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.

1 files changed, 35 insertions, 0 deletions

diff --git a/Ryujinx.Graphics.Shader/CodeGen/Glsl/Declarations.cs b/Ryujinx.Graphics.Shader/CodeGen/Glsl/Declarations.cs
index bd947ab7..f9d61928 100644
--- a/Ryujinx.Graphics.Shader/CodeGen/Glsl/Declarations.cs
+++ b/Ryujinx.Graphics.Shader/CodeGen/Glsl/Declarations.cs
@@ -137,6 +137,14 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Glsl
                 context.AppendLine();
             }
 
+            if (context.Config.Stage == ShaderStage.Fragment || context.Config.Stage == ShaderStage.Compute)
+            {
+                if (DeclareRenderScale(context))
+                {
+                    context.AppendLine();
+                }
+            }
+
             if ((info.HelperFunctionsMask & HelperFunctionsMask.MultiplyHighS32) != 0)
             {
                 AppendHelperFunction(context, "Ryujinx.Graphics.Shader/CodeGen/Glsl/HelperFunctions/MultiplyHighS32.glsl");
@@ -219,6 +227,33 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Glsl
             }
         }
 
+        private static bool DeclareRenderScale(CodeGenContext context)
+        {
+            if ((context.Config.UsedFeatures & (FeatureFlags.FragCoordXY | FeatureFlags.IntegerSampling)) != 0)
+            {
+                string stage = OperandManager.GetShaderStagePrefix(context.Config.Stage);
+
+                int scaleElements = context.TextureDescriptors.Count;
+                
+                if (context.Config.Stage == ShaderStage.Fragment)
+                {
+                    scaleElements++; // Also includes render target scale, for gl_FragCoord.
+                }
+
+                context.AppendLine($"uniform float {stage}_renderScale[{scaleElements}];");
+
+                if (context.Config.UsedFeatures.HasFlag(FeatureFlags.IntegerSampling))
+                {
+                    context.AppendLine();
+                    AppendHelperFunction(context, $"Ryujinx.Graphics.Shader/CodeGen/Glsl/HelperFunctions/TexelFetchScale_{stage}.glsl");
+                }
+
+                return true;
+            }
+
+            return false;
+        }
+
         private static void DeclareStorages(CodeGenContext context, StructuredProgramInfo info)
         {
             string sbName = OperandManager.GetShaderStagePrefix(context.Config.Stage);