[osg-users] When optimizing with LOD changes, should I change UV map resolutions?

Paul Martz pmartz at skew-matrix.com
Thu Jul 10 09:20:57 PDT 2008


The OSG Ref Man v2.2 (www.osgbooks.com) has a complete reference of OSG
environment variables. The one you want is OSG_MAX_TEXTURE_SIZE.
   -Paul

 


________________________________

	From: osg-users-bounces at lists.openscenegraph.org
[mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of Rick Pingry
	Sent: Thursday, July 10, 2008 10:14 AM
	To: OpenSceneGraph Users
	Subject: Re: [osg-users] When optimizing with LOD changes,should I
change UV map resolutions?
	
	
	Wow, the ability to limit the maximum texture memory sounds like it
would really help.  What/where might I find that environment variable?
	 
	-- Rick
	
	
	On Thu, Jul 10, 2008 at 11:26 AM, Paul Martz
<pmartz at skew-matrix.com> wrote:
	

		Robert's comment regarding texture atlas usage in low-res
LOD children is an excellent suggestion.
		 
		Going further, your post begs the question: Do you suspect
that texture memory usage is the bottleneck to your performance? One way to
test this (if you haven't already done so) is to set the OSG environment
variable to limit the maximum texture dimension to something ridiculously
small. If your app runs faster with this setting, then texture memory usage
might be causing performance problems, and you might need to address that in
some way.
		 
		You should keep in mind that most OpenGL device drivers are
smart enough to page out large mipmap levels when they are not in use.
		 
		Another thing to keep in mind is that a texture never needs
to be larger than its max representation on-screen. For example, it's
pointless to have a 2kx2k texture applied to an object that will never
subtend more than 500x500 pixels.
		 
		Hope that helps.
		   -Paul
		 


________________________________

			From: osg-users-bounces at lists.openscenegraph.org
[mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of
rpingry at gmail.com
			Sent: Thursday, July 10, 2008 7:09 AM
			To: OpenSceneGraph Users
			Subject: [osg-users] When optimizing with LOD
changes,should I change UV map resolutions?
			
			
			Hello All,
			 
			I have been trying to get my scenes to run faster,
balancing my scene graphs using LOD.  I use quite a bit of UV mapping in my
models, and they can be fairly high res because I want them to look good up
close.  There are usually several instances of the same model in the scene,
all pointing to the same scene graph.  I was wondering about the best way to
create LOD changes for them.  I was going to cut out some polygons, but I
was also thinking of cutting the resolution back on the UV maps.  Is this
valuable?  On first assessment, it seems it would be, but then I realize
that it might cause MORE of a memory usage, and the graphics card (or OSG)
might be doing this kind of optimization anyway (dropping image map
resolutions based on pixel size or whatever).  What are your
recommendations?
			
			-- Thanks for everything
			>> Rick
			Check us out at http://fringe-online.com/ 


		_______________________________________________
		osg-users mailing list
		osg-users at lists.openscenegraph.org
	
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
		
		




	-- 
	>> Rick
	Check us out at http://fringe-online.com/ 





More information about the osg-users mailing list