Implemented generate reactive pass, which can be used separately from the main FSR2 upscale process.

Untested still, but its fairly straightforward.

Assets/Scripts/Fsr2.cs

@@ -157,6 +157,18 @@ namespace FidelityFX
             public float CameraFovAngleVertical;
             public float ViewSpaceToMetersFactor;
         }
+
+        public class GenerateReactiveDescription
+        {
+            public Texture ColorOpaqueOnly;
+            public Texture ColorPreUpscale;
+            public RenderTexture OutReactive;
+            public Vector2Int RenderSize;
+            public float Scale;
+            public float CutoffThreshold;
+            public float BinaryValue;
+            public uint Flags;
+        }
         
         [Serializable, StructLayout(LayoutKind.Sequential)]
         internal struct Fsr2Constants

Assets/Scripts/Fsr2Context.cs

@@ -63,11 +63,6 @@ namespace FidelityFX
             CreatePipelines();
         }
 
-        // private void InitShaders()
-        // {
-        //     LoadComputeShader("FSR2/ffx_fsr2_autogen_reactive_pass", ref _generateReactiveShader, out _generateReactiveKernel);
-        // }
-
         private void CreatePipelines()
         {
             _computeLuminancePyramidPipeline = new Fsr2ComputeLuminancePyramidPipeline(_contextDescription, _resources, _fsr2ConstantsBuffer, _spdConstantsBuffer);
@@ -77,6 +72,7 @@ namespace FidelityFX
             _accumulatePipeline = new Fsr2AccumulatePipeline(_contextDescription, _resources, _fsr2ConstantsBuffer);
             _accumulateSharpenPipeline = new Fsr2AccumulateSharpenPipeline(_contextDescription, _resources, _fsr2ConstantsBuffer);
             _rcasPipeline = new Fsr2RcasPipeline(_contextDescription, _resources, _fsr2ConstantsBuffer, _rcasConstantsBuffer);
+            _generateReactivePipeline = new Fsr2GenerateReactivePipeline(_contextDescription, _resources, _generateReactiveConstantsBuffer);
         }
         
         public void Destroy()
@@ -194,6 +190,25 @@ namespace FidelityFX
             Fsr2Pipeline.UnregisterResources(_commandBuffer);
         }
 
+        public void GenerateReactiveMask(Fsr2.GenerateReactiveDescription dispatchParams)
+        {
+            _commandBuffer.Clear();
+
+            const int threadGroupWorkRegionDim = 8;
+            int dispatchSrcX = (dispatchParams.RenderSize.x + (threadGroupWorkRegionDim - 1)) / threadGroupWorkRegionDim;
+            int dispatchSrcY = (dispatchParams.RenderSize.y + (threadGroupWorkRegionDim - 1)) / threadGroupWorkRegionDim;
+
+            GenReactiveConsts.scale = dispatchParams.Scale;
+            GenReactiveConsts.threshold = dispatchParams.CutoffThreshold;
+            GenReactiveConsts.binaryValue = dispatchParams.BinaryValue;
+            GenReactiveConsts.flags = dispatchParams.Flags;
+            _generateReactiveConstantsBuffer.SetData(_generateReactiveConstantsArray);
+            
+            ((Fsr2GenerateReactivePipeline)_generateReactivePipeline).ScheduleDispatch(_commandBuffer, dispatchParams, dispatchSrcX, dispatchSrcY);
+            
+            Graphics.ExecuteCommandBuffer(_commandBuffer);
+        }
+
         private void SetupConstants(Fsr2.DispatchDescription dispatchParams, bool resetAccumulation)
         {
             ref Fsr2.Fsr2Constants constants = ref Constants;

Assets/Scripts/Fsr2Pipeline.cs

@@ -52,6 +52,7 @@ namespace FidelityFX
         protected static readonly int UavInternalUpscaled = Shader.PropertyToID("rw_internal_upscaled_color");
         protected static readonly int UavLockStatus = Shader.PropertyToID("rw_lock_status");
         protected static readonly int UavLumaHistory = Shader.PropertyToID("rw_luma_history");
+        protected static readonly int UavAutoReactive = Shader.PropertyToID("rw_output_autoreactive");
 
         // Constant buffer bindings
         protected static readonly int CbFsr2 = Shader.PropertyToID("cbFSR2");
@@ -338,4 +339,32 @@ namespace FidelityFX
             commandBuffer.DispatchCompute(ComputeShader, KernelIndex, dispatchX, dispatchY, 1);
         }
     }
+
+    internal class Fsr2GenerateReactivePipeline : Fsr2Pipeline
+    {
+        private readonly ComputeBuffer _generateReactiveConstants;
+
+        public Fsr2GenerateReactivePipeline(Fsr2.ContextDescription contextDescription, Fsr2Resources resources, ComputeBuffer generateReactiveConstants)
+            : base(contextDescription, resources, null)
+        {
+            _generateReactiveConstants = generateReactiveConstants;
+            
+            LoadComputeShader("FSR2/ffx_fsr2_autogen_reactive_pass");
+        }
+
+        public override void ScheduleDispatch(CommandBuffer commandBuffer, Fsr2.DispatchDescription dispatchParams, int frameIndex, int dispatchX, int dispatchY)
+        {
+        }
+
+        public void ScheduleDispatch(CommandBuffer commandBuffer, Fsr2.GenerateReactiveDescription dispatchParams, int dispatchX, int dispatchY)
+        {
+            commandBuffer.SetComputeTextureParam(ComputeShader, KernelIndex, SrvOpaqueOnly, dispatchParams.ColorOpaqueOnly);
+            commandBuffer.SetComputeTextureParam(ComputeShader, KernelIndex, SrvInputColor, dispatchParams.ColorPreUpscale);
+            commandBuffer.SetComputeTextureParam(ComputeShader, KernelIndex, UavAutoExposure, dispatchParams.OutReactive);
+            
+            commandBuffer.SetComputeConstantBufferParam(ComputeShader, CbGenReactive, _generateReactiveConstants, 0, Marshal.SizeOf<Fsr2.GenerateReactiveConstants>());
+            
+            commandBuffer.DispatchCompute(ComputeShader, KernelIndex, dispatchX, dispatchY, 1);
+        }
+    }
 }