Hi Nicolas, On Wed, Feb 27, 2008 at 12:55 PM, nicolas peña <[EMAIL PROTECTED]> wrote: > Another thing that I don't understand is why adding the view with the FBO > and the > image attached makes my process suck all the CPU available. > I am limiting the number of frames to 60 per second (forcing sync) > I understand that copying the image to main memory each frame takes time, > but this effect occurs even if the image is very small. > > Any ideas of what is happening?
I haven't had a chance to look at your example yet, but in general read back from the GPU is quite expensive even with small images as the OpenGL driver has to flush the whole OpenGL fifo and then wait for the rendering to complete down on the GPU, then do the copy back to main members. The read call will be stalled waiting for all this to happen, and good driver implementation shouldn't such all CPU resources though, it should wait on this read in a sleep state if the driver is any good. Robert. _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
