Re: [Plib-users] Asymmetric view frustums

[Steve B. <sjb...@ai...>]

Curtis L. Olson wrote:
> I have an application where I need to setup an asymmetric view frustum.
> I can't find my Red Book tonight (maybe left at work?) but I'm not sure
> it would be much help anyway?  Is there a reasonably easy way to setup
> asymetric view frustums in ssg?

Yes, there is a member function of ssgContext called 'setFrustum' (and
a convenience function: ssgSetFrustum that calls it on the current context).

That takes the left, right, bottom, top, near and far plane distances
as parameters.  The meaning of these is exactly as for OpenGL's glOrtho
and glFrustum calls.  Assuming you need perspective, this means:

        left, right Specify the coordinates for the left and right
                    vertical clipping planes.

        bottom, top Specify the coordinates for the bottom and top
                    horizontal clipping planes.

        near_val, far_val
                    Specify the distances  to  the  near  and  far
                    depth clipping planes.  Both distances must be
                    positive.

(left, bottom, -near_val) and (right, top, -near_val) specify
the points on the near clipping plane that are  mapped  to
the  lower  left  and  upper  right corners of the window,
assuming that the eye is located at (0, 0,  0).   -far_val
specifies  the  location  of the far clipping plane.  Both
near_val and far_val must be positive.

----------------------- Steve Baker -------------------------
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