Re: Newbie Q: Is it possible to draw functional "Cocoa Controls" in an OpenGL context?

FROM : Alastair Houghton
DATE : Thu Feb 15 00:51:37 2007

On 14 Feb 2007, at 23:21, Daniel Steward wrote:

> OK - now I'm curious.  Not having used NSOpenGLView myself I'm just 
> throwing things out.  How would it work to build a composite 
> subclass of NSView which includes an NSOpenGLView as a subview 
> along with buttons above it.


Like Scott said, you can't do that at the moment; you aren't supposed 
to overlap views (and you'd very likely have trouble anyway with an 
NSOpenGLView because it's a hardware accelerated surface), and you 
can't have subviews of NSOpenGLView.

>  Creating a separate window seems like a hard way to do this 
> because it seems like you would have to write some sort of glue 
> (literally) code to tie the two together spatially.


I don't think you need any code for that :-)

Take a look at NSWindow's -addChildWindow:ordered:.

> I suppose the other question is why can't other things draw on top 
> of the OpenGL view?  Is there something about the glContext that 
> makes this a problem?


Yes, it's hardware accelerated.  The memory backing it may be 
organised differently than normal, and it will be updated by the 3D 
engine on the video card as and when necessary.

Kind regards,

Alastair

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