I have a texture map that looks like a checkerboard. The image is created at runtime as an array of GLbytes. I have a simple geometric object (composed of a small about of 4 sides polygons), and the image is texture-mapped onto each polygon.
I need to know, for each texel in the image, what 3D point on the object the center of the texel is mapped to.
In other words you want to do the reverse of texture mapping, right ?
Do you want, for each pixel of the screen, to find the 3D world location ? Or rather, as i understand it, for each texel of your texture, to find the 3D world location of a point that was “texture mapped” to this particular texel ?
If you’re meaning the later, why do you need that ? What if multiple polygons are mapped to the same texel ? In that case, starting from the texel, you’ve got multiple solutions to the problem. If you also add tiling (repeating textures), the same texel can be unmapped to a single triangle multiple times.
It can certainly be done, but frankly i think the easiest for you would be to describe WHY you need this functionnality, and find other, easier alternatives.
Y.
[This message has been edited by Ysaneya (edited 12-04-2003).]