Shadertoy compatibility

RITEG.V2 is designed to be almost compatible with Shadertoy shaders and pipelines. In fact, here's an example of a pipeline that has been directly copy-pasted from RITEG

Semi-supported uniform values

• iMouse is always filled with zero values as if the host machine had no mouse attached while running Shadertoy in browser
• iDate is always filled with zero values as if it was day 00 of month 00 of year 0000