Re: [osg-users] Color array optimization
HI Martin, On Wed, Apr 7, 2010 at 9:27 PM, Martin Beckett m...@mgbeckett.com wrote: Don't know if it applies to OSG, but a common speedup with OpenGL used to be to sort by vertex color so you draw all the vertex of the same color at once. Was this in the glBegin/glEnd days? That might be out of date with modern cards and VBOs but shouldn't be too difficult to implement. With modern cards they just send all the vertex attributes required in the vertex shader into the shader so it won't make a difference whether the colour values change or not. A small possible benefit might be gained If you did sort by colour and the batches of the same colour were long enough to justify using a single glColor instead of a color array per batch. This would save on memory and bandwidth, but if you made the batching too small then the cost of too many small batches would outweigh this completely and you'd end up with worse performance. I would only expect a performance benefit if the batches could be kept to over a thousand vertices or so - i.e. you had continous blocks of same colour in a array that you can group together. This sorting isn't just something that could be done for colour, but for all vertex attributes save for the vertex array, however, the same batching granularity issues apply, if you can't keep the batches very large then it's counterproductive. Robert. ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Color array optimization
Don't know if it applies to OSG, but a common speedup with OpenGL used to be to sort by vertex color so you draw all the vertex of the same color at once. That might be out of date with modern cards and VBOs but shouldn't be too difficult to implement. Martin -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=26534#26534 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
[osg-users] Color array optimization
Hi all, Looking for optimization I'm currently searching a color Array optimizer. Something modifying the color array and its binding when possible, of course without modifying the render of the geometry. Is there something like that ? I didn't found anything in the osgUtil::optimizer documentation. Thanks. Regards, Vincent. ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Color array optimization
Hi Vincent, On Tue, Apr 6, 2010 at 8:31 AM, Vincent Bourdier vincent.bourd...@gmail.com wrote: Looking for optimization I'm currently searching a color Array optimizer. Something modifying the color array and its binding when possible, of course without modifying the render of the geometry. Is there something like that ? I didn't found anything in the osgUtil::optimizer documentation. There isn't a specific color array optimization. I'm rather curious about what you'd optimize about a colour array. Robert. ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
