How do I trap display driver drawing commands on Mac OS X?

Question

I am trying to find a clean and elegant way to trap all display driver drawing commands on Mac OS X so I have visibility to anything that gets drawn on the screen, before it goes to the physical display driver. Simple bitmaps won't do it -- I need the actual drawing commands and not just notifications on which areas have changed.

This could be Quartz drawing commands or just pure OpenGL, I can live with any API as long as it's detailed enough.

Is there any way to get into Quartz Extreme to catch its OpenGL commands or something?

Thanks in advance!

Answer 1

I can't answer your question directly. But I remember a talk by Amit Singh, who near the end of the talk scambled the way applications were drawn on the screen (I can't describe it in words, you'll better see it yourself). Maybe it can give you some insights.

• http://chaosradio.ccc.de/23c3_m4v_1721.html
• http://chaosradio.ccc.de/media/congress/2006/video/23C3-1721-en-software_protection_and_the_tpm.m4v (Note: 281M)

The effect and explanation is at around 56:00.

Answer 2

Look into the technique GLIntercept uses. You'll probably have to adapt it to whatever OSX uses for LD_PRELOAD.