Could somebody help me with implementing my own gluUnProject? I read the manpage to learn how it works but I'm a little uncertain... I unfortunately threw out my own implementation ( which didn't work ) months ago in frustration or else I'd post it here for you all to help me with.

The reason I want to write my own is I'm about to write some code which will use gluUnProject heavily -- right now I'm wasting a bit of time converting my modelview and projection matrices from floats to doubles each time I call gluUnproject. It would be nice to have a gluUnProjectf which doesn't need to work with doubles...

Thanks,

(specifically, the situation is that I'm implementing render to texture for my user interface code so you can have a working UI in 3d in a game, say on a computer screen in a room or whatever. To be able to interact with this UI, I need to be able to convert mouse coordinates to a vector in world space which I can then do plane intersections with to get the location on the virtual screen in the 3d world. It would be nice to not have to convert 2 4x4 float matrices to double with each update of the game state... my wee powerbook is taxed enough as it is )

EDIT:

I'm a big fat idiot. I found the gluUnProject source in MESA... nevermind. Moderators, delete me if you want.

Does using glGetDoublev instead of glGetFloatv buy you anything?

The source code for gluUnProject is in Mesa CVS

OneSadCookie Wrote:Does using glGetDoublev instead of glGetFloatv buy you anything?

The source code for gluUnProject is in Mesa CVS

That's a good point, but this is actually being used in a situation where the current modelview/projection may not correspond to the matrices I'm needing. I keep my modelview & projection in my camera class, as float, and use them because I know they're always valid -- for *that* camera.

Anyway, I did find the source, I'm making certain I understand it before I start running with it. I think my old version didn't work because it's possible my mat4 inversion function is wrong/naive.

Hey, I'm excited that this works. I've got a hud, rendered in the 3d world ( on a cube ) which can be interacted with, thanks to the help above ( and the help in my question on 3d math )



Thanks,