Reworked SGSR2 classes, moving more logic to the base class, and implemented clip-space delta matrix as well as the is-camera-still logic.

Packages/com.unity.postprocessing@3.2.2/PostProcessing/Runtime/Effects/Upscaling/SGSR2/SGSR2.cs

@@ -10,15 +10,20 @@ public static class SGSR2
     {
         public Vector2Int renderSize;
         public Vector2Int displaySize;
+        
         public Vector2 renderSizeRcp;
         public Vector2 displaySizeRcp;
+        
         public Vector2 jitterOffset;
         public Vector2 padding1;
+        
         public Matrix4x4 clipToPrevClip;
+        
         public float preExposure;
         public float cameraFovAngleHor;
         public float cameraNear;
         public float minLerpContribution;
+        
         public uint bSameCamera;
         public uint reset;
     }

Packages/com.unity.postprocessing@3.2.2/PostProcessing/Runtime/Effects/Upscaling/SGSR2Upscaler.cs

@@ -8,6 +8,8 @@ namespace UnityEngine.Rendering.PostProcessing
     {
         public static bool IsSupported => SystemInfo.supportsComputeShaders;
         
+        protected abstract string VariantName { get; }
+        
         protected RenderTexture _colorLuma;
         protected RenderTexture _motionDepthAlpha;
         protected RenderTexture _motionDepthClipAlpha;
@@ -41,5 +43,66 @@ namespace UnityEngine.Rendering.PostProcessing
             DestroyRenderTexture(ref _motionDepthAlpha);
             DestroyRenderTexture(ref _colorLuma);
         }
+        
+        public override void Render(PostProcessRenderContext context, Upscaling config)
+        {
+            var cmd = context.command;
+            cmd.BeginSample(VariantName);
+            
+            Matrix4x4 clipToPrevClip = Matrix4x4.identity;
+            bool isCameraStill = false;
+            if (_frameCount > 0 && !config.Reset)
+            {
+                // We need to use the projection matrix as it is used on the GPU to match what Unity keeps in Camera.previousViewProjectionMatrix
+                Matrix4x4 viewProj = GL.GetGPUProjectionMatrix(context.camera.nonJitteredProjectionMatrix, true) * context.camera.worldToCameraMatrix;
+                clipToPrevClip = context.camera.previousViewProjectionMatrix * viewProj.inverse;
+                isCameraStill = IsCameraStill(viewProj, context.camera.previousViewProjectionMatrix);
+            }
+            
+            ref var parms = ref _paramsBuffer.Value;
+            parms.renderSize = config.GetScaledRenderSize(context.camera);
+            parms.displaySize = config.UpscaleSize;
+            parms.renderSizeRcp = new Vector2(1.0f / parms.renderSize.x, 1.0f / parms.renderSize.y);
+            parms.displaySizeRcp = new Vector2(1.0f / parms.displaySize.x, 1.0f / parms.displaySize.y);
+            parms.jitterOffset = config.JitterOffset;
+            parms.clipToPrevClip = clipToPrevClip;
+            parms.preExposure = config.preExposure;
+            parms.cameraFovAngleHor = Mathf.Tan(context.camera.fieldOfView * Mathf.Deg2Rad * 0.5f) * (float)parms.renderSize.x / parms.renderSize.y;
+            parms.cameraNear = context.camera.nearClipPlane;
+            parms.minLerpContribution = 0f;
+            parms.bSameCamera = isCameraStill ? 1u : 0u;
+            parms.reset = config.Reset ? 1u : 0u;
+            _paramsBuffer.UpdateBufferData(cmd);
+
+            if (_frameCount == 0 || config.Reset)
+            {
+                cmd.SetRenderTarget(_lumaHistory[0]);
+                cmd.ClearRenderTarget(false, true, Color.clear);
+                cmd.SetRenderTarget(_lumaHistory[1]);
+                cmd.ClearRenderTarget(false, true, Color.clear);
+                cmd.SetRenderTarget(_upscaleHistory[0]);
+                cmd.ClearRenderTarget(false, true, Color.clear);
+                cmd.SetRenderTarget(_upscaleHistory[1]);
+                cmd.ClearRenderTarget(false, true, Color.clear);
+            }
+            
+            DoRender(cmd, context, config);
+
+            cmd.EndSample(VariantName);
+            _frameCount++;
+        }
+
+        protected abstract void DoRender(CommandBuffer cmd, PostProcessRenderContext context, Upscaling config);
+
+        private static bool IsCameraStill(in Matrix4x4 currViewProj, in Matrix4x4 prevViewProj, float threshold = 1e-5f)
+        {
+            float vpDiff = 0f;
+            for (int i = 0; i < 16; i++)
+            {
+                vpDiff += Mathf.Abs(currViewProj[i] - prevViewProj[i]);
+            }
+
+            return vpDiff < threshold;
+        }
     }
 }

Packages/com.unity.postprocessing@3.2.2/PostProcessing/Runtime/Effects/Upscaling/SGSR2Upscaler_2PassCS.cs

@@ -4,43 +4,12 @@ namespace UnityEngine.Rendering.PostProcessing
 {
     internal class SGSR2Upscaler_2PassCS: SGSR2Upscaler
     {
-        public override void Render(PostProcessRenderContext context, Upscaling config)
-        {
-            var cmd = context.command;
-            cmd.BeginSample("SGSR2 2-Pass CS");
-            
-            ref var parms = ref _paramsBuffer.Value;
-            parms.renderSize = config.GetScaledRenderSize(context.camera);
-            parms.displaySize = config.UpscaleSize;
-            parms.renderSizeRcp = new Vector2(1.0f / parms.renderSize.x, 1.0f / parms.renderSize.y);
-            parms.displaySizeRcp = new Vector2(1.0f / parms.displaySize.x, 1.0f / parms.displaySize.y);
-            parms.jitterOffset = config.JitterOffset;
-            parms.clipToPrevClip = Matrix4x4.identity; // TODO: clipToPrevClip => (previous_view_proj * inv_vp)
-            parms.preExposure = config.preExposure;
-            parms.cameraFovAngleHor = Mathf.Tan(context.camera.fieldOfView * Mathf.Deg2Rad * 0.5f) * (float)parms.renderSize.x / parms.renderSize.y;
-            parms.cameraNear = context.camera.nearClipPlane;
-            parms.minLerpContribution = 0f;
-            parms.bSameCamera = 0u;
-            parms.reset = config.Reset ? 1u : 0u;
-            _paramsBuffer.UpdateBufferData(cmd);
+        protected override string VariantName => "SGSR2 2-Pass CS";
 
-            if (_frameCount == 0 || config.Reset)
+        protected override void DoRender(CommandBuffer cmd, PostProcessRenderContext context, Upscaling config)
         {
-                cmd.SetRenderTarget(_lumaHistory[0]);
-                cmd.ClearRenderTarget(false, true, Color.clear);
-                cmd.SetRenderTarget(_lumaHistory[1]);
-                cmd.ClearRenderTarget(false, true, Color.clear);
-                cmd.SetRenderTarget(_upscaleHistory[0]);
-                cmd.ClearRenderTarget(false, true, Color.clear);
-                cmd.SetRenderTarget(_upscaleHistory[1]);
-                cmd.ClearRenderTarget(false, true, Color.clear);
-            }
-
             Convert(cmd, context, config);
             Upscale(cmd, context);
-            
-            cmd.EndSample("SGSR2 2-Pass CS");
-            _frameCount++;
         }
 
         private void Convert(CommandBuffer cmd, PostProcessRenderContext context, Upscaling config)

Packages/com.unity.postprocessing@3.2.2/PostProcessing/Runtime/Effects/Upscaling/SGSR2Upscaler_3PassCS.cs

@@ -4,44 +4,13 @@ namespace UnityEngine.Rendering.PostProcessing
 {
     internal class SGSR2Upscaler_3PassCS: SGSR2Upscaler
     {
-        public override void Render(PostProcessRenderContext context, Upscaling config)
-        {
-            var cmd = context.command;
-            cmd.BeginSample("SGSR2 3-Pass CS");
-            
-            ref var parms = ref _paramsBuffer.Value;
-            parms.renderSize = config.GetScaledRenderSize(context.camera);
-            parms.displaySize = config.UpscaleSize;
-            parms.renderSizeRcp = new Vector2(1.0f / parms.renderSize.x, 1.0f / parms.renderSize.y);
-            parms.displaySizeRcp = new Vector2(1.0f / parms.displaySize.x, 1.0f / parms.displaySize.y);
-            parms.jitterOffset = config.JitterOffset;
-            parms.clipToPrevClip = Matrix4x4.identity; // TODO: clipToPrevClip => (previous_view_proj * inv_vp)
-            parms.preExposure = config.preExposure;
-            parms.cameraFovAngleHor = Mathf.Tan(context.camera.fieldOfView * Mathf.Deg2Rad * 0.5f) * (float)parms.renderSize.x / parms.renderSize.y;
-            parms.cameraNear = context.camera.nearClipPlane;
-            parms.minLerpContribution = 0f;
-            parms.bSameCamera = 0u;
-            parms.reset = config.Reset ? 1u : 0u;
-            _paramsBuffer.UpdateBufferData(cmd);
+        protected override string VariantName => "SGSR2 3-Pass CS";
         
-            if (_frameCount == 0 || config.Reset)
+        protected override void DoRender(CommandBuffer cmd, PostProcessRenderContext context, Upscaling config)
         {
-                cmd.SetRenderTarget(_lumaHistory[0]);
-                cmd.ClearRenderTarget(false, true, Color.clear);
-                cmd.SetRenderTarget(_lumaHistory[1]);
-                cmd.ClearRenderTarget(false, true, Color.clear);
-                cmd.SetRenderTarget(_upscaleHistory[0]);
-                cmd.ClearRenderTarget(false, true, Color.clear);
-                cmd.SetRenderTarget(_upscaleHistory[1]);
-                cmd.ClearRenderTarget(false, true, Color.clear);
-            }
-
             Convert(cmd, context, config);
             Activate(cmd, context);
             Upscale(cmd, context);
-            
-            cmd.EndSample("SGSR2 3-Pass CS");
-            _frameCount++;
         }
 
         private void Convert(CommandBuffer cmd, PostProcessRenderContext context, Upscaling config)