Hi Owen, I understand your point which is very true . But i have also used other OpenGL libs before and there, i did not see a single frame drop in the same scenario and OMAP is anyway supposed to be better than the other OpenGL ES implementation i have used. So i was wondering does it have anything to do with the fact that OMAP's OPenGL-ES/EGL implementation is X window system compatible ( I am using clutter with eglx backend), that it is eglSwapBuffers actually rendering to a Xwindow rather than directly rendering to framebuffer?
Also, while running gtk-clutter-test, i filtered all the motion event at the clutter-gtk layer, i.e. i was not letting those motion events coming to clutter, still i was seeing frame drops, so kind of heading a deadend, not enough clue. Rahaman. On Thu, Jul 9, 2009 at 3:35 PM, Owen Taylor <[email protected]> wrote: > On Thu, 2009-07-09 at 11:10 +0530, Mustafizur Rahaman wrote: > > Hi, > > > > I am playing with OpenGL 2.0 on TI OMAP's 3430 ZOOM device with > > clutter. One of the surprising thing i noticed was when the hands are > > normally rotating, i am getting FPS of arouns 40, but if i just press > > my finger on the screen/stage area, the frame rate drops to 30FPS or > > even less, even though i am not doing anything on touch event. > > > > I have a made gtk-clutter test app exactly similar to test-actor and > > there i am not listenning to any input event, still i see the same > > behavior. Does any one has seen similar behavior? Do we have anything > > in clutter itself that we intentionally drops the FPS, where there is > > any input event detected? > > I'd guess what is happening is that your hand isn't completely still, so > when you are touching the screen, Clutter gets a constant stream of > motion events. > > When a motion event is received between the two frames, then Clutter > will draw the scene twice: > > - Draw the scene in "pick mode", find the actor that should receive > the event with glReadPixels() > - Do the motion event > - Draw the scene again > > If you don't have excess graphics power available, then that may well > cause a frame rate drop. > > - Owen > > >
