Wait for graphics queue to become idle before destroying an upscale context, in case a dispatch is still busy. Fixes remaining crashes in Vulkan when enabling/disabling the plugin too rapidly.

FSR3UnityPlugin.cpp

@@ -260,6 +260,16 @@ static void DestroyFeature(uint32_t featureSlot)
             WaitForSingleObjectEx(s_FrameFenceEventHandle, INFINITE, false);
         }
     }
+    else if (s_GraphicsVulkan != nullptr)
+    {
+        UnityVulkanRecordingState state;
+        s_GraphicsVulkan->CommandRecordingState(&state, kUnityVulkanGraphicsQueueAccess_DontCare);
+        if (feature.dispatchFrameValue > state.safeFrameNumber)
+        {
+            UnityVulkanInstance instance = s_GraphicsVulkan->Instance();
+            vkQueueWaitIdle(instance.graphicsQueue);
+        }
+    }
 
     if (feature.upscalingContext != nullptr)
     {
@@ -483,7 +493,7 @@ static void UNITY_INTERFACE_API OnRenderEventAndData(int eventID, void* data)
             s_GraphicsVulkan->CommandRecordingState(&state, kUnityVulkanGraphicsQueueAccess_DontCare);
             dispatchUpscale.commandList = state.commandBuffer;
 
-            // TODO: probably need to make use of state.currentFrameNumber and state.safeFrameNumber to keep track of when it's safe to destroy the upscaling context
+            // Keep track of which frame this dispatch is happening on, so we can verify when it's finished
             feature.dispatchFrameValue = state.currentFrameNumber;
 
             UnityVulkanInstance instance = s_GraphicsVulkan->Instance();