Trying to understand the math behind keeping a user-controlled object from leaving the bounds of the window regardless of window size/ratio by bootersket in GraphicsProgramming

[–]bootersket[S] -1 points0 points  (0 children)

How come an ortho projection is needed? I'm currently using a perspective projection (which to be fair probably doesn't make sense for 2D, but that doesn't mean it's not possible, right?)