Question How do I use an unlit ShaderGraph shader in a custom renderer?

I am trying to render a full-screen quad with some material to a RenderTexture.

If I use the Unlit/Color shader it renders fine. (see the green squares in the screenshots below)

If I use a simple shader graph it renders fine in the scene view and only a pixel-wide stripe on the top and left in the game view. (thee the blue squares in the screenshots below)



If I use the Unlit URP shader then nothing renders at all. (which is fine)

Game view:


Scene view:


What parts of the forward renderer do I need to replicate in order to have the shader graph shader render correctly?

 

I even tried doing this as a renderer feature with and got the same results. I have a feeling that Unity is expecting me to do something in my render pass but IDK what.

In case it helps, here is my full screen quad pass code:

Code (CSharp):

1.     public class FullScreenQuadPass : ScriptableRenderPass
2.     {
3.         private const string ProfilerTag = nameof(FullScreenQuadPass);
4.  
5.         [NotNull]
6.         private readonly FullScreenQuadRenderer.SettingsContainer _settings;
7.  
8.         private readonly ProfilingSampler _profilingSampler;
9.  
10.         public FullScreenQuadPass([NotNull] FullScreenQuadRenderer.SettingsContainer settings)
11.         {
12.             _profilingSampler = new ProfilingSampler(ProfilerTag);
13.             _settings = settings;
14.  
15.             renderPassEvent = RenderPassEvent.AfterRenderingPostProcessing;
16.         }
17.  
18.         public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData)
19.         {
20.             if (!_settings.Material)
21.             {
22.                 Debug.LogWarning("Null material used in full screen quad pass, skipping");
23.                 return;
24.             }
25.  
26.             CommandBuffer cmd = CommandBufferPool.Get(ProfilerTag);
27.  
28.             Camera camera = renderingData.cameraData.camera;
29.  
30.             using (new ProfilingScope(cmd, _profilingSampler))
31.             {
32.                 cmd.BeginSample("Clear Target");
33.                 cmd.ClearRenderTarget(true, true, camera.backgroundColor);
34.                 cmd.EndSample("Clear Target");
35.  
36.                 cmd.BeginSample("Render");
37.                 cmd.SetViewProjectionMatrices(Matrix4x4.identity, Matrix4x4.identity);
38.                 cmd.DrawMesh(RenderingUtils.fullscreenMesh, Matrix4x4.identity, _settings.Material);
39.                 cmd.EndSample("Render");
40.             }
41.  
42.             context.ExecuteCommandBuffer(cmd);
43.             CommandBufferPool.Release(cmd);
44.         }
45.     }

 

Fixed it!

Turns out you just need to specify the shader pass. The default of -1 does not play well with URP shaders:

Code (CSharp):

1. // drawing shader pass 0 is critical here: the default is -1 which does not work with URP shaders
2. cmd.DrawMesh(RenderingUtils.fullscreenMesh, Matrix4x4.identity, material, 0, 0);

Note that I have only tested this with Unity 2010.1.0b14 and URP 8.1.0.