Re: [AD] Interlaced blit

["L. Ross Raszewski" <lraszewski@xxxxxxxxxx>]

Thanks for all the help so far. I think I'm on the right track, but it's
still not working. I revised the code to the version at 
http://hal.dyn.dhs.org/iblit.c

and now it displays nothing, and segfaults when it gets to the bit where
it tries to use a traditional blit again.


The offending code is:


blit_interlaced(int pass, int npasses, BITMAP *src, BITMAP *dst,
                int sx, int sy, int dx, int dy, int w, int h)
{
  int i,j;
  bmp_select(dst);
  for(i=pass;i<h;i+=npasses)
  {
    bmp_write_line(dst,i+dy);
    bmp_read_line(src,i+sy);
    memcpy(((short *)dst->line[i+dy])+sx,
           ((short *)src->line[i+sy])+dx,w*sizeof(short));
  }
  bmp_unwrite_line(src);
  bmp_unwrite_line(dst);
}


There's a couple of tricks I haven't tried yet, but most of them would
bind the code to a single application. Since I'm hoping to put this
together into a general allegro add-on, I'd rather avoid that.


Thanks.


--
L. Ross Raszewski
Allegro Text library and Obscure Format Loaders:
http://www.cs.loyola.edu/~lraszews/if/#libs