yes my impression from what they said was that OpenGl 2.0 under the hood was
already doing some translation in to OpenGl 3.0 style pipe line and had been
for quite while

On mixing of context I don't remember them saying you could have a 2.0 and a
3.0 context in the same app, not sure I would ever want to do that, there
will be choice of which version the context is, but mixing them will
probably be a no no as the driver will probably have to bind certain
requirements to which ever type you chose, but I'm guessing ....

Best Regards

Gordon

__________________________________________________________
Gordon Tomlinson
Email  : gordon.tomlinson @ overwatch.com
YIM/AIM: Gordon3dBrit
MSN IM : Gordon3dBrit @ 3dSceneGraph.com

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Telephone (Cell): (+1) 571-265-2612 <-- Note New Number
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"Self defence is not a function of learning tricks
but is a function of how quickly and intensely one
can arouse one's instinct for survival"
- Master Tambo Tetsura



-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Paul
Martz
Sent: Tuesday, August 14, 2007 12:01 PM
To: [email protected]
Subject: Re: [osg-users] OpenGL 3 announced


> Reading the presentations I didn't read anything of the
> original proposal to provide a backwards compatibility layer
> for GL2.x on top of GL3.  Is this proposal now dropped?

My understanding from the OpenGL BOF is that current hardware is already
OpenGL 3-like, so current drivers are essentially OpenGL 2 layered on top of
OpenGL 3 hardware. I believe the plan for most vendors is to allow apps to
create either an OpenGL 2 or OpenGL 3 context at startup, then use the
appropriate API for that context. Not sure whether mixing heterogeneous
contexts in a single app would be allowed, but it seems theoretically
possible based on what I heard. Gordon? Mike? Did either of you get this
same impression or was I dozing and dreaming this? (It was at the end of a
long day...)

On a related topic, I understand there will be a convenience library of
shaders to mimic old fixed function features.

> Did the vendors give any hint as the timeline they expect?

Nothing specific. We were told "vendors have OpenGL 3 drivers in
development, of course the spec needs to be finalized first". The latency
for public OpenGL 2.0 drivers was ~6 months IIRC and I imagine this might be
comparable. It doesn't sound like this will require radically new hardware
beyond what already exists.

> Will 2.x still be supported in 5 years?  I can imagine that a
> large number of apps would still not be ported by then.

If the PEX/PHIGS/GL ISV shift to OpenGL 1.x is any indication, 5-6 years
sounds about right. OpenGL 1.0 came out in 1992 and by 1998 most all ISVs
had abandoned PEX, PHIGS, Starbase, et al. Perhaps this shift will happen
quicker, as OpenGL 3 hardware is already out, there are fewer IHVs nowadays,
and OpenGL is already widely accepted and has a proven track record.

Paul Martz
Skew Matrix Software LLC
http://www.skew-matrix.com
303 859 9466

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