Hi Michael, There really isn't much to do with texture atlas once you have built the scene graph - the osg::Geometry and osg::Texture/osg::Image you use are all the same type as you'd use for none texture atlas usage, the only difference is the contents of the osg::Image and the texture coordinates used on the osg::Geometry. You can create and save out texture atlas and associated geometry just as normal OSG scene graphs.
Texture atlases are useful for enabling one to group all the geometry and imagery together for particular objects together as a single unit, for instance a house rendered with separate textures for each of the walls and the roof would require 5 images, 5 textures and 5 geometries, while a texture atlas would allow you to use a single image, single texture and a single geometry. As CPU overhead of cull and draw is often a bottleneck then merging 5 sets of state and geometry into a single unit can be a big saving. If you aren't CPU or GPU batch limited then using a texture atlas will help very little. Robert. On 14 February 2013 09:23, michael kapelko <[email protected]> wrote: > Hi. > I want to be able to have to specify several textures which will be mapped > using the same UV, a collection of textures. > I want to put them into a single file, texture atlas. > I've grepped OSG examples on 'tlas' word. Didn't find any example. > I've googled for OSG atlas and only found > osgUtil::Optimizer::Optimizer::TextureAtlasBuilder. > As I understood, I can only build a runtime atlas (not save it) with OSG > from separate textures. > Can I use the builder to create an OSG texture atlas from my atlas file? > Will OSG texture atlas usage reduce draw calls/increase draw performance? > Thanks. > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
