diff --git a/BizHawk.Emulation/Consoles/Nintendo/Gameboy/Gambatte.cs b/BizHawk.Emulation/Consoles/Nintendo/Gameboy/Gambatte.cs
index a199bd82c4..41f6bfac7c 100644
--- a/BizHawk.Emulation/Consoles/Nintendo/Gameboy/Gambatte.cs
+++ b/BizHawk.Emulation/Consoles/Nintendo/Gameboy/Gambatte.cs
@@ -145,6 +145,16 @@ namespace BizHawk.Emulation.Consoles.GB
 				tracecb = null;
 			LibGambatte.gambatte_settracecallback(GambatteState, tracecb);
 
+			// todo: have the gambatte core actually call this at an appropriate time
+			if (scanlinecallback != null)
+			{
+				IntPtr vram = IntPtr.Zero;
+				int vramlength = 0;
+				if (!LibGambatte.gambatte_getmemoryarea(GambatteState, LibGambatte.MemoryAreas.vram, ref vram, ref vramlength))
+					throw new Exception();
+				scanlinecallback(vram, vramlength, LibGambatte.gambatte_cpuread(GambatteState, 0xff40));
+			}
+
 			LibGambatte.gambatte_runfor(GambatteState, VideoBuffer, 160, soundbuff, ref nsamp);
 
 			// upload any modified data to the memory domains
@@ -575,6 +585,34 @@ namespace BizHawk.Emulation.Consoles.GB
 
 		#endregion
 
+		#region ppudebug
+		/// <summary>
+		/// a callback to be registered at a particular scanline
+		/// </summary>
+		/// <param name="vram"></param>
+		/// <param name="vramlength">length of vram in bytes</param>
+		/// <param name="lcdc">current LCDC status</param>
+		public delegate void ScanlineCallback(IntPtr vram, int vramlength, int lcdc);
+
+		ScanlineCallback scanlinecallback;
+
+		/// <summary>
+		/// set up callback
+		/// </summary>
+		/// <param name="callback"></param>
+		/// <param name="line">scanline</param>
+		public void SetScanlineCallback(ScanlineCallback callback, int line)
+		{
+			if (callback == null)
+				this.scanlinecallback = null;
+			else if (line < 0 || line > 153)
+				throw new ArgumentOutOfRangeException("line must be in [0, 153]");
+			else
+				this.scanlinecallback = callback;
+		}
+
+		#endregion
+
 		public void Dispose()
 		{
 			LibGambatte.gambatte_destroy(GambatteState);
diff --git a/BizHawk.MultiClient/BizHawk.MultiClient.csproj b/BizHawk.MultiClient/BizHawk.MultiClient.csproj
index 99e23705de..2e46e42621 100644
--- a/BizHawk.MultiClient/BizHawk.MultiClient.csproj
+++ b/BizHawk.MultiClient/BizHawk.MultiClient.csproj
@@ -217,12 +217,21 @@
     </Compile>
     <Compile Include="DisplayManager\DisplayManager.cs" />
     <Compile Include="DisplayManager\Filters\Hq2x.cs" />
+    <Compile Include="GBtools\BmpView.cs">
+      <SubType>Component</SubType>
+    </Compile>
     <Compile Include="GBtools\ColorChooserForm.cs">
       <SubType>Form</SubType>
     </Compile>
     <Compile Include="GBtools\ColorChooserForm.designer.cs">
       <DependentUpon>ColorChooserForm.cs</DependentUpon>
     </Compile>
+    <Compile Include="GBtools\GBGPUView.cs">
+      <SubType>Form</SubType>
+    </Compile>
+    <Compile Include="GBtools\GBGPUView.Designer.cs">
+      <DependentUpon>GBGPUView.cs</DependentUpon>
+    </Compile>
     <Compile Include="Global.cs" />
     <Compile Include="HawkFile.cs" />
     <Compile Include="Input\ControllerBinding.cs" />
@@ -457,6 +466,9 @@
     <EmbeddedResource Include="GBtools\ColorChooserForm.resx">
       <DependentUpon>ColorChooserForm.cs</DependentUpon>
     </EmbeddedResource>
+    <EmbeddedResource Include="GBtools\GBGPUView.resx">
+      <DependentUpon>GBGPUView.cs</DependentUpon>
+    </EmbeddedResource>
     <EmbeddedResource Include="MainForm.resx">
       <DependentUpon>MainForm.cs</DependentUpon>
       <SubType>Designer</SubType>
diff --git a/BizHawk.MultiClient/GBtools/BmpView.cs b/BizHawk.MultiClient/GBtools/BmpView.cs
new file mode 100644
index 0000000000..5390ff5aba
--- /dev/null
+++ b/BizHawk.MultiClient/GBtools/BmpView.cs
@@ -0,0 +1,51 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Diagnostics;
+using System.Linq;
+using System.Text;
+using System.Drawing;
+using System.Windows.Forms;
+
+namespace BizHawk.MultiClient.GBtools
+{
+	public partial class BmpView : Control
+	{
+		public Bitmap bmp;
+
+		public BmpView()
+		{
+			SetStyle(ControlStyles.AllPaintingInWmPaint, true);
+			SetStyle(ControlStyles.UserPaint, true);
+			SetStyle(ControlStyles.DoubleBuffer, true);
+			SetStyle(ControlStyles.SupportsTransparentBackColor, true);
+			SetStyle(ControlStyles.Opaque, true);
+			this.BackColor = Color.Transparent;
+			this.Paint += new PaintEventHandler(BmpView_Paint);
+			this.SizeChanged += new EventHandler(BmpView_SizeChanged);
+		}
+
+		void BmpView_Paint(object sender, PaintEventArgs e)
+		{
+			if (bmp != null)
+			{
+				e.Graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor;
+				e.Graphics.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.Half;
+				e.Graphics.DrawImageUnscaled(bmp, 0, 0);
+			}
+		}
+
+		void BmpView_SizeChanged(object sender, EventArgs e)
+		{
+			if (bmp != null)
+			{
+				bmp.Dispose();
+				bmp = null;
+			}
+			if (Width == 0 || Height == 0)
+				return;
+			bmp = new Bitmap(Width, Height, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
+		}
+		
+	}
+}
diff --git a/BizHawk.MultiClient/GBtools/GBGPUView.Designer.cs b/BizHawk.MultiClient/GBtools/GBGPUView.Designer.cs
new file mode 100644
index 0000000000..2f4c4c4a2f
--- /dev/null
+++ b/BizHawk.MultiClient/GBtools/GBGPUView.Designer.cs
@@ -0,0 +1,98 @@
+namespace BizHawk.MultiClient.GBtools
+{
+	partial class GBGPUView
+	{
+		/// <summary>
+		/// Required designer variable.
+		/// </summary>
+		private System.ComponentModel.IContainer components = null;
+
+		/// <summary>
+		/// Clean up any resources being used.
+		/// </summary>
+		/// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
+		protected override void Dispose(bool disposing)
+		{
+			if (disposing && (components != null))
+			{
+				components.Dispose();
+			}
+			base.Dispose(disposing);
+		}
+
+		#region Windows Form Designer generated code
+
+		/// <summary>
+		/// Required method for Designer support - do not modify
+		/// the contents of this method with the code editor.
+		/// </summary>
+		private void InitializeComponent()
+		{
+			this.label1 = new System.Windows.Forms.Label();
+			this.label2 = new System.Windows.Forms.Label();
+			this.bmpViewWin = new BizHawk.MultiClient.GBtools.BmpView();
+			this.bmpViewBG = new BizHawk.MultiClient.GBtools.BmpView();
+			this.SuspendLayout();
+			// 
+			// label1
+			// 
+			this.label1.AutoSize = true;
+			this.label1.Location = new System.Drawing.Point(17, 21);
+			this.label1.Name = "label1";
+			this.label1.Size = new System.Drawing.Size(22, 13);
+			this.label1.TabIndex = 2;
+			this.label1.Text = "BG";
+			// 
+			// label2
+			// 
+			this.label2.AutoSize = true;
+			this.label2.Location = new System.Drawing.Point(275, 24);
+			this.label2.Name = "label2";
+			this.label2.Size = new System.Drawing.Size(26, 13);
+			this.label2.TabIndex = 3;
+			this.label2.Text = "Win";
+			// 
+			// bmpViewWin
+			// 
+			this.bmpViewWin.BackColor = System.Drawing.Color.Transparent;
+			this.bmpViewWin.Location = new System.Drawing.Point(278, 37);
+			this.bmpViewWin.Name = "bmpViewWin";
+			this.bmpViewWin.Size = new System.Drawing.Size(256, 256);
+			this.bmpViewWin.TabIndex = 5;
+			this.bmpViewWin.Text = "bmpView2";
+			// 
+			// bmpViewBG
+			// 
+			this.bmpViewBG.BackColor = System.Drawing.Color.Transparent;
+			this.bmpViewBG.Location = new System.Drawing.Point(12, 37);
+			this.bmpViewBG.Name = "bmpViewBG";
+			this.bmpViewBG.Size = new System.Drawing.Size(256, 256);
+			this.bmpViewBG.TabIndex = 4;
+			this.bmpViewBG.Text = "bmpView1";
+			// 
+			// GBGPUView
+			// 
+			this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
+			this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
+			this.ClientSize = new System.Drawing.Size(564, 404);
+			this.Controls.Add(this.bmpViewWin);
+			this.Controls.Add(this.bmpViewBG);
+			this.Controls.Add(this.label2);
+			this.Controls.Add(this.label1);
+			this.Name = "GBGPUView";
+			this.Text = "GB GPU Viewer";
+			this.FormClosed += new System.Windows.Forms.FormClosedEventHandler(this.GBGPUView_FormClosed);
+			this.Load += new System.EventHandler(this.GBGPUView_Load);
+			this.ResumeLayout(false);
+			this.PerformLayout();
+
+		}
+
+		#endregion
+
+		private System.Windows.Forms.Label label1;
+		private System.Windows.Forms.Label label2;
+		private BmpView bmpViewBG;
+		private BmpView bmpViewWin;
+	}
+}
\ No newline at end of file
diff --git a/BizHawk.MultiClient/GBtools/GBGPUView.cs b/BizHawk.MultiClient/GBtools/GBGPUView.cs
new file mode 100644
index 0000000000..9d72d3e6f2
--- /dev/null
+++ b/BizHawk.MultiClient/GBtools/GBGPUView.cs
@@ -0,0 +1,140 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Data;
+using System.Drawing;
+using System.Linq;
+using System.Text;
+using System.Windows.Forms;
+
+namespace BizHawk.MultiClient.GBtools
+{
+	public partial class GBGPUView : Form
+	{
+		Emulation.Consoles.GB.Gameboy gb;
+
+		public GBGPUView()
+		{
+			InitializeComponent();
+
+		}
+
+		public void Restart()
+		{
+			if (Global.Emulator is Emulation.Consoles.GB.Gameboy)
+			{
+				gb = Global.Emulator as Emulation.Consoles.GB.Gameboy;
+			}
+			else
+			{
+				this.Close();
+			}
+		}
+
+		/// <summary>
+		/// put me in ToolsBefore
+		/// </summary>
+		public void UpdateValues()
+		{
+			if (!this.IsHandleCreated || this.IsDisposed)
+				return;
+			if (gb != null)
+				if (this.Visible)
+					gb.SetScanlineCallback(ScanlineCallback, 0);
+				else
+					gb.SetScanlineCallback(null, 0);
+		}
+
+		static unsafe void DrawTile(byte* tile, int* dest, int pitch)
+		{
+			for (int y = 0; y < 8; y++)
+			{
+				int loplane = *tile++;
+				int hiplane = *tile++;
+				hiplane <<= 1; // msb
+				dest += 7;
+				for (int x = 0; x < 8; x++) // right to left
+				{
+					int palcolor = loplane & 1 | hiplane & 2;
+					// todo: palette transformation
+					int color = palcolor * 0x555555 | unchecked((int)0xff000000);
+					*dest-- = color;
+					loplane >>= 1;
+					hiplane >>= 1;
+				}
+				dest++;
+				dest += pitch;
+			}
+		}
+
+		static unsafe void DrawBG(Bitmap b, IntPtr _map, IntPtr _tiles, bool wrap)
+		{
+			if (b.Width != 256 || b.Height != 256)
+				throw new Exception("GPUView screwed up.");
+
+			var lockdata = b.LockBits(new Rectangle(0, 0, 256, 256), System.Drawing.Imaging.ImageLockMode.WriteOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
+
+			byte* map = (byte*)_map;
+
+			int* dest = (int*)lockdata.Scan0;
+
+			int pitch = lockdata.Stride / sizeof(int); // in int*s, not bytes
+			
+			for (int ty = 0; ty < 32; ty++)
+			{			
+				for (int tx = 0; tx < 32; tx++)
+				{
+					int tileindex = map[0];
+					if (wrap && tileindex >= 128)
+						tileindex -= 256;
+					byte* tile = (byte*)(_tiles + tileindex * 16);
+					DrawTile(tile, dest, pitch);
+					map++;
+					dest += 8;
+				}
+				dest -= 256;
+				dest += pitch * 8;
+			}
+			b.UnlockBits(lockdata);
+		}
+
+		/// <summary>
+		/// core calls this on scanlines
+		/// </summary>
+		/// <param name="vram"></param>
+		/// <param name="vramlength"></param>
+		/// <param name="lcdc"></param>
+		void ScanlineCallback(IntPtr vram, int vramlength, int lcdc)
+		{
+
+			DrawBG(
+				bmpViewBG.bmp,
+				vram + (lcdc.Bit(3) ? 0x1c00 : 0x1800),
+				vram + (lcdc.Bit(4) ? 0x0000 : 0x1000),
+				!lcdc.Bit(4));
+			bmpViewBG.Refresh();
+
+			DrawBG(
+				bmpViewWin.bmp,
+				vram + (lcdc.Bit(6) ? 0x1c00 : 0x1800),
+				vram + 0x1000, // force win to second tile bank???
+				true);
+			bmpViewWin.Refresh();
+
+		}
+
+		private void GBGPUView_FormClosed(object sender, FormClosedEventArgs e)
+		{
+			if (gb != null)
+			{
+				gb.SetScanlineCallback(null, 0);
+				gb = null;
+			}
+		}
+
+		private void GBGPUView_Load(object sender, EventArgs e)
+		{
+			gb = Global.Emulator as Emulation.Consoles.GB.Gameboy;
+		}
+	}
+}
diff --git a/BizHawk.MultiClient/GBtools/GBGPUView.resx b/BizHawk.MultiClient/GBtools/GBGPUView.resx
new file mode 100644
index 0000000000..29dcb1b3a3
--- /dev/null
+++ b/BizHawk.MultiClient/GBtools/GBGPUView.resx
@@ -0,0 +1,120 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+    
+    Version 2.0
+    
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+    
+    Example:
+    
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+                
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+    
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+    
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+    
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+    
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+    
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+</root>
\ No newline at end of file
diff --git a/BizHawk.MultiClient/MainForm.Designer.cs b/BizHawk.MultiClient/MainForm.Designer.cs
index d7afa15fe1..e0fa15094b 100644
--- a/BizHawk.MultiClient/MainForm.Designer.cs
+++ b/BizHawk.MultiClient/MainForm.Designer.cs
@@ -306,6 +306,7 @@
 			this.cmiScreenshotClipboard = new System.Windows.Forms.ToolStripMenuItem();
 			this.cmiCloseRom = new System.Windows.Forms.ToolStripMenuItem();
 			this.cmiShowMenu = new System.Windows.Forms.ToolStripMenuItem();
+			this.gPUViewerToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
 			this.menuStrip1.SuspendLayout();
 			this.StatusSlot0.SuspendLayout();
 			this.contextMenuStrip1.SuspendLayout();
@@ -2118,7 +2119,8 @@
             this.multicartCompatibilityToolStripMenuItem,
             this.toolStripSeparator8,
             this.changeDMGPalettesToolStripMenuItem,
-            this.loadGBInSGBToolStripMenuItem1});
+            this.loadGBInSGBToolStripMenuItem1,
+            this.gPUViewerToolStripMenuItem});
 			this.gBToolStripMenuItem.Name = "gBToolStripMenuItem";
 			this.gBToolStripMenuItem.Size = new System.Drawing.Size(32, 17);
 			this.gBToolStripMenuItem.Text = "&GB";
@@ -2645,6 +2647,13 @@
 			this.cmiShowMenu.Text = "Show Menu";
 			this.cmiShowMenu.Click += new System.EventHandler(this.showMenuToolStripMenuItem_Click);
 			// 
+			// gPUViewerToolStripMenuItem
+			// 
+			this.gPUViewerToolStripMenuItem.Name = "gPUViewerToolStripMenuItem";
+			this.gPUViewerToolStripMenuItem.Size = new System.Drawing.Size(190, 22);
+			this.gPUViewerToolStripMenuItem.Text = "GPU Viewer";
+			this.gPUViewerToolStripMenuItem.Click += new System.EventHandler(this.gPUViewerToolStripMenuItem_Click);
+			// 
 			// MainForm
 			// 
 			this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 14F);
@@ -2962,6 +2971,7 @@
 		private System.Windows.Forms.ToolStripMenuItem showMissle2ToolStripMenuItem;
 		private System.Windows.Forms.ToolStripMenuItem showBallToolStripMenuItem;
 		private System.Windows.Forms.ToolStripMenuItem showPlayfieldToolStripMenuItem;
+		private System.Windows.Forms.ToolStripMenuItem gPUViewerToolStripMenuItem;
     }
 }
 
diff --git a/BizHawk.MultiClient/MainForm.cs b/BizHawk.MultiClient/MainForm.cs
index 716bdcd905..8c9bb06b91 100644
--- a/BizHawk.MultiClient/MainForm.cs
+++ b/BizHawk.MultiClient/MainForm.cs
@@ -77,6 +77,7 @@ namespace BizHawk.MultiClient
 		public NESNameTableViewer NESNameTableViewer1 = new NESNameTableViewer();
 		public NESPPU NESPPU1 = new NESPPU();
 		public NESDebugger NESDebug1 = new NESDebugger();
+		public GBtools.GBGPUView GBGPUView1 = new GBtools.GBGPUView();
 		public PCEBGViewer PCEBGViewer1 = new PCEBGViewer();
 		public Cheats Cheats1 = new Cheats();
 		public ToolBox ToolBox1 = new ToolBox();
@@ -2497,6 +2498,7 @@ namespace BizHawk.MultiClient
 			NESNameTableViewer1.UpdateValues();
 			NESPPU1.UpdateValues();
 			PCEBGViewer1.UpdateValues();
+			GBGPUView1.UpdateValues();
 		}
 
 		public void UpdateToolsLoadstate()
@@ -2866,6 +2868,17 @@ namespace BizHawk.MultiClient
 				PCEBGViewer1.Focus();
 		}
 
+		public void LoadGBGPUView()
+		{
+			if (!GBGPUView1.IsHandleCreated || GBGPUView1.IsDisposed)
+			{
+				GBGPUView1 = new GBtools.GBGPUView();
+				GBGPUView1.Show();
+			}
+			else
+				GBGPUView1.Focus();
+		}
+
 		public void LoadTI83KeyPad()
 		{
 			if (!TI83KeyPad1.IsHandleCreated || TI83KeyPad1.IsDisposed)
@@ -3099,6 +3112,7 @@ namespace BizHawk.MultiClient
 			NESPPU1.Restart();
 			NESNameTableViewer1.Restart();
 			NESDebug1.Restart();
+			GBGPUView1.Restart();
 			PCEBGViewer1.Restart();
 			TI83KeyPad1.Restart();
 			Cheats1.Restart();
@@ -3137,6 +3151,7 @@ namespace BizHawk.MultiClient
 			CloseForm(NESNameTableViewer1);
 			CloseForm(NESPPU1);
 			CloseForm(NESDebug1);
+			CloseForm(GBGPUView1);
 			CloseForm(PCEBGViewer1);
 			CloseForm(Cheats1);
 			CloseForm(TI83KeyPad1);
@@ -4249,5 +4264,10 @@ namespace BizHawk.MultiClient
 			Global.Config.Atari2600_ShowPlayfield ^= true;
 			SyncCoreInputComm();
 		}
+
+		private void gPUViewerToolStripMenuItem_Click(object sender, EventArgs e)
+		{
+			LoadGBGPUView();
+		}
 	}
 }