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 CAD / Development / 3086
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Subject: 
Re: Clipping / CCW / CW / INVERT
Newsgroups: 
lugnet.cad.dev
Date: 
Sat, 9 Oct 1999 00:21:07 GMT
Viewed: 
482 times
  
Leonardo Zide wrote:
If you keep changing states (turning backface culling on/off or
changing front faces from CW to CCW) very often, you'll get a *slower*
rendering in OpenGL (don't know about D3D).

Do you know the reason why?
The change-state-calls could cost a little overhead, but don't they just set some flags?
And these flags would just cause negating an orientation test?
/Lars



Message has 1 Reply:
  Re: Clipping / CCW / CW / INVERT
 
(...) I once asked the same question :) Most OpenGL drivers have part of the rendering code create at runtime instead of having if/else statements for all the possible flags. When you change the state, the driver has to rebuild the code again and (...) (25 years ago, 9-Oct-99, to lugnet.cad.dev)

Message is in Reply To:
  Re: Clipping / CCW / CW / INVERT
 
(...) No, when I look at the images I see real alpha-blended surfaces :) I've tried to turn backface culling in the transparent parts and they looked very ugly, it's better to draw everything in those cases. (...) Just a note to correct the (...) (25 years ago, 8-Oct-99, to lugnet.cad.dev)

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