[Gtkradiant] small optimization

[Rudolf Polzer]

On Sun, Feb 19, 2012 at 09:46:41PM -0800, James Canete wrote:
> So I was running q3map2 through a profiler when I noticed that a lot of
> time was being spent in VectorNormalize() in libs/mathlib/mathlib.c during
> the -light phase.  I figured this was due to the math accuracy fixes, but I
> also figured that there weren't really necessary during lighting, so I
> borrowed the fast VectorNormalize2() from ioquake3 and used it in a couple
> of key places during lighting.  I also went ahead and rewrote TraceLine_r()
> in light_trace.c to be iterative when possible, while I was at it.
> 
> These two changes improved the light time on my test map by around 7% (or
> one second, if you prefer), and don't seem to have any bad side effects,
> though I haven't tried running the regression maps on it.
> 
> I put the patch at http://pastebin.com/uUED7Kt8 since I'm still not sure
> where I should be submitting patches.

I put the patch in the NetRadiant git repository:

http://nl.git.xonotic.org/?p=xonotic/netradiant.git;a=commitdiff;h=3b0c5d8f3870412b045f9cfe0a22f18b493359e1

I will test it later and possibly merge it. In review it looked good.

BTW, regarding the accuracy fixes... I wonder if it'd gain even more speed to
do the inaccurate case using Carmack's invsqrt hack. But this is to be tested
later.

Thanks!

Best regards,

Rudolf Polzer