I am currently implementing a particle system, which basically works fine. The particles are sorted, so that those far away from the camera are rendered first (depth testing enabled), and particles behind objects are occluded. Every particle consists of a textured quad.
I have problems displaying the quad in an orthogonal way, so that it always “looks” to the camera, regardless where the camera is positioned.
Can anyone please post the correct code of transforming the quads correctly? I already messed around with glRasterPos, gluProject etc. but I can’t figure it out.