Hi John, On Tue, Nov 24, 2009 at 5:28 PM, John Price <[email protected]> wrote: > I am planning to play with gl3 a little, there must be some advantages to > using it.
I'll have to let Paul Martz dive in a qualify the advantages of GL3 as he's the expert on it, I haven't even yet compiled against a GL3 driver... >From my perspective GL3 doesn't really add much more than the OSG already has support for with GL2 and extensions. GL3 is really about what it takes away, rather than what it adds, without the backwards compatibility it's a trimmed down API without the cruft that OpenGL 1.x and 2.x accumulated over the years. Long term is will hopefully make the life easier for driver developers as they can focus on the smaller by more flexible API. For an OSG user right now going to GLES 2 and GL3.2 (i.e. without backwards compatibility) means that you are sailing with any safety net, going solo - you have to write your own vertex and fragment shaders for everything. This is a big step to take if you aren't used to using shaders, but if you are already using your own shaders in GL2/OSG apps then the transition will be pretty easy - pretty well everything will work for GL2 as for GL3 and GLES2. There is one downside with using shaders for everything, and that is you loose a lot of the compositional power of the fixed function pipeline as you have to replace everything with only a single osg::Program active at one time. The osgshadercompositor example is an experimental approach at trying to bring the ability of composing programs form shaders on the fly, but as yet we don't have a final form of shader composition that is supported in the core - it's a real tough problem to crack. It's my plan to tackle shader composition prior to the OSG-3.0 release, and hopefully start my work on it early December. First up I need to clear the submissions backlog and get a dev release out the door. Robert. _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
