The shadersA program that runs on the GPU. More info
See in Glossary in the Universal Render PipelineA series of operations that take the contents of a Scene, and displays them on a screen. Unity lets you choose from pre-built render pipelines, or write your own. More info
See in Glossary (URP) use shader keywords to support many different features, which can mean Unity compiles a lot of shader variantsA verion of a shader program that Unity generates according to a specific combination of shader keywords and their status. A Shader object can contain multiple shader variants. More info
See in Glossary.
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: