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.