NEED HELP: two dimensional to one dimensional projection matrix.

[mirhagk]

two dimensional to one dimensional projection matrix, if that makes any sense. I understand 3D world matrices perfectly, but I don't know much about projection matrices. WHat I want to do is convert a 2 dimensional point into 1 dimensional space, but not an orthogonal projection, and I need to retain depth information. Like instead of and (x,y,z) to (x,y,depth), I want (x,y) to (x,depth). Can someone explain to me how to do this? I know matrices pretty well, I just don't fully understand projection matrices, so I don't really get how to do this, can someone please explain?