Re: CHANGES--version 1.4 geomview for Next

[slevy]

Yeow.  Thanks for your careful scrutiny!

Transparency controls - I should have noted that these apply only to the SGI
version.  Quick Renderman isn't supposed to even support transparency.

Software-shaded fog -- there aren't controls for this either, except the
"Software Shading" button on the camera inspector; the only hook for fog
is through the command language right now, something like
   (merge-baseap { lighting { attenconst .25 } } )

N-D viewing: I should have known it would be too tempting a feature to ignore.
Yes, it can look at 4off's (and 4quads and 4meshes).  4vects don't yet work.

The controls are intended to be set up by an external module, so there's
nothing on any of geomview's panels; Olaf has written one for the Iris,
but there's none for the NeXT.  But, 4-D views are easy enough to set up
using a canned script.  Put this in a file and load it:

(progn
    (backcolor allcams .5 .5 .5)
    (bbox-draw allgeoms off)
    (dimension 4)

    (window default { position 150 400 150 400 })	# xmin xmax ymin ymax
    (new-camera yzw)
    (ND-axes yzw cluster1 1 2 3)

    (window default { position 150 400 500 750 })	# xmin xmax ymin ymax
    (new-camera xyz)
    (ND-axes xyz cluster1 0 1 2)
)

This gives one window operating on the X-Y-Z subspace, one on the Y-Z-W space.
Then load some 4-D object(s).   (A nice one to begin with is /u/holt/nd/4daxes,
a set of four orthogonal axes in red, green, blue, and white.)  Try turning the
axes in one window, then the other.

There's also support for coloring according to the projection along some axis;
this is more complicated to use, and even the geomview command-help doesn't
describe it.  Here's a script which sets up one kind of coloring; you can
probably see how to tweak it:

(ND-color yzw	# Color this way in window "yzw"
        (
          (
            # Projection axis (in camera space)
            # Points are colored by their inner product with this vector.
            ( 0 0 1 0 )

            # Then, a series of <projection value> <RGBA color> items.
            -.4          1  0  0  1
             0           0  1  0  1
            .4           0  0  1  1
          1e10          .3 .3 .3  1     # Need sentinel to work around code bug!
          )
        )
)

You can load this in conjunction with the first script to enable coloring.