[osg-users] setLODScale affecting near far planes?

Paul Martz pmartz at skew-matrix.com
Mon Sep 22 10:52:48 PDT 2008


> FYI, Roland is correct, the OSG just does culling on sides of 
> the frustum by default.
> 
> OpenGL does no culling, is just does near and far *clipping*.   The
> OSG of course doesn't change this so will do near/far 
> clipping and the only way to switch this off is to disable 
> GL_DEPTH_TEST.

Even that won't work; DEPTH_TEST is a fragment op, and clipping against the
clip planes is done before rasterization.

> It would seem that Paul and Gordon have confused the clipping 
> and culling a little.

Yes, I thought the original poster was talking about enabling OpenGL
near/far clipping (probably because I have seen so many newbies ask how to
disable this in the OpenGL forums and newsgroups). Clearly, the original
poster said "culling"... My mistake, and thanks to all for the
clarification.

Back to the original issue:

So, you see this problem when you enable OSG culling for near/far. What
happens if you leave this disabled (as osgviewer does)?
   -Paul




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