Feature Request: cursor location mapping

[evlli]

when using slang shaders that add screen distortion / curvature / whatever, the mouse selection input no longer lines up with the selected area.

I'm sure we could do some "render known image through filter and derive transfer function"-type of magic here but that would probably be out of scope and prone to failure if other visual effects are applied.

Instead, I propose using a user-specified input transform function in the configuration.
It would probably not line up perfectly most of the time, but good enough for the brain to ignore