Rasagar/Library/PackageCache/com.unity.render-pipelines.universal/Documentation~/shader-stripping.md

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urp-shader-stripping

Shader Stripping

The shaders in the Universal Render Pipeline (URP) use shader keywords to support many different features, which can mean Unity compiles a lot of shader variants.

If you disable features in the URP Asset, URP automatically excludes ('strips') the related shader variants. This speeds up builds, and reduces memory usage and file sizes.

For example, if your project doesn't use shadows for directional lights, by default Unity still includes variants that support directional light shadows in your build. If you disable Cast Shadows in the URP Asset, URP strips these variants.

If you want to examine the code that strips shaders in URP, check the Editor/ShaderPreprocessor.cs file. The file uses the IPreprocessShaders API.

For more information on stripping shader variants, refer to the following pages:

• Check how many shader variants you have.
• General guidance on shader stripping, which applies to all render pipelines.

Check how many shader variants your build has

To log how many variants Unity compiles and strips in total, follow these steps:

1. Open the Graphics settings window.
2. In the Shader Stripping section, select a logging level other than Disabled.
3. Build your project.
4. To see the logged information, open the Editor.log log file and search for ShaderStrippingReport. For the location of Editor.log, refer to log files.

To log more detailed shader variant information, follow these steps:

1. Open the Graphics settings window.
2. In the Additional Shader Stripping Settings section, select Export Shader Variants.
3. Build your project.
4. In the folder with your project files, open Temp/graphics-settings-stripping.json and Temp/shader-stripping.json.

For more information, refer to the following in the Unity User Manual:

• Check how many shader variants you have
• Shader variant stripping

Strip feature shader variants

By default, URP compiles variants where a feature is enabled, and variants where a feature is disabled.

To reduce the number of variants, you can enable Strip Unused Variants in URP Graphics settings and do the following:

• Disable a feature in all URP Assets in your build, so URP keeps only variants where the feature is disabled.
• Enable a feature in all URP Assets in your build, so URP keeps only variants where the feature is enabled.

If you disable the Strip Unused Variants setting, URP can't strip variants where the feature is disabled. This might increase the number of variants.

Disable a feature

To let Unity strip variants related to a feature, make sure you disable it in all the URP Assets in your build.

Unity includes the following URP Assets in your build:

• The URP Asset you set as the default render pipeline asset in Graphics settings.
• Any URP Asset you set as a Render Pipeline Asset in a Quality settings level you enable for the current build target.

Avoid including URP Assets in your build that use different rendering paths because this causes Unity to create two sets of variants for each keyword.

Feature	How to disable the feature	Shader keywords this turns off	Rendering Path
Accurate G-buffer normals	Disable Accurate G-buffer normals in the URP Asset. This has no effect on platforms that use the Vulkan graphics API.	_GBUFFER_NORMALS_OCT	Deferred
Additional lights	In the URP Asset, in the Lighting section, disable Additional Lights.	_ADDITIONAL_LIGHTS, _ADDITIONAL_LIGHTS_VERTEX	Forward
Ambient occlusion	Remove the Ambient Occlusion Renderer Feature in all Renderers that URP Assets use.	_SCREEN_SPACE_OCCLUSION	Forward and Deferred
Decals	Remove the Decals Renderer Feature in all Renderers that URP Assets use.	_DBUFFER_MRT1, _DBUFFER_MRT2, _DBUFFER_MRT3, _DECAL_NORMAL_BLEND_LOW, _DECAL_NORMAL_BLEND_MEDIUM, _DECAL_NORMAL_BLEND_HIGH, _DECAL_LAYERS	Forward and Deferred
Fast sRGB to linear conversion	In the URP Asset, in the Post-processing section, disable Fast sRGB/Linear conversions.	_USE_FAST_SRGB_LINEAR_CONVERSION	Forward and Deferred
Holes in terrain	In the URP Asset, in the Rendering section, disable Terrain Holes.	_ALPHATEST_ON	Forward
Light cookies	Remove Cookie textures from all the lights in your project.	_LIGHT_COOKIES	Forward and Deferred
Rendering Layers for lights	Disable Rendering Layers for Lights.	_LIGHT_LAYERS	Forward and Deferred
Reflection Probe blending	Disable Probe Blending.	_REFLECTION_PROBE_BLENDING	Forward and Deferred
Reflection Probe box projection	Disable Box Projection.	_REFLECTION_PROBE_BOX_PROJECTION	Forward and Deferred
Render Pass	Disable Native Render in all Renderers that URP Assets use.	_RENDER_PASS_ENABLED	Forward and Deferred
Shadows from additional lights	In the URP Asset, in the Additional Lights section, disable Cast Shadows.	_ADDITIONAL_LIGHT_SHADOWS	Forward and Deferred
Shadows from the main light	In the URP Asset, in the Main Light section, disable Cast Shadows. The keywords Unity removes might depend on your settings.	_MAIN_LIGHT_SHADOWS, _MAIN_LIGHT_SHADOWS_CASCADE, _MAIN_LIGHT_SHADOWS_SCREEN	Forward and Deferred
Soft shadows	In the URP Asset, in the Shadows section, disable Soft shadows.	_SHADOWS_SOFT	Forward and Deferred

Strip post-processing shader variants

Enable Strip Unused Post Processing Variants in URP Graphics settings to strip shader variants for Volume Overrides you don't use.

For example if your project uses only the Bloom effect, URP keeps Bloom variants but strips all other post-processing variants.

Unity checks for Volume Overrides in all scenes, so you can't strip variants by removing a scene from your build but keeping it in your project.

Volume Override removed	Shader keywords this turns off
Bloom	_BLOOM_HQ, BLOOM_HQ_DIRT, _BLOOM_LQ, BLOOM_LQ_DIRT
Chromatic Aberration	_CHROMATIC_ABERRATION
Film Grain	_FILM_GRAIN
HDR Grading	_HDR_GRADING
Lens Distortion	_DISTORTION
Tonemapping	_TONEMAP_ACES, _TONEMAP_NEUTRAL, _TONEMAP_GRADING

You should also enable Strip Screen Coord Override Variants in URP Graphics settings, unless you override screen coordinates to support post processing on large numbers of multiple displays ('cluster' displays).

Strip XR and VR shader variants

If you don't use XR or VR, you can disable the XR and VR modules. This allows URP to strip XR and VR related shader variants from its standard shaders.

Remove variants if you use a custom Renderer Feature

If you create a custom Renderer Feature, you can use the FilterAttribute API to remove shader variants when you enable or disable settings in the URP Asset.

For example, you can do the following:

1. Use [SerializeField] to add a Boolean variable to the custom Renderer Feature and add it as a checkbox in the URP Asset Inspector.
2. Use ShaderKeywordFilter.RemoveIf to remove shader variants when you enable the checkbox.