Merge pull request #952 from Unity-Technologies/taa-edit-mode-fix

Fixed TAA only partially working in edit mode

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Camera/HDCamera.cs

         {
             // If TAA is enabled projMatrix will hold a jittered projection matrix. The original,
             // non-jittered projection matrix can be accessed via nonJitteredProjMatrix.
-            bool taaEnabled = Application.isPlaying && camera.cameraType == CameraType.Game &&
+            bool taaEnabled = camera.cameraType == CameraType.Game &&
                 CoreUtils.IsTemporalAntialiasingActive(postProcessLayer);
 
             var nonJitteredCameraProj = camera.projectionMatrix;
                 isFirstFrame = false;
             }
 
-            const uint taaFrameCount = 8;
-            taaFrameIndex = taaEnabled ? (uint)Time.renderedFrameCount % taaFrameCount : 0;
+            taaFrameIndex = taaEnabled ? (uint)postProcessLayer.temporalAntialiasing.sampleIndex : 0;
             taaFrameRotation = new Vector2(Mathf.Sin(taaFrameIndex * (0.5f * Mathf.PI)),
                                            Mathf.Cos(taaFrameIndex * (0.5f * Mathf.PI)));