Get the square position in 3D chess board

Hi all,

I’m design a 3D chess with openGL.

Each piece is model and the board is one other model

I got a camera moved. (forward, backward … )

I would like to be able to move a piece when the user will click on the piece square

My problem is : when I will move the camera, the coordonate of each square will
move as well.

I would like a algorithm or a function to know which square was picked by the user.

Because I don’t want to calculate again the square coordonate every time that the camera move.



1)Just read the depth of the pixel you clicked at and pass it (along with the x,y) to gluUnproject (if I haven’t messed anything up…). Then you will have exact coords of where you clicked - deriving which square was clicked won’t be too difficult.
2) The board is on a fixed level (say y = 2.0). You can get the Matrix and assume certain y. X and z will be relatively easy to calculate within your own code(Done it long ago, don’t remember exactly how…).
3)As far as I remember, there is a tutorial on picking on
I hope that’s what you asked about…

Thanks Lurker_pas

I looked at gluUnProject it is exactly that I wanted

I have to work on now