I searched the whole internet, but I couldn't find something useful. How to do picking (like ray picking) in lwjgl in orthographic mode (2d)? I think this is less confusing than picking in 3d, but I really can't figure out how to do it. Picking for rectangles is easy because you can use the mouse coordinates and the quad coordinates and test if the mouse coords are inside the area of the quad. But my biggest problem is how to do this with rectangles, and circles? Or quads that looks like a circle because I use a texture of a circle (with transparent corners). Please can someone explain it to me?