Eliminate redundant multiplications by gl_FragCoord.w on the shader (#4578)

* Eliminate redundant multiplications by gl_FragCoord.w on the shader

* Shader cache version bump

Directory.Packages.props

@@ -13,7 +13,7 @@
     <PackageVersion Include="CommandLineParser" Version="2.9.1" />
     <PackageVersion Include="Concentus" Version="1.1.7" />
     <PackageVersion Include="DiscordRichPresence" Version="1.1.3.18" />
-    <PackageVersion Include="DynamicData" Version="7.13.5" />
+    <PackageVersion Include="DynamicData" Version="7.13.8" />
     <PackageVersion Include="FluentAvaloniaUI" Version="1.4.5" />
     <PackageVersion Include="GtkSharp.Dependencies" Version="1.1.1" />
     <PackageVersion Include="GtkSharp.Dependencies.osx" Version="0.0.5" />

src/Ryujinx.Graphics.Gpu/Engine/Threed/StateUpdater.cs

@@ -23,6 +23,8 @@ namespace Ryujinx.Graphics.Gpu.Engine.Threed
         public const int PrimitiveRestartStateIndex = 12;
         public const int RenderTargetStateIndex = 27;
 
+        private const ulong MaxUnknownStorageSize = 0x100000;
+
         private readonly GpuContext _context;
         private readonly GpuChannel _channel;
         private readonly DeviceStateWithShadow<ThreedClassState> _state;
@@ -356,7 +358,19 @@ namespace Ryujinx.Graphics.Gpu.Engine.Threed
 
                     SbDescriptor sbDescriptor = _channel.MemoryManager.Physical.Read<SbDescriptor>(sbDescAddress);
 
-                    _channel.BufferManager.SetGraphicsStorageBuffer(stage, sb.Slot, sbDescriptor.PackAddress(), (uint)sbDescriptor.Size, sb.Flags);
+                    uint size;
+                    if (sb.SbCbSlot == 0)
+                    {
+                        // Only trust the SbDescriptor size if it comes from slot 0.
+                        size = (uint)sbDescriptor.Size;
+                    }
+                    else
+                    {
+                        // TODO: Use full mapped size and somehow speed up buffer sync.
+                        size = (uint)_channel.MemoryManager.GetMappedSize(sbDescriptor.PackAddress(), MaxUnknownStorageSize);
+                    }
+
+                    _channel.BufferManager.SetGraphicsStorageBuffer(stage, sb.Slot, sbDescriptor.PackAddress(), size, sb.Flags);
                 }
             }
         }

src/Ryujinx.Graphics.Gpu/Memory/MemoryManager.cs

@@ -637,6 +637,33 @@ namespace Ryujinx.Graphics.Gpu.Memory
             return UnpackPaFromPte(pte) + (va & PageMask);
         }
 
+        /// <summary>
+        /// Translates a GPU virtual address and returns the number of bytes that are mapped after it.
+        /// </summary>
+        /// <param name="va">GPU virtual address to be translated</param>
+        /// <param name="maxSize">Maximum size in bytes to scan</param>
+        /// <returns>Number of bytes, 0 if unmapped</returns>
+        public ulong GetMappedSize(ulong va, ulong maxSize)
+        {
+            if (!ValidateAddress(va))
+            {
+                return 0;
+            }
+
+            ulong startVa = va;
+            ulong endVa = va + maxSize;
+
+            ulong pte = GetPte(va);
+
+            while (pte != PteUnmapped && va < endVa)
+            {
+                va += PageSize - (va & PageMask);
+                pte = GetPte(va);
+            }
+
+            return Math.Min(maxSize, va - startVa);
+        }
+
         /// <summary>
         /// Gets the kind of a given memory page.
         /// This might indicate the type of resource that can be allocated on the page, and also texture tiling.

src/Ryujinx.Graphics.Gpu/Shader/DiskCache/DiskCacheHostStorage.cs

@@ -22,7 +22,7 @@ namespace Ryujinx.Graphics.Gpu.Shader.DiskCache
         private const ushort FileFormatVersionMajor = 1;
         private const ushort FileFormatVersionMinor = 2;
         private const uint FileFormatVersionPacked = ((uint)FileFormatVersionMajor << 16) | FileFormatVersionMinor;
-        private const uint CodeGenVersion = 4892;
+        private const uint CodeGenVersion = 4578;
 
         private const string SharedTocFileName = "shared.toc";
         private const string SharedDataFileName = "shared.data";

src/Ryujinx.Graphics.Shader/Translation/Optimizations/Optimizer.cs

@@ -20,6 +20,12 @@ namespace Ryujinx.Graphics.Shader.Translation.Optimizations
                 GlobalToStorage.RunPass(blocks[blkIndex], config, ref sbUseMask, ref ubeUseMask);
                 BindlessToIndexed.RunPass(blocks[blkIndex], config);
                 BindlessElimination.RunPass(blocks[blkIndex], config);
+
+                // FragmentCoord only exists on fragment shaders, so we don't need to check other stages.
+                if (config.Stage == ShaderStage.Fragment)
+                {
+                    EliminateMultiplyByFragmentCoordW(blocks[blkIndex]);
+                }
             }
 
             config.SetAccessibleBufferMasks(sbUseMask, ubeUseMask);
@@ -281,6 +287,75 @@ namespace Ryujinx.Graphics.Shader.Translation.Optimizations
             return modified;
         }
 
+        private static void EliminateMultiplyByFragmentCoordW(BasicBlock block)
+        {
+            foreach (INode node in block.Operations)
+            {
+                if (node is Operation operation)
+                {
+                    EliminateMultiplyByFragmentCoordW(operation);
+                }
+            }
+        }
+
+        private static void EliminateMultiplyByFragmentCoordW(Operation operation)
+        {
+            // We're looking for the pattern:
+            //  y = x * gl_FragCoord.w
+            //  v = y * (1.0 / gl_FragCoord.w)
+            // Then we transform it into:
+            //  v = x
+            // This pattern is common on fragment shaders due to the way how perspective correction is done.
+
+            // We are expecting a multiplication by the reciprocal of gl_FragCoord.w.
+            if (operation.Inst != (Instruction.FP32 | Instruction.Multiply))
+            {
+                return;
+            }
+
+            Operand lhs = operation.GetSource(0);
+            Operand rhs = operation.GetSource(1);
+
+            // Check LHS of the the main multiplication operation. We expect an input being multiplied by gl_FragCoord.w.
+            if (!(lhs.AsgOp is Operation attrMulOp) || attrMulOp.Inst != (Instruction.FP32 | Instruction.Multiply))
+            {
+                return;
+            }
+
+            Operand attrMulLhs = attrMulOp.GetSource(0);
+            Operand attrMulRhs = attrMulOp.GetSource(1);
+
+            // LHS should be any input, RHS should be exactly gl_FragCoord.w.
+            if (!Utils.IsInputLoad(attrMulLhs.AsgOp) || !Utils.IsInputLoad(attrMulRhs.AsgOp, IoVariable.FragmentCoord, 3))
+            {
+                return;
+            }
+
+            // RHS of the main multiplication should be a reciprocal operation (1.0 / x).
+            if (!(rhs.AsgOp is Operation reciprocalOp) || reciprocalOp.Inst != (Instruction.FP32 | Instruction.Divide))
+            {
+                return;
+            }
+
+            Operand reciprocalLhs = reciprocalOp.GetSource(0);
+            Operand reciprocalRhs = reciprocalOp.GetSource(1);
+
+            // Check if the divisor is a constant equal to 1.0.
+            if (reciprocalLhs.Type != OperandType.Constant || reciprocalLhs.AsFloat() != 1.0f)
+            {
+                return;
+            }
+
+            // Check if the dividend is gl_FragCoord.w.
+            if (!Utils.IsInputLoad(reciprocalRhs.AsgOp, IoVariable.FragmentCoord, 3))
+            {
+                return;
+            }
+
+            // If everything matches, we can replace the operation with the input load result.
+            operation.TurnIntoCopy(attrMulLhs);
+        }
+
         private static void RemoveNode(BasicBlock block, LinkedListNode<INode> llNode)
         {
             // Remove a node from the nodes list, and also remove itself

src/Ryujinx.Graphics.Shader/Translation/Optimizations/Utils.cs

@@ -4,6 +4,35 @@ namespace Ryujinx.Graphics.Shader.Translation.Optimizations
 {
     static class Utils
     {
+        public static bool IsInputLoad(INode node)
+        {
+            return (node is Operation operation) &&
+                   operation.Inst == Instruction.Load &&
+                   operation.StorageKind == StorageKind.Input;
+        }
+
+        public static bool IsInputLoad(INode node, IoVariable ioVariable, int elemIndex)
+        {
+            if (!(node is Operation operation) ||
+                operation.Inst != Instruction.Load ||
+                operation.StorageKind != StorageKind.Input ||
+                operation.SourcesCount != 2)
+            {
+                return false;
+            }
+
+            Operand ioVariableSrc = operation.GetSource(0);
+
+            if (ioVariableSrc.Type != OperandType.Constant || (IoVariable)ioVariableSrc.Value != ioVariable)
+            {
+                return false;
+            }
+
+            Operand elemIndexSrc = operation.GetSource(1);
+
+            return elemIndexSrc.Type == OperandType.Constant && elemIndexSrc.Value == elemIndex;
+        }
+
         private static Operation FindBranchSource(BasicBlock block)
         {
             foreach (BasicBlock sourceBlock in block.Predecessors)

src/Ryujinx.Graphics.Vulkan/DescriptorSetUpdater.cs

@@ -228,7 +228,12 @@ namespace Ryujinx.Graphics.Vulkan
             SignalDirty(DirtyFlags.Storage);
         }
 
-        public void SetTextureAndSampler(CommandBufferScoped cbs, ShaderStage stage, int binding, ITexture texture, ISampler sampler)
+        public void SetTextureAndSampler(
+            CommandBufferScoped cbs,
+            ShaderStage stage,
+            int binding,
+            ITexture texture,
+            ISampler sampler)
         {
             if (texture is TextureBuffer textureBuffer)
             {
@@ -251,6 +256,28 @@ namespace Ryujinx.Graphics.Vulkan
             SignalDirty(DirtyFlags.Texture);
         }
 
+        public void SetTextureAndSamplerIdentitySwizzle(
+            CommandBufferScoped cbs,
+            ShaderStage stage,
+            int binding,
+            ITexture texture,
+            ISampler sampler)
+        {
+            if (texture is TextureView view)
+            {
+                view.Storage.InsertWriteToReadBarrier(cbs, AccessFlags.ShaderReadBit, stage.ConvertToPipelineStageFlags());
+
+                _textureRefs[binding] = view.GetIdentityImageView();
+                _samplerRefs[binding] = ((SamplerHolder)sampler)?.GetSampler();
+
+                SignalDirty(DirtyFlags.Texture);
+            }
+            else
+            {
+                SetTextureAndSampler(cbs, stage, binding, texture, sampler);
+            }
+        }
+
         public void SetUniformBuffers(CommandBuffer commandBuffer, ReadOnlySpan<BufferAssignment> buffers)
         {
             for (int i = 0; i < buffers.Length; i++)

src/Ryujinx.Graphics.Vulkan/HelperShader.cs

@@ -415,7 +415,7 @@ namespace Ryujinx.Graphics.Vulkan
 
             var sampler = linearFilter ? _samplerLinear : _samplerNearest;
 
-            _pipeline.SetTextureAndSampler(ShaderStage.Fragment, 0, src, sampler);
+            _pipeline.SetTextureAndSamplerIdentitySwizzle(ShaderStage.Fragment, 0, src, sampler);
 
             Span<float> region = stackalloc float[RegionBufferSize / sizeof(float)];
 
@@ -625,7 +625,7 @@ namespace Ryujinx.Graphics.Vulkan
 
         private void BlitDepthStencilDraw(TextureView src, bool isDepth)
         {
-            _pipeline.SetTextureAndSampler(ShaderStage.Fragment, 0, src, _samplerNearest);
+            _pipeline.SetTextureAndSamplerIdentitySwizzle(ShaderStage.Fragment, 0, src, _samplerNearest);
 
             if (isDepth)
             {
@@ -1037,7 +1037,7 @@ namespace Ryujinx.Graphics.Vulkan
                     var srcView = Create2DLayerView(src, srcLayer + z, srcLevel + l, srcFormat);
                     var dstView = Create2DLayerView(dst, dstLayer + z, dstLevel + l);
 
-                    _pipeline.SetTextureAndSampler(ShaderStage.Compute, 0, srcView, null);
+                    _pipeline.SetTextureAndSamplerIdentitySwizzle(ShaderStage.Compute, 0, srcView, null);
                     _pipeline.SetImage(0, dstView, dstFormat);
 
                     int dispatchX = (Math.Min(srcView.Info.Width, dstView.Info.Width) + 31) / 32;
@@ -1177,7 +1177,7 @@ namespace Ryujinx.Graphics.Vulkan
                     var srcView = Create2DLayerView(src, srcLayer + z, 0, format);
                     var dstView = Create2DLayerView(dst, dstLayer + z, 0);
 
-                    _pipeline.SetTextureAndSampler(ShaderStage.Compute, 0, srcView, null);
+                    _pipeline.SetTextureAndSamplerIdentitySwizzle(ShaderStage.Compute, 0, srcView, null);
                     _pipeline.SetImage(0, dstView, format);
 
                     _pipeline.DispatchCompute(dispatchX, dispatchY, 1);
@@ -1313,7 +1313,7 @@ namespace Ryujinx.Graphics.Vulkan
                     var srcView = Create2DLayerView(src, srcLayer + z, 0, format);
                     var dstView = Create2DLayerView(dst, dstLayer + z, 0);
 
-                    _pipeline.SetTextureAndSampler(ShaderStage.Fragment, 0, srcView, null);
+                    _pipeline.SetTextureAndSamplerIdentitySwizzle(ShaderStage.Fragment, 0, srcView, null);
                     _pipeline.SetRenderTarget(
                         ((TextureView)dstView).GetView(format).GetImageViewForAttachment(),
                         (uint)dst.Width,
@@ -1384,7 +1384,7 @@ namespace Ryujinx.Graphics.Vulkan
 
         private void CopyMSAspectDraw(TextureView src, bool fromMS, bool isDepth)
         {
-            _pipeline.SetTextureAndSampler(ShaderStage.Fragment, 0, src, _samplerNearest);
+            _pipeline.SetTextureAndSamplerIdentitySwizzle(ShaderStage.Fragment, 0, src, _samplerNearest);
 
             if (isDepth)
             {

src/Ryujinx.Graphics.Vulkan/PipelineBase.cs

@@ -1098,6 +1098,11 @@ namespace Ryujinx.Graphics.Vulkan
             _descriptorSetUpdater.SetTextureAndSampler(Cbs, stage, binding, texture, sampler);
         }
 
+        public void SetTextureAndSamplerIdentitySwizzle(ShaderStage stage, int binding, ITexture texture, ISampler sampler)
+        {
+            _descriptorSetUpdater.SetTextureAndSamplerIdentitySwizzle(Cbs, stage, binding, texture, sampler);
+        }
+
         public void SetTransformFeedbackBuffers(ReadOnlySpan<BufferRange> buffers)
         {
             PauseTransformFeedbackInternal();