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Subject: 
Re: Mac Brick CAD and the Imerial Star Destroyer
Newsgroups: 
lugnet.cad.dev.mac
Date: 
Fri, 21 May 2004 01:07:44 GMT
Viewed: 
2331 times
  
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.)

--Travis



Message has 1 Reply:
  Re: Mac Brick CAD and the Imerial Star Destroyer
 
(...) 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 (...) (20 years ago, 21-May-04, to lugnet.cad.dev.mac)

Message is in Reply To:
  Re: Mac Brick CAD and the Imerial Star Destroyer
 
(...) Travis 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 (...) (20 years ago, 20-May-04, to lugnet.cad.dev.mac)

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