You certainly could, but this trades off fill cost against polygon count. I.e. you're using more complex calculations per-pixel for a smaller number of per-ver

You certainly could, but this trades off fill cost against polygon count. I.e. you're using more complex calculations per-pixel for a smaller number of per-vertex/per-polygon computations. It'd be interesting to look into the question empirically of whether this optimization would be worthwhile. Also it depends somewhat on the specifics of the application. Two factors come to mind: (1) Draw distance (drawing many faraway polys that are only a few pixels on-screen probably favors poly-count reduction more) (2) Extra pixel shader complexity. If you're doing fancy per-pixel stuff with lighting or shadows or whatever, your optimization should become more attractive, because starting with your optimization and adding that extra stuff reduces the percentage of the per-pixel computation that's spent on your optimization.