Hi J-S and Michele,
As I was summoned by "shadow" spell, I will drop my two cents in this
discussion. Last time I checked OSG was also creating accompanying color
buffer for the depth shadow map. Which usually multiplies GPU memory
alocation by two (assuming RGBA is 32 bit and Z is 32 bit). Considering the
fact that default multithreaded modes create "double buffered" SceneViews
which again effectively duplicate all RTT buffers, original size requirement
for shadow buffer is often 4 times more. If for example you create 4kx4k RTT
shadow map - OSG will actually allocate 256 MB (!). If your app allocates
aditional buffers and board has not enough memory this may be the cause of
the problems. SingleThreaded mode does not utilize double buffered
SceneViews so this multiplier drops to factor 2.
Cheers,
Wojtek Lewandowski
----- Original Message -----
From: "Jean-Sébastien Guay" <[email protected]>
To: <[email protected]>
Sent: Tuesday, July 21, 2009 5:19 PM
Subject: Re: [osg-users] Frame rates vary dramatically across runs
Hi Michele,
It seems the issue was caused by using shadow maps that were too large. I
switched back to 4096 x 4096 and all is well.
4096^2 is already large... Some of our cards here (9800GT) don't support
them (rendering slows down to ~3fps when at 4096^2, when it's at 60fps
steady at 2048^2). Others support it well though (9800GTX+, etc.)
J-S
--
______________________________________________________
Jean-Sebastien Guay [email protected]
http://www.cm-labs.com/
http://whitestar02.webhop.org/
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