PDA

View Full Version : SGI vs Microsoft



Zork
11-11-2002, 11:16 AM
Is there a difference between SGI's drivers for Windows and Microsoft's?Personally, I tried both, running different programs, but I haven't seen any difference at all.Also, I am a begginer.What do you think?

Melekor
11-11-2002, 05:00 PM
Yes, I would like to know this too. Anyone know?

mikael_aronsson
11-12-2002, 12:56 AM
The original SGI OpenGL driver was a little faster than Microsofts version, but the moment you have hardware support for OpenGL in your videocard the SGI drivers become useless.

Mikael

marcus256
11-13-2002, 12:55 PM
The original SGI OpenGL driver was a little faster than Microsofts version, but the moment you have hardware support for OpenGL in your videocard the SGI drivers become useless.

I tried this the other day, hoping that I would get a "softare reference driver" (want to know how slow things are in SW compared to my GF4), only to notice that even with the SGI opengl.dll driver, I get hardware acceleration (vendor=nVidia etc).

First I thought that I had made some stupid compiler misstake, so that I get opengl32.dll anyway, but no. I also managed to see a slight difference in performance (about 10%, not the kind of difference you expect if it's SW vs. HW) between linking with opengl.dll vs. opengl32.dll & gdi32.dll (even if it's the same vendor, version etc), which I assume has to do with differences in function calling overhead or something.

Anyway, my conclusion is that the SGI OpenGL implementation supports IHV ICDs, so:

SGI OpenGL: Faster SW OpenGL, Slower HW OpenGL
MS OpenGL: Slower SW OpenGL, Faster HW OpenGL

...but not by much.

Bob
11-13-2002, 01:13 PM
Are you sure you actually linked to opengl.lib when building?

*Aaron*
11-14-2002, 07:34 AM
First I thought that I had made some stupid compiler misstake, so that I get opengl32.dll anyway, but no.That answer your question, Bob?

Marcus, what happens when you select a PFD_GENERIC_FORMAT pixel format? Does the vendor string have "SGI" in it? Also, what is the GL version when using this format? Just curious.

Bob
11-14-2002, 09:07 AM
Have done some research, and it looks like SGI's implementation indeed can detect external drivers and load them.

However, something that confuses me is that whenever I select a pixel format that my hardware can't handle, it falls back to software. Nothing odd with that, but the software driver is Microsoft's own. Unless SGI's also report "GDI Generic" and "Microsoft corporation" that is, which I see unlikely. I have not been able to get it to report anything other than Microsoft and NVIDIA yet.

This makes me think that SGI's maybe loads MS's implementation if available, and that in turn loads external drivers. If so, it's not really SGI's implementation that load the external driver.