Implement Zero-Configuration Resolution Scaling (#1365)

* Initial implementation of Render Target Scaling

Works with most games I have. No GUI option right now, it is hardcoded.

Missing handling for texelFetch operation.

* Realtime Configuration, refactoring.

* texelFetch scaling on fragment shader (WIP)

* Improve Shader-Side changes.

* Fix potential crash when no color/depth bound

* Workaround random uses of textures in compute.

This was blacklisting textures in a few games despite causing no bugs. Will eventually add full support so this doesn't break anything.

* Fix scales oscillating when changing between non-native scales.

* Scaled textures on compute, cleanup, lazier uniform update.

* Cleanup.

* Fix stupidity

* Address Thog Feedback.

* Cover most of GDK's feedback (two comments remain)

* Fix bad rename

* Move IsDepthStencil to FormatExtensions, add docs.

* Fix default config, square texture detection.

* Three final fixes:

- Nearest copy when texture is integer format.
- Texture2D -> Texture3D copy correctly blacklists the texture before trying an unscaled copy (caused driver error)
- Discount small textures.

* Remove scale threshold.

Not needed right now - we'll see if we run into problems.

* All CPU modification blacklists scale.

* Fix comment.

4 files changed, 51 insertions, 4 deletions

diff --git a/Ryujinx.Graphics.Shader/Translation/EmitterContext.cs b/Ryujinx.Graphics.Shader/Translation/EmitterContext.cs
index 70476dcd..39532a64 100644
--- a/Ryujinx.Graphics.Shader/Translation/EmitterContext.cs
+++ b/Ryujinx.Graphics.Shader/Translation/EmitterContext.cs
@@ -11,6 +11,8 @@ namespace Ryujinx.Graphics.Shader.Translation
         public Block  CurrBlock { get; set; }
         public OpCode CurrOp    { get; set; }
 
+        public FeatureFlags UsedFeatures { get; set; }
+
         public ShaderConfig Config { get; }
 
         private List<Operation> _operations;
@@ -40,6 +42,20 @@ namespace Ryujinx.Graphics.Shader.Translation
             _operations.Add(operation);
         }
 
+        public void FlagAttributeRead(int attribute)
+        {
+            if (Config.Stage == ShaderStage.Fragment)
+            {
+                switch (attribute)
+                {
+                    case AttributeConsts.PositionX:
+                    case AttributeConsts.PositionY:
+                        UsedFeatures |= FeatureFlags.FragCoordXY;
+                        break;
+                }
+            }
+        }
+
         public void MarkLabel(Operand label)
         {
             Add(Instruction.MarkLabel, label);
diff --git a/Ryujinx.Graphics.Shader/Translation/FeatureFlags.cs b/Ryujinx.Graphics.Shader/Translation/FeatureFlags.cs
new file mode 100644
index 00000000..9c65038a
--- /dev/null
+++ b/Ryujinx.Graphics.Shader/Translation/FeatureFlags.cs
@@ -0,0 +1,18 @@
+using System;
+
+namespace Ryujinx.Graphics.Shader.Translation
+{
+    /// <summary>
+    /// Features used by the shader that are important for the code generator to know in advance.
+    /// These typically change the declarations in the shader header.
+    /// </summary>
+    [Flags]
+    public enum FeatureFlags
+    {
+        None = 0,
+
+        // Affected by resolution scaling.
+        FragCoordXY     = 1 << 1,
+        IntegerSampling = 1 << 0
+    }
+}
diff --git a/Ryujinx.Graphics.Shader/Translation/ShaderConfig.cs b/Ryujinx.Graphics.Shader/Translation/ShaderConfig.cs
index 8b38afb9..aabd9ca6 100644
--- a/Ryujinx.Graphics.Shader/Translation/ShaderConfig.cs
+++ b/Ryujinx.Graphics.Shader/Translation/ShaderConfig.cs
@@ -22,6 +22,8 @@ namespace Ryujinx.Graphics.Shader.Translation
 
         public TranslationFlags Flags { get; }
 
+        public FeatureFlags UsedFeatures { get; set; }
+
         public ShaderConfig(IGpuAccessor gpuAccessor, TranslationFlags flags)
         {
             Stage             = ShaderStage.Compute;
@@ -34,6 +36,7 @@ namespace Ryujinx.Graphics.Shader.Translation
             OmapDepth         = false;
             GpuAccessor       = gpuAccessor;
             Flags             = flags;
+            UsedFeatures      = FeatureFlags.None;
         }
 
         public ShaderConfig(ShaderHeader header, IGpuAccessor gpuAccessor, TranslationFlags flags)
@@ -48,6 +51,7 @@ namespace Ryujinx.Graphics.Shader.Translation
             OmapDepth         = header.OmapDepth;
             GpuAccessor       = gpuAccessor;
             Flags             = flags;
+            UsedFeatures      = FeatureFlags.None;
         }
 
         public int GetDepthRegister()
diff --git a/Ryujinx.Graphics.Shader/Translation/Translator.cs b/Ryujinx.Graphics.Shader/Translation/Translator.cs
index 1a69c511..1d7aacdd 100644
--- a/Ryujinx.Graphics.Shader/Translation/Translator.cs
+++ b/Ryujinx.Graphics.Shader/Translation/Translator.cs
@@ -16,15 +16,19 @@ namespace Ryujinx.Graphics.Shader.Translation
 
         public static ShaderProgram Translate(ulong address, IGpuAccessor gpuAccessor, TranslationFlags flags)
         {
-            Operation[] ops = DecodeShader(address, gpuAccessor, flags, out ShaderConfig config, out int size);
+            Operation[] ops = DecodeShader(address, gpuAccessor, flags, out ShaderConfig config, out int size, out FeatureFlags featureFlags);
+
+            config.UsedFeatures = featureFlags;
 
             return Translate(ops, config, size);
         }
 
         public static ShaderProgram Translate(ulong addressA, ulong addressB, IGpuAccessor gpuAccessor, TranslationFlags flags)
         {
-            Operation[] opsA = DecodeShader(addressA, gpuAccessor, flags | TranslationFlags.VertexA, out _, out int sizeA);
-            Operation[] opsB = DecodeShader(addressB, gpuAccessor, flags, out ShaderConfig config, out int sizeB);
+            Operation[] opsA = DecodeShader(addressA, gpuAccessor, flags | TranslationFlags.VertexA, out _, out int sizeA, out FeatureFlags featureFlagsA);
+            Operation[] opsB = DecodeShader(addressB, gpuAccessor, flags, out ShaderConfig config, out int sizeB, out FeatureFlags featureFlagsB);
+
+            config.UsedFeatures = featureFlagsA | featureFlagsB;
 
             return Translate(Combine(opsA, opsB), config, sizeB, sizeA);
         }
@@ -67,7 +71,8 @@ namespace Ryujinx.Graphics.Shader.Translation
             IGpuAccessor     gpuAccessor,
             TranslationFlags flags,
             out ShaderConfig config,
-            out int          size)
+            out int          size,
+            out FeatureFlags featureFlags)
         {
             Block[] cfg;
 
@@ -90,6 +95,8 @@ namespace Ryujinx.Graphics.Shader.Translation
 
                 size = 0;
 
+                featureFlags = FeatureFlags.None;
+
                 return Array.Empty<Operation>();
             }
 
@@ -192,6 +199,8 @@ namespace Ryujinx.Graphics.Shader.Translation
 
             size = (int)maxEndAddress + (((flags & TranslationFlags.Compute) != 0) ? 0 : HeaderSize);
 
+            featureFlags = context.UsedFeatures;
+
             return context.GetOperations();
         }