If you had a mesh that was an irregular shape like in the shape of a star, the UV coordinates would be hard to find at the point of collision..... If you had a flat, rectangular image and you clicked with the mouse on it, you would be able to use simple math to determine what pixil of that image you were on. In DirectX, the "rayintersect" command will return a variety of info including the Barycentric UV coordinates of the face that was intersected, taking into account that you could even have an unwraped mesh.
If you are unsure what unwraped is: Each face of a mesh can have it's own UV coordinates. In fact they do; It's just that most people make them uniform so that the image goes smoothly accross each face of the mesh.
My problem is not that complicated.... I would be using it to determine the UV coordinates on a trapezoid-- not that hard. I just didn't want to do the math if DBP got the info already.
The fastest code is the code never written.
