Playing around with resetting and recreating FSR context upon resolution or quality mode change. Seems to be working quite well.

Assets/Scripts/Fsr2.cs

@@ -20,6 +20,8 @@ namespace FidelityFX
             else
                 flags &= ~InitializationFlags.EnableDepthInverted;
             
+            Debug.Log($"Setting up FSR2 with render size: {maxRenderSize.x}x{maxRenderSize.y}, display size: {displaySize.x}x{displaySize.y}, flags: {flags}");
+            
             var contextDescription = new ContextDescription
             {
                 Flags = flags,

Assets/Scripts/Fsr2Controller.cs

@@ -4,7 +4,6 @@ using System.Collections.Generic;
 using System.Linq;
 using FidelityFX;
 using UnityEngine;
-using UnityEngine.Experimental.Rendering;
 using UnityEngine.Rendering;
 
 /// <summary>
@@ -20,6 +19,9 @@ public class Fsr2Controller : MonoBehaviour
     [SerializeField, Range(0, 1)]
     private float sharpness = 0.8f;
     
+    [SerializeField]
+    private bool reset;
+    
     [HideInInspector]
     public Camera gameCamera;
 
@@ -37,7 +39,7 @@ public class Fsr2Controller : MonoBehaviour
     private Fsr2Context _context;
     private readonly Fsr2.DispatchDescription _dispatchDescription = new Fsr2.DispatchDescription();
 
-    private RenderTexture _outputRT;
+    private RenderTexture _upscaledOutput;
 
     private Material _copyMotionMat;
     private Material CopyMotionVectorsMaterial
@@ -73,16 +75,16 @@ public class Fsr2Controller : MonoBehaviour
 
         // TODO: do we need a depth buffer for the output? We will need depth & motion vectors for subsequent post-FX. How should FSR2 output these?
         // TODO: can probably be a temporary RT
-        _outputRT = new RenderTexture(DisplaySize.x, DisplaySize.y, 24, RenderTextureFormat.ARGBHalf) { name = "FSR2 Upscaled Output", enableRandomWrite = true };
-        _outputRT.Create();
+        _upscaledOutput = new RenderTexture(DisplaySize.x, DisplaySize.y, 24, RenderTextureFormat.ARGBHalf) { name = "FSR2 Upscaled Output", enableRandomWrite = true };
+        _upscaledOutput.Create();
     }
 
     private void OnDisable()
     {
-        if (_outputRT != null)
+        if (_upscaledOutput != null)
         {
-            _outputRT.Release();
-            _outputRT = null;
+            _upscaledOutput.Release();
+            _upscaledOutput = null;
         }
 
         if (_context != null)
@@ -116,7 +118,7 @@ public class Fsr2Controller : MonoBehaviour
 
         _dispatchDescription.ColorDepth = renderBuffer;
         _dispatchDescription.MotionVectors = motionVectors;
-        _dispatchDescription.Output = _outputRT;
+        _dispatchDescription.Output = _upscaledOutput;
         _dispatchDescription.Exposure = null;
         _dispatchDescription.Reactive = null;
         _dispatchDescription.PreExposure = 0;
@@ -130,6 +132,8 @@ public class Fsr2Controller : MonoBehaviour
         _dispatchDescription.CameraFar = gameCamera.farClipPlane;
         _dispatchDescription.CameraFovAngleVertical = gameCamera.fieldOfView * Mathf.Deg2Rad;
         _dispatchDescription.ViewSpaceToMetersFactor = 1.0f;    // 1 unit is 1 meter in Unity
+        _dispatchDescription.Reset = reset;
+        reset = false;
 
         _context.Dispatch(_dispatchDescription);
         
@@ -137,6 +141,6 @@ public class Fsr2Controller : MonoBehaviour
         
         // Output upscaled image to screen
         // TODO: we should probably use a shader to include depth & motion vectors into the output
-        Graphics.Blit(_outputRT, dest);
+        Graphics.Blit(_upscaledOutput, dest);
     }
 }

Assets/Scripts/SubsampleTest.cs

@@ -22,6 +22,9 @@ public class SubsampleTest : MonoBehaviour
     private Fsr2Controller _fsr2Controller;
     private float _renderScale;
     
+    private Fsr2.QualityMode _prevQualityMode;
+    private Vector2Int _prevScreenSize;
+    
     private void OnEnable()
     {
         _renderScale = 1.0f / Fsr2.GetUpscaleRatioFromQualityMode(qualityMode);
@@ -35,24 +38,19 @@ public class SubsampleTest : MonoBehaviour
             //outputCameraObject.transform.hideFlags = HideFlags.HideInHierarchy | HideFlags.HideInInspector;
 
             outputCamera = outputCameraObject.AddComponent<Camera>();
+            //outputCamera.CopyFrom(gameCamera);
             outputCamera.eventMask = 0;
+            outputCamera.cullingMask = 0;
+            outputCamera.clearFlags = CameraClearFlags.Nothing;
             
             _fsr2Controller = outputCameraObject.AddComponent<Fsr2Controller>();
+        }
+        
         _fsr2Controller.gameCamera = gameCamera;
         _fsr2Controller.outputCamera = outputCamera;
         _fsr2Controller.renderScale = _renderScale;
         _fsr2Controller.enabled = true;
 
-            //outputCamera.CopyFrom(gameCamera);
-            
-            outputCamera.cullingMask = 0;
-            outputCamera.clearFlags = CameraClearFlags.Nothing;
-        }
-        else
-        {
-            _fsr2Controller.enabled = true;
-        }
-
         Fsr2.GetRenderResolutionFromQualityMode(out var renderWidth, out var renderHeight, Screen.width, Screen.height, qualityMode);
         
         gameCamera.targetTexture = new RenderTexture(
@@ -69,6 +67,9 @@ public class SubsampleTest : MonoBehaviour
         // May need to leave this to the game dev, as we don't know which textures do and don't belong to the 3D scene
         float biasOffset = Fsr2.GetMipmapBiasOffset(_renderScale);
         Fsr2.GlobalCallbacks.ApplyMipmapBias(biasOffset);
+
+        _prevScreenSize = new Vector2Int(Screen.width, Screen.height);
+        _prevQualityMode = qualityMode;
     }
 
     private void OnDisable()
@@ -96,6 +97,12 @@ public class SubsampleTest : MonoBehaviour
         //outputCamera.CopyFrom(gameCamera);
 
         outputCamera.clearFlags = CameraClearFlags.Color;
+
+        if (Screen.width != _prevScreenSize.x || Screen.height != _prevScreenSize.y || qualityMode != _prevQualityMode)
+        {
+            enabled = false;
+            enabled = true;
+        }
     }
 
     private Rect _tempRect;