppIndexed or PixelFormat.Format4bppIndexed)
 				{
-					int w = bmp.Width;
-					int h = bmp.Height;
+					var w = bmp.Width;
+					var h = bmp.Height;
 					InitSize(w, h);
-					BitmapData bmpdata = bmp.LockBits(new Rectangle(0, 0, w, h), ImageLockMode.ReadOnly, PixelFormat.Format8bppIndexed);
-					Color[] palette = bmp.Palette.Entries;
-					byte* ptr = (byte*)bmpdata.Scan0.ToPointer();
+					var bmpdata = bmp.LockBits(new(0, 0, w, h), ImageLockMode.ReadOnly, PixelFormat.Format8bppIndexed);
+					var palette = bmp.Palette.Entries;
+					var ptr = (byte*)bmpdata.Scan0.ToPointer();
 					fixed (int* pPtr = &Pixels[0])
 					{
 						for (int idx = 0, y = 0; y < h; y++)
-							for (int x = 0; x < w; x++)
+						{
+							for (var x = 0; x < w; x++)
 							{
 								int srcPixel = ptr[idx];
 								if (srcPixel != 0)
 								{
-									int color = palette[srcPixel].ToArgb();
+									var color = palette[srcPixel].ToArgb();
 									
-									//make transparent pixels turn into black to avoid filtering issues and other annoying issues with stray junk in transparent pixels.
-									//(yes, we can have palette entries with transparency in them (PNGs support this, annoyingly))
+									// make transparent pixels turn into black to avoid filtering issues and other annoying issues with stray junk in transparent pixels.
+									// (yes, we can have palette entries with transparency in them (PNGs support this, annoyingly))
 									if (cleanup)
 									{
-										if ((color & 0xFF000000) == 0) color = 0;
+										if ((color & 0xFF000000) == 0)
+										{
+											color = 0;
+										}
+
 										pPtr[idx] = color;
 									}
 								}
 								idx++;
 							}
+						}
 					}
 
 					bmp.UnlockBits(bmpdata);
 				}
 				else
 				{
-					//dump the supplied bitmap into our pixels array
-					int width = bmp.Width;
-					int height = bmp.Height;
+					// dump the supplied bitmap into our pixels array
+					var width = bmp.Width;
+					var height = bmp.Height;
 					InitSize(width, height);
-					BitmapData bmpdata = bmp.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
-					int* ptr = (int*)bmpdata.Scan0;
-					int stride = bmpdata.Stride / 4;
+					var bmpdata = bmp.LockBits(new(0, 0, width, height), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
+					var ptr = (int*)bmpdata.Scan0;
+					var stride = bmpdata.Stride / 4;
 					LoadFrom(width, stride, height, (byte*)ptr, options);
 					bmp.UnlockBits(bmpdata);
 					needsPad = false;
@@ -373,7 +398,9 @@ namespace BizHawk.Bizware.BizwareGL
 			}
 
 			if (needsPad && options.Pad)
+			{
 				Pad();
+			}
 		}
 
 
@@ -382,29 +409,37 @@ namespace BizHawk.Bizware.BizwareGL
 		/// </summary>
 		public void LoadFrom(int width, int stride, int height, byte* data, BitmapLoadOptions options)
 		{
-			bool cleanup = options.CleanupAlpha0;
+			var cleanup = options.CleanupAlpha0;
 			Width = width;
 			Height = height;
 			Pixels = new int[width * height];
 			fixed (int* pPtr = &Pixels[0])
 			{
 				for (int idx = 0, y = 0; y < Height; y++)
-					for (int x = 0; x < Width; x++)
+				{
+					for (var x = 0; x < Width; x++)
 					{
-						int src = y * stride + x;
-						int srcVal = ((int*)data)[src];
-						
-						//make transparent pixels turn into black to avoid filtering issues and other annoying issues with stray junk in transparent pixels
+						var src = y * stride + x;
+						var srcVal = ((int*)data)[src];
+
+						// make transparent pixels turn into black to avoid filtering issues and other annoying issues with stray junk in transparent pixels
 						if (cleanup)
 						{
-							if ((srcVal & 0xFF000000) == 0) srcVal = 0;
+							if ((srcVal & 0xFF000000) == 0)
+							{
+								srcVal = 0;
+							}
+
 							pPtr[idx++] = srcVal;
 						}
 					}
+				}
 			}
 
 			if (options.Pad)
+			{
 				Pad();
+			}
 		}
 
 		/// <summary>
@@ -412,10 +447,10 @@ namespace BizHawk.Bizware.BizwareGL
 		/// </summary>
 		public static int PremultiplyColor(int srcVal)
 		{
-			int b = (srcVal >> 0) & 0xFF;
-			int g = (srcVal >> 8) & 0xFF;
-			int r = (srcVal >> 16) & 0xFF;
-			int a = (srcVal >> 24) & 0xFF;
+			var b = (srcVal >> 0) & 0xFF;
+			var g = (srcVal >> 8) & 0xFF;
+			var r = (srcVal >> 16) & 0xFF;
+			var a = (srcVal >> 24) & 0xFF;
 			r = (r * a) >> 8;
 			g = (g * a) >> 8;
 			b = (b * a) >> 8;
@@ -434,7 +469,9 @@ namespace BizHawk.Bizware.BizwareGL
 		/// <summary>
 		/// Makes a new bitmap buffer, in ??? state
 		/// </summary>
-		public BitmapBuffer() { }
+		public BitmapBuffer()
+		{
+		}
 
 		/// <summary>
 		/// initializes an empty BitmapBuffer, cleared to all 0
@@ -449,24 +486,24 @@ namespace BizHawk.Bizware.BizwareGL
 		/// </summary>
 		public void ClearWithoutAlloc()
 		{
-			//http://techmikael.blogspot.com/2009/12/filling-array-with-default-value.html
-			//this guy says its faster
+			// http://techmikael.blogspot.com/2009/12/filling-array-with-default-value.html
+			// this guy says its faster
 
-			int size = Width * Height;
-			byte fillValue = 0;
-			ulong fillValueLong = 0;
+			var size = Width * Height;
+			const byte fillValue = 0;
+			const ulong fillValueLong = 0;
 
 			fixed (int* ptr = &Pixels[0])
 			{
-				ulong* dest = (ulong*)ptr;
-				int length = size;
+				var dest = (ulong*)ptr;
+				var length = size;
 				while (length >= 8)
 				{
 					*dest = fillValueLong;
 					dest++;
 					length -= 8;
 				}
-				byte* bDest = (byte*)dest;
+				var bDest = (byte*)dest;
 				for (byte i = 0; i < length; i++)
 				{
 					*bDest = fillValue;
@@ -488,9 +525,12 @@ namespace BizHawk.Bizware.BizwareGL
 		private static int NextHigher(int k)
 		{
 			k--;
-			for (int i = 1; i < 32; i <<= 1)
+			for (var i = 1; i < 32; i <<= 1)
+			{
 				k = k | k >> i;
-			int candidate = k + 1;
+			}
+
+			var candidate = k + 1;
 			return candidate;
 		}
 
@@ -501,11 +541,12 @@ namespace BizHawk.Bizware.BizwareGL
 		public Bitmap ToSysdrawingBitmap()
 		{
 			if (WrappedBitmap != null)
+			{
 				return (Bitmap)WrappedBitmap.Clone();
-			var pf = PixelFormat.Format32bppArgb;
-			if (!HasAlpha)
-				pf = PixelFormat.Format24bppRgb;
-			Bitmap bmp = new Bitmap(Width, Height, pf);
+			}
+
+			var pf = HasAlpha ? PixelFormat.Format32bppArgb : PixelFormat.Format24bppRgb;
+			var bmp = new Bitmap(Width, Height, pf);
 			ToSysdrawingBitmap(bmp);
 			return bmp;
 		}
@@ -519,30 +560,33 @@ namespace BizHawk.Bizware.BizwareGL
 			if (WrappedBitmap != null)
 			{
 				using var g = Graphics.FromImage(bmp);
-				g.CompositingMode = sd.Drawing2D.CompositingMode.SourceCopy;
-				g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighSpeed;
+				g.CompositingMode = CompositingMode.SourceCopy;
+				g.CompositingQuality = CompositingQuality.HighSpeed;
 				g.DrawImageUnscaled(WrappedBitmap, 0, 0);
 				return;
 			}
 
 			//note: we lock it as 32bpp even if the bitmap is 24bpp so we can write to it more conveniently.
-			var bmpdata = bmp.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.WriteOnly, PixelFormat.Format32bppArgb);
+			var bmpdata = bmp.LockBits(new(0, 0, Width, Height), ImageLockMode.WriteOnly, PixelFormat.Format32bppArgb);
 
-			if(bmpdata.Stride == bmpdata.Width*4)
+			if (bmpdata.Stride == bmpdata.Width * 4)
+			{
 				Marshal.Copy(Pixels, 0, bmpdata.Scan0, Width * Height);
+			}
 			else if (bmp.Width != 0 && bmp.Height != 0)
 			{
-				int* ptr = (int*)bmpdata.Scan0.ToPointer();
-				int stride = bmpdata.Stride;
+				var ptr = (int*)bmpdata.Scan0.ToPointer();
 				fixed (int* pPtr = &Pixels[0])
 				{
 					for (int idx = 0, y = 0; y < Height; y++)
-						for (int x = 0; x < Width; x++)
+					{
+						for (var x = 0; x < Width; x++)
 						{
-							int srcPixel = pPtr[idx];
+							var srcPixel = pPtr[idx];
 							ptr[idx] = srcPixel;
 							idx++;
 						}
+					}
 				}
 			}
 

src/BizHawk.Bizware.BizwareGL/GDIPTextureWrapper.cs

@@ -1,12 +1,14 @@
 using System;
+using System.Drawing;
 
 namespace BizHawk.Bizware.BizwareGL
 {
 	public class GDIPTextureWrapper : IDisposable
 	{
-		public System.Drawing.Bitmap SDBitmap;
+		public Bitmap SDBitmap;
 		public TextureMinFilter MinFilter = TextureMinFilter.Nearest;
 		public TextureMagFilter MagFilter = TextureMagFilter.Nearest;
+
 		public void Dispose()
 		{
 			if (SDBitmap != null)

src/BizHawk.Bizware.BizwareGL/GDIPlusGuiRenderer.cs

@@ -1,9 +1,10 @@
-//this is full of bugs probably, related to state from old rendering sessions being all messed up. its only barely good enough to work at all
+// this is full of bugs probably, related to state from old rendering sessions being all messed up. its only barely good enough to work at all
 
 using System;
+using System.Drawing;
+using System.Drawing.Drawing2D;
 using System.Drawing.Imaging;
-
-using sd = System.Drawing;
+using System.Numerics;
 
 namespace BizHawk.Bizware.BizwareGL
 {
@@ -14,7 +15,13 @@ namespace BizHawk.Bizware.BizwareGL
 		public GDIPlusGuiRenderer(IGL_GdiPlus gl)
 			=> Gdi = gl;
 
-		private readonly Vector4[] CornerColors = { new(1.0f, 1.0f, 1.0f, 1.0f), new(1.0f, 1.0f, 1.0f, 1.0f), new(1.0f, 1.0f, 1.0f, 1.0f), new(1.0f, 1.0f, 1.0f, 1.0f) };
+		private readonly Vector4[] CornerColors =
+		{
+			new(1.0f, 1.0f, 1.0f, 1.0f),
+			new(1.0f, 1.0f, 1.0f, 1.0f),
+			new(1.0f, 1.0f, 1.0f, 1.0f),
+			new(1.0f, 1.0f, 1.0f, 1.0f)
+		};
 
 		public void SetCornerColor(int which, Vector4 color)
 		{
@@ -25,9 +32,16 @@ namespace BizHawk.Bizware.BizwareGL
 		public void SetCornerColors(Vector4[] colors)
 		{
 			Flush(); //don't really need to flush with current implementation. we might as well roll modulate color into it too.
-			if (colors.Length != 4) throw new ArgumentException("array must be size 4", nameof(colors));
-			for (int i = 0; i < 4; i++)
+
+			if (colors.Length != 4)
+			{
+				throw new ArgumentException("array must be size 4", nameof(colors));
+			}
+
+			for (var i = 0; i < 4; i++)
+			{
 				CornerColors[i] = colors[i];
+			}
 		}
 
 		public void Dispose()
@@ -45,30 +59,31 @@ namespace BizHawk.Bizware.BizwareGL
 
 		public void SetModulateColorWhite()
 		{
-			SetModulateColor(sd.Color.White);
+			SetModulateColor(Color.White);
 		}
 
 		private ImageAttributes CurrentImageAttributes;
-		public void SetModulateColor(sd.Color color)
+
+		public void SetModulateColor(Color color)
 		{
-			//white is really no color at all
-			if (color.ToArgb() == sd.Color.White.ToArgb())
+			// white is really no color at all
+			if (color.ToArgb() == Color.White.ToArgb())
 			{
 				CurrentImageAttributes.ClearColorMatrix(ColorAdjustType.Bitmap);
 				return;
 			}
 
-			float r = color.R / 255.0f;
-			float g = color.G / 255.0f;
-			float b = color.B / 255.0f;
-			float a = color.A / 255.0f;
+			var r = color.R / 255.0f;
+			var g = color.G / 255.0f;
+			var b = color.B / 255.0f;
+			var a = color.A / 255.0f;
 
 			float[][] colorMatrixElements =
 			{
-				new float[] { r, 0, 0, 0, 0 },
-				new float[] { 0, g, 0, 0, 0 },
-				new float[] { 0, 0, b, 0, 0 },
-				new float[] { 0, 0, 0, a, 0 },
+				new[] { r, 0, 0, 0, 0 },
+				new[] { 0, g, 0, 0, 0 },
+				new[] { 0, 0, b, 0, 0 },
+				new[] { 0, 0, 0, a, 0 },
 				new float[] { 0, 0, 0, 0, 1 },
 			};
 
@@ -76,15 +91,15 @@ namespace BizHawk.Bizware.BizwareGL
 			CurrentImageAttributes.SetColorMatrix(colorMatrix,ColorMatrixFlag.Default, ColorAdjustType.Bitmap);
 		}
 
-		private sd.Color CurrentModulateColor = sd.Color.White;
-
 		private IBlendState CurrentBlendState;
+
 		public void SetBlendState(IBlendState rsBlend)
 		{
 			CurrentBlendState = rsBlend;
 		}
 
 		private MatrixStack _Projection, _Modelview;
+
 		public MatrixStack Projection
 		{
 			get => _Projection;
@@ -94,6 +109,7 @@ namespace BizHawk.Bizware.BizwareGL
 				_Projection.IsDirty = true;
 			}
 		}
+
 		public MatrixStack Modelview
 		{
 			get => _Modelview;
@@ -104,8 +120,10 @@ namespace BizHawk.Bizware.BizwareGL
 			}
 		}
 
-		public void Begin(sd.Size size) { Begin(size.Width, size.Height); }
-
+		public void Begin(Size size)
+		{
+			Begin(size.Width, size.Height);
+		}
 
 		public void Begin(int width, int height)
 		{
@@ -117,31 +135,29 @@ namespace BizHawk.Bizware.BizwareGL
 			Modelview = Owner.CreateGuiViewMatrix(width, height);
 		}
 
-
 		public void Begin()
 		{
-			//uhhmmm I want to throw an exception if its already active, but its annoying.
+			// uhhmmm I want to throw an exception if its already active, but its annoying.
 			IsActive = true;
-			CurrentImageAttributes = new ImageAttributes();
+			CurrentImageAttributes = new();
 		}
 
-
 		public void Flush()
 		{
-			//no batching, nothing to do here yet
+			// no batching, nothing to do here yet
 		}
 
 		/// <exception cref="InvalidOperationException"><see cref="IsActive"/> is <see langword="false"/></exception>
 		public void End()
 		{
 			if (!IsActive)
-				throw new InvalidOperationException($"{nameof(GDIPlusGuiRenderer)} is not active!");
-			IsActive = false;
-			if (CurrentImageAttributes != null)
 			{
-				CurrentImageAttributes.Dispose();
-				CurrentImageAttributes = null;
+				throw new InvalidOperationException($"{nameof(GDIPlusGuiRenderer)} is not active!");
 			}
+
+			IsActive = false;
+			CurrentImageAttributes?.Dispose();
+			CurrentImageAttributes = null;
 		}
 
 		public void RectFill(float x, float y, float w, float h)
@@ -150,24 +166,26 @@ namespace BizHawk.Bizware.BizwareGL
 
 		public void DrawSubrect(Texture2d tex, float x, float y, float w, float h, float u0, float v0, float u1, float v1)
 		{
-			var tw = tex.Opaque as GDIPTextureWrapper;
+			var tw = (GDIPTextureWrapper)tex.Opaque;
 			var g = Gdi.GetCurrentGraphics();
+
 			PrepDraw(g, tex);
 			SetupMatrix(g);
 
-			float x0 = u0 * tex.Width;
-			float y0 = v0 * tex.Height;
-			float x1 = u1 * tex.Width;
-			float y1 = v1 * tex.Height;
+			var x0 = u0 * tex.Width;
+			var y0 = v0 * tex.Height;
+			var x1 = u1 * tex.Width;
+			var y1 = v1 * tex.Height;
 
-			sd.PointF[] destPoints = {
-				new sd.PointF(x,y),
-				new sd.PointF(x+w,y),
-				new sd.PointF(x,y+h),
+			PointF[] destPoints =
+			{
+				new(x, y),
+				new(x+w, y),
+				new(x, y+h),
 			};
 
-			g.DrawImage(tw.SDBitmap, destPoints, new sd.RectangleF(x0, y0, x1 - x0, y1 - y0), sd.GraphicsUnit.Pixel, CurrentImageAttributes);
-			g.Transform = new sd.Drawing2D.Matrix(); //.Reset() doesnt work ? ?
+			g.DrawImage(tw.SDBitmap, destPoints, new(x0, y0, x1 - x0, y1 - y0), GraphicsUnit.Pixel, CurrentImageAttributes);
+			g.Transform = new(); // .Reset() doesnt work?
 		}
 
 
@@ -184,47 +202,49 @@ namespace BizHawk.Bizware.BizwareGL
 			DrawInternal(art, x, y, width, height);
 		}
 
-		private void PrepDraw(sd.Graphics g, Texture2d tex)
+		private void PrepDraw(Graphics g, Texture2d tex)
 		{
-			var tw = tex.Opaque as GDIPTextureWrapper;
-			//TODO - we can support bicubic for the final presentation..
+			var tw = (GDIPTextureWrapper)tex.Opaque;
+
+			// TODO - we can support bicubic for the final presentation...
 			if ((int)tw.MagFilter != (int)tw.MinFilter)
+			{
 				throw new InvalidOperationException($"{nameof(tw)}.{nameof(tw.MagFilter)} != {nameof(tw)}.{nameof(tw.MinFilter)}");
-			if (tw.MagFilter == TextureMagFilter.Linear)
-				g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.Bilinear;
-			if (tw.MagFilter == TextureMagFilter.Nearest)
-				g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor;
+			}
 
-
-			//---------
+			g.InterpolationMode = tw.MagFilter switch
+			{
+				TextureMagFilter.Linear => InterpolationMode.Bilinear,
+				TextureMagFilter.Nearest => InterpolationMode.NearestNeighbor,
+				_ => g.InterpolationMode
+			};
 
 			if (CurrentBlendState == Gdi.BlendNormal)
 			{
-				g.CompositingMode = sd.Drawing2D.CompositingMode.SourceOver;
-				g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.Default; //?
+				g.CompositingMode = CompositingMode.SourceOver;
+				g.CompositingQuality = CompositingQuality.Default; // ?
 
-				//CurrentImageAttributes.ClearColorMatrix(ColorAdjustType.Bitmap);
+				// CurrentImageAttributes.ClearColorMatrix(ColorAdjustType.Bitmap);
 			}
 			else
-			//if(CurrentBlendState == Gdi.BlendNoneCopy)
-			//if(CurrentBlendState == Gdi.BlendNoneOpaque)
+			// if (CurrentBlendState == Gdi.BlendNoneCopy)
+			// if (CurrentBlendState == Gdi.BlendNoneOpaque)
 			{
-				g.CompositingMode = sd.Drawing2D.CompositingMode.SourceCopy;
-				g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighSpeed;
+				g.CompositingMode = CompositingMode.SourceCopy;
+				g.CompositingQuality = CompositingQuality.HighSpeed;
 
-				//WARNING : DO NOT USE COLOR MATRIX TO WIPE THE ALPHA
-				//ITS SOOOOOOOOOOOOOOOOOOOOOOOOOOOO SLOW
-				//instead, we added kind of hacky support for 24bpp images
+				// WARNING : DO NOT USE COLOR MATRIX TO WIPE THE ALPHA
+				// ITS SOOOOOOOOOOOOOOOOOOOOOOOOOOOO SLOW
+				// instead, we added kind of hacky support for 24bpp images
 			}
-
 		}
 
-		private void SetupMatrix(sd.Graphics g)
+		private void SetupMatrix(Graphics g)
 		{
-			//projection is always identity, so who cares i guess
-			//Matrix4 mat = Projection.Top * Modelview.Top;
-			Matrix4 mat = Modelview.Top;
-			g.Transform = new sd.Drawing2D.Matrix(mat.Row0.X, mat.Row0.Y, mat.Row1.X, mat.Row1.Y, mat.Row3.X, mat.Row3.Y);
+			// projection is always identity, so who cares i guess
+			// var mat = Projection.Top * Modelview.Top;
+			var mat = Modelview.Top;
+			g.Transform = new(mat.M11, mat.M12, mat.M21, mat.M22, mat.M41, mat.M42);
 		}
 
 		private void DrawInternal(Art art, float x, float y, float w, float h)
@@ -244,26 +264,27 @@ namespace BizHawk.Bizware.BizwareGL
 
 			SetupMatrix(g);
 
-			sd.PointF[] destPoints = {
-				new sd.PointF(x,y),
-				new sd.PointF(x+w,y),
-				new sd.PointF(x,y+h),
+			PointF[] destPoints =
+			{
+				new(x, y),
+				new(x+w, y),
+				new(x, y+h),
 			};
 
-			float sx = tex.Width * u0;
-			float sy = tex.Height * v0;
-			float sx2 = tex.Width * u1;
-			float sy2 = tex.Height * v1;
-			float sw = sx2 - sx;
-			float sh = sy2 - sy;
+			var sx = tex.Width * u0;
+			var sy = tex.Height * v0;
+			var sx2 = tex.Width * u1;
+			var sy2 = tex.Height * v1;
+			var sw = sx2 - sx;
+			var sh = sy2 - sy;
 
-			var tw = tex.Opaque as GDIPTextureWrapper;
-			g.PixelOffsetMode = sd.Drawing2D.PixelOffsetMode.Half;
-			g.DrawImage(tw.SDBitmap, destPoints, new sd.RectangleF(sx, sy, sw, sh), sd.GraphicsUnit.Pixel, CurrentImageAttributes);
-			g.Transform = new sd.Drawing2D.Matrix(); //.Reset() doesn't work ? ?
+			var tw = (GDIPTextureWrapper)tex.Opaque;
+			g.PixelOffsetMode = PixelOffsetMode.Half;
+			g.DrawImage(tw.SDBitmap, destPoints, new(sx, sy, sw, sh), GraphicsUnit.Pixel, CurrentImageAttributes);
+			g.Transform = new(); // .Reset() doesn't work ? ?
 		}
 
-		private void DrawInternal(Art art, float x, float y, float w, float h, bool fx, bool fy)
+		private static void DrawInternal(Art art, float x, float y, float w, float h, bool fx, bool fy)
 		{
 		}
 

src/BizHawk.Bizware.BizwareGL/IBlendState.cs

@@ -1,4 +1,6 @@
 namespace BizHawk.Bizware.BizwareGL
 {
-	public interface IBlendState {}
+	public interface IBlendState
+	{
+	}
 }

src/BizHawk.Bizware.BizwareGL/IGL.cs

@@ -1,6 +1,7 @@
 using System;
 using System.IO;
 using System.Drawing;
+using System.Numerics;
 
 namespace BizHawk.Bizware.BizwareGL
 {
@@ -55,12 +56,12 @@ namespace BizHawk.Bizware.BizwareGL
 		/// <summary>
 		/// Sets a uniform value
 		/// </summary>
-		void SetPipelineUniformMatrix(PipelineUniform uniform, Matrix4 mat, bool transpose);
+		void SetPipelineUniformMatrix(PipelineUniform uniform, Matrix4x4 mat, bool transpose);
 
 		/// <summary>
 		/// Sets a uniform value
 		/// </summary>
-		void SetPipelineUniformMatrix(PipelineUniform uniform, ref Matrix4 mat, bool transpose);
+		void SetPipelineUniformMatrix(PipelineUniform uniform, ref Matrix4x4 mat, bool transpose);
 
 		/// <summary>
 		/// sets a uniform value
@@ -219,24 +220,24 @@ namespace BizHawk.Bizware.BizwareGL
 		/// <summary>
 		/// generates a proper 2d othographic projection for the given destination size, suitable for use in a GUI
 		/// </summary>
-		Matrix4 CreateGuiProjectionMatrix(int w, int h);
+		Matrix4x4 CreateGuiProjectionMatrix(int w, int h);
 
 		/// <summary>
 		/// generates a proper 2d othographic projection for the given destination size, suitable for use in a GUI
 		/// </summary>
-		Matrix4 CreateGuiProjectionMatrix(Size dims);
+		Matrix4x4 CreateGuiProjectionMatrix(Size dims);
 
 		/// <summary>
 		/// generates a proper view transform for a standard 2d ortho projection, including half-pixel jitter if necessary and
 		/// re-establishing of a normal 2d graphics top-left origin. suitable for use in a GUI
 		/// </summary>
-		Matrix4 CreateGuiViewMatrix(int w, int h, bool autoflip = true);
+		Matrix4x4 CreateGuiViewMatrix(int w, int h, bool autoflip = true);
 
 		/// <summary>
 		/// generates a proper view transform for a standard 2d ortho projection, including half-pixel jitter if necessary and
 		/// re-establishing of a normal 2d graphics top-left origin. suitable for use in a GUI
 		/// </summary>
-		Matrix4 CreateGuiViewMatrix(Size dims, bool autoflip = true);
+		Matrix4x4 CreateGuiViewMatrix(Size dims, bool autoflip = true);
 
 		/// <summary>
 		/// Creates a render target. Only includes a color buffer. Pixel format control TBD

src/BizHawk.Bizware.BizwareGL/IGL_GdiPlus.cs

@@ -1,9 +1,8 @@
 using System;
 using System.IO;
 using System.Drawing;
-
-using sd = System.Drawing;
-using sdi = System.Drawing.Imaging;
+using System.Drawing.Imaging;
+using System.Numerics;
 
 //TODO - maybe a layer to cache Graphics parameters (notably, filtering) ?
 namespace BizHawk.Bizware.BizwareGL
@@ -12,22 +11,25 @@ namespace BizHawk.Bizware.BizwareGL
 	{
 		public EDispMethod DispMethodEnum => EDispMethod.GdiPlus;
 
+#if false
 		// rendering state
 		private RenderTarget _currRenderTarget;
+#endif
 
 		private readonly Func<IGL_GdiPlus, IGraphicsControl> _createGLControlWrapper;
 
 		public IGL_GdiPlus(Func<IGL_GdiPlus, IGraphicsControl> createGLControlWrapper)
 			=> _createGLControlWrapper = createGLControlWrapper;
 
-		void IDisposable.Dispose()
+		public void Dispose()
 		{
+			MyBufferedGraphicsContext.Dispose();
 		}
 
 		public void Clear(ClearBufferMask mask)
 		{
 			var g = GetCurrentGraphics();
-			if((mask & ClearBufferMask.ColorBufferBit) != 0)
+			if ((mask & ClearBufferMask.ColorBufferBit) != 0)
 			{
 				g.Clear(_currentClearColor);
 			}
@@ -41,31 +43,39 @@ namespace BizHawk.Bizware.BizwareGL
 			return null;
 		}
 
-		private sd.Color _currentClearColor = Color.Transparent;
-		public void SetClearColor(sd.Color color)
+		private Color _currentClearColor = Color.Transparent;
+
+		public void SetClearColor(Color color)
 		{
 			_currentClearColor = color;
 		}
-		
-		public void BindArrayData(IntPtr pData) {}
+
+		public void BindArrayData(IntPtr pData)
+		{
+		}
 
 		public void FreeTexture(Texture2d tex)
 		{
-			var tw = tex.Opaque as GDIPTextureWrapper;
+			var tw = (GDIPTextureWrapper)tex.Opaque;
 			tw.Dispose();
 		}
 
-		public Shader CreateFragmentShader(string source, string entry, bool required) => null;
-		public Shader CreateVertexShader(string source, string entry, bool required) => null;
+		public Shader CreateFragmentShader(string source, string entry, bool required)
+			=> null;
+
+		public Shader CreateVertexShader(string source, string entry, bool required)
+			=> null;
 
 		public void SetBlendState(IBlendState rsBlend)
 		{
-			//TODO for real
+			// TODO for real
 		}
 
-		private class MyBlendState : IBlendState { }
+		private class EmptyBlendState : IBlendState
+		{
+		}
 
-		private static readonly MyBlendState _rsBlendNoneVerbatim = new MyBlendState(), _rsBlendNoneOpaque = new MyBlendState(), _rsBlendNormal = new MyBlendState();
+		private static readonly EmptyBlendState _rsBlendNoneVerbatim = new(), _rsBlendNoneOpaque = new(), _rsBlendNormal = new();
 
 		public IBlendState BlendNoneCopy => _rsBlendNoneVerbatim;
 		public IBlendState BlendNoneOpaque => _rsBlendNoneOpaque;
@@ -76,9 +86,12 @@ namespace BizHawk.Bizware.BizwareGL
 			return null;
 		}
 
-		public void FreePipeline(Pipeline pipeline) {}
+		public void FreePipeline(Pipeline pipeline)
+		{
+		}
 
-		public VertexLayout CreateVertexLayout() => new VertexLayout(this, new IntPtr(0));
+		public VertexLayout CreateVertexLayout()
+			=> new(this, null);
 
 		public void SetTextureWrapMode(Texture2d tex, bool clamp)
 		{
@@ -102,11 +115,11 @@ namespace BizHawk.Bizware.BizwareGL
 		
 		}
 
-		public void SetPipelineUniformMatrix(PipelineUniform uniform, Matrix4 mat, bool transpose)
+		public void SetPipelineUniformMatrix(PipelineUniform uniform, Matrix4x4 mat, bool transpose)
 		{
 		}
 
-		public void SetPipelineUniformMatrix(PipelineUniform uniform, ref Matrix4 mat, bool transpose)
+		public void SetPipelineUniformMatrix(PipelineUniform uniform, ref Matrix4x4 mat, bool transpose)
 		{
 		}
 
@@ -131,97 +144,98 @@ namespace BizHawk.Bizware.BizwareGL
 	
 		}
 
-		public void SetMinFilter(Texture2d texture, Bizware.BizwareGL.TextureMinFilter minFilter)
+		public void SetMinFilter(Texture2d texture, TextureMinFilter minFilter)
 			=> ((GDIPTextureWrapper) texture.Opaque).MinFilter = minFilter;
 
-		public void SetMagFilter(Texture2d texture, Bizware.BizwareGL.TextureMagFilter magFilter)
+		public void SetMagFilter(Texture2d texture, TextureMagFilter magFilter)
 			=> ((GDIPTextureWrapper) texture.Opaque).MagFilter = magFilter;
 
 		public Texture2d LoadTexture(Bitmap bitmap)
 		{
 			var sdBitmap = (Bitmap)bitmap.Clone();
-			GDIPTextureWrapper tw = new GDIPTextureWrapper { SDBitmap = sdBitmap };
-			return new Texture2d(this, tw, bitmap.Width, bitmap.Height);
+			var tw = new GDIPTextureWrapper { SDBitmap = sdBitmap };
+			return new(this, tw, bitmap.Width, bitmap.Height);
 		}
 
 		public Texture2d LoadTexture(Stream stream)
 		{
-			using var bmp = new BitmapBuffer(stream, new BitmapLoadOptions());
-			return (this as IGL).LoadTexture(bmp);
+			using var bmp = new BitmapBuffer(stream, new());
+			return LoadTexture(bmp);
 		}
 
-		public Texture2d CreateTexture(int width, int height) => null;
+		public Texture2d CreateTexture(int width, int height)
+			=> null;
 
 		public Texture2d WrapGLTexture2d(IntPtr glTexId, int width, int height)
 		{
-			// TODO - need to rip the texture data. we had code for that somewhere...
+			// only used for OpenGL
 			return null;
 		}
 
 		public void LoadTextureData(Texture2d tex, BitmapBuffer bmp)
 		{
-			var tw = tex.Opaque as GDIPTextureWrapper;
+			var tw = (GDIPTextureWrapper)tex.Opaque;
 			bmp.ToSysdrawingBitmap(tw.SDBitmap);
 		}
 
-
 		public Texture2d LoadTexture(BitmapBuffer bmp)
 		{
 			// definitely needed (by TextureFrugalizer at least)
 			var sdBitmap = bmp.ToSysdrawingBitmap();
 			var tw = new GDIPTextureWrapper { SDBitmap = sdBitmap };
-			return new Texture2d(this, tw, bmp.Width, bmp.Height);
+			return new(this, tw, bmp.Width, bmp.Height);
 		}
 
 		public BitmapBuffer ResolveTexture2d(Texture2d tex)
 		{
-			var tw = tex.Opaque as GDIPTextureWrapper;
+			var tw = (GDIPTextureWrapper)tex.Opaque;
 			var blow = new BitmapLoadOptions
 			{
 				AllowWrap = false // must be an independent resource
 			};
+
 			var bb = new BitmapBuffer(tw.SDBitmap, blow);
 			return bb;
 		}
 
 		public Texture2d LoadTexture(string path)
 		{
-			//todo
-			//using (var fs = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read))
-			//  return (this as IGL).LoadTexture(fs);
-			return null;
+			using var fs = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read);
+			return LoadTexture(fs);
 		}
 
-		public Matrix4 CreateGuiProjectionMatrix(int w, int h)
+		public Matrix4x4 CreateGuiProjectionMatrix(int w, int h)
 		{
-			return CreateGuiProjectionMatrix(new Size(w, h));
+			return CreateGuiProjectionMatrix(new(w, h));
 		}
 
-		public Matrix4 CreateGuiViewMatrix(int w, int h, bool autoFlip)
+		public Matrix4x4 CreateGuiViewMatrix(int w, int h, bool autoFlip)
 		{
-			return CreateGuiViewMatrix(new Size(w, h), autoFlip);
+			return CreateGuiViewMatrix(new(w, h), autoFlip);
 		}
 
-		public Matrix4 CreateGuiProjectionMatrix(Size dims)
+		public Matrix4x4 CreateGuiProjectionMatrix(Size dims)
 		{
-			//see CreateGuiViewMatrix for more
-			return Matrix4.Identity;
+			// see CreateGuiViewMatrix for more
+			return Matrix4x4.Identity;
 		}
 
-		public Matrix4 CreateGuiViewMatrix(Size dims, bool autoFlip)
+		public Matrix4x4 CreateGuiViewMatrix(Size dims, bool autoFlip)
 		{
-			//on account of gdi+ working internally with a default view exactly like we want, we don't need to setup a new one here
-			//furthermore, we _cant_, without inverting the GuiView and GuiProjection before drawing, to completely undo it
-			//this might be feasible, but its kind of slow and annoying and worse, seemingly numerically unstable
-			//if (autoFlip && _CurrRenderTarget != null)
-			//{
-			//  Matrix4 ret = Matrix4.Identity;
-			//  ret.M22 = -1;
-			//  ret.M42 = dims.Height;
-			//  return ret;
-			//}
-			//else
-				return Matrix4.Identity;
+			// on account of gdi+ working internally with a default view exactly like we want, we don't need to setup a new one here
+			// furthermore, we _cant_, without inverting the GuiView and GuiProjection before drawing, to completely undo it
+			// this might be feasible, but its kind of slow and annoying and worse, seemingly numerically unstable
+#if false
+			if (autoFlip && _currRenderTarget != null)
+			{
+				Matrix4 ret = Matrix4.Identity;
+				ret.M22 = -1;
+				ret.M42 = dims.Height;
+				return ret;
+			}
+#endif
+
+			return Matrix4x4.Identity;
 		}
 
 		public void SetViewport(int x, int y, int width, int height)
@@ -242,15 +256,11 @@ namespace BizHawk.Bizware.BizwareGL
 			CurrentControl = control;
 		}
 
-		public void EndControl(IGraphicsControl control)
+		public void EndControl()
 		{
 			CurrentControl = null;
 		}
 
-		public void SwapControl(IGraphicsControl control)
-		{
-		}
-
 		public void BeginScene()
 		{
 		}
@@ -265,17 +275,15 @@ namespace BizHawk.Bizware.BizwareGL
 		public IGraphicsControl Internal_CreateGraphicsControl()
 		{
 			var ret = _createGLControlWrapper(this);
-			
 			// create a render target for this control
 			var rtw = new RenderTargetWrapper(() => MyBufferedGraphicsContext, ret);
 			ret.RenderTargetWrapper = rtw;
-			
 			return ret;
 		}
 
 		public void FreeRenderTarget(RenderTarget rt)
 		{
-			var rtw = rt.Opaque as RenderTargetWrapper;
+			var rtw = (RenderTargetWrapper)rt.Opaque;
 			rtw.Dispose();
 		}
 
@@ -283,7 +291,7 @@ namespace BizHawk.Bizware.BizwareGL
 		{
 			var tw = new GDIPTextureWrapper
 			{
-				SDBitmap = new Bitmap(w, h, sdi.PixelFormat.Format32bppArgb)
+				SDBitmap = new(w, h, PixelFormat.Format32bppArgb)
 			};
 			var tex = new Texture2d(this, tw, w, h);
 
@@ -295,46 +303,55 @@ namespace BizHawk.Bizware.BizwareGL
 
 		public void BindRenderTarget(RenderTarget rt)
 		{
-			if (_CurrentOffscreenGraphics != null)
+			if (_currOffscreenGraphics != null)
 			{
-				_CurrentOffscreenGraphics.Dispose();
-				_CurrentOffscreenGraphics = null;
+				_currOffscreenGraphics.Dispose();
+				_currOffscreenGraphics = null;
 			}
 
+#if false
 			_currRenderTarget = rt;
 			if (CurrentRenderTargetWrapper != null)
 			{
 				if (CurrentRenderTargetWrapper == CurrentControl.RenderTargetWrapper)
 				{
-					//don't do anything til swapbuffers
+					// don't do anything til swapbuffers
 				}
 				else
 				{
-					//CurrentRenderTargetWrapper.MyBufferedGraphics.Render();
+					// CurrentRenderTargetWrapper.MyBufferedGraphics.Render();
 				}
 			}
+#endif
 
 			if (rt == null)
 			{
-				//null means to use the default RT for the current control
+				// null means to use the default RT for the current control
 				CurrentRenderTargetWrapper = CurrentControl.RenderTargetWrapper;
 			}
 			else
 			{
-				var tw = rt.Texture2d.Opaque as GDIPTextureWrapper;
-				CurrentRenderTargetWrapper = rt.Opaque as RenderTargetWrapper;
-				_CurrentOffscreenGraphics = Graphics.FromImage(tw.SDBitmap);
-				//if (CurrentRenderTargetWrapper.MyBufferedGraphics == null)
-				//  CurrentRenderTargetWrapper.CreateGraphics();
+				var tw = (GDIPTextureWrapper)rt.Texture2d.Opaque;
+				CurrentRenderTargetWrapper = (RenderTargetWrapper)rt.Opaque;
+				_currOffscreenGraphics = Graphics.FromImage(tw.SDBitmap);
+#if false
+				if (CurrentRenderTargetWrapper.MyBufferedGraphics == null)
+				{
+					CurrentRenderTargetWrapper.CreateGraphics();
+				}
+#endif
 			}
 		}
 
-		private Graphics _CurrentOffscreenGraphics;
+		private Graphics _currOffscreenGraphics;
 
 		public Graphics GetCurrentGraphics()
 		{
-			if (_CurrentOffscreenGraphics != null)
-				return _CurrentOffscreenGraphics;
+			if (_currOffscreenGraphics != null)
+			{
+				return _currOffscreenGraphics;
+			}
+
 			var rtw = CurrentRenderTargetWrapper;
 			return rtw.MyBufferedGraphics.Graphics;
 		}
@@ -343,7 +360,5 @@ namespace BizHawk.Bizware.BizwareGL
 		public RenderTargetWrapper CurrentRenderTargetWrapper;
 
 		public readonly BufferedGraphicsContext MyBufferedGraphicsContext = new();
-
-
-	} //class IGL_GdiPlus
+	}
 }

src/BizHawk.Bizware.BizwareGL/IGuiRenderer.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Drawing;
+using System.Numerics;
 
 namespace BizHawk.Bizware.BizwareGL
 {
@@ -9,7 +11,7 @@ namespace BizHawk.Bizware.BizwareGL
 		/// </summary>
 		void Begin();
 
-		void Begin(System.Drawing.Size size);
+		void Begin(Size size);
 
 		/// <summary>
 		/// begin rendering, initializing viewport and projections to the given dimensions
@@ -51,7 +53,6 @@ namespace BizHawk.Bizware.BizwareGL
 		/// </summary>
 		void Draw(Texture2d tex, float x, float y);
 
-
 		/// <summary>
 		/// draws the specified Art resource with the given flip flags
 		/// </summary>
@@ -74,10 +75,15 @@ namespace BizHawk.Bizware.BizwareGL
 		void Flush();
 
 		bool IsActive { get; }
+
 		MatrixStack Modelview { get; set; }
+
 		IGL Owner { get; }
+
 		MatrixStack Projection { get; set; }
+
 		void RectFill(float x, float y, float w, float h);
+
 		void SetBlendState(IBlendState rsBlend);
 
 		/// <summary>
@@ -96,7 +102,9 @@ namespace BizHawk.Bizware.BizwareGL
 		/// Restores the pipeline to the default
 		/// </summary>
 		void SetDefaultPipeline();
-		void SetModulateColor(System.Drawing.Color color);
+
+		void SetModulateColor(Color color);
+
 		void SetModulateColorWhite();
 
 		/// <summary>

src/BizHawk.Bizware.BizwareGL/MatrixStack.cs

@@ -1,17 +1,18 @@
 using System.Drawing;
 using System.Collections.Generic;
+using System.Numerics;
 
 namespace BizHawk.Bizware.BizwareGL
 {
-	//note: the sense of these matrices, as well as pre- and post- multiplying may be all mixed up.
-	//conceptually here is how we should be working, in the example of spinning a sprite in place
-	//1. sprite starts with top left at origin
-	//2. translate half size, to center sprite at origin
-	//3. rotate around Z
-	//4. translate to position in world
-	//this class is designed to make that work, that way. the takeaways:
-	//* Use the scale, translate, rotate methods in the order given above
-	//* Use PostMultiplyMatrix to apply more work to a prior matrix (in the manner described above) since I am calling this all post-work
+	// note: the sense of these matrices, as well as pre- and post- multiplying may be all mixed up.
+	// conceptually here is how we should be working, in the example of spinning a sprite in place
+	// 1. sprite starts with top left at origin
+	// 2. translate half size, to center sprite at origin
+	// 3. rotate around Z
+	// 4. translate to position in world
+	// this class is designed to make that work, that way. the takeaways:
+	// * Use the scale, translate, rotate methods in the order given above
+	// * Use PostMultiplyMatrix to apply more work to a prior matrix (in the manner described above) since I am calling this all post-work
 	public class MatrixStack
 	{
 		private const float DEG_TO_RAD_FACTOR = (float) System.Math.PI / 180.0f;
@@ -24,19 +25,22 @@ namespace BizHawk.Bizware.BizwareGL
 			IsDirty = false;
 		}
 
-		public static implicit operator Matrix4(MatrixStack ms) { return ms.Top; }
-		public static implicit operator MatrixStack(Matrix4 m) { return new MatrixStack(m); }
+		public static implicit operator Matrix4x4(MatrixStack ms) { return ms.Top; }
+		public static implicit operator MatrixStack(Matrix4x4 m) { return new(m); }
 
-		public MatrixStack(Matrix4 matrix) { LoadMatrix(matrix); }
+		public MatrixStack(Matrix4x4 matrix)
+		{
+			LoadMatrix(matrix);
+		}
 
 		public bool IsDirty;
 
-		private readonly Stack<Matrix4> stack = new Stack<Matrix4>();
+		private readonly Stack<Matrix4x4> stack = new();
 
 		/// <summary>
 		/// This is made public for performance reasons, to avoid lame copies of the matrix when necessary. Don't mess it up!
 		/// </summary>
-		public Matrix4 Top;
+		public Matrix4x4 Top;
 
 		/// <summary>
 		/// Resets the matrix stack to an empty identity matrix stack
@@ -51,41 +55,143 @@ namespace BizHawk.Bizware.BizwareGL
 		/// <summary>
 		/// Clears the matrix stack and loads the specified value
 		/// </summary>
-		public void Clear(Matrix4 value)
+		public void Clear(Matrix4x4 value)
 		{
 			stack.Clear();
 			Top = value;
 			IsDirty = true;
 		}
 
-		public void LoadMatrix(Matrix4 value) { Top = value; IsDirty = true; }
+		public void LoadMatrix(Matrix4x4 value)
+		{
+			Top = value;
+			IsDirty = true;
+		}
 
-		public void LoadIdentity() { Top = Matrix4.Identity; IsDirty = true; }
+		public void LoadIdentity()
+		{
+			Top = Matrix4x4.Identity;
+			IsDirty = true;
+		}
 
-		public void Pop() { Top = stack.Pop(); IsDirty = true; }
-		public void Push() { stack.Push(Top); IsDirty = true; }
+		public void Pop()
+		{
+			Top = stack.Pop();
+			IsDirty = true;
+		}
 
-		public void RotateAxis(Vector3 axisRotation, float angle) { PostMultiplyMatrix(Matrix4.CreateFromAxisAngle(in axisRotation, angle)); IsDirty = true; }
+		public void Push()
+		{
+			stack.Push(Top);
+			IsDirty = true;
+		}
 
-		public void Scale(Vector3 scale) { PostMultiplyMatrix(Matrix4.CreateScale(in scale)); IsDirty = true; }
-		public void Scale(Vector2 scale) { PostMultiplyMatrix(Matrix4.CreateScale(scale.X, scale.Y, 1)); IsDirty = true; }
-		public void Scale(float x, float y, float z) { PostMultiplyMatrix(Matrix4.CreateScale(x, y, z)); IsDirty = true; }
-		public void Scale(float ratio) { Scale(ratio, ratio, ratio); IsDirty = true; }
-		public void Scale(float x, float y) { Scale(x, y, 1); IsDirty = true; }
+		public void RotateAxis(Vector3 axisRotation, float angle)
+		{
+			PostMultiplyMatrix(Matrix4x4.CreateFromAxisAngle(axisRotation, angle));
+			IsDirty = true;
+		}
 
-		public void RotateAxis(float x, float y, float z, float degrees) { PostMultiplyMatrix(Matrix4.CreateFromAxisAngle(new Vector3(x, y, z), DegreesToRadians(degrees))); IsDirty = true; }
-		public void RotateY(float degrees) { PostMultiplyMatrix(Matrix4.CreateRotationY(DegreesToRadians(degrees))); IsDirty = true; }
-		public void RotateX(float degrees) { PostMultiplyMatrix(Matrix4.CreateRotationX(DegreesToRadians(degrees))); IsDirty = true; }
-		public void RotateZ(float degrees) { PostMultiplyMatrix(Matrix4.CreateRotationZ(DegreesToRadians(degrees))); IsDirty = true; }
+		public void Scale(Vector3 scale)
+		{
+			PostMultiplyMatrix(Matrix4x4.CreateScale(scale));
+			IsDirty = true;
+		}
 
-		public void Translate(Vector2 v) { Translate(v.X, v.Y, 0); IsDirty = true; }
-		public void Translate(Vector3 trans) { PostMultiplyMatrix(Matrix4.CreateTranslation(in trans)); IsDirty = true; }
-		public void Translate(float x, float y, float z) { PostMultiplyMatrix(Matrix4.CreateTranslation(x, y, z)); IsDirty = true; }
-		public void Translate(float x, float y) { Translate(x, y, 0); IsDirty = true; }
-		public void Translate(Point pt) { Translate(pt.X, pt.Y, 0); IsDirty = true; }
+		public void Scale(Vector2 scale)
+		{
+			PostMultiplyMatrix(Matrix4x4.CreateScale(scale.X, scale.Y, 1));
+			IsDirty = true;
+		}
 
-		public void PostMultiplyMatrix(MatrixStack ms) { PostMultiplyMatrix(ms.Top); IsDirty = true; }
-		public void PostMultiplyMatrix(Matrix4 value) { Top = Top * value; IsDirty = true; }
-		public void PreMultiplyMatrix(Matrix4 value) { Top = value * Top; IsDirty = true; }
+		public void Scale(float x, float y, float z)
+		{
+			PostMultiplyMatrix(Matrix4x4.CreateScale(x, y, z));
+			IsDirty = true;
+		}
+
+		public void Scale(float ratio)
+		{
+			Scale(ratio, ratio, ratio);
+			IsDirty = true;
+		}
+
+		public void Scale(float x, float y)
+		{
+			Scale(x, y, 1);
+			IsDirty = true;
+		}
+
+		public void RotateAxis(float x, float y, float z, float degrees)
+		{
+			PostMultiplyMatrix(Matrix4x4.CreateFromAxisAngle(new(x, y, z), DegreesToRadians(degrees)));
+			IsDirty = true;
+		}
+
+		public void RotateY(float degrees)
+		{
+			PostMultiplyMatrix(Matrix4x4.CreateRotationY(DegreesToRadians(degrees)));
+			IsDirty = true;
+		}
+
+		public void RotateX(float degrees)
+		{
+			PostMultiplyMatrix(Matrix4x4.CreateRotationX(DegreesToRadians(degrees)));
+			IsDirty = true;
+		}
+
+		public void RotateZ(float degrees)
+		{
+			PostMultiplyMatrix(Matrix4x4.CreateRotationZ(DegreesToRadians(degrees)));
+			IsDirty = true;
+		}
+
+		public void Translate(Vector2 v)
+		{
+			Translate(v.X, v.Y, 0);
+			IsDirty = true;
+		}
+
+		public void Translate(Vector3 trans)
+		{
+			PostMultiplyMatrix(Matrix4x4.CreateTranslation(trans));
+			IsDirty = true;
+		}
+
+		public void Translate(float x, float y, float z)
+		{
+			PostMultiplyMatrix(Matrix4x4.CreateTranslation(x, y, z));
+			IsDirty = true;
+		}
+
+		public void Translate(float x, float y)
+		{
+			Translate(x, y, 0);
+			IsDirty = true;
+		}
+
+		public void Translate(Point pt)
+		{
+			Translate(pt.X, pt.Y, 0);
+			IsDirty = true;
+		}
+
+		public void PostMultiplyMatrix(MatrixStack ms)
+		{
+			PostMultiplyMatrix(ms.Top);
+			IsDirty = true;
+		}
+
+		public void PostMultiplyMatrix(Matrix4x4 value)
+		{
+			Top *= value;
+			IsDirty = true;
+		}
+
+		public void PreMultiplyMatrix(Matrix4x4 value)
+		{
+			Top = value * Top;
+			IsDirty = true;
+		}
 	}
 }

src/BizHawk.Bizware.BizwareGL/Pipeline.cs

@@ -10,9 +10,9 @@ namespace BizHawk.Bizware.BizwareGL
 	/// </summary>
 	public class Pipeline : IDisposable
 	{
-		public string Memo;
+		public readonly string Memo;
 
-		public Pipeline(IGL owner, object opaque, bool available, VertexLayout vertexLayout, IEnumerable<UniformInfo> uniforms, string memo)
+		public Pipeline(IGL owner, object opaque, bool available, VertexLayout vertexLayout, IReadOnlyList<UniformInfo> uniforms, string memo)
 		{
 			Memo = memo;
 			Owner = owner;
@@ -24,10 +24,10 @@ namespace BizHawk.Bizware.BizwareGL
 			if(!Available)
 				return;
 
-			UniformsDictionary = new SpecialWorkingDictionary(this);
+			UniformsDictionary = new(this);
 			foreach (var ui in uniforms)
 			{
-				UniformsDictionary[ui.Name] = new PipelineUniform(this);
+				UniformsDictionary[ui.Name] = new(this);
 			}
 
 			foreach (var ui in uniforms)
@@ -40,9 +40,9 @@ namespace BizHawk.Bizware.BizwareGL
 		/// Allows us to create PipelineUniforms on the fly, in case a non-existing one has been requested.
 		/// Shader compilers will optimize out unused uniforms, and we wont have a record of it in the uniforms population loop
 		/// </summary>
-		private class SpecialWorkingDictionary : Dictionary<string, PipelineUniform>
+		private class UniformWorkingDictionary : Dictionary<string, PipelineUniform>
 		{
-			public SpecialWorkingDictionary(Pipeline owner)
+			public UniformWorkingDictionary(Pipeline owner)
 			{
 				Owner = owner;
 			}
@@ -59,7 +59,7 @@ namespace BizHawk.Bizware.BizwareGL
 			}
 		}
 
-		private readonly SpecialWorkingDictionary UniformsDictionary;
+		private readonly UniformWorkingDictionary UniformsDictionary;
 		private IDictionary<string, PipelineUniform> Uniforms => UniformsDictionary;
 
 		public IEnumerable<PipelineUniform> GetUniforms() => Uniforms.Values;

src/BizHawk.Bizware.BizwareGL/PipelineUniform.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Numerics;
 
 namespace BizHawk.Bizware.BizwareGL
 {
@@ -12,17 +13,16 @@ namespace BizHawk.Bizware.BizwareGL
 		internal PipelineUniform(Pipeline owner)
 		{
 			Owner = owner;
-			//Opaque = info.Opaque;
-			//SamplerIndex = info.SamplerIndex;
 		}
 
 		internal void AddUniformInfo(UniformInfo ui)
 		{
-			_UniformInfos.Add(ui);
+			_uniformInfos.Add(ui);
 		}
 
-		public IEnumerable<UniformInfo> UniformInfos => _UniformInfos;
-		private readonly List<UniformInfo> _UniformInfos = new List<UniformInfo>();
+		public IEnumerable<UniformInfo> UniformInfos => _uniformInfos;
+
+		private readonly List<UniformInfo> _uniformInfos = new();
 
 		/// <returns>the first and only <see cref="UniformInfo"/></returns>
 		/// <exception cref="InvalidOperationException">more than one <see cref="UniformInfo"/> exists</exception>
@@ -30,14 +30,18 @@ namespace BizHawk.Bizware.BizwareGL
 		{
 			get
 			{
-				if (_UniformInfos.Count != 1) throw new InvalidOperationException();
-				return _UniformInfos[0];
+				if (_uniformInfos.Count != 1)
+				{
+					throw new InvalidOperationException();
+				}
+
+				return _uniformInfos[0];
 			}
 		}
 
 		public Pipeline Owner { get; }
 		
-		public void Set(Matrix4 mat, bool transpose = false)
+		public void Set(Matrix4x4 mat, bool transpose = false)
 		{
 			Owner?.Owner.SetPipelineUniformMatrix(this, mat, transpose);
 		}
@@ -62,7 +66,7 @@ namespace BizHawk.Bizware.BizwareGL
 			Owner?.Owner.SetPipelineUniform(this, vecs);
 		}
 
-		public void Set(ref Matrix4 mat, bool transpose = false)
+		public void Set(ref Matrix4x4 mat, bool transpose = false)
 		{
 			Owner?.Owner.SetPipelineUniformMatrix(this, ref mat, transpose);
 		}

src/BizHawk.Bizware.BizwareGL/RenderTargetWrapper.cs

@@ -1,9 +1,12 @@
 using System;
 using System.Drawing;
+#if false
+using System.Drawing.Drawing2D;
+#endif
 
 namespace BizHawk.Bizware.BizwareGL
 {
-	public class RenderTargetWrapper
+	public class RenderTargetWrapper : IDisposable
 	{
 		public RenderTargetWrapper(
 			Func<BufferedGraphicsContext> getBufferedGraphicsContext,
@@ -15,6 +18,7 @@ namespace BizHawk.Bizware.BizwareGL
 
 		public void Dispose()
 		{
+			MyBufferedGraphics?.Dispose();
 		}
 
 		private readonly Func<BufferedGraphicsContext> _getBufferedGraphicsContext;
@@ -31,7 +35,7 @@ namespace BizHawk.Bizware.BizwareGL
 
 		public BufferedGraphics MyBufferedGraphics;
 
-		public Graphics refGraphics; //?? hacky?
+		public Graphics refGraphics; // ?? hacky?
 
 		public void CreateGraphics()
 		{
@@ -43,19 +47,21 @@ namespace BizHawk.Bizware.BizwareGL
 			}
 			else
 			{
-				var tw = Target.Texture2d.Opaque as GDIPTextureWrapper;
+				var tw = (GDIPTextureWrapper)Target.Texture2d.Opaque;
 				r = Target.Texture2d.Rectangle;
 				refGraphics = Graphics.FromImage(tw.SDBitmap);
 			}
 
 			MyBufferedGraphics?.Dispose();
 			MyBufferedGraphics = _getBufferedGraphicsContext().Allocate(refGraphics, r);
-//			MyBufferedGraphics.Graphics.PixelOffsetMode = PixelOffsetMode.HighSpeed;
+#if false
+			MyBufferedGraphics.Graphics.PixelOffsetMode = PixelOffsetMode.HighSpeed;
 
-			//not sure about this stuff...
-			//it will wreck alpha blending, for one thing
-//			MyBufferedGraphics.Graphics.CompositingMode = CompositingMode.SourceCopy;
-//			MyBufferedGraphics.Graphics.CompositingQuality = CompositingQuality.HighSpeed;
+			// not sure about this stuff...
+			// it will wreck alpha blending, for one thing
+			MyBufferedGraphics.Graphics.CompositingMode = CompositingMode.SourceCopy;
+			MyBufferedGraphics.Graphics.CompositingQuality = CompositingQuality.HighSpeed;
+#endif
 		}
 	}
 }

src/BizHawk.Bizware.BizwareGL/RetroShader.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Drawing;
+using System.Numerics;
 
 namespace BizHawk.Bizware.BizwareGL
 {
@@ -20,9 +21,8 @@ namespace BizHawk.Bizware.BizwareGL
 			VertexLayout.DefineVertexAttribute("tex", 2, 2, VertexAttribPointerType.Float, AttribUsage.Texcoord0, false, 40, 32);
 			VertexLayout.Close();
 
-			string defines = "";
-			string vsSource = $"#define VERTEX\r\n{defines}{source}";
-			string psSource = $"#define FRAGMENT\r\n{defines}{source}";
+			var vsSource = $"#define VERTEX\r\n{source}";
+			var psSource = $"#define FRAGMENT\r\n{source}";
 			var vs = owner.CreateVertexShader(vsSource, "main_vertex", debug);
 			var ps = owner.CreateFragmentShader(psSource, "main_fragment", debug);
 			Pipeline = Owner.CreatePipeline(VertexLayout, vs, ps, debug, "retro");
@@ -39,7 +39,7 @@ namespace BizHawk.Bizware.BizwareGL
 			sampler0 = Pipeline.TryGetUniform("s_p");
 			if (sampler0 == null)
 			{
-				//sampler wasn't named correctly. this can happen on some retroarch shaders
+				// sampler wasn't named correctly. this can happen on some retroarch shaders
 				foreach (var u in Pipeline.GetUniforms())
 				{
 					if (u.Sole.IsSampler && u.Sole.SamplerIndex == 0)
@@ -50,11 +50,8 @@ namespace BizHawk.Bizware.BizwareGL
 				}
 			}
 
-			//if a sampler isn't available, we can't do much, although this does interfere with debugging (shaders just returning colors will malfunction)
-			if (sampler0 == null)
-				return;
-
-			Available = true;
+			// if a sampler isn't available, we can't do much, although this does interfere with debugging (shaders just returning colors will malfunction)
+			Available = sampler0 != null;
 		}
 
 		public bool Available { get; }
@@ -69,16 +66,13 @@ namespace BizHawk.Bizware.BizwareGL
 
 		public void Bind()
 		{
-			//lame...
+			// lame...
 			Owner.BindPipeline(Pipeline);
 		}
 
 		public unsafe void Run(Texture2d tex, Size InputSize, Size OutputSize, bool flip)
 		{
-			flip = false;
-			//test
-
-			//ack! make sure to set the pipeline before setting uniforms
+			// ack! make sure to set the pipeline before setting uniforms
 			Bind();
 
 			Pipeline["IN.video_size"].Set(new Vector2(InputSize.Width, InputSize.Height));
@@ -87,10 +81,9 @@ namespace BizHawk.Bizware.BizwareGL
 			Pipeline["IN.frame_count"].Set(1); //todo
 			Pipeline["IN.frame_direction"].Set(1); //todo
 
-
 			var Projection = Owner.CreateGuiProjectionMatrix(OutputSize);
 			var Modelview = Owner.CreateGuiViewMatrix(OutputSize);
-			var mat = Matrix4.Transpose(Modelview * Projection);
+			var mat = Matrix4x4.Transpose(Modelview * Projection);
 			Pipeline["modelViewProj"].Set(mat, true);
 
 			Owner.SetTextureWrapMode(tex, true);
@@ -98,16 +91,26 @@ namespace BizHawk.Bizware.BizwareGL
 			sampler0.Set(tex);
 			Owner.SetViewport(OutputSize);
 
-			float time = DateTime.Now.Second + (float)DateTime.Now.Millisecond / 1000;
+			var time = DateTime.Now.Second + (float)DateTime.Now.Millisecond / 1000;
 			Pipeline["Time"].Set(time);
 
-			int w = OutputSize.Width;
-			int h = OutputSize.Height;
-			float v0,v1;
-			if (flip) { v0 = 1; v1 = 0; }
-			else { v0 = 0; v1 = 1; }
-			float* pData = stackalloc float[10*4];
-			int i=0;
+			var w = OutputSize.Width;
+			var h = OutputSize.Height;
+
+			float v0, v1;
+			if (flip)
+			{
+				v0 = 1;
+				v1 = 0;
+			}
+			else
+			{
+				v0 = 0;
+				v1 = 1;
+			}
+
+			var pData = stackalloc float[10 * 4];
+			var i = 0;
 			pData[i++] = 0; pData[i++] = 0; pData[i++] = 0; pData[i++] = 1; //topleft vert
 			pData[i++] = 0; pData[i++] = 0; pData[i++] = 0; pData[i++] = 0; //useless color
 			pData[i++] = 0; pData[i++] = v0;
@@ -119,7 +122,7 @@ namespace BizHawk.Bizware.BizwareGL
 			pData[i++] = 0; pData[i++] = v1;
 			pData[i++] = w; pData[i++] = h; pData[i++] = 0; pData[i++] = 1; //bottomright vert
 			pData[i++] = 0; pData[i++] = 0; pData[i++] = 0; pData[i++] = 0; //useless color
-			pData[i++] = 1; pData[i++] = v1;
+			pData[i++] = 1; pData[i] = v1;
 
 			Owner.SetBlendState(Owner.BlendNoneCopy);
 			Owner.BindArrayData(new(pData));
@@ -130,6 +133,6 @@ namespace BizHawk.Bizware.BizwareGL
 		public IGL Owner { get; }
 
 		private readonly VertexLayout VertexLayout;
-		public Pipeline Pipeline;
+		public readonly Pipeline Pipeline;
 	}
 }

src/BizHawk.Bizware.BizwareGL/StringRenderer.cs

@@ -3,9 +3,10 @@
 
 using System;
 using System.Collections.Generic;
+using System.Drawing;
 using System.IO;
+
 using Cyotek.Drawing.BitmapFont;
-using sd=System.Drawing;
 
 namespace BizHawk.Bizware.BizwareGL
 {
@@ -18,7 +19,7 @@ namespace BizHawk.Bizware.BizwareGL
 			FontInfo.LoadXml(xml);
 			
 			// load textures
-			for(int i=0;i<FontInfo.Pages.Length;i++)
+			for (var i=0; i<FontInfo.Pages.Length; i++)
 			{
 				TexturePages.Add(owner.LoadTexture(textures[i]));
 			}
@@ -27,25 +28,30 @@ namespace BizHawk.Bizware.BizwareGL
 		public void Dispose()
 		{
 			foreach (var tex in TexturePages)
+			{
 				tex.Dispose();
+			}
+
 			TexturePages = null;
 		}
 
-		public sd.SizeF Measure(string str)
+		public SizeF Measure(string str)
 		{
 			float x = 0;
 			float y = FontInfo.LineHeight;
-			float ox = x;
-			int len = str.Length;
+			var ox = x;
+			var len = str.Length;
 
-			for (int i = 0; i < len; i++)
+			for (var i = 0; i < len; i++)
 			{
 				var c = str[i];
 
 				if (c == '\r')
 				{
 					if (i != len - 1 && str[i + 1] == '\n')
+					{
 						i++;
+					}
 				}
 
 				if (c == '\r')
@@ -56,33 +62,42 @@ namespace BizHawk.Bizware.BizwareGL
 				if (c == '\n')
 				{
 					if (x > ox)
+					{
 						ox = x;
+					}
+
 					x = 0;
 					y += FontInfo.LineHeight;
 					continue;
 				}
 
 				var bfc = FontInfo[c];
-
 				x += bfc.XAdvance;
 			}
 
-			return new sd.SizeF(Math.Max(x, ox), y);
+			return new(Math.Max(x, ox), y);
 		}
 
 		public void RenderString(IGuiRenderer renderer, float x, float y, string str)
 		{
-			float ox = x;
-			int len = str.Length;
+			if (Owner != renderer.Owner)
+			{
+				throw new InvalidOperationException("Owner mismatch!");
+			}
 
-			for (int i = 0; i < len; i++)
+			var ox = x;
+			var len = str.Length;
+
+			for (var i = 0; i < len; i++)
 			{
 				var c = str[i];
 
 				if (c == '\r')
 				{
 					if (i != len - 1 && str[i + 1] == '\n')
+					{
 						i++;
+					}
 				}
 
 				if (c == '\r')
@@ -90,7 +105,7 @@ namespace BizHawk.Bizware.BizwareGL
 					c = '\n';
 				}
 
-				if(c == '\n')
+				if (c == '\n')
 				{
 					x = ox;
 					y += FontInfo.LineHeight;
@@ -98,19 +113,19 @@ namespace BizHawk.Bizware.BizwareGL
 				}
 
 				var bfc = FontInfo[c];
-				
-				// calculate texcoords (we shouldve already had this cached, but im speedcoding now)
-				Texture2d tex = TexturePages[bfc.TexturePage];
-				float w = tex.Width;
-				float h = tex.Height;
-				sd.Rectangle bounds = new(bfc.X, bfc.Y, bfc.Width, bfc.Height);
-				float u0 = bounds.Left / w;
-				float v0 = bounds.Top / h;
-				float u1 = bounds.Right / w;
-				float v1 = bounds.Bottom / h;
 
-				float gx = x + bfc.XOffset;
-				float gy = y + bfc.YOffset;
+				// calculate texcoords (we shouldve already had this cached, but im speedcoding now)
+				var tex = TexturePages[bfc.TexturePage];
+				var w = tex.Width;
+				var h = tex.Height;
+				var bounds = new Rectangle(bfc.X, bfc.Y, bfc.Width, bfc.Height);
+				var u0 = bounds.Left / w;
+				var v0 = bounds.Top / h;
+				var u1 = bounds.Right / w;
+				var v1 = bounds.Bottom / h;
+
+				var gx = x + bfc.XOffset;
+				var gy = y + bfc.YOffset;
 				renderer.DrawSubrect(tex, gx, gy, bfc.Width, bfc.Height, u0, v0, u1, v1);
 
 				x += bfc.XAdvance;
@@ -120,6 +135,6 @@ namespace BizHawk.Bizware.BizwareGL
 		public IGL Owner { get; }
 
 		private readonly BitmapFont FontInfo;
-		private List<Texture2d> TexturePages = new List<Texture2d>();
+		private List<Texture2d> TexturePages = new();
 	}
 }

src/BizHawk.Bizware.BizwareGL/TexAtlas.cs

@@ -15,6 +15,7 @@ namespace BizHawk.Bizware.BizwareGL
 				Height = height;
 				Item = item;
 			}
+
 			public int X, Y;
 			public int Width, Height;
 			public int TexIndex;
@@ -31,14 +32,14 @@ namespace BizHawk.Bizware.BizwareGL
 			public readonly List<RectangleBinPack.Node> nodes = new List<RectangleBinPack.Node>();
 		}
 
-		public static int MaxSizeBits = 16;
+		public const int MaxSizeBits = 16;
 
 		/// <summary>
 		/// packs the supplied RectItems into an atlas. Modifies the RectItems with x/y values of location in new atlas.
 		/// </summary>
-		public static IReadOnlyList<(Size Size, List<RectItem> Items)> PackAtlas(IReadOnlyCollection<RectItem> items)
+		public static IReadOnlyList<(Size Size, List<RectItem> Items)> PackAtlas(IEnumerable<RectItem> items)
 		{
-			static void AddAtlas(ICollection<(Size, List<RectItem>)> atlases, IReadOnlyCollection<RectItem> initItems)
+			static void AddAtlas(ICollection<(Size, List<RectItem>)> atlases, IEnumerable<RectItem> initItems)
 			{
 				List<RectItem> currentItems = new(initItems);
 				List<RectItem> remainItems = new();
@@ -50,13 +51,13 @@ namespace BizHawk.Bizware.BizwareGL
 					// we run this every time we make an atlas, in case we want to variably control the maximum texture output size.
 					// ALSO - we accumulate data in there, so we need to refresh it each time. ... lame.
 					var todoSizes = new List<TryFitParam>();
-					for (int i = 3; i <= MaxSizeBits; i++)
+					for (var i = 3; i <= MaxSizeBits; i++)
 					{
-						for (int j = 3; j <= MaxSizeBits; j++)
+						for (var j = 3; j <= MaxSizeBits; j++)
 						{
-							int w = 1 << i;
-							int h = 1 << j;
-							TryFitParam tfp = new TryFitParam(w, h);
+							var w = 1 << i;
+							var h = 1 << j;
+							var tfp = new TryFitParam(w, h);
 							todoSizes.Add(tfp);
 						}
 					}
@@ -68,9 +69,10 @@ namespace BizHawk.Bizware.BizwareGL
 						rbp.Init(16384, 16384);
 						param.rbp.Init(param.w, param.h);
 
+						// ReSharper disable once AccessToModifiedClosure
 						foreach (var ri in currentItems)
 						{
-							RectangleBinPack.Node node = param.rbp.Insert(ri.Width, ri.Height);
+							var node = param.rbp.Insert(ri.Width, ri.Height);
 							if (node == null)
 							{
 								param.ok = false;
@@ -83,35 +85,50 @@ namespace BizHawk.Bizware.BizwareGL
 						}
 					});
 
-					//find the best fit among the potential sizes that worked
+					// find the best fit among the potential sizes that worked
 					var best = long.MaxValue;
 					tfpFinal = todoSizes[0];
 					foreach (var tfp in todoSizes)
 					{
-						if (!tfp.ok) continue;
+						if (!tfp.ok)
+						{
+							continue;
+						}
+
 						var area = tfp.w * (long) tfp.h;
-						if (area > best) continue; // larger than best, not interested
+						if (area > best)
+						{
+							continue; // larger than best, not interested
+						}
+
 						if (area == best) // same area, compare perimeter as tie-breaker (to create squares, which are nicer to look at)
 						{
-							if (tfp.w + tfp.h >= tfpFinal.w + tfpFinal.h) continue;
+							if (tfp.w + tfp.h >= tfpFinal.w + tfpFinal.h)
+							{
+								continue;
+							}
 						}
+
 						best = area;
 						tfpFinal = tfp;
 					}
 
 					//did we find any fit?
-					if (best < long.MaxValue) break;
+					if (best < long.MaxValue)
+					{
+						break;
+					}
+
 					//nope - move an item to the remaining list and try again
 					remainItems.Add(currentItems[currentItems.Count - 1]);
 					currentItems.RemoveAt(currentItems.Count - 1);
 				}
 
 				//we found a fit. setup this atlas in the result and drop the items into it
-				atlases.Add((new Size(tfpFinal.w, tfpFinal.h), new List<RectItem>(currentItems)));
+				atlases.Add((new(tfpFinal.w, tfpFinal.h), new(currentItems)));
 				foreach (var item in currentItems)
 				{
-					object o = item.Item;
-					var node = tfpFinal.nodes.Find((x) => x.ri == item);
+					var node = tfpFinal.nodes.Find(x => x.ri == item);
 					item.X = node.x;
 					item.Y = node.y;
 					item.TexIndex = atlases.Count - 1;
@@ -157,7 +174,7 @@ namespace BizHawk.Bizware.BizwareGL
 			{
 				binWidth = width;
 				binHeight = height;
-				root = new Node();
+				root = new();
 				root.left = root.right = null;
 				root.x = root.y = 0;
 				root.width = width;
@@ -176,8 +193,8 @@ namespace BizHawk.Bizware.BizwareGL
 			/// <summary>Computes the ratio of used surface area.</summary>
 			private float Occupancy()
 			{
-				int totalSurfaceArea = binWidth * binHeight;
-				int usedSurfaceArea = UsedSurfaceArea(root);
+				var totalSurfaceArea = binWidth * binHeight;
+				var usedSurfaceArea = UsedSurfaceArea(root);
 
 				return (float)usedSurfaceArea / totalSurfaceArea;
 			}
@@ -189,11 +206,11 @@ namespace BizHawk.Bizware.BizwareGL
 			private int binHeight;
 
 			/// <returns>The surface area used by the subtree rooted at node.</returns>
-			private int UsedSurfaceArea(Node node)
+			private static int UsedSurfaceArea(Node node)
 			{
 				if (node.left != null || node.right != null)
 				{
-					int usedSurfaceArea = node.width * node.height;
+					var usedSurfaceArea = node.width * node.height;
 					if (node.left != null)
 						usedSurfaceArea += UsedSurfaceArea(node.left);
 					if (node.right != null)
@@ -208,7 +225,7 @@ namespace BizHawk.Bizware.BizwareGL
 
 
 			/// <summary>Inserts a new rectangle in the subtree rooted at the given node.</summary>
-			private Node Insert(Node node, int width, int height)
+			private static Node Insert(Node node, int width, int height)
 			{
 
 				// If this node is an internal node, try both leaves for possible space.
@@ -217,13 +234,13 @@ namespace BizHawk.Bizware.BizwareGL
 				{
 					if (node.left != null)
 					{
-						Node newNode = Insert(node.left, width, height);
+						var newNode = Insert(node.left, width, height);
 						if (newNode != null)
 							return newNode;
 					}
 					if (node.right != null)
 					{
-						Node newNode = Insert(node.right, width, height);
+						var newNode = Insert(node.right, width, height);
 						if (newNode != null)
 							return newNode;
 					}
@@ -236,10 +253,10 @@ namespace BizHawk.Bizware.BizwareGL
 
 				// The new cell will fit, split the remaining space along the shorter axis,
 				// that is probably more optimal.
-				int w = node.width - width;
-				int h = node.height - height;
-				node.left = new Node();
-				node.right = new Node();
+				var w = node.width - width;
+				var h = node.height - height;
+				node.left = new();
+				node.right = new();
 				if (w <= h) // Split the remaining space in horizontal direction.
 				{
 					node.left.x = node.x + width;

src/BizHawk.Bizware.BizwareGL/VertexLayout.cs

@@ -16,7 +16,7 @@ namespace BizHawk.Bizware.BizwareGL
 		{
 			Owner = owner;
 			Opaque = opaque;
-			Items = new MyDictionary();
+			Items = new();
 		}
 
 		public object Opaque { get; }
@@ -29,8 +29,10 @@ namespace BizHawk.Bizware.BizwareGL
 			RefCount--;
 			if (RefCount <= 0)
 			{
-				//nothing like this yet
-				//Available = false;
+				// nothing like this yet
+#if false
+				Available = false;
+#endif
 			}
 		}
 
@@ -43,8 +45,11 @@ namespace BizHawk.Bizware.BizwareGL
 		public void DefineVertexAttribute(string name, int index, int components, VertexAttribPointerType attribType, AttribUsage usage, bool normalized, int stride, int offset = 0)
 		{
 			if (Closed)
+			{
 				throw new InvalidOperationException("Type is Closed and is now immutable.");
-			Items[index] = new LayoutItem { Name = name, Components = components, AttribType = attribType, Usage = usage, Normalized = normalized, Stride = stride, Offset = offset };
+			}
+
+			Items[index] = new() { Name = name, Components = components, AttribType = attribType, Usage = usage, Normalized = normalized, Stride = stride, Offset = offset };
 		}
 
 		/// <summary>
@@ -66,7 +71,7 @@ namespace BizHawk.Bizware.BizwareGL
 			public AttribUsage Usage { get; internal set; }
 		}
 
-		public class MyDictionary : WorkingDictionary<int, LayoutItem>
+		public class LayoutItemWorkingDictionary : WorkingDictionary<int, LayoutItem>
 		{
 			public new LayoutItem this[int key]
 			{
@@ -75,8 +80,8 @@ namespace BizHawk.Bizware.BizwareGL
 			}
 		}
 
-		public MyDictionary Items { get; }
-		private bool Closed = false;
+		public LayoutItemWorkingDictionary Items { get; }
+		private bool Closed;
 
 	}
 }

src/BizHawk.Bizware.BizwareGL/math/Matrix4.cs

@@ -1,323 +0,0 @@
-using System;
-
-namespace BizHawk.Bizware.BizwareGL
-{
-	public struct Matrix4
-	{
-		public static readonly Matrix4 Identity = new(new(1.0f, 0.0f, 0.0f, 0.0f), new(0.0f, 1.0f, 0.0f, 0.0f), new(0.0f, 0.0f, 1.0f, 0.0f), new(0.0f, 0.0f, 0.0f, 1.0f));
-
-		public static bool AreEqual(in Matrix4 a, in Matrix4 b) => Vector4.AreEqual(in a.Row0, in b.Row0) && Vector4.AreEqual(in a.Row1, in b.Row1) && Vector4.AreEqual(in a.Row2, in b.Row2) && Vector4.AreEqual(in a.Row3, in b.Row3);
-
-		/// <returns>a <see cref="Matrix4"/> representing a rotation of <paramref name="angle"/> radians CCW around the given <paramref name="axis"/></returns>
-		public static Matrix4 CreateFromAxisAngle(in Vector3 axis, float angle)
-		{
-			var num0 = (float) (1.0 / Math.Sqrt(axis.X * (double) axis.X + axis.Y * (double) axis.Y + axis.Z * (double) axis.Z));
-			var x = axis.X * num0;
-			var y = axis.Y * num0;
-			var z = axis.Z * num0;
-			var num1 = (float) Math.Cos(-(double) angle);
-			var num2 = (float) Math.Sin(-(double) angle);
-			var num3 = 1.0f - num1;
-			var num4 = num3 * x * x;
-			var num5 = num3 * x * y;
-			var num6 = num3 * x * z;
-			var num7 = num3 * y * y;
-			var num8 = num3 * y * z;
-			var num9 = num3 * z * z;
-			var num10 = num2 * x;
-			var num11 = num2 * y;
-			var num12 = num2 * z;
-			return new(
-				new(num4 + num1, num5 - num12, num6 + num11, 0.0f),
-				new(num5 + num12, num7 + num1, num8 - num10, 0.0f),
-				new(num6 - num11, num8 + num10, num9 + num1, 0.0f),
-				new(0.0f, 0.0f, 0.0f, 1.0f));
-		}
-
-		/// <returns>a <see cref="Matrix4"/> representing a rotation of <paramref name="angle"/> radians CCW around the X-axis</returns>
-		public static Matrix4 CreateRotationX(float angle)
-		{
-			var num1 = (float) Math.Cos(angle);
-			var num2 = (float) Math.Sin(angle);
-			var result = Identity; // copy
-			result.Row1.Y = num1;
-			result.Row1.Z = num2;
-			result.Row2.Y = -num2;
-			result.Row2.Z = num1;
-			return result;
-		}
-
-		/// <returns>a <see cref="Matrix4"/> representing a rotation of <paramref name="angle"/> radians CCW around the Y-axis</returns>
-		public static Matrix4 CreateRotationY(float angle)
-		{
-			var num1 = (float) Math.Cos(angle);
-			var num2 = (float) Math.Sin(angle);
-			var result = Identity; // copy
-			result.Row0.X = num1;
-			result.Row0.Z = -num2;
-			result.Row2.X = num2;
-			result.Row2.Z = num1;
-			return result;
-		}
-
-		/// <returns>a <see cref="Matrix4"/> representing a rotation of <paramref name="angle"/> radians CCW around the Z-axis</returns>
-		public static Matrix4 CreateRotationZ(float angle)
-		{
-			var num1 = (float) Math.Cos(angle);
-			var num2 = (float) Math.Sin(angle);
-			var result = Identity; // copy
-			result.Row0.X = num1;
-			result.Row0.Y = num2;
-			result.Row1.X = -num2;
-			result.Row1.Y = num1;
-			return result;
-		}
-
-		/// <returns>a <see cref="Matrix4"/> representing a scaling</returns>
-		public static Matrix4 CreateScale(float x, float y, float z)
-		{
-			var result = Identity; // copy
-			result.Row0.X = x;
-			result.Row1.Y = y;
-			result.Row2.Z = z;
-			return result;
-		}
-
-		/// <returns>a <see cref="Matrix4"/> representing a scaling</returns>
-		public static Matrix4 CreateScale(in Vector3 scale)
-		{
-			var result = Identity; // copy
-			result.Row0.X = scale.X;
-			result.Row1.Y = scale.Y;
-			result.Row2.Z = scale.Z;
-			return result;
-		}
-
-		/// <returns>a <see cref="Matrix4"/> representing a translation</returns>
-		public static Matrix4 CreateTranslation(float x, float y, float z)
-		{
-			var result = Identity; // copy
-			result.Row3.X = x;
-			result.Row3.Y = y;
-			result.Row3.Z = z;
-			return result;
-		}
-
-		/// <returns>a <see cref="Matrix4"/> representing a translation</returns>
-		public static Matrix4 CreateTranslation(in Vector3 vector)
-		{
-			var result = Identity; // copy
-			result.Row3.X = vector.X;
-			result.Row3.Y = vector.Y;
-			result.Row3.Z = vector.Z;
-			return result;
-		}
-
-		private static float GetDeterminant(in Matrix4 m)
-		{
-			var x1 = (double) m.Row0.X;
-			var y1 = (double) m.Row0.Y;
-			var z1 = (double) m.Row0.Z;
-			var w1 = (double) m.Row0.W;
-			var x2 = (double) m.Row1.X;
-			var y2 = (double) m.Row1.Y;
-			var z2 = (double) m.Row1.Z;
-			var w2 = (double) m.Row1.W;
-			var x3 = (double) m.Row2.X;
-			var y3 = (double) m.Row2.Y;
-			var z3 = (double) m.Row2.Z;
-			var w3 = (double) m.Row2.W;
-			var x4 = (double) m.Row3.X;
-			var y4 = (double) m.Row3.Y;
-			var z4 = (double) m.Row3.Z;
-			var w4 = (double) m.Row3.W;
-			return (float) (x1 * y2 * z3 * w4
-				- x1 * y2 * w3 * z4
-				+ x1 * z2 * w3 * y4
-				- x1 * z2 * y3 * w4
-				+ x1 * w2 * y3 * z4
-				- x1 * w2 * z3 * y4
-				- y1 * z2 * w3 * x4
-				+ y1 * z2 * x3 * w4
-				- y1 * w2 * x3 * z4
-				+ y1 * w2 * z3 * x4
-				- y1 * x2 * z3 * w4
-				+ y1 * x2 * w3 * z4
-				+ z1 * w2 * x3 * y4
-				- z1 * w2 * y3 * x4
-				+ z1 * x2 * y3 * w4
-				- z1 * x2 * w3 * y4
-				+ z1 * y2 * w3 * x4
-				- z1 * y2 * x3 * w4
-				- w1 * x2 * y3 * z4
-				+ w1 * x2 * z3 * y4
-				- w1 * y2 * z3 * x4
-				+ w1 * y2 * x3 * z4
-				- w1 * z2 * x3 * y4
-				+ w1 * z2 * y3 * x4);
-		}
-
-		private static unsafe Matrix4 Invert(in Matrix4 mat)
-		{
-			var pDbTemp = stackalloc double[16];
-			fixed (Matrix4* pMatIn = &mat)
-			{
-				var pFlIn = (float*) pMatIn;
-				for (var i = 0; i < 16; i++) pDbTemp[i] = pFlIn[i];
-			}
-			Matrix4 result = default;
-			ref var refResult = ref result;
-			fixed (Matrix4* pMatOut = &refResult)
-			{
-				var pFlOut = (float*) pMatOut;
-				pFlOut[0] = (float) (pDbTemp[5] * pDbTemp[10] * pDbTemp[15] - pDbTemp[5] * pDbTemp[11] * pDbTemp[14] - pDbTemp[9] * pDbTemp[6] * pDbTemp[15] + pDbTemp[9] * pDbTemp[7] * pDbTemp[14] + pDbTemp[13] * pDbTemp[6] * pDbTemp[11] - pDbTemp[13] * pDbTemp[7] * pDbTemp[10]);
-				pFlOut[4] = (float) (-pDbTemp[4] * pDbTemp[10] * pDbTemp[15] + pDbTemp[4] * pDbTemp[11] * pDbTemp[14] + pDbTemp[8] * pDbTemp[6] * pDbTemp[15] - pDbTemp[8] * pDbTemp[7] * pDbTemp[14] - pDbTemp[12] * pDbTemp[6] * pDbTemp[11] + pDbTemp[12] * pDbTemp[7] * pDbTemp[10]);
-				pFlOut[8] = (float) (pDbTemp[4] * pDbTemp[9] * pDbTemp[15] - pDbTemp[4] * pDbTemp[11] * pDbTemp[13] - pDbTemp[8] * pDbTemp[5] * pDbTemp[15] + pDbTemp[8] * pDbTemp[7] * pDbTemp[13] + pDbTemp[12] * pDbTemp[5] * pDbTemp[11] - pDbTemp[12] * pDbTemp[7] * pDbTemp[9]);
-				pFlOut[12] = (float) (-pDbTemp[4] * pDbTemp[9] * pDbTemp[14] + pDbTemp[4] * pDbTemp[10] * pDbTemp[13] + pDbTemp[8] * pDbTemp[5] * pDbTemp[14] - pDbTemp[8] * pDbTemp[6] * pDbTemp[13] - pDbTemp[12] * pDbTemp[5] * pDbTemp[10] + pDbTemp[12] * pDbTemp[6] * pDbTemp[9]);
-				pFlOut[1] = (float) (-pDbTemp[1] * pDbTemp[10] * pDbTemp[15] + pDbTemp[1] * pDbTemp[11] * pDbTemp[14] + pDbTemp[9] * pDbTemp[2] * pDbTemp[15] - pDbTemp[9] * pDbTemp[3] * pDbTemp[14] - pDbTemp[13] * pDbTemp[2] * pDbTemp[11] + pDbTemp[13] * pDbTemp[3] * pDbTemp[10]);
-				pFlOut[5] = (float) (pDbTemp[0] * pDbTemp[10] * pDbTemp[15] - pDbTemp[0] * pDbTemp[11] * pDbTemp[14] - pDbTemp[8] * pDbTemp[2] * pDbTemp[15] + pDbTemp[8] * pDbTemp[3] * pDbTemp[14] + pDbTemp[12] * pDbTemp[2] * pDbTemp[11] - pDbTemp[12] * pDbTemp[3] * pDbTemp[10]);
-				pFlOut[9] = (float) (-pDbTemp[0] * pDbTemp[9] * pDbTemp[15] + pDbTemp[0] * pDbTemp[11] * pDbTemp[13] + pDbTemp[8] * pDbTemp[1] * pDbTemp[15] - pDbTemp[8] * pDbTemp[3] * pDbTemp[13] - pDbTemp[12] * pDbTemp[1] * pDbTemp[11] + pDbTemp[12] * pDbTemp[3] * pDbTemp[9]);
-				pFlOut[13] = (float) (pDbTemp[0] * pDbTemp[9] * pDbTemp[14] - pDbTemp[0] * pDbTemp[10] * pDbTemp[13] - pDbTemp[8] * pDbTemp[1] * pDbTemp[14] + pDbTemp[8] * pDbTemp[2] * pDbTemp[13] + pDbTemp[12] * pDbTemp[1] * pDbTemp[10] - pDbTemp[12] * pDbTemp[2] * pDbTemp[9]);
-				pFlOut[2] = (float) (pDbTemp[1] * pDbTemp[6] * pDbTemp[15] - pDbTemp[1] * pDbTemp[7] * pDbTemp[14] - pDbTemp[5] * pDbTemp[2] * pDbTemp[15] + pDbTemp[5] * pDbTemp[3] * pDbTemp[14] + pDbTemp[13] * pDbTemp[2] * pDbTemp[7] - pDbTemp[13] * pDbTemp[3] * pDbTemp[6]);
-				pFlOut[6] = (float) (-pDbTemp[0] * pDbTemp[6] * pDbTemp[15] + pDbTemp[0] * pDbTemp[7] * pDbTemp[14] + pDbTemp[4] * pDbTemp[2] * pDbTemp[15] - pDbTemp[4] * pDbTemp[3] * pDbTemp[14] - pDbTemp[12] * pDbTemp[2] * pDbTemp[7] + pDbTemp[12] * pDbTemp[3] * pDbTemp[6]);
-				pFlOut[10] = (float) (pDbTemp[0] * pDbTemp[5] * pDbTemp[15] - pDbTemp[0] * pDbTemp[7] * pDbTemp[13] - pDbTemp[4] * pDbTemp[1] * pDbTemp[15] + pDbTemp[4] * pDbTemp[3] * pDbTemp[13] + pDbTemp[12] * pDbTemp[1] * pDbTemp[7] - pDbTemp[12] * pDbTemp[3] * pDbTemp[5]);
-				pFlOut[14] = (float) (-pDbTemp[0] * pDbTemp[5] * pDbTemp[14] + pDbTemp[0] * pDbTemp[6] * pDbTemp[13] + pDbTemp[4] * pDbTemp[1] * pDbTemp[14] - pDbTemp[4] * pDbTemp[2] * pDbTemp[13] - pDbTemp[12] * pDbTemp[1] * pDbTemp[6] + pDbTemp[12] * pDbTemp[2] * pDbTemp[5]);
-				pFlOut[3] = (float) (-pDbTemp[1] * pDbTemp[6] * pDbTemp[11] + pDbTemp[1] * pDbTemp[7] * pDbTemp[10] + pDbTemp[5] * pDbTemp[2] * pDbTemp[11] - pDbTemp[5] * pDbTemp[3] * pDbTemp[10] - pDbTemp[9] * pDbTemp[2] * pDbTemp[7] + pDbTemp[9] * pDbTemp[3] * pDbTemp[6]);
-				pFlOut[7] = (float) (pDbTemp[0] * pDbTemp[6] * pDbTemp[11] - pDbTemp[0] * pDbTemp[7] * pDbTemp[10] - pDbTemp[4] * pDbTemp[2] * pDbTemp[11] + pDbTemp[4] * pDbTemp[3] * pDbTemp[10] + pDbTemp[8] * pDbTemp[2] * pDbTemp[7] - pDbTemp[8] * pDbTemp[3] * pDbTemp[6]);
-				pFlOut[11] = (float) (-pDbTemp[0] * pDbTemp[5] * pDbTemp[11] + pDbTemp[0] * pDbTemp[7] * pDbTemp[9] + pDbTemp[4] * pDbTemp[1] * pDbTemp[11] - pDbTemp[4] * pDbTemp[3] * pDbTemp[9] - pDbTemp[8] * pDbTemp[1] * pDbTemp[7] + pDbTemp[8] * pDbTemp[3] * pDbTemp[5]);
-				pFlOut[15] = (float) (pDbTemp[0] * pDbTemp[5] * pDbTemp[10] - pDbTemp[0] * pDbTemp[6] * pDbTemp[9] - pDbTemp[4] * pDbTemp[1] * pDbTemp[10] + pDbTemp[4] * pDbTemp[2] * pDbTemp[9] + pDbTemp[8] * pDbTemp[1] * pDbTemp[6] - pDbTemp[8] * pDbTemp[2] * pDbTemp[5]);
-				var num1 = (float) (pDbTemp[0] * pFlOut[0] + pDbTemp[1] * pFlOut[4] + pDbTemp[2] * pFlOut[8] + pDbTemp[3] * pFlOut[12]);
-				if (num1 == 0.0f) throw new InvalidOperationException("Matrix is singular and cannot be inverted.");
-				var num2 = 1.0f / num1;
-				for (var i = 0; i < 16; i++) pFlOut[i] *= num2;
-			}
-			return result;
-		}
-
-		public static Matrix4 Transpose(in Matrix4 mat) => new(
-			new(mat.Row0.X, mat.Row1.X, mat.Row2.X, mat.Row3.X),
-			new(mat.Row0.Y, mat.Row1.Y, mat.Row2.Y, mat.Row3.Y),
-			new(mat.Row0.Z, mat.Row1.Z, mat.Row2.Z, mat.Row3.Z),
-			new(mat.Row0.W, mat.Row1.W, mat.Row2.W, mat.Row3.W));
-
-		public static bool operator ==(in Matrix4 a, in Matrix4 b) => AreEqual(in a, in b);
-
-		public static bool operator !=(in Matrix4 a, in Matrix4 b) => !AreEqual(in a, in b);
-
-		/// <summary>Matrix multiplication</summary>
-		/// <param name="left">left-hand operand</param>
-		/// <param name="right">right-hand operand</param>
-		/// <returns>A new Matrix4 which holds the result of the multiplication</returns>
-		public static Matrix4 operator *(in Matrix4 left, in Matrix4 right)
-		{
-			var x1 = (double) left.Row0.X;
-			var y1 = (double) left.Row0.Y;
-			var z1 = (double) left.Row0.Z;
-			var w1 = (double) left.Row0.W;
-			var x2 = (double) left.Row1.X;
-			var y2 = (double) left.Row1.Y;
-			var z2 = (double) left.Row1.Z;
-			var w2 = (double) left.Row1.W;
-			var x3 = (double) left.Row2.X;
-			var y3 = (double) left.Row2.Y;
-			var z3 = (double) left.Row2.Z;
-			var w3 = (double) left.Row2.W;
-			var x4 = (double) left.Row3.X;
-			var y4 = (double) left.Row3.Y;
-			var z4 = (double) left.Row3.Z;
-			var w4 = (double) left.Row3.W;
-			var x5 = (double) right.Row0.X;
-			var y5 = (double) right.Row0.Y;
-			var z5 = (double) right.Row0.Z;
-			var w5 = (double) right.Row0.W;
-			var x6 = (double) right.Row1.X;
-			var y6 = (double) right.Row1.Y;
-			var z6 = (double) right.Row1.Z;
-			var w6 = (double) right.Row1.W;
-			var x7 = (double) right.Row2.X;
-			var y7 = (double) right.Row2.Y;
-			var z7 = (double) right.Row2.Z;
-			var w7 = (double) right.Row2.W;
-			var x8 = (double) right.Row3.X;
-			var y8 = (double) right.Row3.Y;
-			var z8 = (double) right.Row3.Z;
-			var w8 = (double) right.Row3.W;
-			Matrix4 result;
-			result.Row0.X = (float) (x1 * x5 + y1 * x6 + z1 * x7 + w1 * x8);
-			result.Row0.Y = (float) (x1 * y5 + y1 * y6 + z1 * y7 + w1 * y8);
-			result.Row0.Z = (float) (x1 * z5 + y1 * z6 + z1 * z7 + w1 * z8);
-			result.Row0.W = (float) (x1 * w5 + y1 * w6 + z1 * w7 + w1 * w8);
-			result.Row1.X = (float) (x2 * x5 + y2 * x6 + z2 * x7 + w2 * x8);
-			result.Row1.Y = (float) (x2 * y5 + y2 * y6 + z2 * y7 + w2 * y8);
-			result.Row1.Z = (float) (x2 * z5 + y2 * z6 + z2 * z7 + w2 * z8);
-			result.Row1.W = (float) (x2 * w5 + y2 * w6 + z2 * w7 + w2 * w8);
-			result.Row2.X = (float) (x3 * x5 + y3 * x6 + z3 * x7 + w3 * x8);
-			result.Row2.Y = (float) (x3 * y5 + y3 * y6 + z3 * y7 + w3 * y8);
-			result.Row2.Z = (float) (x3 * z5 + y3 * z6 + z3 * z7 + w3 * z8);
-			result.Row2.W = (float) (x3 * w5 + y3 * w6 + z3 * w7 + w3 * w8);
-			result.Row3.X = (float) (x4 * x5 + y4 * x6 + z4 * x7 + w4 * x8);
-			result.Row3.Y = (float) (x4 * y5 + y4 * y6 + z4 * y7 + w4 * y8);
-			result.Row3.Z = (float) (x4 * z5 + y4 * z6 + z4 * z7 + w4 * z8);
-			result.Row3.W = (float) (x4 * w5 + y4 * w6 + z4 * w7 + w4 * w8);
-			return result;
-		}
-
-		/// <returns><paramref name="vec"/> transformed by <paramref name="mat"/></returns>
-		public static Vector4 operator *(in Vector4 vec, in Matrix4 mat) => new(
-			(float) (vec.X * (double) mat.Row0.X + vec.Y * (double) mat.Row1.X + vec.Z * (double) mat.Row2.X + vec.W * (double) mat.Row3.X),
-			(float) (vec.X * (double) mat.Row0.Y + vec.Y * (double) mat.Row1.Y + vec.Z * (double) mat.Row2.Y + vec.W * (double) mat.Row3.Y),
-			(float) (vec.X * (double) mat.Row0.Z + vec.Y * (double) mat.Row1.Z + vec.Z * (double) mat.Row2.Z + vec.W * (double) mat.Row3.Z),
-			(float) (vec.X * (double) mat.Row0.W + vec.Y * (double) mat.Row1.W + vec.Z * (double) mat.Row2.W + vec.W * (double) mat.Row3.W));
-
-		/// <summary>Top row of the matrix.</summary>
-		public Vector4 Row0;
-
-		/// <summary>2nd row of the matrix.</summary>
-		public Vector4 Row1;
-
-		/// <summary>3rd row of the matrix.</summary>
-		public Vector4 Row2;
-
-		/// <summary>Bottom row of the matrix.</summary>
-		public Vector4 Row3;
-
-		/// <param name="row0">Top row of the matrix.</param>
-		/// <param name="row1">Second row of the matrix.</param>
-		/// <param name="row2">Third row of the matrix.</param>
-		/// <param name="row3">Bottom row of the matrix.</param>
-		public Matrix4(Vector4 row0, Vector4 row1, Vector4 row2, Vector4 row3)
-		{
-			Row0 = row0;
-			Row1 = row1;
-			Row2 = row2;
-			Row3 = row3;
-		}
-
-		public unsafe float this[int rowIndex, int columnIndex]
-		{
-			readonly get
-			{
-				if (rowIndex is < 0 or > 3) throw new ArgumentOutOfRangeException(paramName: nameof(rowIndex), rowIndex, message: "index out of range");
-				if (columnIndex is < 0 or > 3) throw new ArgumentOutOfRangeException(paramName: nameof(columnIndex), columnIndex, message: "index out of range");
-				var i = rowIndex * 4 + columnIndex;
-				fixed (Matrix4* p = &this) return ((float*) p)[i];
-			}
-			set
-			{
-				if (rowIndex is < 0 or > 3) throw new ArgumentOutOfRangeException(paramName: nameof(rowIndex), rowIndex, message: "index out of range");
-				if (columnIndex is < 0 or > 3) throw new ArgumentOutOfRangeException(paramName: nameof(columnIndex), columnIndex, message: "index out of range");
-				var i = rowIndex * 4 + columnIndex;
-				fixed (Matrix4* p = &this) ((float*) p)[i] = value;
-			}
-		}
-
-		/// <returns>an inverted copy of this instance, or an identical copy if it is singular</returns>
-		public readonly Matrix4 Inverted() => GetDeterminant(in this) == 0.0f ? this : Invert(in this);
-
-		public override readonly bool Equals(object obj) => obj is Matrix4 other && AreEqual(in this, in other);
-
-		public override readonly int GetHashCode() => ((Row0.GetHashCode() * 397 ^ Row1.GetHashCode()) * 397 ^ Row2.GetHashCode()) * 397 ^ Row3.GetHashCode();
-
-		public override readonly string ToString() => string.Join("\n", Row0, Row1, Row2, Row3);
-	}
-}

src/BizHawk.Bizware.BizwareGL/math/Vector2.cs

@@ -1,29 +0,0 @@
-namespace BizHawk.Bizware.BizwareGL
-{
-	public struct Vector2
-	{
-		public static bool AreEqual(in Vector2 a, in Vector2 b) => a.X == b.X && a.Y == b.Y;
-
-		public static bool operator ==(in Vector2 a, in Vector2 b) => AreEqual(in a, in b);
-
-		public static bool operator !=(in Vector2 a, in Vector2 b) => !AreEqual(in a, in b);
-
-		public static Vector2 operator +(in Vector2 left, in Vector2 right) => new(left.X + right.X, left.Y + right.Y);
-
-		public float X;
-
-		public float Y;
-
-		public Vector2(float x, float y)
-		{
-			X = x;
-			Y = y;
-		}
-
-		public override readonly bool Equals(object obj) => obj is Vector2 other && AreEqual(in this, in other);
-
-		public override readonly int GetHashCode() => X.GetHashCode() * 397 ^ Y.GetHashCode();
-
-		public override readonly string ToString() => $"({X}, {Y})";
-	}
-}

src/BizHawk.Bizware.BizwareGL/math/Vector3.cs

@@ -1,30 +0,0 @@
-namespace BizHawk.Bizware.BizwareGL
-{
-	public readonly struct Vector3
-	{
-		public static bool AreEqual(in Vector3 a, in Vector3 b) => a.X == b.X && a.Y == b.Y && a.Z == b.Z;
-
-		public static bool operator ==(in Vector3 a, in Vector3 b) => AreEqual(in a, in b);
-
-		public static bool operator !=(in Vector3 a, in Vector3 b) => !AreEqual(in a, in b);
-
-		public readonly float X;
-
-		public readonly float Y;
-
-		public readonly float Z;
-
-		public Vector3(float x, float y, float z)
-		{
-			X = x;
-			Y = y;
-			Z = z;
-		}
-
-		public override readonly bool Equals(object obj) => obj is Vector3 other && AreEqual(in this, in other);
-
-		public override readonly int GetHashCode() => (X.GetHashCode() * 397 ^ Y.GetHashCode()) * 397 ^ Z.GetHashCode();
-
-		public override readonly string ToString() => $"({X}, {Y}, {Z})";
-	}
-}

src/BizHawk.Bizware.BizwareGL/math/Vector4.cs

@@ -1,33 +0,0 @@
-namespace BizHawk.Bizware.BizwareGL
-{
-	public struct Vector4
-	{
-		public static bool AreEqual(in Vector4 a, in Vector4 b) => a.X == b.X && a.Y == b.Y && a.Z == b.Z && a.W == b.W;
-
-		public static bool operator ==(in Vector4 a, in Vector4 b) => AreEqual(in a, in b);
-
-		public static bool operator !=(in Vector4 a, in Vector4 b) => !AreEqual(in a, in b);
-
-		public float X;
-
-		public float Y;
-
-		public float Z;
-
-		public float W;
-
-		public Vector4(float x, float y, float z, float w)
-		{
-			X = x;
-			Y = y;
-			Z = z;
-			W = w;
-		}
-
-		public override readonly bool Equals(object obj) => obj is Vector4 other && AreEqual(in this, in other);
-
-		public override readonly int GetHashCode() => ((X.GetHashCode() * 397 ^ Y.GetHashCode()) * 397 ^ Z.GetHashCode()) * 397 ^ W.GetHashCode();
-
-		public override readonly string ToString() => $"({X}, {Y}, {Z}, {W})";
-	}
-}

src/BizHawk.Bizware.Graphics/D3D9/IGL_D3D9.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Drawing;
 using System.IO;
 using System.Linq;
+using System.Numerics;
 using System.Reflection;
 using System.Runtime.InteropServices;
 using System.Threading;
@@ -573,10 +574,10 @@ namespace BizHawk.Bizware.Graphics
 			}
 		}
 
-		public void SetPipelineUniformMatrix(PipelineUniform uniform, Matrix4 mat, bool transpose)
+		public void SetPipelineUniformMatrix(PipelineUniform uniform, Matrix4x4 mat, bool transpose)
 			=> SetPipelineUniformMatrix(uniform, ref mat, transpose);
 
-		public void SetPipelineUniformMatrix(PipelineUniform uniform, ref Matrix4 mat, bool transpose)
+		public void SetPipelineUniformMatrix(PipelineUniform uniform, ref Matrix4x4 mat, bool transpose)
 		{
 			foreach (var ui in uniform.UniformInfos)
 			{
@@ -755,32 +756,32 @@ namespace BizHawk.Bizware.Graphics
 			return LoadTexture(fs);
 		}
 
-		public Matrix4 CreateGuiProjectionMatrix(int w, int h)
+		public Matrix4x4 CreateGuiProjectionMatrix(int w, int h)
 		{
 			return CreateGuiProjectionMatrix(new(w, h));
 		}
 
-		public Matrix4 CreateGuiViewMatrix(int w, int h, bool autoFlip)
+		public Matrix4x4 CreateGuiViewMatrix(int w, int h, bool autoFlip)
 		{
 			return CreateGuiViewMatrix(new(w, h), autoFlip);
 		}
 
-		public Matrix4 CreateGuiProjectionMatrix(Size dims)
+		public Matrix4x4 CreateGuiProjectionMatrix(Size dims)
 		{
-			var ret = Matrix4.Identity;
-			ret.Row0.X = 2.0f / dims.Width;
-			ret.Row1.Y = 2.0f / dims.Height;
+			var ret = Matrix4x4.Identity;
+			ret.M11 = 2.0f / dims.Width;
+			ret.M22 = 2.0f / dims.Height;
 			return ret;
 		}
 
-		public Matrix4 CreateGuiViewMatrix(Size dims, bool autoFlip)
+		public Matrix4x4 CreateGuiViewMatrix(Size dims, bool autoFlip)
 		{
-			var ret = Matrix4.Identity;
-			ret.Row1.Y = -1.0f;
-			ret.Row3.X = -dims.Width * 0.5f - 0.5f;
-			ret.Row3.Y = dims.Height * 0.5f + 0.5f;
+			var ret = Matrix4x4.Identity;
+			ret.M22 = -1.0f;
+			ret.M41 = -dims.Width * 0.5f - 0.5f;
+			ret.M42 = dims.Height * 0.5f + 0.5f;
 
-			// auto-flipping isn't needed on d3d
+			// auto-flipping isn't needed on D3D
 			return ret;
 		}
 

src/BizHawk.Bizware.Graphics/D3D9/SharpDXExtensions.cs

@@ -1,6 +1,5 @@
 using System.Drawing;
-
-using BizHawk.Bizware.BizwareGL;
+using System.Numerics;
 
 using SharpDX.Mathematics.Interop;
 
@@ -8,21 +7,21 @@ namespace BizHawk.Bizware.Graphics
 {
 	internal static class SharpDXExtensions
 	{
-		// SharpDX RawMatrix and BizwareGL Matrix are identical in structure
-		public static RawMatrix ToSharpDXMatrix(this Matrix4 m, bool transpose)
+		// SharpDX RawMatrix and Numerics Matrix4x4 are identical in structure
+		public static RawMatrix ToSharpDXMatrix(this Matrix4x4 m, bool transpose)
 		{
 			// Transpose call could be inlined to reduce 2 sets of copies to 1
 			if (transpose)
 			{
-				m = Matrix4.Transpose(in m);
+				m = Matrix4x4.Transpose(m);
 			}
 
 			return new()
 			{
-				M11 = m.Row0.X, M12 = m.Row0.Y, M13 = m.Row0.Z, M14 = m.Row0.W,
-				M21 = m.Row1.X, M22 = m.Row1.Y, M23 = m.Row1.Z, M24 = m.Row1.W,
-				M31 = m.Row2.X, M32 = m.Row2.Y, M33 = m.Row2.Z, M34 = m.Row2.W,
-				M41 = m.Row3.X, M42 = m.Row3.Y, M43 = m.Row3.Z, M44 = m.Row3.W
+				M11 = m.M11, M12 = m.M12, M13 = m.M13, M14 = m.M14,
+				M21 = m.M21, M22 = m.M22, M23 = m.M23, M24 = m.M24,
+				M31 = m.M31, M32 = m.M32, M33 = m.M33, M34 = m.M34,
+				M41 = m.M41, M42 = m.M42, M43 = m.M43, M44 = m.M44
 			};
 		}
 

src/BizHawk.Bizware.Graphics/GuiRenderer.cs

@@ -7,6 +7,7 @@ using System;
 using System.Diagnostics;
 #endif
 using System.Drawing;
+using System.Numerics;
 
 using BizHawk.Bizware.BizwareGL;
 
@@ -153,7 +154,7 @@ namespace BizHawk.Bizware.Graphics
 		/// <exception cref="InvalidOperationException">no pipeline set (need to call <see cref="SetPipeline"/>)</exception>
 		public void Begin()
 		{
-			//uhhmmm I want to throw an exception if its already active, but its annoying.
+			// uhhmmm I want to throw an exception if its already active, but its annoying.
 
 			if (CurrPipeline == null)
 				throw new InvalidOperationException("Pipeline hasn't been set!");
@@ -176,14 +177,17 @@ namespace BizHawk.Bizware.Graphics
 
 		public void Flush()
 		{
-			//no batching, nothing to do here yet
+			// no batching, nothing to do here yet
 		}
 
 		/// <exception cref="InvalidOperationException"><see cref="IsActive"/> is <see langword="false"/></exception>
 		public void End()
 		{
 			if (!IsActive)
+			{
 				throw new InvalidOperationException($"{nameof(GuiRenderer)} is not active!");
+			}
+
 			IsActive = false;
 		}
 
@@ -199,26 +203,40 @@ namespace BizHawk.Bizware.Graphics
 			DrawSubrectInternal(tex, x, y, w, h, u0, v0, u1, v1);
 		}
 
+		public void Draw(Art art)
+		{
+			DrawInternal(art, 0, 0, art.Width, art.Height, false, false);
+		}
 
-		public void Draw(Art art) { DrawInternal(art, 0, 0, art.Width, art.Height, false, false); }
+		public void Draw(Art art, float x, float y)
+		{
+			DrawInternal(art, x, y, art.Width, art.Height, false, false);
+		}
 
+		public void Draw(Art art, float x, float y, float width, float height)
+		{
+			DrawInternal(art, x, y, width, height, false, false);
+		}
 
-		public void Draw(Art art, float x, float y) { DrawInternal(art, x, y, art.Width, art.Height, false, false); }
+		public void Draw(Art art, Vector2 pos)
+		{
+			DrawInternal(art, pos.X, pos.Y, art.Width, art.Height, false, false);
+		}
 
+		public void Draw(Texture2d tex)
+		{
+			DrawInternal(tex, 0, 0, tex.Width, tex.Height);
+		}
 
-		public void Draw(Art art, float x, float y, float width, float height) { DrawInternal(art, x, y, width, height, false, false); }
+		public void Draw(Texture2d tex, float x, float y)
+		{
+			DrawInternal(tex, x, y, tex.Width, tex.Height);
+		}
 
-
-		public void Draw(Art art, Vector2 pos) { DrawInternal(art, pos.X, pos.Y, art.Width, art.Height, false, false); }
-
-
-		public void Draw(Texture2d tex) { DrawInternal(tex, 0, 0, tex.Width, tex.Height); }
-
-
-		public void Draw(Texture2d tex, float x, float y) { DrawInternal(tex, x, y, tex.Width, tex.Height); }
-
-
-		public void DrawFlipped(Art art, bool xflip, bool yflip) { DrawInternal(art, 0, 0, art.Width, art.Height, xflip, yflip); }
+		public void DrawFlipped(Art art, bool xflip, bool yflip)
+		{
+			DrawInternal(art, 0, 0, art.Width, art.Height, xflip, yflip);
+		}
 
 		public void Draw(Texture2d art, float x, float y, float width, float height)
 		{
@@ -441,7 +459,7 @@ void main()
 	vCornerColor = aColor * uModulateColor;
 }";
 
-		public readonly string DefaultPixelShader_gl = @"
+		public const string DefaultPixelShader_gl = @"
 //opengl 2.0 ~ 2004
 #version 110
 uniform bool uSamplerEnable;

src/BizHawk.Bizware.Graphics/OpenGL/IGL_OpenGL.cs

@@ -7,9 +7,10 @@
 // glBindAttribLocation (programID, 0, "vertexPosition_modelspace");
 
 using System;
+using System.Collections.Generic;
 using System.Drawing;
 using System.IO;
-using System.Collections.Generic;
+using System.Numerics;
 
 using BizHawk.Bizware.BizwareGL;
 using BizHawk.Common;
@@ -445,14 +446,14 @@ namespace BizHawk.Bizware.Graphics
 			GL.Uniform1((int)uniform.Sole.Opaque, value ? 1 : 0);
 		}
 
-		public unsafe void SetPipelineUniformMatrix(PipelineUniform uniform, Matrix4 mat, bool transpose)
+		public unsafe void SetPipelineUniformMatrix(PipelineUniform uniform, Matrix4x4 mat, bool transpose)
 		{
 			GL.UniformMatrix4((int)uniform.Sole.Opaque, 1, transpose, (float*)&mat);
 		}
 
-		public unsafe void SetPipelineUniformMatrix(PipelineUniform uniform, ref Matrix4 mat, bool transpose)
+		public unsafe void SetPipelineUniformMatrix(PipelineUniform uniform, ref Matrix4x4 mat, bool transpose)
 		{
-			fixed (Matrix4* pMat = &mat)
+			fixed (Matrix4x4* pMat = &mat)
 			{
 				GL.UniformMatrix4((int)uniform.Sole.Opaque, 1, transpose, (float*)pMat);
 			}
@@ -646,35 +647,36 @@ namespace BizHawk.Bizware.Graphics
 			return LoadTexture(fs);
 		}
 
-		public Matrix4 CreateGuiProjectionMatrix(int w, int h)
+		public Matrix4x4 CreateGuiProjectionMatrix(int w, int h)
 		{
 			return CreateGuiProjectionMatrix(new(w, h));
 		}
 
-		public Matrix4 CreateGuiViewMatrix(int w, int h, bool autoflip)
+		public Matrix4x4 CreateGuiViewMatrix(int w, int h, bool autoflip)
 		{
 			return CreateGuiViewMatrix(new(w, h), autoflip);
 		}
 
-		public Matrix4 CreateGuiProjectionMatrix(Size dims)
+		public Matrix4x4 CreateGuiProjectionMatrix(Size dims)
 		{
-			var ret = Matrix4.Identity;
-			ret.Row0.X = 2.0f / dims.Width;
-			ret.Row1.Y = 2.0f / dims.Height;
+			var ret = Matrix4x4.Identity;
+			ret.M11 = 2.0f / dims.Width;
+			ret.M22 = 2.0f / dims.Height;
 			return ret;
 		}
 
-		public Matrix4 CreateGuiViewMatrix(Size dims, bool autoflip)
+		public Matrix4x4 CreateGuiViewMatrix(Size dims, bool autoflip)
 		{
-			var ret = Matrix4.Identity;
-			ret.Row1.Y = -1.0f;
-			ret.Row3.X = dims.Width * -0.5f;
-			ret.Row3.Y = dims.Height * 0.5f;
+			var ret = Matrix4x4.Identity;
+			ret.M22 = -1.0f;
+			ret.M41 = dims.Width * -0.5f;
+			ret.M42 = dims.Height * 0.5f;
 			if (autoflip && _currRenderTarget is not null) // flip as long as we're not a final render target
 			{
-				ret.Row1.Y = 1.0f;
-				ret.Row3.Y *= -1;
+				ret.M22 = 1.0f;
+				ret.M42 *= -1;
 			}
+
 			return ret;
 		}
 

src/BizHawk.Client.Common/DisplayManager/DisplayManagerBase.cs

@@ -6,7 +6,7 @@ using System.Collections.Generic;
 using System.Drawing;
 using System.Drawing.Text;
 using System.IO;
-using System.Linq;
+using System.Numerics;
 using System.Runtime.InteropServices;
 
 using BizHawk.Bizware.BizwareGL;
@@ -52,7 +52,7 @@ namespace BizHawk.Client.Common
 
 		private IEmulator GlobalEmulator;
 
-		public DisplayManagerBase(
+		protected DisplayManagerBase(
 			Config config,
 			IEmulator emulator,
 			InputManager inputManager,
@@ -63,58 +63,58 @@ namespace BizHawk.Client.Common
 		{
 			GlobalConfig = config;
 			GlobalEmulator = emulator;
-			OSD = new OSDManager(config, emulator, inputManager, movieSession);
+			OSD = new(config, emulator, inputManager, movieSession);
 			_gl = gl;
 			_renderer = renderer;
 
 			// it's sort of important for these to be initialized to something nonzero
 			_currEmuWidth = _currEmuHeight = 1;
 
-			_videoTextureFrugalizer = new TextureFrugalizer(_gl);
+			_videoTextureFrugalizer = new(_gl);
 
 			_shaderChainFrugalizers = new RenderTargetFrugalizer[16]; // hacky hardcoded limit.. need some other way to manage these
-			for (int i = 0; i < 16; i++)
+			for (var i = 0; i < 16; i++)
 			{
-				_shaderChainFrugalizers[i] = new RenderTargetFrugalizer(_gl);
+				_shaderChainFrugalizers[i] = new(_gl);
 			}
 
 			{
 				using var xml = ReflectionCache.EmbeddedResourceStream("Resources.courier16px.fnt");
 				using var tex = ReflectionCache.EmbeddedResourceStream("Resources.courier16px_0.png");
-				_theOneFont = new StringRenderer(_gl, xml, tex);
+				_theOneFont = new(_gl, xml, tex);
 				using var gens = ReflectionCache.EmbeddedResourceStream("Resources.gens.ttf");
 				LoadCustomFont(gens);
 				using var fceux = ReflectionCache.EmbeddedResourceStream("Resources.fceux.ttf");
 				LoadCustomFont(fceux);
 			}
 
-			if (dispMethod == EDispMethod.OpenGL || dispMethod == EDispMethod.D3D9)
+			if (dispMethod is EDispMethod.OpenGL or EDispMethod.D3D9)
 			{
 				var fiHq2x = new FileInfo(Path.Combine(PathUtils.ExeDirectoryPath, "Shaders/BizHawk/hq2x.cgp"));
 				if (fiHq2x.Exists)
 				{
 					using var stream = fiHq2x.OpenRead();
-					_shaderChainHq2X = new RetroShaderChain(_gl, new RetroShaderPreset(stream), Path.Combine(PathUtils.ExeDirectoryPath, "Shaders/BizHawk"));
+					_shaderChainHq2X = new(_gl, new(stream), Path.Combine(PathUtils.ExeDirectoryPath, "Shaders/BizHawk"));
 				}
 				var fiScanlines = new FileInfo(Path.Combine(PathUtils.ExeDirectoryPath, "Shaders/BizHawk/BizScanlines.cgp"));
 				if (fiScanlines.Exists)
 				{
 					using var stream = fiScanlines.OpenRead();
-					_shaderChainScanlines = new RetroShaderChain(_gl, new RetroShaderPreset(stream), Path.Combine(PathUtils.ExeDirectoryPath, "Shaders/BizHawk"));
+					_shaderChainScanlines = new(_gl, new(stream), Path.Combine(PathUtils.ExeDirectoryPath, "Shaders/BizHawk"));
 				}
 				var bicubicPath = dispMethod == EDispMethod.D3D9 ? "Shaders/BizHawk/bicubic-normal.cgp" : "Shaders/BizHawk/bicubic-fast.cgp";
 				var fiBicubic = new FileInfo(Path.Combine(PathUtils.ExeDirectoryPath, bicubicPath));
 				if (fiBicubic.Exists)
 				{
 					using var stream = fiBicubic.Open(FileMode.Open, FileAccess.Read, FileShare.Read);
-					_shaderChainBicubic = new RetroShaderChain(_gl, new RetroShaderPreset(stream), Path.Combine(PathUtils.ExeDirectoryPath, "Shaders/BizHawk"));
+					_shaderChainBicubic = new(_gl, new(stream), Path.Combine(PathUtils.ExeDirectoryPath, "Shaders/BizHawk"));
 				}
 			}
 
 			_apiHawkSurfaceSets[DisplaySurfaceID.EmuCore] = new(CreateDisplaySurface);
 			_apiHawkSurfaceSets[DisplaySurfaceID.Client] = new(CreateDisplaySurface);
-			_apiHawkSurfaceFrugalizers[DisplaySurfaceID.EmuCore] = new TextureFrugalizer(_gl);
-			_apiHawkSurfaceFrugalizers[DisplaySurfaceID.Client] = new TextureFrugalizer(_gl);
+			_apiHawkSurfaceFrugalizers[DisplaySurfaceID.EmuCore] = new(_gl);
+			_apiHawkSurfaceFrugalizers[DisplaySurfaceID.Client] = new(_gl);
 
 			RefreshUserShader();
 		}
@@ -130,7 +130,11 @@ namespace BizHawk.Client.Common
 
 		public void Dispose()
 		{
-			if (Disposed) return;
+			if (Disposed)
+			{
+				return;
+			}
+
 			Disposed = true;
 
 			// OpenGL context needs to be active when Dispose()'ing
@@ -185,7 +189,7 @@ namespace BizHawk.Client.Common
 		/// <summary>
 		/// custom fonts that don't need to be installed on the user side
 		/// </summary>
-		public PrivateFontCollection CustomFonts { get; } = new PrivateFontCollection();
+		public PrivateFontCollection CustomFonts { get; } = new();
 
 		private readonly TextureFrugalizer _videoTextureFrugalizer;
 
@@ -193,11 +197,11 @@ namespace BizHawk.Client.Common
 
 		protected readonly RenderTargetFrugalizer[] _shaderChainFrugalizers;
 
-		private RetroShaderChain _shaderChainHq2X;
+		private readonly RetroShaderChain _shaderChainHq2X;
 
-		private RetroShaderChain _shaderChainScanlines;
+		private readonly RetroShaderChain _shaderChainScanlines;
 
-		private RetroShaderChain _shaderChainBicubic;
+		private readonly RetroShaderChain _shaderChainBicubic;
 
 		private RetroShaderChain _shaderChainUser;
 
@@ -214,7 +218,7 @@ namespace BizHawk.Client.Common
 			{
 				var fi = new FileInfo(GlobalConfig.DispUserFilterPath);
 				using var stream = fi.OpenRead();
-				_shaderChainUser = new RetroShaderChain(_gl, new RetroShaderPreset(stream), Path.GetDirectoryName(GlobalConfig.DispUserFilterPath));
+				_shaderChainUser = new(_gl, new(stream), Path.GetDirectoryName(GlobalConfig.DispUserFilterPath));
 			}
 		}
 
@@ -261,26 +265,24 @@ namespace BizHawk.Client.Common
 			// select user special FX shader chain
 			var selectedChainProperties = new Dictionary<string, object>();
 			RetroShaderChain selectedChain = null;
-			if (GlobalConfig.TargetDisplayFilter == 1 && _shaderChainHq2X != null && _shaderChainHq2X.Available)
+			switch (GlobalConfig.TargetDisplayFilter)
 			{
-				selectedChain = _shaderChainHq2X;
-			}
-
-			if (GlobalConfig.TargetDisplayFilter == 2 && _shaderChainScanlines != null && _shaderChainScanlines.Available)
-			{
-				selectedChain = _shaderChainScanlines;
-				selectedChainProperties["uIntensity"] = 1.0f - GlobalConfig.TargetScanlineFilterIntensity / 256.0f;
-			}
-
-			if (GlobalConfig.TargetDisplayFilter == 3 && _shaderChainUser != null && _shaderChainUser.Available)
-			{
-				selectedChain = _shaderChainUser;
+				case 1 when _shaderChainHq2X is { Available: true }:
+					selectedChain = _shaderChainHq2X;
+					break;
+				case 2 when _shaderChainScanlines is { Available: true }:
+					selectedChain = _shaderChainScanlines;
+					selectedChainProperties["uIntensity"] = 1.0f - GlobalConfig.TargetScanlineFilterIntensity / 256.0f;
+					break;
+				case 3 when _shaderChainUser is { Available: true }:
+					selectedChain = _shaderChainUser;
+					break;
 			}
 
 			if (!includeUserFilters)
 				selectedChain = null;
 
-			BaseFilter fCoreScreenControl = CreateCoreScreenControl();
+			var fCoreScreenControl = CreateCoreScreenControl();
 
 			var fPresent = new FinalPresentation(chainOutSize);
 			var fInput = new SourceImage(chainInSize);
@@ -311,7 +313,9 @@ namespace BizHawk.Client.Common
 			chain.AddFilter(fInput, "input");
 
 			if (fCoreScreenControl != null)
+			{
 				chain.AddFilter(fCoreScreenControl, "CoreScreenControl");
+			}
 
 			// if a non-zero padding is required, add a filter to allow for that
 			// note, we have two sources of padding right now.. one can come from the VideoProvider and one from the user.
@@ -322,35 +326,37 @@ namespace BizHawk.Client.Common
 			if (padding != (0, 0, 0, 0))
 			{
 				// TODO - add another filter just for this, its cumbersome to use final presentation... I think. but maybe there's enough similarities to justify it.
-				Size size = chainInSize;
+				var size = chainInSize;
 				size.Width += padding.Left + padding.Right;
 				size.Height += padding.Top + padding.Bottom;
 
-				//in case the user requested so much padding that the dimensions are now negative, just turn it to something small
+				// in case the user requested so much padding that the dimensions are now negative, just turn it to something small
 				if (size.Width < 1) size.Width = 1;
 				if (size.Height < 1) size.Height = 1;
 
-				FinalPresentation fPadding = new FinalPresentation(size);
+				var fPadding = new FinalPresentation(size);
 				chain.AddFilter(fPadding, "padding");
-				fPadding.GuiRenderer = _renderer;
-				fPadding.GL = _gl;
 				fPadding.Config_PadOnly = true;
 				fPadding.Padding = padding;
 			}
 
-			//add lua layer 'emu'
+			// add lua layer 'emu'
 			AppendApiHawkLayer(chain, DisplaySurfaceID.EmuCore);
 
-			if(includeUserFilters)
+			if (includeUserFilters)
+			{
 				if (GlobalConfig.DispPrescale != 1)
 				{
 					var fPrescale = new PrescaleFilter() { Scale = GlobalConfig.DispPrescale };
 					chain.AddFilter(fPrescale, "user_prescale");
 				}
+			}
 
 			// add user-selected retro shader
 			if (selectedChain != null)
+			{
 				AppendRetroShaderChain(chain, "retroShader", selectedChain, selectedChainProperties);
+			}
 
 			// AutoPrescale makes no sense for a None final filter
 			if (GlobalConfig.DispAutoPrescale && GlobalConfig.DispFinalFilter != (int)FinalPresentation.eFilterOption.None)
@@ -359,22 +365,18 @@ namespace BizHawk.Client.Common
 				chain.AddFilter(apf, "auto_prescale");
 			}
 
-			//choose final filter
-			var finalFilter = FinalPresentation.eFilterOption.None;
-			if (GlobalConfig.DispFinalFilter == 1)
+			// choose final filter
+			var finalFilter = GlobalConfig.DispFinalFilter switch
 			{
-				finalFilter = FinalPresentation.eFilterOption.Bilinear;
-			}
+				1 => FinalPresentation.eFilterOption.Bilinear,
+				2 => FinalPresentation.eFilterOption.Bicubic,
+				_ => FinalPresentation.eFilterOption.None
+			};
 
-			if (GlobalConfig.DispFinalFilter == 2)
-			{
-				finalFilter = FinalPresentation.eFilterOption.Bicubic;
-			}
-
-			//if bicubic is selected and unavailable, don't use it. use bilinear instead I guess
+			// if bicubic is selected and unavailable, don't use it. use bilinear instead I guess
 			if (finalFilter == FinalPresentation.eFilterOption.Bicubic)
 			{
-				if (_shaderChainBicubic == null || !_shaderChainBicubic.Available)
+				if (_shaderChainBicubic is not { Available: true })
 				{
 					finalFilter = FinalPresentation.eFilterOption.Bilinear;
 				}
@@ -398,18 +400,20 @@ namespace BizHawk.Client.Common
 			// and OSD goes on top of that
 			// TODO - things break if this isn't present (the final presentation filter gets messed up when used with prescaling)
 			// so, always include it (we'll handle this flag in the callback to do no rendering)
-			if (true /*includeOSD*/) chain.AddFilter(fOSD, "osd");
+			if (true /*includeOSD*/)
+			{
+				chain.AddFilter(fOSD, "osd");
+			}
 
 			return chain;
 		}
 
-		private void AppendRetroShaderChain(FilterProgram program, string name, RetroShaderChain retroChain, Dictionary<string, object> properties)
+		private static void AppendRetroShaderChain(FilterProgram program, string name, RetroShaderChain retroChain, Dictionary<string, object> properties)
 		{
-			for (int i = 0; i < retroChain.Passes.Length; i++)
+			for (var i = 0; i < retroChain.Passes.Length; i++)
 			{
-				var pass = retroChain.Passes[i];
 				var rsp = new RetroShaderPass(retroChain, i);
-				string fname = $"{name}[{i}]";
+				var fname = $"{name}[{i}]";
 				program.AddFilter(rsp, fname);
 				rsp.Parameters = properties;
 			}
@@ -423,13 +427,13 @@ namespace BizHawk.Client.Common
 				return;
 			}
 
-			Texture2d luaNativeTexture = _apiHawkSurfaceFrugalizers[surfaceID].Get(luaNativeSurface);
+			var luaNativeTexture = _apiHawkSurfaceFrugalizers[surfaceID].Get(luaNativeSurface);
 			var fLuaLayer = new LuaLayer();
 			fLuaLayer.SetTexture(luaNativeTexture);
 			chain.AddFilter(fLuaLayer, surfaceID.GetName());
 		}
 
-		protected virtual Point GraphicsControlPointToClient(Point p) => throw new NotImplementedException();
+		protected abstract Point GraphicsControlPointToClient(Point p);
 
 		/// <summary>
 		/// Using the current filter program, turn a mouse coordinate from window space to the original emulator screen space.
@@ -454,7 +458,7 @@ namespace BizHawk.Client.Common
 		/// </summary>
 		public Point TransformPoint(Point p)
 		{
-			//now, if there's no filter program active, just give up
+			// now, if there's no filter program active, just give up
 			if (_currentFilterProgram == null)
 			{
 				return p;
@@ -466,9 +470,9 @@ namespace BizHawk.Client.Common
 			return new((int)v.X, (int)v.Y);
 		}
 
-		public virtual Size GetPanelNativeSize() => throw new NotImplementedException();
+		public abstract Size GetPanelNativeSize();
 
-		protected virtual Size GetGraphicsControlSize() => throw new NotImplementedException();
+		protected abstract Size GetGraphicsControlSize();
 
 		/// <summary>
 		/// This will receive an emulated output frame from an IVideoProvider and run it through the complete frame processing pipeline
@@ -476,7 +480,7 @@ namespace BizHawk.Client.Common
 		/// </summary>
 		public void UpdateSource(IVideoProvider videoProvider)
 		{
-			bool displayNothing = GlobalConfig.DispSpeedupFeatures == 0;
+			var displayNothing = GlobalConfig.DispSpeedupFeatures == 0;
 			var job = new JobInfo
 			{
 				VideoProvider = videoProvider,
@@ -485,6 +489,7 @@ namespace BizHawk.Client.Common
 				IncludeOSD = true,
 				IncludeUserFilters = true
 			};
+
 			UpdateSourceInternal(job);
 		}
 
@@ -512,6 +517,7 @@ namespace BizHawk.Client.Common
 				IncludeOSD = includeOSD,
 				IncludeUserFilters = true,
 			};
+
 			UpdateSourceInternal(job);
 			return job.OffscreenBb;
 		}
@@ -524,37 +530,42 @@ namespace BizHawk.Client.Common
 			{
 				VideoProvider = videoProvider,
 				Simulate = false,
-				ChainOutsize = new Size(videoProvider.BufferWidth, videoProvider.BufferHeight),
+				ChainOutsize = new(videoProvider.BufferWidth, videoProvider.BufferHeight),
 				Offscreen = true,
 				IncludeOSD = false,
 				IncludeUserFilters = false,
 			};
+
 			UpdateSourceInternal(job);
 			return job.OffscreenBb;
 		}
 
 		private class FakeVideoProvider : IVideoProvider
 		{
+			public FakeVideoProvider(int bw, int bh, int vw, int vh)
+			{
+				BufferWidth = bw;
+				BufferHeight = bh;
+				VirtualWidth = vw;
+				VirtualHeight = vh;
+			}
+
 			public int[] GetVideoBuffer()
 				=> Array.Empty<int>();
 
-			public int VirtualWidth { get; set; }
-			public int VirtualHeight { get; set; }
+			public int VirtualWidth { get; }
+			public int VirtualHeight { get; }
+			public int BufferWidth { get; }
+			public int BufferHeight { get; }
+			public int BackgroundColor => 0;
 
-			public int BufferWidth { get; set; }
-			public int BufferHeight { get; set; }
-			public int BackgroundColor { get; set; }
-
-			/// <exception cref="InvalidOperationException">always</exception>
-			public int VsyncNumerator => throw new InvalidOperationException();
-
-			/// <exception cref="InvalidOperationException">always</exception>
-			public int VsyncDenominator => throw new InvalidOperationException();
+			public int VsyncNumerator => throw new NotImplementedException();
+			public int VsyncDenominator => throw new NotImplementedException();
 		}
 
-		private void FixRatio(float x, float y, int inw, int inh, out int outW, out int outH)
+		private static void FixRatio(float x, float y, int inw, int inh, out int outW, out int outH)
 		{
-			float ratio = x / y;
+			var ratio = x / y;
 			if (ratio <= 1)
 			{
 				// taller. weird. expand height.
@@ -576,17 +587,17 @@ namespace BizHawk.Client.Common
 		/// </summary>
 		public Size CalculateClientSize(IVideoProvider videoProvider, int zoom)
 		{
-			bool arActive = GlobalConfig.DispFixAspectRatio;
-			bool arSystem = GlobalConfig.DispManagerAR == EDispManagerAR.System;
-			bool arCustom = GlobalConfig.DispManagerAR == EDispManagerAR.CustomSize;
-			bool arCustomRatio = GlobalConfig.DispManagerAR == EDispManagerAR.CustomRatio;
-			bool arCorrect = arSystem || arCustom || arCustomRatio;
-			bool arInteger = GlobalConfig.DispFixScaleInteger;
+			var arActive = GlobalConfig.DispFixAspectRatio;
+			var arSystem = GlobalConfig.DispManagerAR == EDispManagerAR.System;
+			var arCustom = GlobalConfig.DispManagerAR == EDispManagerAR.CustomSize;
+			var arCustomRatio = GlobalConfig.DispManagerAR == EDispManagerAR.CustomRatio;
+			var arCorrect = arSystem || arCustom || arCustomRatio;
+			var arInteger = GlobalConfig.DispFixScaleInteger;
 
-			int bufferWidth = videoProvider.BufferWidth;
-			int bufferHeight = videoProvider.BufferHeight;
-			int virtualWidth = videoProvider.VirtualWidth;
-			int virtualHeight = videoProvider.VirtualHeight;
+			var bufferWidth = videoProvider.BufferWidth;
+			var bufferHeight = videoProvider.BufferHeight;
+			var virtualWidth = videoProvider.VirtualWidth;
+			var virtualHeight = videoProvider.VirtualHeight;
 
 			if (arCustom)
 			{
@@ -596,17 +607,18 @@ namespace BizHawk.Client.Common
 
 			if (arCustomRatio)
 			{
-				FixRatio(GlobalConfig.DispCustomUserArx, GlobalConfig.DispCustomUserAry, videoProvider.BufferWidth, videoProvider.BufferHeight, out virtualWidth, out virtualHeight);
+				FixRatio(GlobalConfig.DispCustomUserArx, GlobalConfig.DispCustomUserAry,
+					videoProvider.BufferWidth, videoProvider.BufferHeight, out virtualWidth, out virtualHeight);
 			}
 
-			//TODO: it is bad that this is happening outside the filter chain
-			//the filter chain has the ability to add padding...
-			//for now, we have to have some hacks. this could be improved by refactoring the filter setup hacks to be in one place only though
-			//could the PADDING be done as filters too? that would be nice.
+			// TODO: it is bad that this is happening outside the filter chain
+			// the filter chain has the ability to add padding...
+			// for now, we have to have some hacks. this could be improved by refactoring the filter setup hacks to be in one place only though
+			// could the PADDING be done as filters too? that would be nice.
 			var fCoreScreenControl = CreateCoreScreenControl();
-			if(fCoreScreenControl != null)
+			if (fCoreScreenControl != null)
 			{
-				var sz = fCoreScreenControl.PresizeInput("default", new Size(bufferWidth, bufferHeight));
+				var sz = fCoreScreenControl.PresizeInput("default", new(bufferWidth, bufferHeight));
 				virtualWidth = bufferWidth = sz.Width;
 				virtualHeight = bufferHeight = sz.Height;
 			}
@@ -619,21 +631,14 @@ namespace BizHawk.Client.Common
 			bufferWidth += padding.Horizontal;
 			bufferHeight += padding.Vertical;
 
-			//in case the user requested so much padding that the dimensions are now negative, just turn it to something small.
+			// in case the user requested so much padding that the dimensions are now negative, just turn it to something small.
 			if (virtualWidth < 1) virtualWidth = 1;
 			if (virtualHeight < 1) virtualHeight = 1;
 			if (bufferWidth < 1) bufferWidth = 1;
 			if (bufferHeight < 1) bufferHeight = 1;
 
 			// old stuff
-			var fvp = new FakeVideoProvider
-			{
-				BufferWidth = bufferWidth,
-				BufferHeight = bufferHeight,
-				VirtualWidth = virtualWidth,
-				VirtualHeight = virtualHeight
-			};
-
+			var fvp = new FakeVideoProvider(bufferWidth, bufferHeight, virtualWidth, virtualHeight);
 			Size chainOutsize;
 
 			if (arActive)
@@ -643,51 +648,45 @@ namespace BizHawk.Client.Common
 					if (arInteger)
 					{
 						// ALERT COPYPASTE LAUNDROMAT
-						Vector2 AR = new(virtualWidth / (float) bufferWidth, virtualHeight / (float) bufferHeight);
-						float targetPar = AR.X / AR.Y;
+						var AR = new Vector2(virtualWidth / (float) bufferWidth, virtualHeight / (float) bufferHeight);
+						var targetPar = AR.X / AR.Y;
 
 						// this would malfunction for AR <= 0.5 or AR >= 2.0
 						// EDIT - in fact, we have AR like that coming from PSX, sometimes, so maybe we should solve this better
-						Vector2 PS = new Vector2(1, 1);
+						var PS = Vector2.One; // this would malfunction for AR <= 0.5 or AR >= 2.0
 
 						// here's how we define zooming, in this case:
 						// make sure each step is an increment of zoom for at least one of the dimensions (or maybe both of them)
 						// look for the increment which helps the AR the best
-						//TODO - this cant possibly support scale factors like 1.5x
-						//TODO - also, this might be messing up zooms and stuff, we might need to run this on the output size of the filter chain
-						for (int i = 1; i < zoom;i++)
+						// TODO - this cant possibly support scale factors like 1.5x
+						// TODO - also, this might be messing up zooms and stuff, we might need to run this on the output size of the filter chain
+
+						Span<Vector2> trials = stackalloc Vector2[3];
+						for (var i = 1; i < zoom; i++)
 						{
-							//would not be good to run this per frame, but it seems to only run when the resolution changes, etc.
-							Vector2[] trials =
-							{
-								PS + new Vector2(1, 0),
-								PS + new Vector2(0, 1),
-								PS + new Vector2(1, 1)
-							};
-							int bestIndex = -1;
-							float bestValue = 1000.0f;
-							for (int t = 0; t < trials.Length; t++)
+							// would not be good to run this per frame, but it seems to only run when the resolution changes, etc.
+							trials[0] = PS + Vector2.UnitX;
+							trials[1] = PS + Vector2.UnitY;
+							trials[2] = PS + Vector2.One;
+
+							var bestIndex = -1;
+							var bestValue = 1000.0f;
+							for (var t = 0; t < trials.Length; t++)
 							{
 								//I.
-								float testAr = trials[t].X / trials[t].Y;
+								var testAr = trials[t].X / trials[t].Y;
 
 								// II.
-								//Vector2 calc = Vector2.Multiply(trials[t], VS);
-								//float test_ar = calc.X / calc.Y;
+								// var calc = Vector2.Multiply(trials[t], VS);
+								// var test_ar = calc.X / calc.Y;
 
 								// not clear which approach is superior
-								float deviationLinear = Math.Abs(testAr - targetPar);
-								float deviationGeom = testAr / targetPar;
-								if (deviationGeom < 1)
-								{
-									deviationGeom = 1.0f / deviationGeom;
-								}
 
-								float value = deviationLinear;
-								if (value < bestValue)
+								var deviationLinear = Math.Abs(testAr - targetPar);
+								if (deviationLinear < bestValue)
 								{
 									bestIndex = t;
-									bestValue = value;
+									bestValue = deviationLinear;
 								}
 							}
 
@@ -699,26 +698,26 @@ namespace BizHawk.Client.Common
 							}
 						}
 
-						chainOutsize = new Size((int)(bufferWidth * PS.X), (int)(bufferHeight * PS.Y));
+						chainOutsize = new((int)(bufferWidth * PS.X), (int)(bufferHeight * PS.Y));
 					}
 					else
 					{
 						// obey the AR, but allow free scaling: just zoom the virtual size
-						chainOutsize = new Size(virtualWidth * zoom, virtualHeight * zoom);
+						chainOutsize = new(virtualWidth * zoom, virtualHeight * zoom);
 					}
 				}
 				else
 				{
 					// ar_unity:
 					// just choose to zoom the buffer (make no effort to incorporate AR)
-					chainOutsize = new Size(bufferWidth * zoom, bufferHeight * zoom);
+					chainOutsize = new(bufferWidth * zoom, bufferHeight * zoom);
 				}
 			}
 			else
 			{
 				// !ar_active:
 				// just choose to zoom the buffer (make no effort to incorporate AR)
-				chainOutsize = new Size(bufferWidth * zoom, bufferHeight * zoom);
+				chainOutsize = new(bufferWidth * zoom, bufferHeight * zoom);
 			}
 
 			chainOutsize.Width += ClientExtraPadding.Left + ClientExtraPadding.Right;
@@ -738,11 +737,10 @@ namespace BizHawk.Client.Common
 			// we need some other more sensible client size.
 			if (filterProgram == null)
 			{
-				return new Size(256, 192);
+				return new(256, 192);
 			}
 
-			var size = filterProgram.Filters.Last().FindOutput().SurfaceFormat.Size;
-
+			var size = filterProgram.Filters[filterProgram.Filters.Count - 1].FindOutput().SurfaceFormat.Size;
 			return size;
 		}
 
@@ -795,10 +793,10 @@ namespace BizHawk.Client.Common
 			var vw = videoProvider.VirtualWidth;
 			var vh = videoProvider.VirtualHeight;
 
-			//TODO: it is bad that this is happening outside the filter chain
-			//the filter chain has the ability to add padding...
-			//for now, we have to have some hacks. this could be improved by refactoring the filter setup hacks to be in one place only though
-			//could the PADDING be done as filters too? that would be nice.
+			// TODO: it is bad that this is happening outside the filter chain
+			// the filter chain has the ability to add padding...
+			// for now, we have to have some hacks. this could be improved by refactoring the filter setup hacks to be in one place only though
+			// could the PADDING be done as filters too? that would be nice.
 			var fCoreScreenControl = CreateCoreScreenControl();
 			if(fCoreScreenControl != null)
 			{
@@ -809,25 +807,26 @@ namespace BizHawk.Client.Common
 
 			if (GlobalConfig.DispFixAspectRatio)
 			{
-				if (GlobalConfig.DispManagerAR == EDispManagerAR.None)
+				switch (GlobalConfig.DispManagerAR)
 				{
-					vw = bufferWidth;
-					vh = bufferHeight;
-				}
-				if (GlobalConfig.DispManagerAR == EDispManagerAR.System)
-				{
-					//Already set
-				}
-				if (GlobalConfig.DispManagerAR == EDispManagerAR.CustomSize)
-				{
-					//not clear what any of these other options mean for "screen controlled" systems
-					vw = GlobalConfig.DispCustomUserARWidth;
-					vh = GlobalConfig.DispCustomUserARHeight;
-				}
-				if (GlobalConfig.DispManagerAR == EDispManagerAR.CustomRatio)
-				{
-					//not clear what any of these other options mean for "screen controlled" systems
-					FixRatio(GlobalConfig.DispCustomUserArx, GlobalConfig.DispCustomUserAry, videoProvider.BufferWidth, videoProvider.BufferHeight, out vw, out vh);
+					case EDispManagerAR.None:
+						vw = bufferWidth;
+						vh = bufferHeight;
+						break;
+					case EDispManagerAR.System:
+						// Already set
+						break;
+					case EDispManagerAR.CustomSize:
+						// not clear what any of these other options mean for "screen controlled" systems
+						vw = GlobalConfig.DispCustomUserARWidth;
+						vh = GlobalConfig.DispCustomUserARHeight;
+						break;
+					case EDispManagerAR.CustomRatio:
+						// not clear what any of these other options mean for "screen controlled" systems
+						FixRatio(GlobalConfig.DispCustomUserArx, GlobalConfig.DispCustomUserAry, videoProvider.BufferWidth, videoProvider.BufferHeight, out vw, out vh);
+						break;
+					default:
+						throw new InvalidOperationException();
 				}
 			}
 
@@ -884,20 +883,9 @@ namespace BizHawk.Client.Common
 				fPresent.VirtualTextureSize = new(vw, vh);
 				fPresent.TextureSize = new(presenterTextureWidth, presenterTextureHeight);
 				fPresent.BackgroundColor = videoProvider.BackgroundColor;
-				fPresent.GuiRenderer = _renderer;
 				fPresent.Config_FixAspectRatio = GlobalConfig.DispFixAspectRatio;
 				fPresent.Config_FixScaleInteger = GlobalConfig.DispFixScaleInteger;
 				fPresent.Padding = (ClientExtraPadding.Left, ClientExtraPadding.Top, ClientExtraPadding.Right, ClientExtraPadding.Bottom);
-				fPresent.AutoPrescale = GlobalConfig.DispAutoPrescale;
-
-				fPresent.GL = _gl;
-			}
-
-			//POOPY. why are we delivering the GL context this way? such bad
-			if (filterProgram["CoreScreenControl"] is ScreenControlNDS fNDS)
-			{
-				fNDS.GuiRenderer = _renderer;
-				fNDS.GL = _gl;
 			}
 
 			filterProgram.Compile("default", chainInsize, chainOutsize, !job.Offscreen);
@@ -938,12 +926,12 @@ namespace BizHawk.Client.Common
 			//GraphicsControl.Begin(); // CRITICAL POINT for yabause+GL
 
 			//TODO - auto-create and age these (and dispose when old)
-			int rtCounter = 0;
-
+			var rtCounter = 0;
+			// ReSharper disable once AccessToModifiedClosure
 			_currentFilterProgram.RenderTargetProvider = new DisplayManagerRenderTargetProvider(size => _shaderChainFrugalizers[rtCounter++].Get(size));
 
 			_gl.BeginScene();
-			RunFilterChainSteps(ref rtCounter, out var rtCurr, out var inFinalTarget);
+			RunFilterChainSteps(ref rtCounter, out var rtCurr, out _);
 			_gl.EndScene();
 
 			job.OffscreenBb = rtCurr.Texture2d.Resolve();
@@ -977,19 +965,25 @@ namespace BizHawk.Client.Common
 					inFinalTarget = true;
 					break;
 				default:
-					throw new Exception();
+					throw new InvalidOperationException();
 			}
 		}
 
 		private void LoadCustomFont(Stream fontStream)
 		{
-			IntPtr data = Marshal.AllocCoTaskMem((int)fontStream.Length);
-			byte[] fontData = new byte[fontStream.Length];
-			fontStream.Read(fontData, 0, (int)fontStream.Length);
-			Marshal.Copy(fontData, 0, data, (int)fontStream.Length);
-			CustomFonts.AddMemoryFont(data, fontData.Length);
-			fontStream.Close();
-			Marshal.FreeCoTaskMem(data);
+			var data = Marshal.AllocCoTaskMem((int)fontStream.Length);
+			try
+			{
+				var fontData = new byte[fontStream.Length];
+				fontStream.Read(fontData, 0, (int)fontStream.Length);
+				Marshal.Copy(fontData, 0, data, (int)fontStream.Length);
+				CustomFonts.AddMemoryFont(data, fontData.Length);
+			}
+			finally
+			{
+				Marshal.FreeCoTaskMem(data);
+				fontStream.Close();
+			}
 		}
 
 		private readonly Dictionary<DisplaySurfaceID, IDisplaySurface> _apiHawkIDToSurface = new();
@@ -1041,8 +1035,12 @@ namespace BizHawk.Client.Common
 					if (PeekApiHawkLockedSurface(kvp.Key) == null)
 					{
 						var surfLocked = LockApiHawkSurface(kvp.Key, true);
-						if (surfLocked != null) UnlockApiHawkSurface(surfLocked);
+						if (surfLocked != null)
+						{
+							UnlockApiHawkSurface(surfLocked);
+						}
 					}
+
 					_apiHawkSurfaceSets[kvp.Key].SetPending(null);
 				}
 				catch (InvalidOperationException)
@@ -1056,8 +1054,16 @@ namespace BizHawk.Client.Common
 		/// <exception cref="InvalidOperationException">already unlocked</exception>
 		public void UnlockApiHawkSurface(IDisplaySurface surface)
 		{
-			if (surface is not DisplaySurface dispSurfaceImpl) throw new ArgumentException("don't mix " + nameof(IDisplaySurface) + " implementations!", nameof(surface));
-			if (!_apiHawkSurfaceToID.TryGetValue(dispSurfaceImpl, out var surfaceID)) throw new InvalidOperationException("Surface was not locked as a lua surface");
+			if (surface is not DisplaySurface dispSurfaceImpl)
+			{
+				throw new ArgumentException("don't mix " + nameof(IDisplaySurface) + " implementations!", nameof(surface));
+			}
+
+			if (!_apiHawkSurfaceToID.TryGetValue(dispSurfaceImpl, out var surfaceID))
+			{
+				throw new InvalidOperationException("Surface was not locked as a lua surface");
+			}
+
 			_apiHawkSurfaceToID.Remove(dispSurfaceImpl);
 			_apiHawkIDToSurface.Remove(surfaceID);
 			_apiHawkSurfaceSets[surfaceID].SetPending(dispSurfaceImpl);

src/BizHawk.Client.Common/DisplayManager/FilterManager.cs

@@ -1,6 +1,10 @@
+using System;
 using System.Diagnostics;
 using System.Collections.Generic;
 using System.Drawing;
+using System.Linq;
+using System.Numerics;
+
 using BizHawk.Client.Common.Filters;
 
 using BizHawk.Bizware.BizwareGL;
@@ -14,21 +18,22 @@ namespace BizHawk.Client.Common.FilterManager
 
 	public class SurfaceFormat
 	{
-		public SurfaceFormat(Size size) => Size = size;
+		public SurfaceFormat(Size size)
+			=> Size = size;
+
 		public Size Size { get; }
 	}
 
-	public class SurfaceState
+	public readonly ref struct SurfaceState
 	{
-		public SurfaceState() { }
 		public SurfaceState(SurfaceFormat surfaceFormat, SurfaceDisposition surfaceDisposition = SurfaceDisposition.Unspecified)
 		{
 			SurfaceFormat = surfaceFormat;
 			SurfaceDisposition = surfaceDisposition;
 		}
 
-		public SurfaceFormat SurfaceFormat { get; set; }
-		public SurfaceDisposition SurfaceDisposition { get; set; }
+		public readonly SurfaceFormat SurfaceFormat;
+		public readonly SurfaceDisposition SurfaceDisposition;
 	}
 
 	public interface IRenderTargetProvider
@@ -38,7 +43,7 @@ namespace BizHawk.Client.Common.FilterManager
 
 	public class FilterProgram
 	{
-		private readonly Dictionary<string, BaseFilter> _filterNameIndex = new Dictionary<string, BaseFilter>();
+		private readonly Dictionary<string, BaseFilter> _filterNameIndex = new();
 
 		public readonly IList<BaseFilter> Filters = new List<BaseFilter>();
 		public readonly IList<ProgramStep> Program = new List<ProgramStep>();
@@ -63,12 +68,12 @@ namespace BizHawk.Client.Common.FilterManager
 		public IGuiRenderer GuiRenderer;
 		public IGL GL;
 		public IRenderTargetProvider RenderTargetProvider;
-		public RenderTarget GetRenderTarget(string channel = "default") { return CurrRenderTarget; }
+
 		public RenderTarget CurrRenderTarget;
 
 		public RenderTarget GetTempTarget(int width, int height)
 		{
-			return RenderTargetProvider.Get(new Size(width, height));
+			return RenderTargetProvider.Get(new(width, height));
 		}
 
 		public void AddFilter(BaseFilter filter, string name = "")
@@ -98,22 +103,24 @@ namespace BizHawk.Client.Common.FilterManager
 		/// </summary>
 		public Vector2 TransformPoint(string channel, Vector2 point)
 		{
-			foreach (var filter in Filters)
-			{
-				point = filter.TransformPoint(channel, point);
-			}
-
+			point = Filters.Aggregate(point, (current, filter) => filter.TransformPoint(channel, current));
 			// we COULD handle the case where the output size is 0,0, but it's not mathematically sensible
 			// it should be considered a bug to call this under those conditions
 			// in case the output size is zero, transform all points to zero, since the above maths may have malfunctioned
-			////var size = Filters[Filters.Count - 1].FindOutput().SurfaceFormat.Size;
-			////if (size.Width == 0) point.X = 0;
-			////if (size.Height == 0) point.Y = 0;
+#if false
+			var size = Filters[Filters.Count - 1].FindOutput().SurfaceFormat.Size;
+			if (size.Width == 0) point.X = 0;
+			if (size.Height == 0) point.Y = 0;
+#endif
 			return point;
 		}
 
-		public class ProgramStep
+		public readonly struct ProgramStep
 		{
+			public readonly ProgramStepType Type;
+			public readonly object Args;
+			public readonly string Comment;
+
 			public ProgramStep(ProgramStepType type, object args, string comment = null)
 			{
 				Type = type;
@@ -121,9 +128,6 @@ namespace BizHawk.Client.Common.FilterManager
 				Comment = comment;
 			}
 
-			public ProgramStepType Type;
-			public object Args;
-			public string Comment;
 			public override string ToString()
 			{
 				return Type switch
@@ -148,30 +152,36 @@ namespace BizHawk.Client.Common.FilterManager
 			}
 
 			//propagate input size forwards through filter chain to allow a 'flex' filter to determine what its input will be
-			Size presize = inSize;
+			var presize = inSize;
 			foreach (var filter in Filters)
 			{
 				presize = filter.PresizeInput(channel, presize);
 			}
 
-			//propagate output size backwards through filter chain to allow a 'flex' filter to determine its output based on the desired output needs
+			// propagate output size backwards through filter chain to allow a 'flex' filter to determine its output based on the desired output needs
 			presize = outsize;
-			for (int i = Filters.Count - 1; i >= 0; i--)
+			for (var i = Filters.Count - 1; i >= 0; i--)
 			{
 				var filter = Filters[i];
 				presize = filter.PresizeOutput(channel, presize);
 			}
 
-			SurfaceState currState = null;
+			var obtainedFirstOutput = false;
+			var currState = new SurfaceState(null);
 
-			for (int i = 0; i < Filters.Count; i++)
+			for (var i = 0; i < Filters.Count; i++)
 			{
-				BaseFilter f = Filters[i];
+				var f = Filters[i];
 
 				// check whether this filter needs input. if so, notify it of the current pipeline state
 				var iosi = f.FindInput(channel);
 				if (iosi != null)
 				{
+					if (!obtainedFirstOutput)
+					{
+						throw new InvalidOperationException("Obtained input before first output in filter chain");
+					}
+
 					iosi.SurfaceFormat = currState.SurfaceFormat;
 					f.SetInputFormat(channel, currState);
 
@@ -180,23 +190,29 @@ namespace BizHawk.Client.Common.FilterManager
 						continue;
 					}
 
-					// check if the desired disposition needs to change from texture to render target
-					// (if so, insert a render filter)
-					if (iosi.SurfaceDisposition == SurfaceDisposition.RenderTarget && currState.SurfaceDisposition == SurfaceDisposition.Texture)
+					switch (iosi.SurfaceDisposition)
 					{
-						var renderer = new Render();
-						Filters.Insert(i, renderer);
-						Compile(channel, inSize, outsize, finalTarget);
-						return;
-					}
-					// check if the desired disposition needs to change from a render target to a texture
-					// (if so, the current render target gets resolved, and made no longer current
-					else if (iosi.SurfaceDisposition == SurfaceDisposition.Texture && currState.SurfaceDisposition == SurfaceDisposition.RenderTarget)
-					{
-						var resolver = new Resolve();
-						Filters.Insert(i, resolver);
-						Compile(channel, inSize, outsize, finalTarget);
-						return;
+						// check if the desired disposition needs to change from texture to render target
+						// (if so, insert a render filter)
+						case SurfaceDisposition.RenderTarget when currState.SurfaceDisposition == SurfaceDisposition.Texture:
+						{
+							var renderer = new Render();
+							Filters.Insert(i, renderer);
+							Compile(channel, inSize, outsize, finalTarget);
+							return;
+						}
+						// check if the desired disposition needs to change from a render target to a texture
+						// (if so, the current render target gets resolved, and made no longer current
+						case SurfaceDisposition.Texture when currState.SurfaceDisposition == SurfaceDisposition.RenderTarget:
+						{
+							var resolver = new Resolve();
+							Filters.Insert(i, resolver);
+							Compile(channel, inSize, outsize, finalTarget);
+							return;
+						}
+						case SurfaceDisposition.Unspecified:
+						default:
+							break;
 					}
 				}
 
@@ -204,13 +220,10 @@ namespace BizHawk.Client.Common.FilterManager
 				iosi = f.FindOutput(channel);
 				if (iosi != null)
 				{
-					if (currState == null)
+					if (!obtainedFirstOutput)
 					{
-						currState = new SurfaceState
-						{
-							SurfaceFormat = iosi.SurfaceFormat,
-							SurfaceDisposition = iosi.SurfaceDisposition
-						};
+						currState = new(iosi.SurfaceFormat, iosi.SurfaceDisposition);
+						obtainedFirstOutput = true;
 					}
 					else
 					{
@@ -220,29 +233,36 @@ namespace BizHawk.Client.Common.FilterManager
 							iosi.SurfaceDisposition = currState.SurfaceDisposition;
 						}
 
-						bool newTarget = false;
+						var newTarget = false;
 						if (iosi.SurfaceFormat.Size != currState.SurfaceFormat.Size)
+						{
 							newTarget = true;
-						else if (currState.SurfaceDisposition == SurfaceDisposition.Texture && iosi.SurfaceDisposition == SurfaceDisposition.RenderTarget)
+						}
+						else if (currState.SurfaceDisposition == SurfaceDisposition.Texture &&
+								iosi.SurfaceDisposition == SurfaceDisposition.RenderTarget)
+						{
 							newTarget = true;
+						}
 
 						if (newTarget)
 						{
-							currState = new SurfaceState();
-							iosi.SurfaceFormat = currState.SurfaceFormat = iosi.SurfaceFormat;
-							iosi.SurfaceDisposition = currState.SurfaceDisposition = iosi.SurfaceDisposition;
-							Program.Add(new ProgramStep(ProgramStepType.NewTarget, currState.SurfaceFormat.Size));
+							currState = new(iosi.SurfaceFormat, iosi.SurfaceDisposition);
+							Program.Add(new(ProgramStepType.NewTarget, currState.SurfaceFormat.Size));
 						}
 						else
 						{
-							currState.SurfaceDisposition = iosi.SurfaceDisposition;
+							currState = new(currState.SurfaceFormat, iosi.SurfaceDisposition);
 						}
 					}
 				}
 
-				Program.Add(new ProgramStep(ProgramStepType.Run, i, f.GetType().Name));
+				Program.Add(new(ProgramStepType.Run, i, f.GetType().Name));
+			}
 
-			} // filter loop
+			if (!obtainedFirstOutput)
+			{
+				throw new InvalidOperationException("Did not obtain any output in filter chain");
+			}
 
 			// if the current output disposition is a texture, we need to render it
 			if (currState.SurfaceDisposition == SurfaceDisposition.Texture)
@@ -256,15 +276,14 @@ namespace BizHawk.Client.Common.FilterManager
 			// patch the program so that the final RenderTarget set operation is the framebuffer instead
 			if (finalTarget)
 			{
-				for (int i = Program.Count - 1; i >= 0; i--)
+				for (var i = Program.Count - 1; i >= 0; i--)
 				{
 					var ps = Program[i];
 					if (ps.Type == ProgramStepType.NewTarget)
 					{
 						var size = (Size)ps.Args;
 						Debug.Assert(size == outsize);
-						ps.Type = ProgramStepType.FinalTarget;
-						ps.Args = size;
+						Program[i] = new(ProgramStepType.FinalTarget, size, ps.Comment);
 						break;
 					}
 				}

src/BizHawk.Client.Common/DisplayManager/Filters/BaseFilter.cs

@@ -1,8 +1,9 @@
 using System.Collections.Generic;
 using System.Drawing;
-using BizHawk.Client.Common.FilterManager;
+using System.Numerics;
 
 using BizHawk.Bizware.BizwareGL;
+using BizHawk.Client.Common.FilterManager;
 
 // Here's how to make a filter:
 // 1. Reset your state entirely in Initialize().
@@ -19,13 +20,30 @@ namespace BizHawk.Client.Common.Filters
 	public class BaseFilter
 	{
 		// initialization stuff
-		public void BeginInitialization(FilterProgram program) { _ioSurfaceInfos.Clear(); FilterProgram = program; }
-		public virtual void Initialize() { }
-		public virtual Size PresizeInput(string channel, Size size) => size;
-		public virtual Size PresizeOutput(string channel, Size size) => size;
-		public virtual void SetInputFormat(string channel, SurfaceState state) { } //TODO - why a different param order than DeclareOutput?
-		public Dictionary<string, object> Parameters = new Dictionary<string, object>();
-		public bool IsNop { get; set; }
+		public void BeginInitialization(FilterProgram program)
+		{
+			_ioSurfaceInfos.Clear();
+			FilterProgram = program;
+		}
+
+		public virtual void Initialize()
+		{
+		}
+
+		public virtual Size PresizeInput(string channel, Size size)
+			=> size;
+
+		public virtual Size PresizeOutput(string channel, Size size)
+			=> size;
+
+		// TODO - why a different param order than DeclareOutput?
+		public virtual void SetInputFormat(string channel, SurfaceState state)
+		{
+		}
+
+		public Dictionary<string, object> Parameters = new();
+
+		public bool IsNop { get; protected set; }
 
 		// runtime signals
 		public virtual Vector2 UntransformPoint(string channel, Vector2 point)
@@ -38,6 +56,7 @@ namespace BizHawk.Client.Common.Filters
 				point.X *= input.SurfaceFormat.Size.Width / (float)output.SurfaceFormat.Size.Width;
 				point.Y *= input.SurfaceFormat.Size.Height / (float)output.SurfaceFormat.Size.Height;
 			}
+
 			return point;
 		}
 
@@ -51,6 +70,7 @@ namespace BizHawk.Client.Common.Filters
 				point.X *= output.SurfaceFormat.Size.Width / (float)input.SurfaceFormat.Size.Width;
 				point.Y *= output.SurfaceFormat.Size.Height / (float)input.SurfaceFormat.Size.Height;
 			}
+
 			return point;
 		}
 
@@ -58,8 +78,13 @@ namespace BizHawk.Client.Common.Filters
 		{
 			InputTexture = tex;
 		}
-		public virtual void Run() { }
-		public Texture2d GetOutput() => _outputTexture;
+
+		public virtual void Run()
+		{
+		}
+
+		public Texture2d GetOutput()
+			=> _outputTexture;
 
 		// filter actions
 		protected void YieldOutput(Texture2d tex)
@@ -121,20 +146,12 @@ namespace BizHawk.Client.Common.Filters
 			return iosi;
 		}
 
-		private readonly List<IOSurfaceInfo> _ioSurfaceInfos = new List<IOSurfaceInfo>();
+		private readonly List<IOSurfaceInfo> _ioSurfaceInfos = new();
 
 
 		private IOSurfaceInfo FindIOSurfaceInfo(string channel, SurfaceDirection direction)
 		{
-			foreach (var iosi in _ioSurfaceInfos)
-			{
-				if (iosi.Channel == channel && iosi.SurfaceDirection == direction)
-				{
-					return iosi;
-				}
-			}
-
-			return null;
+			return _ioSurfaceInfos.Find(iosi => iosi.Channel == channel && iosi.SurfaceDirection == direction);
 		}
 
 		public class IOSurfaceInfo

src/BizHawk.Client.Common/DisplayManager/Filters/Gui.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Drawing;
+using System.Numerics;
 
 using BizHawk.Bizware.BizwareGL;
 using BizHawk.Client.Common.FilterManager;
@@ -28,19 +29,21 @@ namespace BizHawk.Client.Common.Filters
 		/// <summary>
 		/// In case you want to do it yourself
 		/// </summary>
-		public LetterboxingLogic() { }
+		public LetterboxingLogic()
+		{
+		}
 
 		// do maths on the viewport and the native resolution and the user settings to get a display rectangle
 		public LetterboxingLogic(bool maintainAspect, bool maintainInteger, int targetWidth, int targetHeight, int sourceWidth, int sourceHeight, Size textureSize, Size virtualSize)
 		{
-			int textureWidth = textureSize.Width;
-			int textureHeight = textureSize.Height;
-			int virtualWidth = virtualSize.Width;
-			int virtualHeight = virtualSize.Height;
+			var textureWidth = textureSize.Width;
+			var textureHeight = textureSize.Height;
+			var virtualWidth = virtualSize.Width;
+			var virtualHeight = virtualSize.Height;
 
-			//zero 02-jun-2014 - we passed these in, but ignored them. kind of weird..
-			int oldSourceWidth = sourceWidth;
-			int oldSourceHeight = sourceHeight;
+			// zero 02-jun-2014 - we passed these in, but ignored them. kind of weird..
+			var oldSourceWidth = sourceWidth;
+			var oldSourceHeight = sourceHeight;
 			sourceWidth = virtualWidth;
 			sourceHeight = virtualHeight;
 
@@ -50,8 +53,8 @@ namespace BizHawk.Client.Common.Filters
 				maintainInteger = false;
 			}
 
-			float widthScale = (float)targetWidth / sourceWidth;
-			float heightScale = (float)targetHeight / sourceHeight;
+			var widthScale = (float)targetWidth / sourceWidth;
+			var heightScale = (float)targetHeight / sourceHeight;
 
 			if (maintainAspect
 				// zero 20-jul-2014 - hacks upon hacks, this function needs rewriting
@@ -68,61 +71,60 @@ namespace BizHawk.Client.Common.Filters
 				// apply the zooming algorithm (pasted and reworked, for now)
 				// ALERT COPYPASTE LAUNDROMAT
 
-				Vector2 AR = new(virtualWidth / (float) textureWidth, virtualHeight / (float) textureHeight);
-				float targetPar = (AR.X / AR.Y);
-				Vector2 PS = new Vector2(1, 1); //this would malfunction for AR <= 0.5 or AR >= 2.0
+				var AR = new Vector2(virtualWidth / (float) textureWidth, virtualHeight / (float) textureHeight);
+				var targetPar = AR.X / AR.Y;
+				var PS = Vector2.One; // this would malfunction for AR <= 0.5 or AR >= 2.0
 
-				for(;;)
+				Span<Vector2> trials = stackalloc Vector2[3];
+				Span<bool> trialsLimited = stackalloc bool[3];
+				while (true)
 				{
 					// TODO - would be good not to run this per frame....
-					Vector2[] trials =
-					{
-						PS + new Vector2(1, 0),
-						PS + new Vector2(0, 1),
-						PS + new Vector2(1, 1)
-					};
+					trials[0] = PS + Vector2.UnitX;
+					trials[1] = PS + Vector2.UnitY;
+					trials[2] = PS + Vector2.One;
 
-					bool[] trialsLimited = { false, false, false };
-					int bestIndex = -1;
-					float bestValue = 1000.0f;
-					for (int t = 0; t < trials.Length; t++)
+					var bestIndex = -1;
+					var bestValue = 1000.0f;
+					for (var t = 0; t < trials.Length; t++)
 					{
-						Vector2 vTrial = trials[t];
+						var vTrial = trials[t];
 						trialsLimited[t] = false;
 
 						//check whether this is going to exceed our allotted area
-						int testVw = (int)(vTrial.X * textureWidth);
-						int testVh = (int)(vTrial.Y * textureHeight);
+						var testVw = (int)(vTrial.X * textureWidth);
+						var testVh = (int)(vTrial.Y * textureHeight);
 						if (testVw > targetWidth) trialsLimited[t] = true;
 						if (testVh > targetHeight) trialsLimited[t] = true;
 
 						// I.
-						float testAr = vTrial.X / vTrial.Y;
+						var testAr = vTrial.X / vTrial.Y;
 
 						// II.
-						// Vector2 calc = Vector2.Multiply(trials[t], VS);
-						// float test_ar = calc.X / calc.Y;
+						// var calc = Vector2.Multiply(trials[t], VS);
+						// var test_ar = calc.X / calc.Y;
 
 						// not clear which approach is superior
-						float deviationLinear = Math.Abs(testAr - targetPar);
-						float deviationGeom = testAr / targetPar;
-						if (deviationGeom < 1) deviationGeom = 1.0f / deviationGeom;
 
-						float value = deviationLinear;
-						if (value < bestValue)
+						var deviationLinear = Math.Abs(testAr - targetPar);
+						if (deviationLinear < bestValue)
 						{
 							bestIndex = t;
-							bestValue = value;
+							bestValue = deviationLinear;
 						}
 					}
 
 					// last result was best, so bail out
 					if (bestIndex == -1)
+					{
 						break;
+					}
 
 					// if the winner ran off the edge, bail out
 					if (trialsLimited[bestIndex])
+					{
 						break;
+					}
 
 					PS = trials[bestIndex];
 				}
@@ -132,8 +134,10 @@ namespace BizHawk.Client.Common.Filters
 				// vh = (int)(PS.Y * oldSourceHeight);
 				vw = (int)(PS.X * sourceWidth);
 				vh = (int)(PS.Y * sourceHeight);
+#if false
 				widthScale = PS.X;
 				heightScale = PS.Y;
+#endif
 			}
 			else
 			{
@@ -154,17 +158,20 @@ namespace BizHawk.Client.Common.Filters
 				vh = targetHeight;
 			}
 
-			//determine letterboxing parameters
+			// determine letterboxing parameters
 			vx = (targetWidth - vw) / 2;
 			vy = (targetHeight - vh) / 2;
 
 			// zero 09-oct-2014 - changed this for TransformPoint. scenario: basic 1x (but system-specified AR) NES window.
 			// vw would be 293 but WidthScale would be 1.0. I think it should be something different.
 			// FinalPresentation doesn't use the LL.WidthScale, so this is unlikely to be breaking anything old that depends on it
-			// WidthScale = widthScale;
-			// HeightScale = heightScale;
+#if false
+			WidthScale = widthScale;
+			HeightScale = heightScale;
+#else
 			WidthScale = (float)vw / oldSourceWidth;
 			HeightScale = (float)vh / oldSourceHeight;
+#endif
 		}
 	}
 
@@ -173,34 +180,26 @@ namespace BizHawk.Client.Common.Filters
 	/// </summary>
 	public class ScreenControlNDS : BaseFilter
 	{
-		public IGL GL;
-		public IGuiRenderer GuiRenderer;
+		private readonly NDS _nds;
 
-		private readonly NDS nds;
+		// TODO: actually use this
+#if false
+		private bool Nop = false;
+#endif
 
-		//TODO: actually use this
-		private bool nop = false;
+		// matrices used for transforming screens
+		private Matrix4x4 matTop, matBot;
+		private Matrix4x4 matTopInvert, matBotInvert;
 
-		//matrices used for transforming screens
-		private Matrix4 matTop, matBot;
-		private Matrix4 matTopInvert, matBotInvert;
-		
-		//final output area size
+		// final output area size
 		private Size outputSize;
 
-		private static float Round(float f) { return (float)Math.Round(f); }
-
-		//TODO: put somewhere in extension methods useful for fixing deficiencies in opentk matrix types
-		private static Vector2 Transform(Matrix4 m, Vector2 v)
-		{
-			var r = new Vector4(v.X,v.Y,0,1) * m;
-			return new Vector2(r.X, r.Y);
-		}
+		private static float Round(float f)
+			=> (float)Math.Round(f);
 
 		public ScreenControlNDS(NDS nds)
 		{
-			//not sure if we actually need this nds instance yet
-			this.nds = nds;
+			_nds = nds;
 		}
 
 		public override void Initialize()
@@ -211,63 +210,65 @@ namespace BizHawk.Client.Common.Filters
 
 		private void CrunchNumbers()
 		{
-			MatrixStack top = new MatrixStack(), bot = new MatrixStack();
+			MatrixStack top = new(), bot = new();
 
-			//-----------------------------------
-			//set up transforms for each screen based on screen control values
-			//this will be TRICKY depending on how many features we have, but once it's done, everything should be easy
+			// set up transforms for each screen based on screen control values
+			// this will be TRICKY depending on how many features we have, but once it's done, everything should be easy
 
-			var settings = nds.GetSettings();
+			var settings = _nds.GetSettings();
 
-			//gap only applies to vertical, I guess
-			if (settings.ScreenLayout == NDS.ScreenLayoutKind.Vertical)
+			switch (settings.ScreenLayout)
 			{
-				bot.Translate(0, 192);
-				bot.Translate(0, settings.ScreenGap);
-			}
-			else if (settings.ScreenLayout == NDS.ScreenLayoutKind.Horizontal)
-			{
-				bot.Translate(256, 0);
-			}
-			else if (settings.ScreenLayout == NDS.ScreenLayoutKind.Top)
-			{
-				//do nothing here, we'll discard bottom screen
+				//gap only applies to vertical, I guess
+				case NDS.ScreenLayoutKind.Vertical:
+					bot.Translate(0, 192);
+					bot.Translate(0, settings.ScreenGap);
+					break;
+				case NDS.ScreenLayoutKind.Horizontal:
+					bot.Translate(256, 0);
+					break;
+				case NDS.ScreenLayoutKind.Top:
+				case NDS.ScreenLayoutKind.Bottom:
+					// do nothing here, we'll discard the other screen
+					break;
+				default:
+					throw new InvalidOperationException();
 			}
 
-			//this doesn't make any sense, it's likely to be too much for a monitor to gracefully handle too
+			// this doesn't make any sense, it's likely to be too much for a monitor to gracefully handle too
 			if (settings.ScreenLayout != NDS.ScreenLayoutKind.Horizontal)
 			{
-				int rot = 0;
-				if (settings.ScreenRotation == NDS.ScreenRotationKind.Rotate90) rot = 90;
-				if (settings.ScreenRotation == NDS.ScreenRotationKind.Rotate180) rot = 180;
-				if (settings.ScreenRotation == NDS.ScreenRotationKind.Rotate270) rot = 270;
+				var rot = settings.ScreenRotation switch
+				{
+					NDS.ScreenRotationKind.Rotate90 => 90,
+					NDS.ScreenRotationKind.Rotate180 => 180,
+					NDS.ScreenRotationKind.Rotate270 => 270,
+					_ => 0
+				};
+
 				top.RotateZ(rot);
 				bot.RotateZ(rot);
 			}
 
-			//-----------------------------------
-
-			//TODO: refactor some of the below into a class that doesn't require having top and bottom replica code
+			// TODO: refactor some of the below into a class that doesn't require having top and bottom replica code
 
 			matTop = top.Top;
 			matBot = bot.Top;
-			matTopInvert = matTop.Inverted();
-			matBotInvert = matBot.Inverted();
 
-			//apply transforms from standard input screen positions to output screen positions
-			Vector2 top_TL = Transform(matTop, new Vector2(0, 0));
-			Vector2 top_TR = Transform(matTop, new Vector2(256, 0));
-			Vector2 top_BL = Transform(matTop, new Vector2(0, 192));
-			Vector2 top_BR = Transform(matTop, new Vector2(256, 192));
-			Vector2 bot_TL = Transform(matBot, new Vector2(0, 0));
-			Vector2 bot_TR = Transform(matBot, new Vector2(256, 0));
-			Vector2 bot_BL = Transform(matBot, new Vector2(0, 192));
-			Vector2 bot_BR = Transform(matBot, new Vector2(256, 192));
+			// apply transforms from standard input screen positions to output screen positions
+			var top_TL = Vector2.Transform(new(0, 0), matTop);
+			var top_TR = Vector2.Transform(new(256, 0), matTop);
+			var top_BL = Vector2.Transform(new(0, 192), matTop);
+			var top_BR = Vector2.Transform(new(256, 192), matTop);
+			var bot_TL = Vector2.Transform(new(0, 0), matBot);
+			var bot_TR = Vector2.Transform(new(256, 0), matBot);
+			var bot_BL = Vector2.Transform(new(0, 192), matBot);
+			var bot_BR = Vector2.Transform(new(256, 192), matBot);
 
-			//in case of math errors in the transforms, we'll round this stuff.. although...
-			//we're gonna use matrix transforms for drawing later, so it isn't extremely helpful
+			// in case of math errors in the transforms, we'll round this stuff.. although...
+			// we're gonna use matrix transforms for drawing later, so it isn't extremely helpful
 
-			//TODO - need more consideration of numerical precision here, because the typical case should be rock solid
+			// TODO - need more consideration of numerical precision here, because the typical case should be rock solid
 			top_TL.X = Round(top_TL.X); top_TL.Y = Round(top_TL.Y);
 			top_TR.X = Round(top_TR.X); top_TR.Y = Round(top_TR.Y);
 			top_BL.X = Round(top_BL.X); top_BL.Y = Round(top_BL.Y);
@@ -277,13 +278,15 @@ namespace BizHawk.Client.Common.Filters
 			bot_BL.X = Round(bot_BL.X); bot_BL.Y = Round(bot_BL.Y);
 			bot_BR.X = Round(bot_BR.X); bot_BR.Y = Round(bot_BR.Y);
 
-			////precalculate some useful metrics
-			//top_width = (int)(top_TR.X - top_TL.X);
-			//top_height = (int)(top_BR.Y - top_TR.Y);
-			//bot_width = (int)(bot_TR.X - bot_TL.X);
-			//bot_height = (int)(bot_BR.Y - bot_TR.Y);
+#if false
+			// precalculate some useful metrics
+			top_width = (int)(top_TR.X - top_TL.X);
+			top_height = (int)(top_BR.Y - top_TR.Y);
+			bot_width = (int)(bot_TR.X - bot_TL.X);
+			bot_height = (int)(bot_BR.Y - bot_TR.Y);
+#endif
 
-			//the size can now be determined in a kind of fluffily magical way by transforming edges and checking the bounds
+			// the size can now be determined in a kind of fluffily magical way by transforming edges and checking the bounds
 			float fxmin = 100000, fymin = 100000, fxmax = -100000, fymax = -100000;
 			if (settings.ScreenLayout != NDS.ScreenLayoutKind.Bottom)
 			{
@@ -300,24 +303,37 @@ namespace BizHawk.Client.Common.Filters
 				fymax = Math.Max(Math.Max(Math.Max(Math.Max(bot_TL.Y, bot_TR.Y), bot_BL.Y), bot_BR.Y), fymax);
 			}
 
-			//relocate whatever we got back into the viewable area
+			// relocate whatever we got back into the viewable area
 			top.Translate(-fxmin, -fymin);
 			bot.Translate(-fxmin, -fymin);
 			matTop = top.Top;
 			matBot = bot.Top;
 
-			//do some more rounding
-			for (int r = 0; r < 4; r++)
-				for (int c = 0; c < 4; c++)
+			// do some more rounding
+			unsafe
+			{
+				fixed (Matrix4x4* matTopP = &matTop, matBotP = &matBot)
 				{
-					if (Math.Abs(matTop[r, c]) < 0.0000001f) matTop[r, c] = 0;
-					if (Math.Abs(matBot[r, c]) < 0.0000001f) matBot[r, c] = 0;
+					float* matTopF = (float*)matTopP, matBotF = (float*)matBotP;
+					for (var i = 0; i < 4 * 4; i++)
+					{
+						if (Math.Abs(matTopF[i]) < 0.0000001f)
+						{
+							matTopF[i] = 0;
+						}
+
+						if (Math.Abs(matBotF[i]) < 0.0000001f)
+						{
+							matBotF[i] = 0;
+						}
+					}
 				}
+			}
 
-			matTopInvert = matTop.Inverted();
-			matBotInvert = matBot.Inverted();
+			Matrix4x4.Invert(matTop, out matTopInvert);
+			Matrix4x4.Invert(matBot, out matBotInvert);
 
-			outputSize = new Size((int)(fxmax-fxmin), (int)(fymax-fymin));
+			outputSize = new((int)(fxmax - fxmin), (int)(fymax - fymin));
 		}
 
 		public override Size PresizeInput(string channel, Size size)
@@ -335,86 +351,100 @@ namespace BizHawk.Client.Common.Filters
 		public override void SetInputFormat(string channel, SurfaceState state)
 		{
 			CrunchNumbers();
-			var ss = new SurfaceState(new SurfaceFormat(outputSize), SurfaceDisposition.RenderTarget);
+			var ss = new SurfaceState(new(outputSize), SurfaceDisposition.RenderTarget);
 			DeclareOutput(ss, channel);
 		}
 
 		public override Vector2 UntransformPoint(string channel, Vector2 point)
 		{
-			var settings = nds.GetSettings();
-			bool invert = settings.ScreenInvert
+			var settings = _nds.GetSettings();
+			var invert = settings.ScreenInvert
 				&& settings.ScreenLayout != NDS.ScreenLayoutKind.Top
 				&& settings.ScreenLayout != NDS.ScreenLayoutKind.Bottom;
 
-			point = Transform(invert ? matTopInvert : matBotInvert, point);
+			point = Vector2.Transform(point, invert ? matTopInvert : matBotInvert);
 
-			//hack to accomodate input tracking system's float-point sense (based on the core's VideoBuffer height)
-			//actually, this is needed for a reason similar to the "TouchScreenStart" that I removed.
-			//So, something like that needs readding if we're to get rid of this hack.
-			//(should redo it as a mouse coordinate offset or something.. but the key is to pipe it to the point where this is needed.. that is where MainForm does DisplayManager.UntransformPoint()
+			// hack to accomodate input tracking system's float-point sense (based on the core's VideoBuffer height)
+			// actually, this is needed for a reason similar to the "TouchScreenStart" that I removed.
+			// So, something like that needs readding if we're to get rid of this hack.
+			// (should redo it as a mouse coordinate offset or something.. but the key is to pipe it to the point where this is needed.. that is where MainForm does DisplayManager.UntransformPoint()
 			point.Y *= 2;
 
-			//in case we're in this layout, we get confused, so fix it
+			// in case we're in this layout, we get confused, so fix it
 			if (settings.ScreenLayout == NDS.ScreenLayoutKind.Top) point = new(0.0f, 0.0f);
 
-			//TODO: we probably need more subtle logic here.
-			//some capability to return -1,-1 perhaps in case the cursor is nowhere.
-			//not sure about that
+			// TODO: we probably need more subtle logic here.
+			// some capability to return -1,-1 perhaps in case the cursor is nowhere.
+			// not sure about that
 
 			return point;
 		}
 
 		public override Vector2 TransformPoint(string channel, Vector2 point)
 		{
-			point = Transform(matBot, point);
-			return point;
+			return Vector2.Transform(point, matTop);
 		}
 
 		public override void Run()
 		{
-			if (nop)
+#if false
+			if (Nop)
+			{
 				return;
+			}
+#endif
 
-			//TODO: this could be more efficient (draw only in gap)
-			GL.SetClearColor(Color.Black);
-			GL.Clear(ClearBufferMask.ColorBufferBit);
+			// TODO: this could be more efficient (draw only in gap)
+			FilterProgram.GL.SetClearColor(Color.Black);
+			FilterProgram.GL.Clear(ClearBufferMask.ColorBufferBit);
 
 			FilterProgram.GuiRenderer.Begin(outputSize);
-			GuiRenderer.SetBlendState(GL.BlendNoneCopy);
+			FilterProgram.GuiRenderer.SetBlendState(FilterProgram.GL.BlendNoneCopy);
 
-			//TODO: may depend on input, or other factors, not sure yet
-			//watch out though... if we filter linear, then screens will bleed into each other.
-			//so we will have to break them into render targets first.
+			// TODO: may depend on input, or other factors, not sure yet
+			// watch out though... if we filter linear, then screens will bleed into each other.
+			// so we will have to break them into render targets first.
 			InputTexture.SetFilterNearest();
 
 			//draw screens
-			bool renderTop = false;
-			bool renderBottom = false;
-			var settings = nds.GetSettings();
-			if (settings.ScreenLayout == NDS.ScreenLayoutKind.Bottom) renderBottom = true;
-			if (settings.ScreenLayout == NDS.ScreenLayoutKind.Top) renderTop = true;
-			if (settings.ScreenLayout == NDS.ScreenLayoutKind.Vertical) renderTop = renderBottom = true;
-			if (settings.ScreenLayout == NDS.ScreenLayoutKind.Horizontal) renderTop = renderBottom = true;
+			var renderTop = false;
+			var renderBottom = false;
+			var settings = _nds.GetSettings();
+			switch (settings.ScreenLayout)
+			{
+				case NDS.ScreenLayoutKind.Bottom:
+					renderBottom = true;
+					break;
+				case NDS.ScreenLayoutKind.Top:
+					renderTop = true;
+					break;
+				case NDS.ScreenLayoutKind.Vertical:
+				case NDS.ScreenLayoutKind.Horizontal:
+					renderTop = renderBottom = true;
+					break;
+				default:
+					throw new InvalidOperationException();
+			}
 
-			bool invert = settings.ScreenInvert && renderTop && renderBottom;
+			var invert = settings.ScreenInvert && renderTop && renderBottom;
 
 			if (renderTop)
 			{
-				GuiRenderer.Modelview.Push();
-				GuiRenderer.Modelview.PreMultiplyMatrix(invert ? matBot : matTop);
-				GuiRenderer.DrawSubrect(InputTexture, 0, 0, 256, 192, 0.0f, 0.0f, 1.0f, 0.5f);
-				GuiRenderer.Modelview.Pop();
+				FilterProgram.GuiRenderer.Modelview.Push();
+				FilterProgram.GuiRenderer.Modelview.PreMultiplyMatrix(invert ? matBot : matTop);
+				FilterProgram.GuiRenderer.DrawSubrect(InputTexture, 0, 0, 256, 192, 0.0f, 0.0f, 1.0f, 0.5f);
+				FilterProgram.GuiRenderer.Modelview.Pop();
 			}
 
 			if (renderBottom)
 			{
-				GuiRenderer.Modelview.Push();
-				GuiRenderer.Modelview.PreMultiplyMatrix(invert ? matTop : matBot);
-				GuiRenderer.DrawSubrect(InputTexture, 0, 0, 256, 192, 0.0f, 0.5f, 1.0f, 1.0f);
-				GuiRenderer.Modelview.Pop();
+				FilterProgram.GuiRenderer.Modelview.Push();
+				FilterProgram.GuiRenderer.Modelview.PreMultiplyMatrix(invert ? matTop : matBot);
+				FilterProgram.GuiRenderer.DrawSubrect(InputTexture, 0, 0, 256, 192, 0.0f, 0.5f, 1.0f, 1.0f);
+				FilterProgram.GuiRenderer.Modelview.Pop();
 			}
 
-			GuiRenderer.End();
+			FilterProgram.GuiRenderer.End();
 		}
 	}
 
@@ -505,12 +535,8 @@ namespace BizHawk.Client.Common.Filters
 		private Size OutputSize, InputSize;
 		public Size TextureSize, VirtualTextureSize;
 		public int BackgroundColor;
-		public bool AutoPrescale;
-		public IGuiRenderer GuiRenderer;
-		public IGL GL;
-		private bool nop;
+		private bool Nop;
 		private LetterboxingLogic LL;
-		private Size ContentSize;
 
 		public bool Config_FixAspectRatio, Config_FixScaleInteger, Config_PadOnly;
 
@@ -522,7 +548,7 @@ namespace BizHawk.Client.Common.Filters
 		public override void Initialize()
 		{
 			DeclareInput();
-			nop = false;
+			Nop = false;
 		}
 
 		public override Size PresizeOutput(string channel, Size size)
@@ -533,6 +559,7 @@ namespace BizHawk.Client.Common.Filters
 				size.Height = LL.vh;
 				return size;
 			}
+
 			return base.PresizeOutput(channel, size);
 		}
 
@@ -543,8 +570,8 @@ namespace BizHawk.Client.Common.Filters
 
 			if (Config_PadOnly)
 			{
-				//TODO - redundant fix
-				LL = new LetterboxingLogic();
+				// TODO - redundant fix
+				LL = new();
 				LL.vx += Padding.Left;
 				LL.vy += Padding.Top;
 				LL.vw = size.Width;
@@ -552,7 +579,7 @@ namespace BizHawk.Client.Common.Filters
 			}
 			else
 			{
-				LL = new LetterboxingLogic(Config_FixAspectRatio, Config_FixScaleInteger, OutputSize.Width, OutputSize.Height, size.Width, size.Height, TextureSize, VirtualTextureSize);
+				LL = new(Config_FixAspectRatio, Config_FixScaleInteger, OutputSize.Width, OutputSize.Height, size.Width, size.Height, TextureSize, VirtualTextureSize);
 				LL.vx += Padding.Left;
 				LL.vy += Padding.Top;
 			}
@@ -562,22 +589,20 @@ namespace BizHawk.Client.Common.Filters
 
 		public override void SetInputFormat(string channel, SurfaceState state)
 		{
-			bool need = state.SurfaceFormat.Size != OutputSize || FilterOption != eFilterOption.None;
-
+			var need = state.SurfaceFormat.Size != OutputSize || FilterOption != eFilterOption.None;
 			if (!need)
 			{
-				nop = true;
-				ContentSize = state.SurfaceFormat.Size;
+				Nop = true;
 				return;
 			}
 
 			FindInput().SurfaceDisposition = SurfaceDisposition.Texture;
-			DeclareOutput(new SurfaceState(new SurfaceFormat(OutputSize), SurfaceDisposition.RenderTarget));
+			DeclareOutput(new SurfaceState(new(OutputSize), SurfaceDisposition.RenderTarget));
 			InputSize = state.SurfaceFormat.Size;
 			if (Config_PadOnly)
 			{
-				//TODO - redundant fix
-				LL = new LetterboxingLogic();
+				// TODO - redundant fix
+				LL = new();
 				LL.vx += Padding.Left;
 				LL.vy += Padding.Top;
 				LL.vw = InputSize.Width;
@@ -587,26 +612,28 @@ namespace BizHawk.Client.Common.Filters
 			}
 			else
 			{
-				int ow = OutputSize.Width;
-				int oh = OutputSize.Height;
+				var ow = OutputSize.Width;
+				var oh = OutputSize.Height;
 				ow -= Padding.Left + Padding.Right;
 				oh -= Padding.Top + Padding.Bottom;
-				LL = new LetterboxingLogic(Config_FixAspectRatio, Config_FixScaleInteger, ow, oh, InputSize.Width, InputSize.Height, TextureSize, VirtualTextureSize);
+				LL = new(Config_FixAspectRatio, Config_FixScaleInteger, ow, oh, InputSize.Width, InputSize.Height, TextureSize, VirtualTextureSize);
 				LL.vx += Padding.Left;
 				LL.vy += Padding.Top;
 			}
-			ContentSize = new Size(LL.vw,LL.vh);
 
-			if (InputSize == OutputSize) //any reason we need to check vx and vy?
-				IsNop = true;
+			if (InputSize == OutputSize) // any reason we need to check vx and vy?
+			{
+				Nop = true;
+			}
 		}
 
-		public Size GetContentSize() => ContentSize;
-
 		public override Vector2 UntransformPoint(string channel, Vector2 point)
 		{
-			if (nop)
+			if (Nop)
+			{
 				return point;
+			}
+
 			point.X -= LL.vx;
 			point.Y -= LL.vy;
 			point.X /= LL.WidthScale;
@@ -616,8 +643,11 @@ namespace BizHawk.Client.Common.Filters
 
 		public override Vector2 TransformPoint(string channel, Vector2 point)
 		{
-			if (nop)
+			if (Nop)
+			{
 				return point;
+			}
+
 			point.X *= LL.WidthScale;
 			point.Y *= LL.HeightScale;
 			point.X += LL.vx;
@@ -627,31 +657,37 @@ namespace BizHawk.Client.Common.Filters
 
 		public override void Run()
 		{
-			if (nop)
+			if (Nop)
+			{
 				return;
+			}
 
-			GL.SetClearColor(Color.FromArgb(BackgroundColor));
-			GL.Clear(ClearBufferMask.ColorBufferBit);
+			FilterProgram.GL.SetClearColor(Color.FromArgb(BackgroundColor));
+			FilterProgram.GL.Clear(ClearBufferMask.ColorBufferBit);
 
-			GuiRenderer.Begin(OutputSize.Width, OutputSize.Height);
-			GuiRenderer.SetBlendState(GL.BlendNoneCopy);
+			FilterProgram.GuiRenderer.Begin(OutputSize.Width, OutputSize.Height);
+			FilterProgram.GuiRenderer.SetBlendState(FilterProgram.GL.BlendNoneCopy);
 
-			if(FilterOption != eFilterOption.None)
+			if (FilterOption != eFilterOption.None)
+			{
 				InputTexture.SetFilterLinear();
+			}
 			else
+			{
 				InputTexture.SetFilterNearest();
+			}
 
 			if (FilterOption == eFilterOption.Bicubic)
 			{
-				//this was handled earlier by another filter
+				// this was handled earlier by another filter
 			}
 
-			GuiRenderer.Draw(InputTexture, LL.vx, LL.vy, LL.vw, LL.vh);
-			GuiRenderer.End();
+			FilterProgram.GuiRenderer.Draw(InputTexture, LL.vx, LL.vy, LL.vw, LL.vh);
+			FilterProgram.GuiRenderer.End();
 		}
 	}
 
-	//TODO - turn this into a NOP at 1x, just in case something accidentally activates it with 1x
+	// TODO - turn this into a NOP at 1x, just in case something accidentally activates it with 1x
 	public class PrescaleFilter : BaseFilter
 	{
 		public int Scale;
@@ -666,7 +702,7 @@ namespace BizHawk.Client.Common.Filters
 			var outputSize = state.SurfaceFormat.Size;
 			outputSize.Width *= Scale;
 			outputSize.Height *= Scale;
-			var ss = new SurfaceState(new SurfaceFormat(outputSize), SurfaceDisposition.RenderTarget);
+			var ss = new SurfaceState(new(outputSize), SurfaceDisposition.RenderTarget);
 			DeclareOutput(ss, channel);
 		}
 
@@ -683,7 +719,7 @@ namespace BizHawk.Client.Common.Filters
 
 	public class AutoPrescaleFilter : BaseFilter
 	{
-		private Size OutputSize, InputSize;
+		private Size OutputSize;
 		private int XIS, YIS;
 
 		public override void Initialize()
@@ -693,7 +729,7 @@ namespace BizHawk.Client.Common.Filters
 
 		public override void SetInputFormat(string channel, SurfaceState state)
 		{
-			//calculate integer scaling factors
+			// calculate integer scaling factors
 			XIS = OutputSize.Width / state.SurfaceFormat.Size.Width;
 			YIS = OutputSize.Height / state.SurfaceFormat.Size.Height;
 
@@ -712,11 +748,7 @@ namespace BizHawk.Client.Common.Filters
 				OutputSize.Height *= YIS;
 			}
 
-			DeclareOutput(new SurfaceState
-			{
-				SurfaceFormat = new SurfaceFormat(OutputSize),
-				SurfaceDisposition = SurfaceDisposition.RenderTarget
-			});
+			DeclareOutput(new SurfaceState(new(OutputSize), SurfaceDisposition.RenderTarget));
 		}
 
 		public override Size PresizeOutput(string channel, Size size)
@@ -727,7 +759,6 @@ namespace BizHawk.Client.Common.Filters
 
 		public override Size PresizeInput(string channel, Size inSize)
 		{
-			InputSize = inSize;
 			return inSize;
 		}
 
@@ -748,6 +779,7 @@ namespace BizHawk.Client.Common.Filters
 		{
 			DeclareInput(SurfaceDisposition.RenderTarget);
 		}
+
 		public override void SetInputFormat(string channel, SurfaceState state)
 		{
 			DeclareOutput(state);
@@ -772,19 +804,24 @@ namespace BizHawk.Client.Common.Filters
 
 	public class OSD : BaseFilter
 	{
-		//this class has the ability to disable its operations for higher performance when the callback is removed,
-		//without having to take it out of the chain. although, its presence in the chain may slow down performance due to added resolves/renders
-		//so, we should probably rebuild the chain.
+		// this class has the ability to disable its operations for higher performance when the callback is removed,
+		// without having to take it out of the chain. although, its presence in the chain may slow down performance due to added resolves/renders
+		// so, we should probably rebuild the chain.
 
 		public override void Initialize()
 		{
-			if (RenderCallback == null) return;
-			DeclareInput(SurfaceDisposition.RenderTarget);
+			if (RenderCallback != null)
+			{
+				DeclareInput(SurfaceDisposition.RenderTarget);
+			}
 		}
+
 		public override void SetInputFormat(string channel, SurfaceState state)
 		{
-			if (RenderCallback == null) return;
-			DeclareOutput(state);
+			if (RenderCallback != null)
+			{
+				DeclareOutput(state);
+			}
 		}
 
 		public Action RenderCallback;

src/BizHawk.Client.Common/DisplayManager/Filters/Retro.cs

@@ -4,9 +4,11 @@
 
 using System;
 using System.Collections.Generic;
-using System.IO;
-using System.Text.RegularExpressions;
 using System.Drawing;
+using System.IO;
+using System.Numerics;
+using System.Text.RegularExpressions;
+
 using BizHawk.Client.Common.FilterManager;
 
 using BizHawk.Bizware.BizwareGL;
@@ -17,48 +19,56 @@ namespace BizHawk.Client.Common.Filters
 {
 	public class RetroShaderChain : IDisposable
 	{
-		private static readonly Regex RxInclude = new Regex(@"^(\s)?\#include(\s)+(""|<)(.*)?(""|>)", RegexOptions.Multiline | RegexOptions.IgnoreCase);
+		private static readonly Regex RxInclude = new(@"^(\s)?\#include(\s)+(""|<)(.*)?(""|>)", RegexOptions.Multiline | RegexOptions.IgnoreCase);
 
 		private static string ResolveIncludes(string content, string baseDirectory)
 		{
-			for (; ; )
+			while (true)
 			{
 				var match = RxInclude.Match(content);
-				if(match.Value == "") break;
-				string fname = match.Groups[4].Value;
+				if (match.Value == string.Empty)
+				{
+					return content;
+				}
+
+				var fname = match.Groups[4].Value;
 				fname = Path.Combine(baseDirectory,fname);
-				string includedContent = ResolveIncludes(File.ReadAllText(fname),Path.GetDirectoryName(fname));
+				var includedContent = ResolveIncludes(File.ReadAllText(fname),Path.GetDirectoryName(fname));
 				content = content.Substring(0, match.Index) + includedContent + content.Substring(match.Index + match.Length);
 			}
-			return content;
 		}
 
 		public RetroShaderChain(IGL owner, RetroShaderPreset preset, string baseDirectory, bool debug = false)
 		{
 			Owner = owner;
-			Preset = preset;
 			Passes = preset.Passes.ToArray();
-			Errors = "";
+			Errors = string.Empty;
 
-			//load up the shaders
+			// load up the shaders
 			var shaders = new RetroShader[preset.Passes.Count];
 			for (var i = 0; i < preset.Passes.Count; i++)
 			{
-				//acquire content. we look for it in any reasonable filename so that one preset can bind to multiple shaders
+				// acquire content. we look for it in any reasonable filename so that one preset can bind to multiple shaders
 				string content;
 				var path = Path.Combine(baseDirectory, preset.Passes[i].ShaderPath);
 				if (!File.Exists(path))
 				{
 					if (!Path.HasExtension(path))
+					{
 						path += ".cg";
+					}
+
 					if (!File.Exists(path))
 					{
-						if (owner.API == "OPENGL")
-							path = Path.ChangeExtension(path, ".glsl");
-						else
-							path = Path.ChangeExtension(path, ".hlsl");
+						path = owner.API switch
+						{
+							"OPENGL" => Path.ChangeExtension(path, ".glsl"),
+							"D3D9" => Path.ChangeExtension(path, ".hlsl"),
+							_ => throw new InvalidOperationException(),
+						};
 					}
 				}
+
 				try
 				{
 					content = ResolveIncludes(File.ReadAllText(path), Path.GetDirectoryName(path));
@@ -68,16 +78,17 @@ namespace BizHawk.Client.Common.Filters
 					Errors += $"caught {nameof(DirectoryNotFoundException)}: {e.Message}\n";
 					return;
 				}
+
 				catch (FileNotFoundException e)
 				{
 					Errors += $"could not read file {e.FileName}\n";
 					return;
 				}
 
-				var shader = shaders[i] = new RetroShader(Owner, content, debug);
+				var shader = shaders[i] = new(Owner, content, debug);
 				if (!shader.Available)
 				{
-					Errors += $"-------------------\r\nPass {i}:\r\n{(shader.Errors??"").Replace("\n","\r\n")}\n";
+					Errors += $"-------------------\r\nPass {i}:\r\n{(shader.Errors ?? string.Empty).Replace("\n","\r\n")}\n";
 					return;
 				}
 			}
@@ -105,7 +116,6 @@ namespace BizHawk.Client.Common.Filters
 		public readonly bool Available;
 		public readonly string Errors;
 		public readonly IGL Owner;
-		public readonly RetroShaderPreset Preset;
 		public readonly IReadOnlyList<RetroShader> Shaders = Array.Empty<RetroShader>();
 		public readonly RetroShaderPreset.ShaderPass[] Passes;
 
@@ -122,55 +132,70 @@ namespace BizHawk.Client.Common.Filters
 			var content = new StreamReader(stream).ReadToEnd();
 			var dict = new Dictionary<string, string>();
 
-			//parse the key-value-pair format of the file
+			// parse the key-value-pair format of the file
 			content = content.Replace("\r", "");
 			foreach (var splitLine in content.Split('\n'))
 			{
 				var line = splitLine.Trim();
-				if (line.Length is 0) continue;
-				if (line.StartsWith('#')) continue; // comments
-				int eq = line.IndexOf('=');
+				if (line.Length is 0)
+				{
+					continue;
+				}
+
+				if (line.StartsWith('#'))
+				{
+					continue; // comments
+				}
+
+				var eq = line.IndexOf('=');
 				var key = line.Substring(0, eq).Trim();
 				var value = line.Substring(eq + 1).Trim();
-				int quote = value.IndexOf('\"');
+				var quote = value.IndexOf('\"');
 				if (quote != -1)
+				{
 					value = value.Substring(quote + 1, value.IndexOf('\"', quote + 1) - (quote + 1));
+				}
 				else
 				{
-					//remove comments from end of value. exclusive from above condition, since comments after quoted strings would be snipped by the quoted string extraction
-					int hash = value.IndexOf('#');
+					// remove comments from end of value. exclusive from above condition, since comments after quoted strings would be snipped by the quoted string extraction
+					var hash = value.IndexOf('#');
 					if (hash != -1)
+					{
 						value = value.Substring(0, hash);
+					}
+
 					value = value.Trim();
 				}
+
 				dict[key.ToLower()] = value;
 			}
 
 			// process the keys
-			int nShaders = FetchInt(dict, "shaders", 0);
-			for (int i = 0; i < nShaders; i++)
+			var nShaders = FetchInt(dict, "shaders", 0);
+			for (var i = 0; i < nShaders; i++)
 			{
 				var sp = new ShaderPass { Index = i };
 				Passes.Add(sp);
 
-				sp.InputFilterLinear = FetchBool(dict, $"filter_linear{i}", false); //Should this value not be defined, the filtering option is implementation defined.
+				sp.InputFilterLinear = FetchBool(dict, $"filter_linear{i}", false); // Should this value not be defined, the filtering option is implementation defined.
 				sp.OutputFloat = FetchBool(dict, $"float_framebuffer{i}", false);
 				sp.FrameCountMod = FetchInt(dict, $"frame_count_mod{i}", 1);
-				sp.ShaderPath = FetchString(dict, $"shader{i}", "?"); //todo - change extension to .cg for better compatibility? just change .cg to .glsl transparently at last second?
+				sp.ShaderPath = FetchString(dict, $"shader{i}", "?"); // todo - change extension to .cg for better compatibility? just change .cg to .glsl transparently at last second?
 
 				// If no scale type is assumed, it is assumed that it is set to "source" with scaleN set to 1.0.
 				// It is possible to set scale_type_xN and scale_type_yN to specialize the scaling type in either direction. scale_typeN however overrides both of these.
 				sp.ScaleTypeX = (ScaleType)Enum.Parse(typeof(ScaleType), FetchString(dict, $"scale_type_x{i}", "Source"), true);
 				sp.ScaleTypeY = (ScaleType)Enum.Parse(typeof(ScaleType), FetchString(dict, $"scale_type_y{i}", "Source"), true);
-				ScaleType st = (ScaleType)Enum.Parse(typeof(ScaleType), FetchString(dict, $"scale_type{i}", "NotSet"), true);
+				var st = (ScaleType)Enum.Parse(typeof(ScaleType), FetchString(dict, $"scale_type{i}", "NotSet"), true);
 				if (st != ScaleType.NotSet)
+				{
 					sp.ScaleTypeX = sp.ScaleTypeY = st;
+				}
 
 				// scaleN controls both scaling type in horizontal and vertical directions. If scaleN is defined, scale_xN and scale_yN have no effect.
 				sp.Scale.X = FetchFloat(dict, $"scale_x{i}", 1);
 				sp.Scale.Y = FetchFloat(dict, $"scale_y{i}", 1);
-				float scale = FetchFloat(dict, $"scale{i}", -999);
-				if (scale != -999)
+				if (dict.ContainsValue($"scale{i}"))
 				{
 					sp.Scale.X = sp.Scale.Y = FetchFloat(dict, $"scale{i}", 1);
 				}
@@ -179,8 +204,7 @@ namespace BizHawk.Client.Common.Filters
 			}
 		}
 
-		public List<ShaderPass> Passes { get; set; } = new List<ShaderPass>();
-
+		public List<ShaderPass> Passes { get; set; } = new();
 
 		public enum ScaleType
 		{
@@ -214,19 +238,28 @@ namespace BizHawk.Client.Common.Filters
 			return dict.TryGetValue(key, out var str) ? float.Parse(str) : @default;
 		}
 
-		private bool FetchBool(IDictionary<string, string> dict, string key, bool @default)
+		private static bool FetchBool(IDictionary<string, string> dict, string key, bool @default)
 		{
 			return dict.TryGetValue(key, out var str) ? ParseBool(str) : @default;
 		}
 
-		private bool ParseBool(string value)
+		private static bool ParseBool(string value)
 		{
-			if (value == "1") return true;
-			if (value == "0") return false;
-			value = value.ToLower();
-			if (value == "true") return true;
-			if (value == "false") return false;
-			throw new InvalidOperationException("Unparsable bool in CGP file content");
+			switch (value)
+			{
+				case "1":
+					return true;
+				case "0":
+					return false;
+			}
+
+			value = value.ToLowerInvariant();
+			return value switch
+			{
+				"true" => true,
+				"false" => false,
+				_ => throw new InvalidOperationException("Unparsable bool in CGP file content")
+			};
 		}
 	}
 
@@ -253,17 +286,23 @@ namespace BizHawk.Client.Common.Filters
 
 		public override void SetInputFormat(string channel, SurfaceState state)
 		{
-			Size inSize = state.SurfaceFormat.Size;
-			if (_sp.ScaleTypeX == RetroShaderPreset.ScaleType.Absolute) _outputSize.Width = (int)_sp.Scale.X;
-			if (_sp.ScaleTypeY == RetroShaderPreset.ScaleType.Absolute) _outputSize.Height = (int)_sp.Scale.Y;
-			if (_sp.ScaleTypeX == RetroShaderPreset.ScaleType.Source) _outputSize.Width = (int)(inSize.Width * _sp.Scale.X);
-			if (_sp.ScaleTypeY == RetroShaderPreset.ScaleType.Source) _outputSize.Height = (int)(inSize.Height * _sp.Scale.Y);
+			var inSize = state.SurfaceFormat.Size;
 
-			DeclareOutput(new SurfaceState
+			_outputSize.Width = _sp.ScaleTypeX switch
 			{
-				SurfaceFormat = new SurfaceFormat(_outputSize),
-				SurfaceDisposition = SurfaceDisposition.RenderTarget
-			});
+				RetroShaderPreset.ScaleType.Absolute => (int)_sp.Scale.X,
+				RetroShaderPreset.ScaleType.Source => (int)(inSize.Width * _sp.Scale.X),
+				_ => _outputSize.Width
+			};
+
+			_outputSize.Height = _sp.ScaleTypeY switch
+			{
+				RetroShaderPreset.ScaleType.Absolute => (int)_sp.Scale.Y,
+				RetroShaderPreset.ScaleType.Source => (int)(inSize.Height * _sp.Scale.Y),
+				_ => _outputSize.Height
+			};
+
+			DeclareOutput(new SurfaceState(new(_outputSize), SurfaceDisposition.RenderTarget));
 		}
 
 		public override Size PresizeOutput(string channel, Size size)
@@ -274,11 +313,22 @@ namespace BizHawk.Client.Common.Filters
 
 		public override Size PresizeInput(string channel, Size inSize)
 		{
-			Size outsize = inSize;
-			if (_sp.ScaleTypeX == RetroShaderPreset.ScaleType.Absolute) outsize.Width = (int)_sp.Scale.X;
-			if (_sp.ScaleTypeY == RetroShaderPreset.ScaleType.Absolute) outsize.Height = (int)_sp.Scale.Y;
-			if (_sp.ScaleTypeX == RetroShaderPreset.ScaleType.Source) outsize.Width = (int)(inSize.Width * _sp.Scale.X);
-			if (_sp.ScaleTypeY == RetroShaderPreset.ScaleType.Source) outsize.Height = (int)(inSize.Height * _sp.Scale.Y);
+			var outsize = inSize;
+
+			outsize.Width = _sp.ScaleTypeX switch
+			{
+				RetroShaderPreset.ScaleType.Absolute => (int)_sp.Scale.X,
+				RetroShaderPreset.ScaleType.Source => (int)(inSize.Width * _sp.Scale.X),
+				_ => outsize.Width
+			};
+
+			outsize.Height = _sp.ScaleTypeY switch
+			{
+				RetroShaderPreset.ScaleType.Absolute => (int)_sp.Scale.Y,
+				RetroShaderPreset.ScaleType.Source => (int)(inSize.Height * _sp.Scale.Y),
+				_ => outsize.Height
+			};
+
 			return outsize;
 		}
 
@@ -288,7 +338,7 @@ namespace BizHawk.Client.Common.Filters
 			shader.Bind();
 
 			// apply all parameters to this shader.. even if it was meant for other shaders. kind of lame.
-			if(Parameters != null)
+			if (Parameters != null)
 			{
 				foreach (var (k, v) in Parameters)
 				{

src/BizHawk.Client.Common/DisplayManager/Filters/Utils.cs

@@ -1,7 +1,7 @@
 using System.Drawing;
-using BizHawk.Client.Common.FilterManager;
 
 using BizHawk.Bizware.BizwareGL;
+using BizHawk.Client.Common.FilterManager;
 
 namespace BizHawk.Client.Common.Filters
 {
@@ -23,7 +23,7 @@ namespace BizHawk.Client.Common.Filters
 
 		public override void Initialize()
 		{
-			DeclareOutput(new SurfaceState(new SurfaceFormat(_size), SurfaceDisposition.Texture));
+			DeclareOutput(new SurfaceState(new(_size), SurfaceDisposition.Texture));
 		}
 
 		public override void SetInputFormat(string channel, SurfaceState format)
@@ -71,7 +71,7 @@ namespace BizHawk.Client.Common.Filters
 
 		public override void Run()
 		{
-			YieldOutput(FilterProgram.GetRenderTarget().Texture2d);
+			YieldOutput(FilterProgram.CurrRenderTarget.Texture2d);
 		}
 	}
 }

src/BizHawk.Client.EmuHawk/GraphicsImplementations/GLControlWrapper_GdiPlus.cs

@@ -1,5 +1,6 @@
 using System.Drawing.Drawing2D;
 using System.Windows.Forms;
+
 using BizHawk.Bizware.BizwareGL;
 
 namespace BizHawk.Client.EmuHawk
@@ -17,9 +18,6 @@ namespace BizHawk.Client.EmuHawk
 
 		private readonly IGL_GdiPlus _gdi;
 
-		public Control Control => this;
-
-
 		/// <summary>
 		/// the render target for rendering to this control
 		/// </summary>
@@ -34,24 +32,29 @@ namespace BizHawk.Client.EmuHawk
 		{
 			_gdi.BeginControl(this);
 			RenderTargetWrapper.CreateGraphics();
-			//using (var g = CreateGraphics())
-			//  MyBufferedGraphics = Gdi.MyBufferedGraphicsContext.Allocate(g, ClientRectangle);
-			//MyBufferedGraphics.Graphics.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.HighSpeed;
 
-			////not sure about this stuff...
-			////it will wreck alpha blending, for one thing
-			//MyBufferedGraphics.Graphics.CompositingMode = System.Drawing.Drawing2D.CompositingMode.SourceCopy;
-			//MyBufferedGraphics.Graphics.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighSpeed;
+#if false
+			using (var g = CreateGraphics())
+			{
+				MyBufferedGraphics = _gdi.MyBufferedGraphicsContext.Allocate(g, ClientRectangle);
+			}
+
+			MyBufferedGraphics.Graphics.PixelOffsetMode = PixelOffsetMode.HighSpeed;
+
+			// not sure about this stuff...
+			// it will wreck alpha blending, for one thing
+			MyBufferedGraphics.Graphics.CompositingMode = CompositingMode.SourceCopy;
+			MyBufferedGraphics.Graphics.CompositingQuality = CompositingQuality.HighSpeed;
+#endif
 		}
 
 		public void End()
 		{
-			_gdi.EndControl(this);
+			_gdi.EndControl();
 		}
 
 		public void SwapBuffers()
 		{
-			_gdi.SwapControl(this);
 			if (RenderTargetWrapper.MyBufferedGraphics == null)
 			{
 				return;