Re: Swarm and OpenGL

[Scott Christley]

Hello Patrick,

I cannot say about Swarm specifically, but I know that there is no problem
with using OpenGL with ObjC.  We've written an ObjC 3D class hierarchy
(somewhat based upon NeXT's 3DKit) that uses OpenGL as its underlying
rendering engine.  We hope to change it to use Renderman with the Vision
project, but things have been going slow...

Anyways, we found that we could not use the existing aux functions because
they have their own event loop with little ability to interact with other
loops.  This was no good for our purpose because GNUstep handles the event
loops for the complete application, we ended up writing the implementation
similar to NeXT's 3DKit in that each "shape" object has a -render: method
which gets called by the application kit when it should render itself.

Our 3D Library utilizes GNUstep (OpenStep) for its foundation, so we've
shown the exact same program running on Windows NT (with its native OpenGL
suport) and Linux using Mesa.

Scott

At 10:32 PM 3/27/97 -0500, Patrick McNeill wrote:
>Recently, I've been trying to create a 3d display for my sim using OpenGL
>(actually Mesa -- a freeware implementation of OpenGL).  I have code that I
>know works (I tested it independently), but when I move it into my
>simulation, it stops working.  The window gets generated but is drawn
>black.  Then I noticed I was missing the auxMainLoop() call, so I added
>that in and everything stops working (actually stalls)...  I'm assuming
>that the auxMainLoop triggers some loop in OpenGL that doesn't allow
>anything else in the process to run (kind of like the Swarm kernel).  I
>have a call to my display function (actually an ObjC message that calls the
>display function) in the observer swarm schedule, thinking that would
>emulate the auxMainLoop, but I still get an empty window...  If someone out
>there knows more about how OpenGL would react to Objective C (and if my
>problem is a result) please let me know...  Otherwise I'll just start
>digging around the Mesa source code (yuck...)...
>
>Thanks!
>
>-Patrick McNeill
> address@hidden
>