As I understand it, the clip coords must first be divided with the Wc coord to yield NDC coords before the viewport transformation is applied…
However, the technique for projective textures calls for concatenating the projection matrix with the viewport transformation matrix(which consists of a scaling followed by a translation) into a single matrix which is then applied to the eye coords, finally performing perspective division with the Q coord to yield the actual texture coords.
Can this possibly be correct? I thought performing perspective division after viewport transformation would give different(and incorrect) results than performing perspective division before viewport transformation?
Puzzled.