Partly update the screen or copying buffers

Hi,

My application updates the whole screen frequently, but there are a few situations that updates only a very small part of the screen.

I already tried to use glScissor and/or glViewport to make eglSwapBuffers update only a small part, but the rest of the screen is black. Is there a way to let opengl update only a small part of the screen? Or copy the contents of the back buffer into the front buffer and then update the whole screen?

thanks

guich

Just updating the entire screen every frame - even if only a part of it needs to be updated - is still likely to be much faster than any tricks to get a partial update (especially tricks that involve copying stuff around). GPUs are designed to work that way, so if you work with them rather than against them you’ll do better.