[Fluxus] pixels texture problem

[gabor papp]

i'm trying to fix the fluxus invaders script to work with the flipped
textures and encountered a problem. because the png is flipped while
read, the pdata does not start from the top-left corner anymore. for
example, i use load-primitive to load a png file to a pixels primitive.
if i use (pdata-set! "c" 0 (vector 1 0 0)), i set the first pixel of the
last line, not the first pixel of the first line.

best,
gabor