Add support for alpha to coverage dithering (#3069)

* Add support for alpha to coverage dithering

* Shader cache version bump

* Fix wrong alpha register

* Ensure support buffer is cleared

* New shader specialization based approach

Ryujinx.Graphics.Gpu/Shader/Cache/Migration.cs

@@ -167,6 +167,8 @@ namespace Ryujinx.Graphics.Gpu.Shader.Cache
                             accessorHeader.StateFlags.HasFlag(GuestGpuStateFlags.EarlyZForce),
                             topology,
                             tessMode,
+                            false,
+                            false,
                             false);
 
                         TransformFeedbackDescriptor[] tfdNew = null;

Ryujinx.Graphics.Gpu/Shader/DiskCache/DiskCacheGpuAccessor.cs

@@ -67,6 +67,12 @@ namespace Ryujinx.Graphics.Gpu.Shader.DiskCache
             return MemoryMarshal.Cast<byte, ulong>(_data.Span.Slice((int)address));
         }
 
+        /// <inheritdoc/>
+        public bool QueryAlphaToCoverageDitherEnable()
+        {
+            return _oldSpecState.GraphicsState.AlphaToCoverageEnable && _oldSpecState.GraphicsState.AlphaToCoverageDitherEnable;
+        }
+
         /// <inheritdoc/>
         public int QueryBindingConstantBuffer(int index)
         {

Ryujinx.Graphics.Gpu/Shader/DiskCache/DiskCacheHostStorage.cs

@@ -21,7 +21,7 @@ namespace Ryujinx.Graphics.Gpu.Shader.DiskCache
         private const ushort FileFormatVersionMajor = 1;
         private const ushort FileFormatVersionMinor = 1;
         private const uint FileFormatVersionPacked = ((uint)FileFormatVersionMajor << 16) | FileFormatVersionMinor;
-        private const uint CodeGenVersion = 3424;
+        private const uint CodeGenVersion = 3069;
 
         private const string SharedTocFileName = "shared.toc";
         private const string SharedDataFileName = "shared.data";

Ryujinx.Graphics.Gpu/Shader/GpuAccessor.cs

@@ -66,6 +66,12 @@ namespace Ryujinx.Graphics.Gpu.Shader
             return MemoryMarshal.Cast<byte, ulong>(_channel.MemoryManager.GetSpan(address, size));
         }
 
+        /// <inheritdoc/>
+        public bool QueryAlphaToCoverageDitherEnable()
+        {
+            return _state.GraphicsState.AlphaToCoverageEnable && _state.GraphicsState.AlphaToCoverageDitherEnable;
+        }
+
         /// <inheritdoc/>
         public int QueryBindingConstantBuffer(int index)
         {

Ryujinx.Graphics.Gpu/Shader/GpuChannelGraphicsState.cs

@@ -30,6 +30,16 @@ namespace Ryujinx.Graphics.Gpu.Shader
         /// </summary>
         public readonly bool ViewportTransformDisable;
 
+        /// <summary>
+        /// Indicates whenever alpha-to-coverage is enabled.
+        /// </summary>
+        public readonly bool AlphaToCoverageEnable;
+
+        /// <summary>
+        /// Indicates whenever alpha-to-coverage dithering is enabled.
+        /// </summary>
+        public readonly bool AlphaToCoverageDitherEnable;
+
         /// <summary>
         /// Creates a new GPU graphics state.
         /// </summary>
@@ -37,12 +47,22 @@ namespace Ryujinx.Graphics.Gpu.Shader
         /// <param name="topology">Primitive topology</param>
         /// <param name="tessellationMode">Tessellation mode</param>
         /// <param name="viewportTransformDisable">Indicates whenever the viewport transform is disabled</param>
-        public GpuChannelGraphicsState(bool earlyZForce, PrimitiveTopology topology, TessMode tessellationMode, bool viewportTransformDisable)
+        /// <param name="alphaToCoverageEnable">Indicates whenever alpha-to-coverage is enabled</param>
+        /// <param name="alphaToCoverageDitherEnable">Indicates whenever alpha-to-coverage dithering is enabled</param>
+        public GpuChannelGraphicsState(
+            bool earlyZForce,
+            PrimitiveTopology topology,
+            TessMode tessellationMode,
+            bool viewportTransformDisable,
+            bool alphaToCoverageEnable,
+            bool alphaToCoverageDitherEnable)
         {
             EarlyZForce = earlyZForce;
             Topology = topology;
             TessellationMode = tessellationMode;
             ViewportTransformDisable = viewportTransformDisable;
+            AlphaToCoverageEnable = alphaToCoverageEnable;
+            AlphaToCoverageDitherEnable = alphaToCoverageDitherEnable;
         }
     }
 }

Ryujinx.Graphics.Gpu/Shader/ShaderSpecializationState.cs

@@ -455,6 +455,14 @@ namespace Ryujinx.Graphics.Gpu.Shader
                 return false;
             }
 
+            bool thisA2cDitherEnable = GraphicsState.AlphaToCoverageEnable && GraphicsState.AlphaToCoverageDitherEnable;
+            bool otherA2cDitherEnable = graphicsState.AlphaToCoverageEnable && graphicsState.AlphaToCoverageDitherEnable;
+
+            if (otherA2cDitherEnable != thisA2cDitherEnable)
+            {
+                return false;
+            }
+
             return Matches(channel, poolState, checkTextures, isCompute: false);
         }