rewrote a simple little system i made for a 2019 game: a barebones implementation of the unity gizmos api. differences are:
- you can call it from anywhere (no need to put it in a special OnDrawGizmos callback)
- just lines (build other shapes out of lines)
- supports gradients (for fun)
essential for debugging spatial problems and thinking through 3d geometry problems
the gradients are probably too much lol. thats where all the complexity is. i will probably remove them but i love gradients on gl lines so much.
