🚀 go-pugleaf

     -=> Greg Alt spoke of "Re: bitmaps" <=-
    To All at 08-12-92  08:27
 GA> It sounds like you are claiming that it is possible to do real-time 
 GA> sprite rotations without multiplies.
it is!
here is the "pseudo" code.
BMP image[N][X] { image is X columns by N lines }
vectors[N]      { N vectors [x1,y1 to x2,y2] }

setvectors(X,Y,W,H,vectors);    { Sets vectors for laying out BMP }
rotate_vector_end_points(X,Y,13/180*pi); {rotate endpoints in radians}
for I = 1 to N do
    { using line algorythm plot pixels of each raster scan along
        line drawn }
    stroke(image[N],vectors[N]); 

 GA> I don't believe that is possible on a PC (even a 386), but I would
 GA> love to be proven wrong.

It is possible, using a standard line draw algorythm [whose name
eludes me right now].

 GA> I'm planning on doing some sprite rotation stuff for a game, and my
 GA> plan was to pre-compute it all which would be fast but take tons of
 GA> space. 

YEP that would the speed of the above technique is fast but not
as fast as computing rotations first then doing it.  However the
overhead for doing that is ludicris.  This technique should be
fast enough even for a XT.  Hmmm maybe I should try it :) hehehe

        Stephen Cyberman@Toz.Buffalo.NY.US
        Scripted at Thu  08-13-1992  17:06:29

... ARRRRRGGGHHH!!!! ... Tension breaker, had to be done.
--- Blue Wave/QWK v2.10