Jonathan, Many thanks for your concise yet thorough explanation. Now I don't have to worry about this issue any more :) "Jonathan Osuch" <osuchj@avalon.net> wrote: [...]
The parser does not make this optimization. The formula is read in and put into one executable string of op codes and then called as the once per pixel routine for the formula type. Currently there is no way to split out part of the formula and only execute it once per image.
Perhaps a "const" or "perimage" keyword that .frm writers could apply to assignment expressions in the per_pixel section?
Your optimization should work with most passes types except possibly diffusion. The major problem is that if you save a partially completed image, it will not resume correctly because then the first pixel calculated will no longer be (0,0). Certain key strokes may have the same effect if the formula gets read into memory again (like <z> followed by <esc>).
Hmm. That makes sense. I tried using some other points as triggers in the formula to change the image parameters... and they sometimes happened at places other than where one would expect assuming either column-major or row-major rendering, even with PASSES=1. Thanks again for answering, -- Hiram Berry