[Bf-committers] Re: OpenGl in windowsVista ... bad news....

Aras Pranckevicius nearaz at gmail.com
Mon Aug 8 12:48:40 CEST 2005


(first post to the list! :))

> * OpenGL performance will be significantly reduced - perhaps as much as 50%
> * OpenGL on Windows will be fixed at a vanilla version of OpenGL 1.4
> * No extensions will be possible to expose future hardware innovations

I really doubt about the performance part. The only overhead I see is
that it's more work on the CPU side to translate from GL to D3D
calls/commands/whatever. The rest is performed on the video card
anyway, and once GL->D3D translation is done (on the CPU), the rest
proceeds as usual.

Now, Vista should have an improved display driver model that lowers
driver overhead significantly. So, that's lowered general driver
overhead, but some perf hit because of GL->D3D translation. In the
end, I wouldn't be surprised if the whole thing runs at the same speed
as now on WinXP.

> It wouldn't be too hard to mimic the basic Blender lighting,
> material and texture options with GLSL, enhancing and
> speeding up the 'shaded display' mode quite some.

While surely not being "trivial", this is still doable. Lighting
computations are a piece of cake I think; the most problematic things
are exotic textures (animated procedural anyone?) and visibility
(shadows etc.).

> The coding work would involve writing a sortof wrapper
> though, to enable in Blender to set an "OpenGL Profile" to denote
> which level of HW support you have.

Definitely. Some sort of "viewport renderer" that can scale down to
the older hardware. Not very hard, methinks.

Aras 'NeARAZ' Pranckevicius
http://nesnausk.org/nearaz | http://nearaz.blogspot.com

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