1 files changed, 280 insertions, 0 deletions
diff --git a/src/Ryujinx.Graphics.OpenGL/VertexArray.cs b/src/Ryujinx.Graphics.OpenGL/VertexArray.cs
new file mode 100644
index 00000000..7d22033e
--- /dev/null
+++ b/src/Ryujinx.Graphics.OpenGL/VertexArray.cs
@@ -0,0 +1,280 @@
+using OpenTK.Graphics.OpenGL;
+using Ryujinx.Graphics.GAL;
+using System;
+using System.Numerics;
+using System.Runtime.CompilerServices;
+
+namespace Ryujinx.Graphics.OpenGL
+{
+    class VertexArray : IDisposable
+    {
+        public int Handle { get; private set; }
+
+        private readonly VertexAttribDescriptor[] _vertexAttribs;
+        private readonly VertexBufferDescriptor[] _vertexBuffers;
+
+        private int _minVertexCount;
+
+        private uint _vertexAttribsInUse;
+        private uint _vertexBuffersInUse;
+        private uint _vertexBuffersLimited;
+
+        private BufferRange _indexBuffer;
+        private BufferHandle _tempIndexBuffer;
+        private BufferHandle _tempVertexBuffer;
+        private int _tempVertexBufferSize;
+
+        public VertexArray()
+        {
+            Handle = GL.GenVertexArray();
+
+            _vertexAttribs = new VertexAttribDescriptor[Constants.MaxVertexAttribs];
+            _vertexBuffers = new VertexBufferDescriptor[Constants.MaxVertexBuffers];
+
+            _tempIndexBuffer = Buffer.Create();
+        }
+
+        public void Bind()
+        {
+            GL.BindVertexArray(Handle);
+        }
+
+        public void SetVertexBuffers(ReadOnlySpan<VertexBufferDescriptor> vertexBuffers)
+        {
+            int minVertexCount = int.MaxValue;
+
+            int bindingIndex;
+            for (bindingIndex = 0; bindingIndex < vertexBuffers.Length; bindingIndex++)
+            {
+                VertexBufferDescriptor vb = vertexBuffers[bindingIndex];
+
+                if (vb.Buffer.Handle != BufferHandle.Null)
+                {
+                    int vertexCount = vb.Stride <= 0 ? 0 : vb.Buffer.Size / vb.Stride;
+                    if (minVertexCount > vertexCount)
+                    {
+                        minVertexCount = vertexCount;
+                    }
+
+                    GL.BindVertexBuffer(bindingIndex, vb.Buffer.Handle.ToInt32(), (IntPtr)vb.Buffer.Offset, vb.Stride);
+                    GL.VertexBindingDivisor(bindingIndex, vb.Divisor);
+                    _vertexBuffersInUse |= 1u << bindingIndex;
+                }
+                else
+                {
+                    if ((_vertexBuffersInUse & (1u << bindingIndex)) != 0)
+                    {
+                        GL.BindVertexBuffer(bindingIndex, 0, IntPtr.Zero, 0);
+                        _vertexBuffersInUse &= ~(1u << bindingIndex);
+                    }
+                }
+
+                _vertexBuffers[bindingIndex] = vb;
+            }
+
+            _minVertexCount = minVertexCount;
+        }
+
+        public void SetVertexAttributes(ReadOnlySpan<VertexAttribDescriptor> vertexAttribs)
+        {
+            int index = 0;
+
+            for (; index < vertexAttribs.Length; index++)
+            {
+                VertexAttribDescriptor attrib = vertexAttribs[index];
+
+                if (attrib.Equals(_vertexAttribs[index]))
+                {
+                    continue;
+                }
+
+                FormatInfo fmtInfo = FormatTable.GetFormatInfo(attrib.Format);
+
+                if (attrib.IsZero)
+                {
+                    // Disabling the attribute causes the shader to read a constant value.
+                    // We currently set the constant to (0, 0, 0, 0).
+                    DisableVertexAttrib(index);
+                }
+                else
+                {
+                    EnableVertexAttrib(index);
+                }
+
+                int offset = attrib.Offset;
+                int size   = fmtInfo.Components;
+
+                bool isFloat = fmtInfo.PixelType == PixelType.Float ||
+                               fmtInfo.PixelType == PixelType.HalfFloat;
+
+                if (isFloat || fmtInfo.Normalized || fmtInfo.Scaled)
+                {
+                    VertexAttribType type = (VertexAttribType)fmtInfo.PixelType;
+
+                    GL.VertexAttribFormat(index, size, type, fmtInfo.Normalized, offset);
+                }
+                else
+                {
+                    VertexAttribIntegerType type = (VertexAttribIntegerType)fmtInfo.PixelType;
+
+                    GL.VertexAttribIFormat(index, size, type, offset);
+                }
+
+                GL.VertexAttribBinding(index, attrib.BufferIndex);
+
+                _vertexAttribs[index] = attrib;
+            }
+
+            for (; index < Constants.MaxVertexAttribs; index++)
+            {
+                DisableVertexAttrib(index);
+            }
+        }
+
+        public void SetIndexBuffer(BufferRange range)
+        {
+            _indexBuffer = range;
+            GL.BindBuffer(BufferTarget.ElementArrayBuffer, range.Handle.ToInt32());
+        }
+
+        public void SetRangeOfIndexBuffer()
+        {
+            Buffer.Resize(_tempIndexBuffer, _indexBuffer.Size);
+            Buffer.Copy(_indexBuffer.Handle, _tempIndexBuffer, _indexBuffer.Offset, 0, _indexBuffer.Size);
+            GL.BindBuffer(BufferTarget.ElementArrayBuffer, _tempIndexBuffer.ToInt32());
+        }
+
+        public void RestoreIndexBuffer()
+        {
+            GL.BindBuffer(BufferTarget.ElementArrayBuffer, _indexBuffer.Handle.ToInt32());
+        }
+
+        public void PreDraw(int vertexCount)
+        {
+            LimitVertexBuffers(vertexCount);
+        }
+
+        public void PreDrawVbUnbounded()
+        {
+            UnlimitVertexBuffers();
+        }
+
+        public void LimitVertexBuffers(int vertexCount)
+        {
+            // Is it possible for the draw to fetch outside the bounds of any vertex buffer currently bound?
+
+            if (vertexCount <= _minVertexCount)
+            {
+                return;
+            }
+
+            // If the draw can fetch out of bounds, let's ensure that it will only fetch zeros rather than memory garbage.
+
+            int currentTempVbOffset = 0;
+            uint buffersInUse = _vertexBuffersInUse;
+
+            while (buffersInUse != 0)
+            {
+                int vbIndex = BitOperations.TrailingZeroCount(buffersInUse);
+
+                ref var vb = ref _vertexBuffers[vbIndex];
+
+                int requiredSize = vertexCount * vb.Stride;
+
+                if (vb.Buffer.Size < requiredSize)
+                {
+                    BufferHandle tempVertexBuffer = EnsureTempVertexBufferSize(currentTempVbOffset + requiredSize);
+
+                    Buffer.Copy(vb.Buffer.Handle, tempVertexBuffer, vb.Buffer.Offset, currentTempVbOffset, vb.Buffer.Size);
+                    Buffer.Clear(tempVertexBuffer, currentTempVbOffset + vb.Buffer.Size, requiredSize - vb.Buffer.Size, 0);
+
+                    GL.BindVertexBuffer(vbIndex, tempVertexBuffer.ToInt32(), (IntPtr)currentTempVbOffset, vb.Stride);
+
+                    currentTempVbOffset += requiredSize;
+                    _vertexBuffersLimited |= 1u << vbIndex;
+                }
+
+                buffersInUse &= ~(1u << vbIndex);
+            }
+        }
+
+        private BufferHandle EnsureTempVertexBufferSize(int size)
+        {
+            BufferHandle tempVertexBuffer = _tempVertexBuffer;
+
+            if (_tempVertexBufferSize < size)
+            {
+                _tempVertexBufferSize = size;
+
+                if (tempVertexBuffer == BufferHandle.Null)
+                {
+                    tempVertexBuffer = Buffer.Create(size);
+                    _tempVertexBuffer = tempVertexBuffer;
+                    return tempVertexBuffer;
+                }
+
+                Buffer.Resize(_tempVertexBuffer, size);
+            }
+
+            return tempVertexBuffer;
+        }
+
+        public void UnlimitVertexBuffers()
+        {
+            uint buffersLimited = _vertexBuffersLimited;
+
+            if (buffersLimited == 0)
+            {
+                return;
+            }
+
+            while (buffersLimited != 0)
+            {
+                int vbIndex = BitOperations.TrailingZeroCount(buffersLimited);
+
+                ref var vb = ref _vertexBuffers[vbIndex];
+
+                GL.BindVertexBuffer(vbIndex, vb.Buffer.Handle.ToInt32(), (IntPtr)vb.Buffer.Offset, vb.Stride);
+
+                buffersLimited &= ~(1u << vbIndex);
+            }
+
+            _vertexBuffersLimited = 0;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private void EnableVertexAttrib(int index)
+        {
+            uint mask = 1u << index;
+
+            if ((_vertexAttribsInUse & mask) == 0)
+            {
+                _vertexAttribsInUse |= mask;
+                GL.EnableVertexAttribArray(index);
+            }
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private void DisableVertexAttrib(int index)
+        {
+            uint mask = 1u << index;
+
+            if ((_vertexAttribsInUse & mask) != 0)
+            {
+                _vertexAttribsInUse &= ~mask;
+                GL.DisableVertexAttribArray(index);
+                GL.VertexAttrib4(index, 0f, 0f, 0f, 1f);
+            }
+        }
+
+        public void Dispose()
+        {
+            if (Handle != 0)
+            {
+                GL.DeleteVertexArray(Handle);
+
+                Handle = 0;
+            }
+        }
+    }
+}