Question Problem when upgrading Unity 2021 to 2022, URP for blit post process

I'm trying to upgrade to Unity 2022.

But my post process is broken if I use a RTHandle for a temporary render texure.

Here a working code with the obsolete API (RenderTargetHandle for a temporary render texture).

Code (CSharp):

1. using UnityEngine;
2. using UnityEngine.Rendering;
3. using UnityEngine.Rendering.Universal;
4.  
5. public class BlitMaterialFeature : ScriptableRendererFeature
6. {
7.     class RenderPass : ScriptableRenderPass
8.     {
9.         private string profilingName;
10.         private Material material;
11.         private int materialPassIndex;
12.         private RTHandle rtSource;
13.         private RTHandle rtTempTextureHandle;
14.         RenderTargetHandle tempTextureHandle;
15.         ProfilingSampler profilingSampler = new ProfilingSampler("Blit");
16.  
17.         public RenderPass(string profilingName, Material material, int passIndex) : base()
18.         {
19.             this.profilingName = profilingName;
20.             this.material = material;
21.             this.materialPassIndex = passIndex;
22.             //tempTextureHandle.Init("_TempBlitMaterialTexture");
23.             //RTHandles.Initialize(Screen.width, Screen.height);
24.             rtTempTextureHandle = RTHandles.Alloc("_TempBlitMaterialTexture2", name: "_TempBlitMaterialTexture2");
25.         }
26.  
27.         public override void OnCameraSetup(CommandBuffer cmd, ref RenderingData renderingData)
28.         {
29.             ConfigureTarget(rtTempTextureHandle);
30.         }
31.  
32.         public void SetSource(RTHandle source)
33.         {
34.             rtSource = source;
35.         }
36.  
37.         public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData)
38.         {
39.             var cameraData = renderingData.cameraData;
40.             if (cameraData.camera.cameraType != CameraType.Game)
41.                 return;
42.  
43.             CommandBuffer cmd = CommandBufferPool.Get(profilingName);
44.  
45.             RenderTextureDescriptor cameraTextureDesc = renderingData.cameraData.cameraTargetDescriptor;
46.             cameraTextureDesc.depthBufferBits = 0;
47.  
48.             //RenderingUtils.ReAllocateIfNeeded(ref rtTempTextureHandle, cameraTextureDesc, FilterMode.Bilinear);
49.             cmd.GetTemporaryRT(tempTextureHandle.id, cameraTextureDesc, FilterMode.Bilinear);
50.             //cmd.GetTemporaryRT(Shader.PropertyToID(rtTempTextureHandle.name), cameraTextureDesc, FilterMode.Bilinear);
51.             using (new ProfilingScope(cmd, profilingSampler))
52.             {
53.                 //Blitter.BlitTexture(cmd, rtSource, rtTempTextureHandle, material, materialPassIndex);
54.                 Blit(cmd, rtSource, /*rtTempTextureHandle*/tempTextureHandle.Identifier(), material, materialPassIndex);
55.                 //Blitter.BlitCameraTexture(cmd, rtTempTextureHandle, rtSource);
56.                 Blit(cmd, /*rtTempTextureHandle*/ tempTextureHandle.Identifier(), rtSource);
57.             }
58.  
59.             context.ExecuteCommandBuffer(cmd);
60.             cmd.Clear();
61.             CommandBufferPool.Release(cmd);
62.         }
63.  
64.         public void Dispose()
65.         {
66.             rtTempTextureHandle?.Release();
67.         }
68.     }
69.  
70.     [System.Serializable]
71.     public class Settings
72.     {
73.         public Material material;
74.         public int materialPassIndex = -1; // -1 means render all passes
75.         public RenderPassEvent renderEvent = RenderPassEvent.AfterRenderingOpaques;
76.     }
77.  
78.     [SerializeField]
79.     private Settings settings = new Settings();
80.  
81.     private RenderPass renderPass;
82.  
83.     public Material Material
84.     {
85.         get => settings.material;
86.     }
87.  
88.     public override void Create()
89.     {
90.         renderPass = new RenderPass(name, settings.material, settings.materialPassIndex);
91.         renderPass.renderPassEvent = settings.renderEvent;
92.     }
93.  
94.     public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData)
95.     {
96.         if (renderingData.cameraData.cameraType == CameraType.Game)
97.             renderer.EnqueuePass(renderPass); // letting the renderer know which passes will be used before allocation
98.     }
99.  
100.     public override void SetupRenderPasses(ScriptableRenderer renderer, in RenderingData renderingData)
101.     {
102.         if (renderingData.cameraData.cameraType == CameraType.Game)
103.         {
104.             // Calling ConfigureInput with the ScriptableRenderPassInput.Color argument
105.             // ensures that the opaque texture is available to the Render Pass.
106.             renderPass.ConfigureInput(ScriptableRenderPassInput.Color);
107.             renderPass.SetSource(renderer.cameraColorTargetHandle);  // use of target after allocation
108.         }
109.     }
110. }

Code (CSharp):

1. RenderingUtils.ReAllocateIfNeeded(ref rtTempTextureHandle, cameraTextureDesc, FilterMode.Bilinear);

Always give me a black screen in the Frame debugger.

If I skip it I have null exception in the Blit method (rtTempTextureHandle is null).

I look at these threads but I'm still helpless:
https://forum.unity.com/threads/ren...lete-deprecated-in-favor-of-rthandle.1211052/
https://forum.unity.com/threads/urp-13-1-8-proper-rthandle-usage-in-a-renderer-feature.1341164/
https://docs.unity3d.com/Packages/c...iversal@13.1/manual/upgrade-guide-2022-1.html

For example this version give me NullReferenceException

Code (CSharp):

1.     //RenderingUtils.ReAllocateIfNeeded(ref rtTempTextureHandle, cameraTextureDesc, FilterMode.Bilinear);
2.             //cmd.GetTemporaryRT(tempTextureHandle.id, cameraTextureDesc, FilterMode.Bilinear);
3.             cmd.GetTemporaryRT(Shader.PropertyToID(rtTempTextureHandle.name), cameraTextureDesc, FilterMode.Bilinear);
4.             using (new ProfilingScope(cmd, profilingSampler))
5.             {
6.                 //Blitter.BlitTexture(cmd, rtSource, rtTempTextureHandle, material, materialPassIndex);
7.                 Blit(cmd, rtSource, rtTempTextureHandle/*tempTextureHandle.Identifier()*/, material, materialPassIndex);
8.                 //Blitter.BlitCameraTexture(cmd, rtTempTextureHandle, rtSource);
9.                 Blit(cmd, rtTempTextureHandle/* tempTextureHandle.Identifier()*/, rtSource);
10.             }

NullReferenceException: Object reference not set to an instance of an object

UnityEngine.Rendering.Universal.Internal.CopyDepthPass.ExecutePass (UnityEngine.Rendering.ScriptableRenderContext context, UnityEngine.Rendering.Universal.Internal.CopyDepthPass+PassData passData, UnityEngine.Rendering.CommandBuffer& cmd, UnityEngine.Rendering.Universal.CameraData& cameraData, UnityEngine.Rendering.RTHandle source, UnityEngine.Rendering.RTHandle destination) (at ./Library/PackageCache/com.unity.render-pipelines.universal@14.0.6/Runtime/Passes/CopyDepthPass.cs:161)

UnityEngine.Rendering.Universal.Internal.CopyDepthPass.Execute (UnityEngine.Rendering.ScriptableRenderContext context, UnityEngine.Rendering.Universal.RenderingData& renderingData) (at ./Library/PackageCache/com.unity.render-pipelines.universal@14.0.6/Runtime/Passes/CopyDepthPass.cs:103)

UnityEngine.Rendering.Universal.ScriptableRenderer.ExecuteRenderPass (UnityEngine.Rendering.ScriptableRenderContext context, UnityEngine.Rendering.Universal.ScriptableRenderPass renderPass, UnityEngine.Rendering.Universal.RenderingData& renderingData) (at ./Library/PackageCache/com.unity.render-pipelines.universal@14.0.6/Runtime/ScriptableRenderer.cs:1446)

UnityEngine.Rendering.Universal.ScriptableRenderer.ExecuteBlock (System.Int32 blockIndex, UnityEngine.Rendering.Universal.ScriptableRenderer+RenderBlocks& renderBlocks, UnityEngine.Rendering.ScriptableRenderContext context, UnityEngine.Rendering.Universal.RenderingData& renderingData, System.Boolean submit) (at ./Library/PackageCache/com.unity.render-pipelines.universal@14.0.6/Runtime/ScriptableRenderer.cs:1402)

UnityEngine.Rendering.Universal.ScriptableRenderer.Execute (UnityEngine.Rendering.ScriptableRenderContext context, UnityEngine.Rendering.Universal.RenderingData& renderingData) (at ./Library/PackageCache/com.unity.render-pipelines.universal@14.0.6/Runtime/ScriptableRenderer.cs:1185)

UnityEngine.Rendering.Universal.UniversalRenderPipeline.RenderSingleCamera (UnityEngine.Rendering.ScriptableRenderContext context, UnityEngine.Rendering.Universal.CameraData& cameraData, System.Boolean anyPostProcessingEnabled) (at ./Library/PackageCache/com.unity.render-pipelines.universal@14.0.6/Runtime/UniversalRenderPipeline.cs:642)

UnityEngine.Rendering.Universal.UniversalRenderPipeline.RenderSingleCameraInternal (UnityEngine.Rendering.ScriptableRenderContext context, UnityEngine.Camera camera) (at ./Library/PackageCache/com.unity.render-pipelines.universal@14.0.6/Runtime/UniversalRenderPipeline.cs:527)

UnityEngine.Rendering.Universal.UniversalRenderPipeline.Render (UnityEngine.Rendering.ScriptableRenderContext renderContext, System.Collections.Generic.List`1[T] cameras) (at ./Library/PackageCache/com.unity.render-pipelines.universal@14.0.6/Runtime/UniversalRenderPipeline.cs:369)

UnityEngine.Rendering.RenderPipeline.InternalRender (UnityEngine.Rendering.ScriptableRenderContext context, System.Collections.Generic.List`1[T] cameras) (at <0ae5

 

Hey
I had the exact same problem, and from the Frame Debugger, it seemed that the ReAllocateIfNeeded function was creating a RT with no color format.
So I got it working by simply creating a descriptor instead of using the camera one (maybe it is not initialized correctly?)

Code (CSharp):

1.  
2.  
3. public override void OnCameraSetup(CommandBuffer cmd, ref RenderingData renderingData)
4. {
5.     base.OnCameraSetup(cmd, ref renderingData);
6.  
7.     RenderTextureDescriptor descriptor = new RenderTextureDescriptor(128, 128, RenderTextureFormat.Default);
8.     RenderingUtils.ReAllocateIfNeeded(ref effectColorTarget, descriptor, name: "_Pixel_Buffer");
9. }
10.  
11.  

The GetTemporaryRT API seems to be "deprecated", as in the new versions of URP expect you to use ReAllocateIfNeeded from what I could gather, this API is massively under-documented.
As I am trying to make a pixel effect, the fixed RT size is what I want, but you probably want to use the Screen size for yours.
Hope this helps!