2d mouseclicks to 3d space

OpenGL OpenGL: Basic Coding
1

HI
Anyone knows how to convert 2d mouseclicks to 3d coords?

Thanks
Bruno

2

yer, see, that would be an underconstrained problem. since an infintite number of 3D points project to the same 2D point, how do you get back the third dimension?

(cue music, and enter my thesis in computer vision on the trifocal tensor from a video sequence!!) ta-da!

but, really, you can’t get three degrees of freedom from a two degrees of information. you can’t. just can’t; and it’s no use trying.

What you CAN do is somehow pick the third dimesnion. But how you do this is up to you. Me? I wrote an app that read the depth buffer at the cusor adn used that. I had a 3D cursor (a soccor ball, actually) “rolling” over the landscape following my mouse.

cheers
John