[fpc-pascal] FPC Graphics options?

Sven Barth pascaldragon at googlemail.com
Fri May 19 17:48:21 CEST 2017


Am 19.05.2017 16:39 schrieb "Karoly Balogh (Charlie/SGR)" <
charlie at scenergy.dfmk.hu>:
>
> Hi,
>
> On Fri, 19 May 2017, Reimar Grabowski wrote:
>
> > Final: The render function takes about 90%, the cast-to-int about 5%. No
> > other interesting functions shown. So the missing time must be spent
> > doing floating point math and branching (ifs), as that's all the render
> > function does.
>
> Well, if I comment out the three additions where the ray is actually
> traced and the tex := line, it's actually 60fps on my macbook. But
> actually the real difference is made with the additions. If i comment out
> everything, but those 3 (4 in fact) additions are in still there, it's
> still slow.
>
> Which made me thinking. I think you can vectorize that quite easily, and
> use some packed SIMD instruction, maybe that will make a difference. C/C++
> has some compiler intrinsics for that. I can't remember from the top of my
> head if it's doable with FPC. Someone who feels like fiddling with this,
> might want to try some assembly magic there, if it's possible somehow...

I think Jeppe wanted to add vector support. Though the question here is
whether one wants to optimize/detect this at the AST level and convert that
to implicit vectors or at the CSE level.

By the way: I think my commit today of a SSE Frac() implementation sped up
the framerate by a third on Win64 compared to the one without it :D

Regards,
Sven
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