Better index buffer management

src/Ryujinx.Graphics.Metal/BufferManager.cs

@@ -135,6 +135,18 @@ namespace Ryujinx.Graphics.Metal
             return null;
         }
 
+        public Auto<DisposableBuffer> GetBuffer(BufferHandle handle, bool isWrite, out int size)
+        {
+            if (TryGetBuffer(handle, out var holder))
+            {
+                size = holder.Size;
+                return holder.GetBuffer(isWrite);
+            }
+
+            size = 0;
+            return null;
+        }
+
         public Auto<DisposableBuffer> GetBuffer(BufferHandle handle, int offset, int size, bool isWrite)
         {
             if (TryGetBuffer(handle, out var holder))

src/Ryujinx.Graphics.Metal/EncoderState.cs

@@ -93,9 +93,7 @@ namespace Ryujinx.Graphics.Metal
         public readonly BufferRef[] StorageBufferRefs = new BufferRef[Constants.MaxStorageBufferBindings];
         public readonly TextureRef[] TextureRefs = new TextureRef[Constants.MaxTextureBindings];
 
-        public Auto<DisposableBuffer> IndexBuffer = default;
-        public MTLIndexType IndexType = MTLIndexType.UInt16;
-        public ulong IndexBufferOffset = 0;
+        public IndexBufferState IndexBuffer = default;
 
         public MTLDepthClipMode DepthClipMode = MTLDepthClipMode.Clip;
 
@@ -115,7 +113,7 @@ namespace Ryujinx.Graphics.Metal
         public MTLScissorRect[] Scissors = new MTLScissorRect[Constants.MaxViewports];
 
         // Changes to attachments take recreation!
-        public Texture DepthStencil = default;
+        public Texture DepthStencil;
         public Texture[] RenderTargets = new Texture[Constants.MaxColorAttachments];
         public ITexture PreMaskDepthStencil = default;
         public ITexture[] PreMaskRenderTargets;

src/Ryujinx.Graphics.Metal/EncoderStateManager.cs

@@ -23,9 +23,7 @@ namespace Ryujinx.Graphics.Metal
         private readonly EncoderState _mainState = new();
         private EncoderState _currentState;
 
-        public readonly Auto<DisposableBuffer> IndexBuffer => _currentState.IndexBuffer;
-        public readonly MTLIndexType IndexType => _currentState.IndexType;
-        public readonly ulong IndexBufferOffset => _currentState.IndexBufferOffset;
+        public readonly IndexBufferState IndexBuffer => _currentState.IndexBuffer;
         public readonly PrimitiveTopology Topology => _currentState.Topology;
         public readonly Texture[] RenderTargets => _currentState.RenderTargets;
         public readonly Texture DepthStencil => _currentState.DepthStencil;
@@ -305,18 +303,11 @@ namespace Ryujinx.Graphics.Metal
         {
             if (buffer.Handle != BufferHandle.Null)
             {
-                if (type == GAL.IndexType.UByte)
-                {
-                    _currentState.IndexType = MTLIndexType.UInt16;
-                    _currentState.IndexBufferOffset = 0;
-                    _currentState.IndexBuffer = _bufferManager.GetBufferI8ToI16(_pipeline.Cbs, buffer.Handle, buffer.Offset, buffer.Size);
-                }
-                else
-                {
-                    _currentState.IndexType = type.Convert();
-                    _currentState.IndexBufferOffset = (ulong)buffer.Offset;
-                    _currentState.IndexBuffer = _bufferManager.GetBuffer(buffer.Handle, false);
-                }
+                _currentState.IndexBuffer = new IndexBufferState(buffer.Handle, buffer.Offset, buffer.Size, type);
+            }
+            else
+            {
+                _currentState.IndexBuffer = IndexBufferState.Null;
             }
         }
 

src/Ryujinx.Graphics.Metal/IndexBufferState.cs

@@ -0,0 +1,74 @@
+using Ryujinx.Graphics.GAL;
+using SharpMetal.Metal;
+using System;
+using System.Runtime.Versioning;
+
+namespace Ryujinx.Graphics.Metal
+{
+    [SupportedOSPlatform("macos")]
+    internal struct IndexBufferState
+    {
+        public static IndexBufferState Null => new(BufferHandle.Null, 0, 0);
+
+        private readonly int _offset;
+        private readonly int _size;
+        private readonly IndexType _type;
+
+        private readonly BufferHandle _handle;
+
+        public IndexBufferState(BufferHandle handle, int offset, int size, IndexType type)
+        {
+            _handle = handle;
+            _offset = offset;
+            _size = size;
+            _type = type;
+        }
+
+        public IndexBufferState(BufferHandle handle, int offset, int size)
+        {
+            _handle = handle;
+            _offset = offset;
+            _size = size;
+            _type = IndexType.UInt;
+        }
+
+        public (MTLBuffer, int, MTLIndexType) GetIndexBuffer(MetalRenderer renderer, CommandBufferScoped cbs)
+        {
+            Auto<DisposableBuffer> autoBuffer;
+            int offset, size;
+            MTLIndexType type;
+
+            if (_type == IndexType.UByte)
+            {
+                // Index type is not supported. Convert to I16.
+                autoBuffer = renderer.BufferManager.GetBufferI8ToI16(cbs, _handle, _offset, _size);
+
+                type = MTLIndexType.UInt16;
+                offset = 0;
+                size = _size * 2;
+            }
+            else
+            {
+                autoBuffer = renderer.BufferManager.GetBuffer(_handle, false, out int bufferSize);
+
+                if (_offset >= bufferSize)
+                {
+                    autoBuffer = null;
+                }
+
+                type = _type.Convert();
+                offset = _offset;
+                size = _size;
+            }
+
+            if (autoBuffer != null)
+            {
+                DisposableBuffer buffer = autoBuffer.Get(cbs, offset, size);
+
+                return (buffer.Value, offset, type);
+            }
+
+            return (new MTLBuffer(IntPtr.Zero), 0, MTLIndexType.UInt16);
+        }
+    }
+}

src/Ryujinx.Graphics.Metal/Pipeline.cs

@@ -377,8 +377,6 @@ namespace Ryujinx.Graphics.Metal
                 return;
             }
 
-            var renderCommandEncoder = GetOrCreateRenderEncoder(true);
-
             // TODO: Reindex unsupported topologies
             if (TopologyUnsupported(_encoderStateManager.Topology))
             {
@@ -387,21 +385,22 @@ namespace Ryujinx.Graphics.Metal
 
             var primitiveType = TopologyRemap(_encoderStateManager.Topology).Convert();
 
-            var indexBuffer = _encoderStateManager.IndexBuffer;
+            (MTLBuffer mtlBuffer, int offset, MTLIndexType type) = _encoderStateManager.IndexBuffer.GetIndexBuffer(_renderer, Cbs);
 
-            ulong offset = _encoderStateManager.IndexBufferOffset;
-            MTLIndexType type = _encoderStateManager.IndexType;
-            int indexSize = type == MTLIndexType.UInt32 ? sizeof(int) : sizeof(short);
+            if (mtlBuffer.NativePtr != IntPtr.Zero)
+            {
+                var renderCommandEncoder = GetOrCreateRenderEncoder(true);
 
-            renderCommandEncoder.DrawIndexedPrimitives(
-                primitiveType,
-                (ulong)indexCount,
-                type,
-                indexBuffer.Get(Cbs, (int)offset, indexCount * indexSize).Value,
-                offset,
-                (ulong)instanceCount,
-                firstVertex,
-                (ulong)firstInstance);
+                renderCommandEncoder.DrawIndexedPrimitives(
+                    primitiveType,
+                    (ulong)indexCount,
+                    type,
+                    mtlBuffer,
+                    (ulong)offset,
+                    (ulong)instanceCount,
+                    firstVertex,
+                    (ulong)firstInstance);
+            }
         }
 
         public void DrawIndexedIndirect(BufferRange indirectBuffer)