Somehow I was under the impression that the const keyword for function parameters in #GLSL was mostly there for the benefit of programmers, so we'd get an error if we try to modify something we're not supposed to, but that the compiler would figure out if it does get modified or not on its own.
I was wrong. I have a case where just adding the const keyword to one parameter makes a shader twice as fast - from 750µs to 300µs.
Totally unexpected for me, am I the only one?
