Added some extra safety checks

FSR2UnityPlugin.cpp

@@ -160,6 +160,11 @@ static uint32_t AllocateFeatureSlot()
 
 static void FreeFeatureSlot(uint32_t featureSlot)
 {
+    // Prevent duplicate free slots
+    auto& slots = s_FeatureSlots._Get_container();
+    if (std::find(slots.begin(), slots.end(), featureSlot) != slots.end())
+        return;
+
     s_FeatureSlots.push(featureSlot);
     memset(&s_Features[featureSlot], 0, sizeof(FSR2Feature));
 }
@@ -221,6 +226,8 @@ extern "C" bool UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API AMDUP_InitApi()
 static void DestroyFeature(uint32_t featureSlot)
 {
     auto& feature = s_Features[featureSlot];
+    if (!feature.isValid)
+        return;
 
     if (s_GraphicsD3D12 != nullptr)
     {
@@ -244,11 +251,8 @@ static void DestroyFeature(uint32_t featureSlot)
         }
     }
 
-    if (feature.isValid)
-    {
-        ffxFsr2ContextDestroy(&feature.upscalingContext);
-        FreeFeatureSlot(featureSlot);
-    }
+    ffxFsr2ContextDestroy(&feature.upscalingContext);
+    FreeFeatureSlot(featureSlot);
 }
 
 extern "C" void UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API AMDUP_ShutdownApi()