Re: OGL View Matrix --> pfChan view matrix

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Angus Dorbie (dorbie++at++sgi.com)
Thu, 11 Jun 1998 14:52:33 -0700

Allen wrote:
>
> I think I found the solution now. (Thanks to a message Angus replied to
> about a year ago)
>
> ...
> pfViewMat.set(ogl_matrix);
> pfViewMat.transpose(pfViewMat);
> pfViewMat.preRot(-90, 1, 0, 0, pfViewMat);
> pfViewMat.postRot(pfViewMat, 90, 1, 0, 0);
>
> chan->setViewMat(pfViewMat);
> ...
>
> That "seems" to work. Can anyone confirm if this is the correct
> solution?
>

Yes it's correct.

The idea is to rotate the Performer up axiz (z) onto OpenGL
up axis (y) perform the viewing transform in OpenGL coordinate
space, then transform y back onto z, in otherwords you can apply.

The transpose is to go from the viewing transfprmation of
OpenGL to the model transformation style used for the
pfChannel in Performer.

Cheers,Angus.

-- 
"Only the mediocre are always at their best." -- Jean Giraudoux 


For advanced 3D graphics Performer + OpenGL based examples and tutors:
http://www.dorbie.com/
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