Support separate textures and samplers (#1216)

* Support separate textures and samplers

* Add missing bindless flag, fix SNORM format on buffer textures

* Add missing separation

* Add comments about the new handles

3 files changed, 130 insertions, 2 deletions

diff --git a/Ryujinx.Graphics.Shader/Translation/Lowering.cs b/Ryujinx.Graphics.Shader/Translation/Lowering.cs
index 6f52ce96..6da25983 100644
--- a/Ryujinx.Graphics.Shader/Translation/Lowering.cs
+++ b/Ryujinx.Graphics.Shader/Translation/Lowering.cs
@@ -1,6 +1,7 @@
 using Ryujinx.Graphics.Shader.IntermediateRepresentation;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Linq;
 
 using static Ryujinx.Graphics.Shader.IntermediateRepresentation.OperandHelper;
 using static Ryujinx.Graphics.Shader.Translation.GlobalMemory;
@@ -27,9 +28,17 @@ namespace Ryujinx.Graphics.Shader.Translation
                         node = RewriteGlobalAccess(node, config);
                     }
 
-                    if (operation.Inst == Instruction.TextureSample)
+                    if (operation is TextureOperation texOp)
                     {
-                        node = RewriteTextureSample(node, config);
+                        if (texOp.Inst == Instruction.TextureSample)
+                        {
+                            node = RewriteTextureSample(node, config);
+                        }
+
+                        if (texOp.Type == SamplerType.TextureBuffer)
+                        {
+                            node = InsertSnormNormalization(node, config);
+                        }
                     }
                 }
             }
@@ -419,5 +428,57 @@ namespace Ryujinx.Graphics.Shader.Translation
 
             return node;
         }
+
+        private static LinkedListNode<INode> InsertSnormNormalization(LinkedListNode<INode> node, ShaderConfig config)
+        {
+            TextureOperation texOp = (TextureOperation)node.Value;
+
+            TextureFormat format = config.GpuAccessor.QueryTextureFormat(texOp.Handle);
+
+            int maxPositive = format switch
+            {
+                TextureFormat.R8Snorm           => sbyte.MaxValue,
+                TextureFormat.R8G8Snorm         => sbyte.MaxValue,
+                TextureFormat.R8G8B8A8Snorm     => sbyte.MaxValue,
+                TextureFormat.R16Snorm          => short.MaxValue,
+                TextureFormat.R16G16Snorm       => short.MaxValue,
+                TextureFormat.R16G16B16A16Snorm => short.MaxValue,
+                _                               => 0
+            };
+
+            // The value being 0 means that the format is not a SNORM format, so there's nothing to do here.
+            if (maxPositive == 0)
+            {
+                return node;
+            }
+
+            // Do normalization. We assume SINT formats are being used as replacement for SNORM (that is not supported).
+            INode[] uses = texOp.Dest.UseOps.ToArray();
+
+            Operation convOp = new Operation(Instruction.ConvertS32ToFP, Local(), texOp.Dest);
+            Operation normOp = new Operation(Instruction.FP32 | Instruction.Multiply, Local(), convOp.Dest, ConstF(1f / maxPositive));
+
+            node = node.List.AddAfter(node, convOp);
+            node = node.List.AddAfter(node, normOp);
+
+            foreach (INode useOp in uses)
+            {
+                if (!(useOp is Operation op))
+                {
+                    continue;
+                }
+
+                // Replace all uses of the texture pixel value with the normalized value.
+                for (int index = 0; index < op.SourcesCount; index++)
+                {
+                    if (op.GetSource(index) == texOp.Dest)
+                    {
+                        op.SetSource(index, normOp.Dest);
+                    }
+                }
+            }
+
+            return node;
+        }
     }
 }
\ No newline at end of file
diff --git a/Ryujinx.Graphics.Shader/Translation/Optimizations/BindlessElimination.cs b/Ryujinx.Graphics.Shader/Translation/Optimizations/BindlessElimination.cs
new file mode 100644
index 00000000..9515c349
--- /dev/null
+++ b/Ryujinx.Graphics.Shader/Translation/Optimizations/BindlessElimination.cs
@@ -0,0 +1,50 @@
+using Ryujinx.Graphics.Shader.IntermediateRepresentation;
+using System.Collections.Generic;
+
+namespace Ryujinx.Graphics.Shader.Translation.Optimizations
+{
+    class BindlessElimination
+    {
+        public static void RunPass(BasicBlock block)
+        {
+            // We can turn a bindless into regular access by recognizing the pattern
+            // produced by the compiler for separate texture and sampler.
+            // We check for the following conditions:
+            // - The handle is the result of a bitwise OR logical operation.
+            // - Both sources of the OR operation comes from CB2 (used by NVN to hold texture handles).
+            for (LinkedListNode<INode> node = block.Operations.First; node != null; node = node.Next)
+            {
+                if (!(node.Value is TextureOperation texOp))
+                {
+                    continue;
+                }
+
+                if ((texOp.Flags & TextureFlags.Bindless) == 0)
+                {
+                    continue;
+                }
+
+                if (!(texOp.GetSource(0).AsgOp is Operation handleCombineOp))
+                {
+                    continue;
+                }
+
+                if (handleCombineOp.Inst != Instruction.BitwiseOr)
+                {
+                    continue;
+                }
+
+                Operand src0 = handleCombineOp.GetSource(0);
+                Operand src1 = handleCombineOp.GetSource(1);
+
+                if (src0.Type != OperandType.ConstantBuffer || src0.GetCbufSlot() != 2 ||
+                    src1.Type != OperandType.ConstantBuffer || src1.GetCbufSlot() != 2)
+                {
+                    continue;
+                }
+
+                texOp.SetHandle(src0.GetCbufOffset() | (src1.GetCbufOffset() << 16));
+            }
+        }
+    }
+}
diff --git a/Ryujinx.Graphics.Shader/Translation/Optimizations/Optimizer.cs b/Ryujinx.Graphics.Shader/Translation/Optimizations/Optimizer.cs
index c5db4678..10a0e780 100644
--- a/Ryujinx.Graphics.Shader/Translation/Optimizations/Optimizer.cs
+++ b/Ryujinx.Graphics.Shader/Translation/Optimizations/Optimizer.cs
@@ -1,4 +1,5 @@
 using Ryujinx.Graphics.Shader.IntermediateRepresentation;
+using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
@@ -88,6 +89,22 @@ namespace Ryujinx.Graphics.Shader.Translation.Optimizations
             for (int blkIndex = 0; blkIndex < blocks.Length; blkIndex++)
             {
                 BindlessToIndexed.RunPass(blocks[blkIndex]);
+                BindlessElimination.RunPass(blocks[blkIndex]);
+
+                // Try to eliminate any operations that are now unused.
+                LinkedListNode<INode> node = blocks[blkIndex].Operations.First;
+
+                while (node != null)
+                {
+                    LinkedListNode<INode> nextNode = node.Next;
+
+                    if (IsUnused(node.Value))
+                    {
+                        RemoveNode(blocks[blkIndex], node);
+                    }
+
+                    node = nextNode;
+                }
             }
         }