[osg-users] OpenGL 3.1 at GDC

Alberto Luaces aluaces at udc.es
Wed Mar 25 08:45:09 PDT 2009


Hi Shayne,

I think the answer would be "it was partially compatible". Given a DirectX 
version, you couldn't ask for any older interface version, just for the newer 
ones. On recent versions of DirectX IIRC, you couldn't ask for a version 
older than version 5. However today the break is greater since DirectX 10 
doesn't give access to older versions of the API. According to the Wikipedia, 
Windows keep several versions of DirectX in order to continue running older 
programs:

"Prior to DirectX 10, DirectX was designed to be backward compatible with 
older drivers, meaning that newer versions of the APIs were designed to 
interoperate with older drivers written against a previous version's DDI. For 
example, a game designed for and running on Direct3D 9 with a graphics 
adapter driver designed for Direct3D 6 would still work, albeit possibly with 
gracefully degraded functionality. However, as of Windows Vista, due to the 
significantly updated DDI for Windows Display Driver Model drivers, Direct3D 
10 cannot run on older hardware drivers.

Various releases of Windows have included and supported various versions of 
DirectX, allowing newer versions of the operating system to continue running 
applications designed for earlier versions of DirectX until those versions 
can be gradually phased out in favor of newer APIs, drivers, and hardware."

Regards,

Alberto

El Miércoles 25 Marzo 2009ES 16:29:07 Tueller, Shayne R Civ USAF AFMC 519 
SMXS/MXDEC escribió:
> Paul,
>
> In answer to your question, the answer is no, it can't.
>
> I appreciate what OpenGL can do in terms of its extensions but that isn't
> what my response was in reference to. I was asking Robert if he was
> implying that D3D is not backwards compatible in his earlier comment...
>
> -Shayne
>
> -----Original Message-----
> From: osg-users-bounces at lists.openscenegraph.org
> [mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of Paul Martz
> Sent: Wednesday, March 25, 2009 9:20 AM
> To: 'OpenSceneGraph Users'
> Subject: Re: [osg-users] OpenGL 3.1 at GDC
>
> Does that D3D 3.0 app get access to any new features?
>
> OpenGL 3.1 adds new ARB extensions to OpenGL 2.1, so that old OpenGL apps
> (even OpenGL 1.0 apps) running on an OpenGL 2.1 implementation can access
> new features analogous to those found in OpenGL 3.1.
>
> Paul Martz
> Skew Matrix Software LLC
> http://www.skew-matrix.com
> +1 303 859 9466
>
> -----Original Message-----
> From: osg-users-bounces at lists.openscenegraph.org
> [mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of Tueller,
> Shayne R Civ USAF AFMC 519 SMXS/MXDEC
> Sent: Wednesday, March 25, 2009 9:08 AM
> To: OpenSceneGraph Users
> Subject: Re: [osg-users] OpenGL 3.1 at GDC
>
>
> Are you implying that the current D3D is not backwards compatible with
> previous versions? I believe that a current D3D application can query
> earlier versions of the D3D interface through COM. A D3D 3.0 application
> can still run under D3D 10.0 as I understand it...
>
> -Shayne
>
>
>
>
>
> _______________________________________________
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> osg-users at lists.openscenegraph.org
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org





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