Robert, In answer to your inquiry, I'm using a database based on osgTerrain::TerrainTile so the texture settings are embedded in the tiles as you asserted earlier. I wasn't planning on using linear filtering. I was just giving it as an example on how I wanted to issue a particular call programmatically.
Rather than attempt to tweak the texture settings per your suggestions, I was able to change the settings on the graphics card to get what I wanted thereby overriding the settings in the database. With anisotropic filtering in the database set at 16x, it was actually adding to the problem of texture crawling at far distances when flying "low". Setting the anisotropic filtering down to 2x blurred the texture a bit more out far but it got rid of the crawling artifacts. We are using high resolution texture imagery (.25m texture) in the database which exacerbates the problem. In this case, the devil is truly in the details. Thanks again for your help... -Shayne -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Robert Osfield Sent: Tuesday, January 26, 2010 2:44 AM To: OpenSceneGraph Users Subject: Re: [osg-users] altering terrain texture... Hi Shayne, On Mon, Jan 25, 2010 at 9:28 PM, Tueller, Shayne R Civ USAF AFMC 519 SMXS/MXDEC <[email protected]> wrote: > What I'm trying to do is minimize the texture "crawling" artifact I see when > I fly at a low azimuth view looking out along the terrain skin to the > horizon. I thought that playing with the texture filter setting on the > terrain texture might cure the problem. When I pipe the video out to a > projector, the crawling is even more pronounced. Changing the filtering to linear will likely make the texture aliasing far worse. You'll need to use anisotropic filtering to improve the quality of textures at low viewing levels. osgTerrain::GeometryTechnique set the value to 16.0 which is the highest value so you won't be able to improve on it. You haven't said what type of database you have - an osg::Geometry based one or an osgTerrain::TerrainTile based one. Current svn/trunk version of VPB builds osgTerrain databases by default, while older versions built osg::Geometry polygonal based models. For the later you could set the max anisotropy filtering via an option, and also set it in the DatabasePager. Robert. _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
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