From a576f94e9549c4527040342455f3bb5b9f7fc9ce Mon Sep 17 00:00:00 2001
From: Nico de Poel <ndepoel@gmail.com>
Date: Sat, 18 Feb 2023 13:08:12 +0100
Subject: [PATCH] A bit of reorganization in how shaders and buffers are
 created and destroyed. Also using Unity's system info to decide on inverted
 depth or not.

---
 Assets/Scripts/Fsr2.cs          |  6 ++-
 Assets/Scripts/Fsr2Callbacks.cs |  5 +++
 Assets/Scripts/Fsr2Context.cs   | 71 +++++++++++++++++++++------------
 3 files changed, 55 insertions(+), 27 deletions(-)

diff --git a/Assets/Scripts/Fsr2.cs b/Assets/Scripts/Fsr2.cs
index d10e047..062b2f5 100644
--- a/Assets/Scripts/Fsr2.cs
+++ b/Assets/Scripts/Fsr2.cs
@@ -1,5 +1,6 @@
 using System;
 using UnityEngine;
+using UnityEngine.Rendering;
 
 namespace FidelityFX
 {
@@ -63,7 +64,10 @@ namespace FidelityFX
         /// </summary>
         public static Fsr2Context CreateContext(InitializationFlags flags = 0)
         {
-            // flags |= InitializationFlags.EnableDepthInverted;   // Depends on the runtime platform
+            if (SystemInfo.usesReversedZBuffer)
+                flags |= InitializationFlags.EnableDepthInverted;
+            else
+                flags &= ~InitializationFlags.EnableDepthInverted;
             
             var contextDescription = new ContextDescription
             {
diff --git a/Assets/Scripts/Fsr2Callbacks.cs b/Assets/Scripts/Fsr2Callbacks.cs
index 0238bee..83845d3 100644
--- a/Assets/Scripts/Fsr2Callbacks.cs
+++ b/Assets/Scripts/Fsr2Callbacks.cs
@@ -14,6 +14,11 @@ namespace FidelityFX
             return Resources.Load<ComputeShader>(name);
         }
 
+        public virtual void UnloadComputeShader(ComputeShader shader)
+        {
+            Resources.UnloadAsset(shader);
+        }
+
         public virtual void ApplyMipmapBias(float biasOffset)
         {
             foreach (var texture in Resources.FindObjectsOfTypeAll<Texture2D>())
diff --git a/Assets/Scripts/Fsr2Context.cs b/Assets/Scripts/Fsr2Context.cs
index 8625692..8f7578d 100644
--- a/Assets/Scripts/Fsr2Context.cs
+++ b/Assets/Scripts/Fsr2Context.cs
@@ -32,9 +32,9 @@ namespace FidelityFX
         {
             _contextDescription = contextDescription;
             
-            _fsr2ConstantsBuffer = new ComputeBuffer(1, Marshal.SizeOf<Fsr2Constants>(), ComputeBufferType.Constant);
-            _spdConstantsBuffer = new ComputeBuffer(1, Marshal.SizeOf<SpdConstants>(), ComputeBufferType.Constant);
-            _rcasConstantsBuffer = new ComputeBuffer(1, Marshal.SizeOf<RcasConstants>(), ComputeBufferType.Constant);
+            _fsr2ConstantsBuffer = CreateConstantBuffer<Fsr2Constants>();
+            _spdConstantsBuffer = CreateConstantBuffer<SpdConstants>();
+            _rcasConstantsBuffer = CreateConstantBuffer<RcasConstants>();
 
             // Set defaults
             _fsr2ConstantsArray[0].displaySize = _contextDescription.DisplaySize;
@@ -71,12 +71,6 @@ namespace FidelityFX
             LoadComputeShader("FSR2/ffx_fsr2_tcr_autogen_pass", ref _tcrAutogenShader);
         }
 
-        private void LoadComputeShader(string name, ref ComputeShader shaderRef)
-        {
-            if (shaderRef == null)
-                shaderRef = _contextDescription.Callbacks.LoadComputeShader(name);
-        }
-        
         public void Dispatch(Fsr2.DispatchDescription dispatchDescription)
         {
             _fsr2ConstantsArray[0].preExposure = dispatchDescription.PreExposure;
@@ -110,25 +104,21 @@ namespace FidelityFX
 
         public void Destroy()
         {
-            if (_rcasConstantsBuffer != null)
-            {
-                _rcasConstantsBuffer.Release();
-                _rcasConstantsBuffer = null;
-            }
+            DestroyConstantBuffer(ref _rcasConstantsBuffer);
+            DestroyConstantBuffer(ref _spdConstantsBuffer);
+            DestroyConstantBuffer(ref _fsr2ConstantsBuffer);
 
-            if (_spdConstantsBuffer != null)
-            {
-                _spdConstantsBuffer.Release();
-                _spdConstantsBuffer = null;
-            }
-
-            if (_fsr2ConstantsBuffer != null)
-            {
-                _fsr2ConstantsBuffer.Release();
-                _fsr2ConstantsBuffer = null;
-            }
+            DestroyComputeShader(ref _tcrAutogenShader);
+            DestroyComputeShader(ref _generateReactiveShader);
+            DestroyComputeShader(ref _accumulateShader);
+            DestroyComputeShader(ref _lockShader);
+            DestroyComputeShader(ref _reconstructPreviousDepthShader);
+            DestroyComputeShader(ref _depthClipShader);
+            DestroyComputeShader(ref _prepareInputColorShader);
+            DestroyComputeShader(ref _rcasShader);
+            DestroyComputeShader(ref _computeLuminancePyramidShader);
         }
-        
+
         [Serializable, StructLayout(LayoutKind.Sequential)]
         private struct Fsr2Constants
         {
@@ -203,5 +193,34 @@ namespace FidelityFX
             new(1064229695u, 997604214u),
             new(1065353216u, 1006648320),
         };
+        
+        private static ComputeBuffer CreateConstantBuffer<TConstants>() where TConstants: struct
+        {
+            return new ComputeBuffer(1, Marshal.SizeOf<TConstants>(), ComputeBufferType.Constant);
+        }
+        
+        private void LoadComputeShader(string name, ref ComputeShader shaderRef)
+        {
+            if (shaderRef == null)
+                shaderRef = _contextDescription.Callbacks.LoadComputeShader(name);
+        }
+        
+        private static void DestroyConstantBuffer(ref ComputeBuffer bufferRef)
+        {
+            if (bufferRef == null)
+                return;
+            
+            bufferRef.Release();
+            bufferRef = null;
+        }
+
+        private void DestroyComputeShader(ref ComputeShader shaderRef)
+        {
+            if (shaderRef == null)
+                return;
+
+            _contextDescription.Callbacks.UnloadComputeShader(shaderRef);
+            shaderRef = null;
+        }
     }
 }