[osg-users] Using SSE within OSG

James Killian James_Killian at hotmail.com
Tue Jul 29 08:49:42 PDT 2008


"
Ok, you can do here much for the collision detection.
I expect that you should optimize that algorithmically and gain magnitudes
without sse.
"

You are probably right, but Rick is the OSG guru in the team, and I do not
understand osg that well yet as most of my time has been spent developing
other aspects of the game.  My strength lies with general purpose optimizing
code, and so this helps our game tremendously.  The least I can do is
contribute this to the community and hope others get a boost as well.

"
So the question is more if such optimizations will bring performance
improvements for the usual scenegraph case.
"

When I get home tonight I'll disable the collision detection and run the
profiler again, and post the results, hopefully that data should answer this
question.


----- Original Message ----- 
From: "Mathias Fröhlich" <M.Froehlich at science-computing.de>
To: "OpenSceneGraph Users" <osg-users at lists.openscenegraph.org>
Sent: Tuesday, July 29, 2008 10:14 AM
Subject: Re: [osg-users] Using SSE within OSG



James,

On Tuesday 29 July 2008 16:59, James Killian wrote:
> Paul asked me the same question a few days ago, and I just realized that
we
> took that offline so I'll repost here:
> One of the things I should add is the actual profile dump, since that
shows
> a more comprehensive picture.  The actual game demo is free to download
and
> play here:
> http://www.fringe-online.com/
>
> The current installer of the game does not have my optimization in it yet,
> but it should be noted even with the optimization the postmult is still at
> the top.  The Invert4x4() however got pushed way down to the bottom (which
> is great).  I'll post my profiles when I get home.
>
>
> ---------------------------------snip-------------------------------------
-
>- ---
> That is a good question, and I believe the answer is collision detection.
> I should disable it and run the numbers again to confirm.  All ships fire
> machine guns at a fast rate, and each bullet that gets close enough to a
> bounding box/sphere region has to go through the osg code to get the
> precise point where it hit.  Rick would probably have a better explanation
> of this and other factors since he coded the bulk of the collision
> detection (and osg integration).  Most of my time development in the game
> has been spent on the physics and flight dynamics (and now optimization).
>
> It may turn out that we could find some caching technique to reduce the
> collision stress (like the KBDtree), but in the mean time, matrix
> optimizations can benefit the whole community if we do them right, and I
> would like to make some contribution to the community.

Ok, you can do here much for the collision detection.
I expect that you should optimize that algorithmically and gain magnitudes
without sse.

So the question is more if such optimizations will bring performance
improovements for the usual scenegraph case.

Greetings

Mathias

-- 
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