20001030: 3D ProjectionControl matrix & point of view

>From: Bill Hibbard <hibbard@xxxxxxxxxxxxxxxxx>
>Organization: SSEC
>Keywords: 200010301901.e9UJ1s413936

Hi Bill-

>However, there may be differences between the Java3D matrices used
>in VisAD and the OpenGL matrices used in Vis5D (e.g., transpose).
>If the make_matrix parameters from vis5d_set_ortho_view() don't
>work quite right, it may only be a matter of permuting them a bit.
>This should not be all that hard to do with a little experimentation.
>Let me know if you need a little help.

It seems that using the Java matrices, the Y takes precedence over
the X.  So EAST and WEST did not work right and should be:

display.make_matrix(0.0, 90.0, 90.0, 1.0, 0.0, 0.0, 0.0);

and 

display.make_matrix(0.0, -90.0, -90.0, 1.0, 0.0, 0.0, 0.0);

respectively.  However, by creating a matrix and then setting the matrix
in this way you lose any aspect and scaling that was there before and
the box takes up the whole display.  Is there an easy way to keep
those around?

>Once this is working it would be very useful to add a set_ortho_view()
>method to ProjectionControlJ3D or MouseBehaviorJ3D.

I agree.  There are some issues when you are dealing with non-linear
map projections (like what does NORTH mean when you are looking at
a polar stereographic view of the northern hemisphere centered on
the pole), but we could use these cardinal directions like BorderLayout
does to refer to sections of the original display space.

Of course, I'd prefer setOrthoView() ;-). Once I get the aspect and
scaling right, I'll add this method in.

Don
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Don Murray                               UCAR Unidata Program
dmurray@xxxxxxxxxxxxxxxx                        P.O. Box 3000
(303) 497-8628                              Boulder, CO 80307
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