Video clipping mask with OpenGL ES

Hi There,

I implemented this into an iOS app and ran into the problem of iOS using OpenGL es, The FBO doesn’t work as desired i think because of the differences in colour space (GL_RGB). I understand that for the linked code to work on iOS there would have to be an intermediary to copy the pixel data from the FBO to then be applied later, this is obviously verrrrrry slow.

I’m trying to make a polygon clipping mask fro video, the only way i can think to do it at the moment is to actually draw a block colour donut style polygon over the top. Are there any smarter ways to do this?

Any pointers or links to docs so i can understand this better would be very useful.

Many Thanks,
Miles