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.

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);