2fmlcalls@kuhub.cc.ukans.edu (03/27/91)
What is the quickest way to blast bits to the screen? I'm aware of CopyBits long and shortcomings and I thought (know) there must be a better way. First, is drawing into a bitmap as opposed to an offscreen port quicker? If you know that the size of the source and dest (and they are the same size and have a width on a word boundary) and you also know that the dest needs no clipping (will appear entirely on the screen) - is there not a faster method than CopyBits? Assume as well that srcCopy is the only transfer mode you need. I've considered BlockMove from ptr to ptr grabbing the appropriate number of bytes. Anyone have experience doing this? I've dreamed about page-flipping as well, but is it possible to do it on all models of the Mac? It seems as though you should be able to just maintain two screen-sized windows (a and b) and just bounce a pointer back and forth for screenmemory's address. Why isn't this possible? Sorry, to bother everyone with this probably-age-old-question. I would be indebted to any help. john calhoun
Lawson.English@p88.f15.n300.z1.fidonet.org (Lawson English) (03/28/91)
2fmlcalls@kuhub.cc.ukans.edu writes in a message to All
2> What is the quickest way to blast bits to the screen?
2> I'm aware of CopyBits long and shortcomings and I thought (know)
2> there must be a better way
I don't know about screen vs off-screen, but CopyBits is pretty well optimized:
on a Plus machine (the last I Mac-Nosy-ed), CopyBits spends the greatest part
of its time in a loop using 16 move.w instructions. I would *assume* that on
32 bit machines, there is optimizatiion to check for long words, but if not,
then, assuming a long word boundry, one might use 16 or 32 (more then that is
reaching the point of diminishing returns if I recall correctly from my Apple
II graphic days and if the instruction set timing is ball-parkish) move.l's
to blast your bits around. It wouldn't know the first thing about regions and
such, but you said that you didn't need them. Also, this only works in black
and white...
Lawson
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