Implement Viewport Transform Disable (#3328)

* Initial implementation (no specialization)

* Use specialization

* Fix render scale, increase code gen version

* Revert accidental change

* Address Feedback

3 files changed, 58 insertions, 1 deletions

diff --git a/Ryujinx.Graphics.Shader/Translation/AttributeConsts.cs b/Ryujinx.Graphics.Shader/Translation/AttributeConsts.cs
index 370af009..ada60ab9 100644
--- a/Ryujinx.Graphics.Shader/Translation/AttributeConsts.cs
+++ b/Ryujinx.Graphics.Shader/Translation/AttributeConsts.cs
@@ -67,6 +67,9 @@ namespace Ryujinx.Graphics.Shader.Translation
         public const int FragmentOutputIsBgraBase = 0x1000100;
         public const int FragmentOutputIsBgraEnd  = FragmentOutputIsBgraBase + 8 * 4;
 
+        public const int SupportBlockViewInverseX = 0x1000200;
+        public const int SupportBlockViewInverseY = 0x1000204;
+
         public const int ThreadIdX = 0x2000000;
         public const int ThreadIdY = 0x2000004;
         public const int ThreadIdZ = 0x2000008;
diff --git a/Ryujinx.Graphics.Shader/Translation/EmitterContext.cs b/Ryujinx.Graphics.Shader/Translation/EmitterContext.cs
index 775f1217..ba3b551d 100644
--- a/Ryujinx.Graphics.Shader/Translation/EmitterContext.cs
+++ b/Ryujinx.Graphics.Shader/Translation/EmitterContext.cs
@@ -154,9 +154,56 @@ namespace Ryujinx.Graphics.Shader.Translation
             return label;
         }
 
+        public void PrepareForVertexReturn()
+        {
+            if (Config.GpuAccessor.QueryViewportTransformDisable())
+            {
+                Operand x = Attribute(AttributeConsts.PositionX | AttributeConsts.LoadOutputMask);
+                Operand y = Attribute(AttributeConsts.PositionY | AttributeConsts.LoadOutputMask);
+                Operand xScale = Attribute(AttributeConsts.SupportBlockViewInverseX);
+                Operand yScale = Attribute(AttributeConsts.SupportBlockViewInverseY);
+                Operand negativeOne = ConstF(-1.0f);
+
+                this.Copy(Attribute(AttributeConsts.PositionX), this.FPFusedMultiplyAdd(x, xScale, negativeOne));
+                this.Copy(Attribute(AttributeConsts.PositionY), this.FPFusedMultiplyAdd(y, yScale, negativeOne));
+            }
+        }
+
+        public void PrepareForVertexReturn(out Operand oldXLocal, out Operand oldYLocal, out Operand oldZLocal)
+        {
+            if (Config.GpuAccessor.QueryViewportTransformDisable())
+            {
+                oldXLocal = Local();
+                this.Copy(oldXLocal, Attribute(AttributeConsts.PositionX | AttributeConsts.LoadOutputMask));
+                oldYLocal = Local();
+                this.Copy(oldYLocal, Attribute(AttributeConsts.PositionY | AttributeConsts.LoadOutputMask));
+            }
+            else
+            {
+                oldXLocal = null;
+                oldYLocal = null;
+            }
+
+            // Will be used by Vulkan backend for depth mode emulation.
+            oldZLocal = null;
+
+            PrepareForVertexReturn();
+        }
+
         public void PrepareForReturn()
         {
-            if (!IsNonMain && Config.Stage == ShaderStage.Fragment)
+            if (IsNonMain)
+            {
+                return;
+            }
+
+            if (Config.LastInVertexPipeline &&
+                (Config.Stage == ShaderStage.Vertex || Config.Stage == ShaderStage.TessellationEvaluation) &&
+                (Config.Options.Flags & TranslationFlags.VertexA) == 0)
+            {
+                PrepareForVertexReturn();
+            }
+            else if (Config.Stage == ShaderStage.Fragment)
             {
                 if (Config.OmapDepth)
                 {
diff --git a/Ryujinx.Graphics.Shader/Translation/ShaderConfig.cs b/Ryujinx.Graphics.Shader/Translation/ShaderConfig.cs
index 23b8b951..27d72cd5 100644
--- a/Ryujinx.Graphics.Shader/Translation/ShaderConfig.cs
+++ b/Ryujinx.Graphics.Shader/Translation/ShaderConfig.cs
@@ -14,6 +14,7 @@ namespace Ryujinx.Graphics.Shader.Translation
         public ShaderStage Stage { get; }
 
         public bool GpPassthrough { get; }
+        public bool LastInVertexPipeline { get; private set; }
 
         public int ThreadsPerInputPrimitive { get; }
 
@@ -135,6 +136,7 @@ namespace Ryujinx.Graphics.Shader.Translation
             OmapSampleMask           = header.OmapSampleMask;
             OmapDepth                = header.OmapDepth;
             TransformFeedbackEnabled = gpuAccessor.QueryTransformFeedbackEnabled();
+            LastInVertexPipeline     = header.Stage < ShaderStage.Fragment;
         }
 
         public int GetDepthRegister()
@@ -274,6 +276,11 @@ namespace Ryujinx.Graphics.Shader.Translation
             NextInputAttributesPerPatchComponents = config.ThisInputAttributesPerPatchComponents;
             NextUsesFixedFuncAttributes = config.UsedFeatures.HasFlag(FeatureFlags.FixedFuncAttr);
             MergeOutputUserAttributes(config.UsedInputAttributes, config.UsedInputAttributesPerPatch);
+
+            if (config.Stage != ShaderStage.Fragment)
+            {
+                LastInVertexPipeline = false;
+            }
         }
 
         public void MergeOutputUserAttributes(int mask, int maskPerPatch)