https://docs.godotengine.org/en/stable/tutorials/shaders/shader_reference/index.html
Shading reference — Godot Engine (stable) documentation in English
Shading language, Built-in functions, Shader preprocessor, Spatial shaders, CanvasItem shaders, Particle shaders, Sky shaders, Fog shaders.
shading referencegodot enginestabledocumentationenglish