Rasagar/Library/PackageCache/com.unity.render-pipelines.universal/Documentation~/customize/custom-pass-injection-points.md

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urp-custom-pass-injection-points

Injection points

URP contains multiple injection points that let you inject render passes into the frame rendering loop and execute them upon different events.

Injection points give a custom render pass access to URP buffers. A render pass has read and write access to all buffers at each injection point.

Unity provides the following events in the rendering loop. You can use these events to inject your custom passes.

Injection point	Description
BeforeRendering	Executes a ScriptableRenderPass instance before rendering any other passes in the pipeline for the current Camera. Camera matrices and stereo rendering are not setup at this point. You can use this injection point to draw to custom input textures used later in the pipeline, for example, LUT textures.
BeforeRenderingShadows	Executes a ScriptableRenderPass instance before rendering shadow maps (MainLightShadow, AdditionalLightsShadow passes). Camera matrices and stereo rendering are not set up at this point.
AfterRenderingShadows	Executes a ScriptableRenderPass instance after rendering shadow maps (MainLightShadow, AdditionalLightsShadow passes). Camera matrices and stereo rendering are not set up this point.
BeforeRenderingPrePasses	Executes a ScriptableRenderPass instance before rendering prepasses (DepthPrepass, DepthNormalPrepass passes). Camera matrices and stereo rendering are already set up at this point.
AfterRenderingPrePasses	Executes a ScriptableRenderPass instance after rendering prepasses (DepthPrepass, DepthNormalPrepass passes). Camera matrices and stereo rendering are set up at this point.
BeforeRenderingGbuffer	Executes a ScriptableRenderPass instance before rendering the GBuffer pass.
AfterRenderingGbuffer	Executes a ScriptableRenderPass instance after rendering the GBuffer pass.
BeforeRenderingDeferredLights	Executes a ScriptableRenderPass instance before rendering the Deferred pass.
AfterRenderingDeferredLights	Executes a ScriptableRenderPass instance after rendering the Deferred pass.
BeforeRenderingOpaques	Executes a ScriptableRenderPass instance before rendering opaque objects (DrawOpaqueObjects pass).
AfterRenderingOpaques	Executes a ScriptableRenderPass instance after rendering opaque objects (DrawOpaqueObjects pass).
BeforeRenderingSkybox	Executes a ScriptableRenderPass instance before rendering the skybox (Camera.RenderSkybox pass).
AfterRenderingSkybox	Executes a ScriptableRenderPass instance after rendering the skybox (Camera.RenderSkybox pass).
BeforeRenderingTransparents	Executes a ScriptableRenderPass instance before rendering transparent objects (DrawTransparentObjects pass).
AfterRenderingTransparents	Executes a ScriptableRenderPass instance after rendering transparent objects (DrawTransparentObjects pass).
BeforeRenderingPostProcessing	Executes a ScriptableRenderPass instance before rendering post-processing effects (Render PostProcessing Effects pass).
AfterRenderingPostProcessing	Executes a ScriptableRenderPass instance after rendering post-processing effects but before the final blit, post-processing anti-aliasing effects, and color grading.
AfterRendering	Executes ScriptableRenderPass instance after rendering all other passes.

The following diagram shows the passes and the flow of frame resources in a URP frame: