I wish to know if the processor can be used during the painting of a face or a calllist.
No, they don’t block as far as I know. Most calls call into the driver and return immediately. In the driver that may block, but in the client they shouldn’t.
Siwko
glFinish() will block until the rendering is done, as well as wglSwapBuffers(), and possibly some other similar calls, as well as calls which read back data from card memory. Most state-setting and rendering calls do not necessarily block (depending on driver and card).