Inject a render pass using the RenderPipelineManager API in URP

To inject a custom render pass into the rendering loop in the Universal Rendering Pipeline (URP), subscribe to one of the events in the RenderPipelineManager API and use the EnqueuePass API.

For example, you can render extra cameras to render textures, and use those textures for effects like planar reflections or surveillance camera views.

Note: RenderPipelineManager events trigger only if a camera is active.

If you want to apply a render pass across multiple cameras, scenes, or across your entire project, the recommended best practice is to use a Scriptable Renderer Feature instead. For more information, refer to Inject a custom render pass using a Scriptable Renderer Feature.

Follow these steps to use the RenderPipelineManager API:

1. Attach a new MonoBehaviour script to a GameObject, then create an instance of a custom render pass. For example:

   public class InjectPass : MonoBehaviour
   {
       // Declare a custom render pass
       private ExampleRenderPass exampleRenderPass;
   
       private void OnEnable()
       {
           // Create the custom render pass
           exampleRenderPass = new ExampleRenderPass(settings);
       }
   }
   

   For more information about writing a render pass, refer to Write a render pass using the render graph system.

2. Subscribe a method to one of the events in the RenderPipelineManager API. For example:

       private void OnEnable()
       {
           ...
           // Call the InjectRenderPass method when the beginCameraRendering event is raised.
           RenderPipelineManager.beginCameraRendering += InjectRenderPass;            
       }
   

3. In the subscribed method, use the EnqueuePass API method to inject a custom render pass into the URP rendering loop.

   public class InjectPass : MonoBehaviour
   {
       ...
   
       // Add the method that Unity calls after the beginCameraRendering event is raised.
       // The method must accept the ScriptableRenderContext and Camera parameters the event delegate defines.
       private void InjectRenderPass(ScriptableRenderContext context, Camera cam)
       {
           ...
           // Use the EnqueuePass API to inject the custom render pass.
           cam.GetUniversalAdditionalCameraData().scriptableRenderer.EnqueuePass(exampleRenderPass);
       }
   }
   

4. Unsubscribe from the event in the OnDisable method. For example:

   public class InjectPass : MonoBehaviour
   {
       ...
   
       private void OnDisable()
       {
           RenderPipelineManager.beginCameraRendering -= InjectRenderPass;
       }
   }
   

Additional resources

• Write a render pass using the render graph system
• Custom render pass workflow