Use the Unity low-level shader compiler APIs to inject different variants into a shader. This is an event-driven approach in which the plug-in receives callbacks when certain built-in events happen.

The shader compiler access extension definition exposed by Unity is to be found in header file, located in the PluginAPI folder.

IUnityShaderCompilerAccess.h

To use the rendering extension, plug-ins must export . For more information on implementing the API, refer to the code comments in the header file.

A plug-in receives a callback via whenever Unity triggers one of the built-in events. The callbacks can also be added to CommandBuffers via or commands from scripts.

In addition to the basic script interface, native plug-ins in Unity can receive callbacks when certain events happen. This is mostly used to implement low-level rendering in your plug-in and enable it to work with Unity's multithreaded rendering.

Unity provides the () interface for configuring shader compiler access. A plug-in can use this interface to reserve its own keyword(s) and configure shader program and GPU program compiler masks. This determines which shader types or GPU programs to invoke the plug-in for.