Textrued poly question

I think the way matrix transformations are involved in the calculations of what becomes every single pixel, on a per-pixel basis, it doesn't matter what angle you're drawing at or how much interpolation there is ie what shape the polygon is. As Fetze said an image is just a textured polygon in the shape of a rectangle. It should not speed up or slow down by adding rotation or by moving the corners to cause the image to stretch or warp. The only difference would be that if more pixels need to be drawn as a result of moving the points on the polygon then there will be more `fill rate` consumed.