[luaKmua]

At their heart, that's what pixel/fragment shaders are. They're calculations for determining what color a pixel should be.

A really basic one returning red for every pixel would make a red screen. The most common use would be rendering a textured mesh and determining how lighting should effect it (is it skin? A metal surface?).

Then you can look at crazy things like https://www.shadertoy.com/ which are all purely made in pixel shaders (also that site is run by the creator of the Human Shader)

[balloonthief]

Hmmm, this looks kinda familiar....

https://www.shadertoy.com/view/ddjBRK