[PD] system requirements video

[chris clepper]

>I wonder how fast these two mainstream brands handle texture upload on
>different OS'es.
>
>It may not be very optimized in the driver since this operation is
>rarely used during gameplay, but it's a potential bottleneck for video
>processing. I expect major performance differences here.
>
>Did anyone compare nVidia vs ATI on different OS's on this aspect?

We actually have fairly extensive data on this.

Starting with OSX 10.2 all textures can be uploaded using DMA 
resulting in 0% CPU time for the transfer.  Plus 10.2 can handle 
non-power-of-two texture sizes and YUV pixels for even more 
efficiency.  This applies for both ATI Radeon (not Rage) and Nvidia 
Geforce hardware on OSX.  Of course GEM fully supports these 
features. ;)

Windows does not feature any of these enhancements in it's standard 
OpenGL implementation, so significant CPU time can be spent handling 
the texture uploads.  There might be some vendor specific extensions 
to enable fast texturing, but to my knowledge none of them have been 
implemented in GEM.  Windows will be getting system wide support for 
using video as textures, unfortunately it will be for Direct3D and 
won't be released until 2005 or 2006 (as part of the Longhorn GDI).

Linux is closer to Windows than OSX as far as drivers go with Nvidia 
hardware, so you can expect similar texturing performance.

I can post measured performance data between Win32 and OSX GEM if you 
are interested.

cgc

>  j#|@
>