Reworked auto-exposure to use a double buffered render texture, which allows the smooth exposure transition logic to load a value that's guaranteed to be from the previous frame. Fixes artifacting and flickering issues caused by loading & storing to the same texture.

Packages/com.unity.postprocessing@3.2.2/PostProcessing/Runtime/Effects/Upscaling/ASR/Runtime/AsrContext.cs

@@ -148,7 +148,7 @@ namespace ArmASR
 
             // If auto exposure is enabled use the auto exposure SRV, otherwise what the app sends
             if ((_contextDescription.Flags & Asr.InitializationFlags.EnableAutoExposure) != 0)
-                dispatchParams.Exposure = new ResourceView(_resources.AutoExposure);
+                dispatchParams.Exposure = new ResourceView(_resources.AutoExposure[frameIndex]);
             else if (!dispatchParams.Exposure.IsValid) 
                 dispatchParams.Exposure = new ResourceView(_resources.DefaultExposure);
             
@@ -185,8 +185,8 @@ namespace ArmASR
                 commandBuffer.ClearRenderTarget(false, true, Color.clear);
                 
                 // Auto exposure always used to track luma changes in locking logic
-                commandBuffer.SetRenderTarget(_resources.AutoExposure);
-                commandBuffer.ClearRenderTarget(false, true, new Color(0f, 1e8f, 0f, 0f));
+                commandBuffer.SetRenderTarget(_resources.AutoExposure[frameIndex ^ 1]);
+                commandBuffer.ClearRenderTarget(false, true, new Color(-1f, 1e8f, 0f, 0f));
                 
                 // Reset atomic counter to 0
                 commandBuffer.SetRenderTarget(_resources.SpdAtomicCounter);

Packages/com.unity.postprocessing@3.2.2/PostProcessing/Runtime/Effects/Upscaling/ASR/Runtime/AsrPass.cs

@@ -147,11 +147,12 @@ namespace ArmASR
         protected override void DoScheduleDispatch(CommandBuffer commandBuffer, Asr.DispatchDescription dispatchParams, int frameIndex, int dispatchX, int dispatchY)
         {
             commandBuffer.SetComputeResourceParam(ComputeShader, KernelIndex, AsrShaderIDs.SrvInputColor, dispatchParams.Color);
+            commandBuffer.SetComputeTextureParam(ComputeShader, KernelIndex, AsrShaderIDs.SrvAutoExposure, Resources.AutoExposure[frameIndex ^ 1]);
 
             commandBuffer.SetComputeTextureParam(ComputeShader, KernelIndex, AsrShaderIDs.UavSpdAtomicCount, Resources.SpdAtomicCounter);
             commandBuffer.SetComputeTextureParam(ComputeShader, KernelIndex, AsrShaderIDs.UavExposureMipLumaChange, Resources.SceneLuminance, ShadingChangeMipLevel);
             commandBuffer.SetComputeTextureParam(ComputeShader, KernelIndex, AsrShaderIDs.UavExposureMip5, Resources.SceneLuminance, 5);
-            commandBuffer.SetComputeTextureParam(ComputeShader, KernelIndex, AsrShaderIDs.UavAutoExposure, Resources.AutoExposure);
+            commandBuffer.SetComputeTextureParam(ComputeShader, KernelIndex, AsrShaderIDs.UavAutoExposure, Resources.AutoExposure[frameIndex]);
 
             commandBuffer.SetComputeConstantBufferParam(ComputeShader, AsrShaderIDs.CbFsr2, Constants, 0, Constants.stride);
             commandBuffer.SetComputeConstantBufferParam(ComputeShader, AsrShaderIDs.CbSpd, _spdConstants, 0, _spdConstants.stride);
@@ -273,7 +274,7 @@ namespace ArmASR
             commandBuffer.SetGlobalTexture(AsrShaderIDs.SrvLanczosLut, Resources.LanczosLut);
             commandBuffer.SetGlobalTexture(AsrShaderIDs.SrvUpscaleMaximumBiasLut, Resources.MaximumBiasLut);
             commandBuffer.SetGlobalTexture(AsrShaderIDs.SrvSceneLuminanceMips, Resources.SceneLuminance);
-            commandBuffer.SetGlobalTexture(AsrShaderIDs.SrvAutoExposure, Resources.AutoExposure);
+            commandBuffer.SetGlobalTexture(AsrShaderIDs.SrvAutoExposure, Resources.AutoExposure[frameIndex]);
             commandBuffer.SetGlobalTexture(AsrShaderIDs.SrvLumaHistory, Resources.LumaHistory[frameIndex ^ 1]);
             commandBuffer.SetGlobalTexture(AsrShaderIDs.SrvInternalTemporalReactive, Resources.InternalReactive[frameIndex ^ 1]);
             

Packages/com.unity.postprocessing@3.2.2/PostProcessing/Runtime/Effects/Upscaling/ASR/Runtime/AsrResources.cs

@@ -36,8 +36,8 @@ namespace ArmASR
         public Texture2D LanczosLut;
         public Texture2D MaximumBiasLut;
         public RenderTexture SpdAtomicCounter;
-        public RenderTexture AutoExposure;
         public RenderTexture SceneLuminance;
+        public readonly RenderTexture[] AutoExposure = new RenderTexture[2];
         public readonly RenderTexture[] DilatedMotionVectors = new RenderTexture[2];
         public readonly RenderTexture[] LockStatus = new RenderTexture[2];
         public readonly RenderTexture[] InternalUpscaled = new RenderTexture[2];
@@ -90,10 +90,6 @@ namespace ArmASR
             SpdAtomicCounter = new RenderTexture(1, 1, 0, GraphicsFormat.R32_UInt) { name = "ASR_SpdAtomicCounter", enableRandomWrite = true };
             SpdAtomicCounter.Create();
 
-            // Resource FSR2_AutoExposure: FFX_RESOURCE_USAGE_UAV, FFX_SURFACE_FORMAT_R32G32_FLOAT, FFX_RESOURCE_FLAGS_NONE
-            AutoExposure = new RenderTexture(1, 1, 0, rg16Format) { name = "ASR_AutoExposure", enableRandomWrite = true };
-            AutoExposure.Create();
-            
             // Resource FSR2_ExposureMips: FFX_RESOURCE_USAGE_UAV, FFX_SURFACE_FORMAT_R16_FLOAT, FFX_RESOURCE_FLAGS_ALIASABLE
             // This is a rather special case: it's an aliasable resource, but because we require a mipmap chain and bind specific mip levels per shader, we can't easily use temporary RTs for this.
             int w = contextDescription.MaxRenderSize.x / 2, h = contextDescription.MaxRenderSize.y / 2;
@@ -101,6 +97,9 @@ namespace ArmASR
             SceneLuminance = new RenderTexture(w, h, 0, r16Format, mipCount) { name = "ASR_ExposureMips", enableRandomWrite = true, useMipMap = true, autoGenerateMips = false };
             SceneLuminance.Create();
             
+            // Resource FSR2_AutoExposure: FFX_RESOURCE_USAGE_UAV, FFX_SURFACE_FORMAT_R32G32_FLOAT, FFX_RESOURCE_FLAGS_NONE
+            CreateDoubleBufferedResource(AutoExposure, "ASR_AutoExposure", Vector2Int.one, rg16Format);
+            
             // Resources FSR2_InternalDilatedVelocity1/2: FFX_RESOURCE_USAGE_RENDERTARGET | FFX_RESOURCE_USAGE_UAV, FFX_SURFACE_FORMAT_R16G16_FLOAT, FFX_RESOURCE_FLAGS_NONE
             CreateDoubleBufferedResource(DilatedMotionVectors, "ASR_InternalDilatedVelocity", contextDescription.MaxRenderSize, GraphicsFormat.R16G16_SFloat);
             
@@ -194,8 +193,8 @@ namespace ArmASR
             DestroyResource(InternalUpscaled);
             DestroyResource(LockStatus);
             DestroyResource(DilatedMotionVectors);
+            DestroyResource(AutoExposure);
             DestroyResource(ref SceneLuminance);
-            DestroyResource(ref AutoExposure);
             DestroyResource(ref DefaultReactive);
             DestroyResource(ref DefaultExposure);
             DestroyResource(ref MaximumBiasLut);

Packages/com.unity.postprocessing@3.2.2/PostProcessing/Runtime/Effects/Upscaling/ASR/Shaders/shaders/ffxm_fsr2_compute_luminance_pyramid_pass.hlsl

@@ -20,6 +20,7 @@
 // SOFTWARE.
 
 #define FSR2_BIND_SRV_INPUT_COLOR                     0
+#define FSR2_BIND_SRV_AUTO_EXPOSURE                   1
 
 #define FSR2_BIND_UAV_SPD_GLOBAL_ATOMIC               1
 #define FSR2_BIND_UAV_EXPOSURE_MIP_LUMA_CHANGE        2

Packages/com.unity.postprocessing@3.2.2/PostProcessing/Runtime/Effects/Upscaling/ASR/Shaders/shaders/fsr2/ffxm_fsr2_callbacks_hlsl.h

@@ -946,7 +946,9 @@ FfxFloat32x3 LoadOpaqueOnly(FFXM_PARAMETER_IN FFXM_MIN16_I2 iPxPos)
 
 FfxFloat32x2 SPD_LoadExposureBuffer()
 {
-#if defined FSR2_BIND_UAV_AUTO_EXPOSURE
+#if defined FSR2_BIND_SRV_AUTO_EXPOSURE
+    return r_auto_exposure[FfxInt32x2(0, 0)].rg;
+#elif defined FSR2_BIND_UAV_AUTO_EXPOSURE
     return rw_auto_exposure[FfxInt32x2(0, 0)].rg;
 #else
     return FfxFloat32x2(0.f, 0.f);