Hi Andreas, Implementing picking using OpenGL is typically very inefficient as it forces a round trip to the GPU and stalls the CPU and GPU while they wait for each other. Is there a reason why you can't do the picking using a CPU operation?
As for doing custom Camera traversals, there is no need to add/remove from the GraphicsContext, simply assign a Camera and toggle it on/off using the Camera::NodeMask, do camera->setNodeMask(0x0) to turn off and camera->setNodeMask(0xffffffff) to switch on. On 22 January 2014 23:00, Andreas Henne <[email protected]> wrote: > Hi, > I implemented picking by rendering each object with a unique color ID to a > texture. A lookup in the texture on the mouse cursor position then gives the > color id of the selected object. When the user performs a mouse click, I need > to update the picking texture. To avoid unnecessary rendering, I want to > update only the picking texture and not all other cameras. I found that this > simple task (taking a picture with one RTT camera without updating the > others) is difficult to implement in OSG, because > GraphicsContext::runOperations renders images for all cameras attached to the > context. Of course I could use a seperate context for the picking, but that > shouldn't be necessary in my opinion. > I managed to implement what I want by adding and removing cameras to the > context on the fly, but is this a good way to do this? For example, in > GraphicsContext::removeCamera the function releaseGLObjects is called and I'm > not sure how this could impact performance. > > Thank you! > > Cheers, > Andreas > > ------------------ > Read this topic online here: > http://forum.openscenegraph.org/viewtopic.php?p=57958#57958 > > > > > > _______________________________________________ > 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
