Mail Archives: djgpp/1996/04/11/04:32:28
On 10 Apr 1996, o'toole casey wrote:
> 3d program was running at about 16 FPS. So I commented out all of the
> transform and draw functions and only left the ClearContext and
> GrBitBltNC functions. I was STARTLED to see that I could only achieve
> around 40 FPS just clearing a memory context then writing it to the
> screen in 320 x 200 x 256 mode. A similiar program written in
> Borland C 4.5 REAL mode accomplishes 160+ FPS.
>
> Now, I imagine in order to accomplishe the speed Im looking for that
> Im going to have to switch back to real mode and write my own
> bitblt functions.. I read about this in the DJ-TUT file somewhre..
I'm not sure you aren't jumping to conclusions too fast. I hear that GRX
2.0 is not polished enough in some areas, so you might as well look into
the source of those bitblt functions. If handled correctly (e.g. with
the `nearptr' facilities of DJGPP) there is no reason that bitblt should
be slower than in real mode, since no mode-switching should be involved.
In fact, with SVGAs that sit on a 32-bit wide bus (VLB or PCI), you might
even see greater speed, because in real mode you move in 16-bit words.
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