Classification: UNCLASSIFIED
Caveats: NONE
I don't have the 2.2 book to compare against, so I apoligize if I get
something wrong. All this assumes you are using osgViewer::Viewer.
Changing the environment variable
OSG_MINIMUM_COMPILE_TIME_PER_FRAME
wouldn't do anything right now. Same goes for the function equivalent.
Setting targetFrameRate also isn't used.
Here is the doxygen comment that talks about these 2 variables
/** Set the target frame rate that the DatabasePager should assume.
* Typically one would set this to the value refresh rate of your display
system i.e. 60Hz.
* Default value is 100.
* Usage notes. The TargetFrameRate and the
MinimumTimeAvailableForGLCompileAndDeletePerFrame
* parameters are not directly used by DatabasePager, but are should be
used as a guide for how
* long to set aside per frame for compiling and deleting OpenGL objects
- ie. the value to use
* when calling DatabasePager::compileGLObjectgs(state,availableTime,).
The longer amount of
* time to set aside cthe faster databases will be paged in but with
increased chance of frame drops,
* the lower the amount of time the set aside the slower databases will
paged it but with better
* chance of avoid any frame drops. The default values are chosen to
achieve the later when running
* on a modern mid to high end PC.
* The way to compute the amount of available time use a scheme such as :
*availableTime = maximum(1.0/targetFrameRate -
timeTakenDuringUpdateCullAndDraw,
minimumTimeAvailableForGLCompileAndDeletePerFrame).
*/
So, if you used DatabasePager in your own viewer, using a different
Renderer class, you could look up these variables and use them. Frankly,
if you went to that much trouble, you probably already know what kind of
time slice you would give to compileGLObjects.
Mike Dorsett - Software Engineer - SAIC
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Paul
Martz
Sent: Wednesday, February 27, 2008 10:46 AM
To: 'OpenSceneGraph Users'
Subject: Re: [osg-users] VPB and PagedDatabase performance
-compileGLObjects(UNCLASSIFIED)
I happened to be looking at that today. I noticed that the call in
Renderer.cpp (2.2 and trunk):
databasePager-compileGLObjects
Always uses 0.004 for available time. So, unless you roll your own
Viewer, your stuck with this time. Also, it doesn't seem that
variables:
minimumTimeAvailableForGLCompileAndDeletePerFrame
Or
targetFrameRate
are used at all, not even as a hint. But, I could be missing
something.
If you believe the Reference Manual has incorrectly documented
something, please point me to the page or section number, say what you
think is wrong, and state how you think it should read. I'll be glad to
look into it and make changes in a future revision.
Paul Martz
Skew Matrix Software LLC
http://www.skew-matrix.com
303 859 9466
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Classification: UNCLASSIFIED
Caveats: NONE
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