RE: Choosing a rendere

From: Jean-Francois Roy [mailto:email@hidden]
Sent: Sunday, November 11, 2007 4:29 PM
To: Yaron Tadmor
Cc: email@hidden
Subject: Re: Choosing a rendere

So basically I’d need to create a pixel format for the accelerated renderer, create the context and check the gl extension string. If it doesn’t contain what I need, I’d then need to create a pixel format for the software renderer and create context for that. Is this right?

That will work. 

In the case of hardware limits (rather than missing extensions), you can omit to specify the NO_RECOVERY flag when creating your context. When that flag is not set, OpenGL on Mac OS X will automatically fallback to the software renderer when it breaks a hardware limit.

Some cases are also a bit more complex. For example, geometry shading is supported by the software renderer but is not available on a lot of hardware yet. OpenGL will transparently do geometry shading in software, while continuing to use hardware for vertex and fragment shading. There is a hefty cost to that, but if it's acceptable to your context, it's a viable solution.