On Sun, 15 Apr 2001, Brian S. Julin wrote:
>
> On Sun, 15 Apr 2001, Christoph Egger wrote:
> > Brian pointed me to the matrox mystique doc, which describes its
> > stretching algorithm. Xavier Hienne sent me his code, he wrote some
> > time and Andy gave me a good comment (accidently to the list :).
>
> As this is meant only for scaling without any filtering, the
> behavior is well defined so comments boil down to efficiency, of
> which I have only a few off the top of my head:
Filtering can be added easily. You can do any ROPs you like between
GetPixel() and PutPixel().
> > GetPixel((int)(bob_idx) - bob_ystart, (int)bob_y, &color);
>
> ...if for some reason you are emulating a stretch operation
> across a bus, you will want to cache the GetPixel results so you
> do not generate uneccessary bus traffic.
This works only with solid filled BOBs. But a BOB has usually a
image in it. So we have to use something like a "texture"-renderer.
> Secondly, it is likely that using *HLine operations will give a
> speed increase over the *Pixel operations on any targets that use
> either accel or direct FB access, by reducing function call
> overhead.
Yes. But as I mentioned above ...
CU,
Christoph Egger
E-Mail: [EMAIL PROTECTED]
