Re: Drawing to NSView with OpenGL questions

FROM : Erik Buck
DATE : Sun Feb 10 18:18:27 2008

It is easy to overlay gl over quartz or quartz over gl, but it's 
tricky to interleave them.  Approaches for overlays include the 
following samples :  <http://developer.apple.com/cgi-bin/search.pl?q=gl+NSView&num=50&site=(samplecode)
>


If you must interleave gl and quartz, render quartz drawing into gl 
textures and draw with gl  You are correct that reading back from VRAM 
is seldom the right solution.  Instead of reading your gl images back 
from the card, write your quartz images to the card and do the mixing 
there.  This sample shows one approach: http://developer.apple.com/samplecode/CocoaGL/listing10.html

Core Animation in Mac OS X 10.5 essentially draws with quartz into gl 
textures when views are layer backed.