i found an interesting issue with a QC composition of George Toledo. Renders well with 60fps in QC, but if add a Syphon Server for the comp, which has a client, the frame rate drops to 30 fps. How no idea why this happens, maybe an issue with GL state restore?
I get 60 fps. This may just be a fill rate / GPU usage issue. That comp might be pushing you close to 1/60th a second, adding Syphon (a render to FBO phase for the screen size introduces more fill rate), maybe pushing you over the edge.
Does the FPS change with the size of your viewer changing?
Right, because its either a fill rate, or programmable pipeline issue using up the GPU cores. Adding additional operations are never “free”. Syphon tries its best to be as lightweight as possible, but sometimes a copy operation (and in the other client app, additional drawing) happens.
Alas, not much we can do about that. But it seems like that comp in and of itself is borderline too heavy for whatever you are running it on.
I’m kind of surprised to think of that shader program as being very intense.
On a non-Syphon note, try changing the depth parameter to something like 8~10 instead of the current. The lower that number, the less iterations of spheres will happen, and the fragment shader will tend to perform more quickly.