Subject:
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Re: Mac Brick CAD and the Imerial Star Destroyer
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Newsgroups:
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lugnet.cad.dev.mac
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Date:
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Fri, 21 May 2004 01:59:49 GMT
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Viewed:
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4757 times
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In lugnet.cad.dev.mac, Travis Cobbs wrote:
> In lugnet.cad.dev.mac, Andrew Allan wrote:
> > Having done some experiments and research over the last couple of days, it seems
> > that to get very fast drawing in OpenGL generally, vertex arrays are necessary.
> > OpenGL has specific commands such as glBufferDataARB that will explicitly
> > transfer the info into the graphic card's RAM (only availible on newer cards)
> > and likewise MacOS X also has commands that give the graphic card DMA access to
> > the Mac's RAM (again only for newer cards).
>
> Just as a note, I found that Vertex Buffer Objects (VBOs) would crash my ATI
> card in Windows when used inside a display list. As far as I can tell, this
> isn't supposed to happen. Regular vertex arrays work fine inside a display
> list. General consensus on the OpenGL.org discussion forum was that even if it
> didn't crash it wouldn't speed things up, since a display list is supposed to
> automatically figure out how to draw the geometry as fast as possible.
>
> Also, it really sounds like something is causing your app to be running in
> software mode, not hardware. I don't know how OpenGL windows are created in Mac
> OS X, but you might want to make sure you aren't requesting any features that
> force software rendering. I know on Windows it's relatively easy to request
> something not supported by the video hardware, and this causes it to create a
> software-rendered OpenGL window, instead of a hardware-rendered one. (I realize
> this is a long shot, because Mac OS X is a whole lot easier to program than
> Windows, but I thought I'd at least mention it.)
Yeah, watch out for that software rendering on the Mac. It sneeks up on
you. I know it can switch you over while your program is running, but I
don't know what causes it to happen other than resizing a window. You
might want to query it about the driver as you build up your display lists
to see if it switches you over to software rendering at some point.
Don
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Message has 1 Reply:
 | | Re: Mac Brick CAD and the Imerial Star Destroyer
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| (...) Actually, the same thing can happen in Windows if you resize a window too big (say 1600x1200) on an older video card. However, I'm not sure you can tell that it has switched to software mode on Windows, because as far as I know it is still (...) (21 years ago, 21-May-04, to lugnet.cad.dev.mac)
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Message is in Reply To:
| | Re: Mac Brick CAD and the Imerial Star Destroyer
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| (...) Just as a note, I found that Vertex Buffer Objects (VBOs) would crash my ATI card in Windows when used inside a display list. As far as I can tell, this isn't supposed to happen. Regular vertex arrays work fine inside a display list. General (...) (21 years ago, 21-May-04, to lugnet.cad.dev.mac)
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