geomview

[mosher at andromeda.rutgers.edu (Lee Mosher)]

Greetings!!

I am getting forms to work very nicely with my pleated surface program. 
But now that I have some new capabilities, I am not getting geomview
to behave correctly. I've included a sample of the commands that
my program sends to geomview; let me explain what is going on, and 
then say how geomview behaves.

First the program uses the ``read'' command to define two different
objects, called ``Triangle'' and ``TwoEdges''. Then the program
uses the ``geometry'' command to draw an object called ``Triangles'',
which is an INST whose unit may be either Triangle or TwoEdges; then
there will be a bunch of transforms. In the form, I can switch the unit
back and forth between Triangle and TwoEdges. The transforms may vary
as well. Thus, every time I want to redraw Triangles, a new
geometry command is issued to draw Triangles, with one of the two units
Triangle or TwoEdges and perhaps a new list of transforms.

The problem is this. The program starts out using Triangle as the unit.
All is well. Then I switch the unit to TwoEdges. All is still well.
But when I switch the unit back to Triangle, nothing is drawn. 
Thenceforth, as I switch the unit back and forth between Triangle and
TwoEdges, nothing is ever drawn again.

I've included a sample output below. This is what my program sends to
geomview through the pipe. I have filtered out some of the output; for
instance, I have filtered out all commands to a scene which controls
which transforms are used in the INST. Also, I have shown only three
``geometry'' commands: the first uses Triangle as the unit, the second uses
TwoEdges, and the third uses Triangle. Usually, there are several 
repetitions of the geometry command before the unit is switched, as the 
program goes around its event loop waiting for the command to switch. For 
instance, in one run there were four or five consecutve uses of the unit 
Triangle, then four or five uses of TwoEdges; all was OK. But then when I 
switched back to the unit Triangle, despite several consecutive geometry
commands with that unit, nothing was drawn, and so on as the unit was
switched back and forth.

My only possible guess is that somehow geomview is forgetting the
definition of Triangle and TwoEdges after they are not used anymore,
but that doesn't ring true.

Much thanks. Here is the glop.
Lee




(space hyperbolic)
(geometry Triangles { LIST } )
(bbox-draw Triangles no)
(read geometry { define Triangle 
{ appearance { material { ambient 1.0 0.0 0.0 }}
4QUAD
1.000000 0.000000 0.000000 1.000000 
0.000000 1.000000 0.000000 1.000000 
0.000000 0.000000 1.000000 1.000000 
1.000000 0.000000 0.000000 1.000000 
}
} )
(read geometry { define TwoEdges { 
appearance { linewidth 3 }
4VECT
1 3 1
3
1
0.000000 1.000000 0.000000 1.000000 
0.000000 0.000000 1.000000 1.000000 
1.000000 0.000000 0.000000 1.000000 
1.0 0.0 0.0 1.0
}})
(pickable Triangles no)
(geometry Triangles { INST 
unit : Triangle 
transforms { TLIST

1.000000 0.000000 0.000000 0.000000 
0.000000 1.000000 0.000000 0.000000 
0.000000 0.000000 1.000000 0.000000 
0.000000 0.000000 0.000000 1.000000 


-1.000000 0.000000 -2.000000 -2.000000 
-2.000000 0.000000 -1.000000 -2.000000 
0.000000 -1.000000 0.000000 0.000000 
2.000000 0.000000 2.000000 3.000000 


0.000000 -2.000000 -1.000000 -2.000000 
0.000000 -1.000000 -2.000000 -2.000000 
-1.000000 0.000000 0.000000 0.000000 
0.000000 2.000000 2.000000 3.000000 


-2.000000 -1.000000 0.000000 -2.000000 
-1.000000 -2.000000 0.000000 -2.000000 
0.000000 0.000000 -1.000000 0.000000 
2.000000 2.000000 0.000000 3.000000 

} } )
(geometry Triangles { INST 
unit : TwoEdges 
transforms { TLIST

-1.000000 0.000000 -2.000000 -2.000000 
-2.000000 0.000000 -1.000000 -2.000000 
0.000000 -1.000000 0.000000 0.000000 
2.000000 0.000000 2.000000 3.000000 


0.000000 -2.000000 -1.000000 -2.000000 
0.000000 -1.000000 -2.000000 -2.000000 
-1.000000 0.000000 0.000000 0.000000 
0.000000 2.000000 2.000000 3.000000 


-2.000000 -1.000000 0.000000 -2.000000 
-1.000000 -2.000000 0.000000 -2.000000 
0.000000 0.000000 -1.000000 0.000000 
2.000000 2.000000 0.000000 3.000000 

} } )
(geometry Triangles { INST 
unit : Triangle 
transforms { TLIST

1.000000 0.000000 0.000000 0.000000 
0.000000 1.000000 0.000000 0.000000 
0.000000 0.000000 1.000000 0.000000 
0.000000 0.000000 0.000000 1.000000 


-1.000000 0.000000 -2.000000 -2.000000 
-2.000000 0.000000 -1.000000 -2.000000 
0.000000 -1.000000 0.000000 0.000000 
2.000000 0.000000 2.000000 3.000000 


0.000000 -2.000000 -1.000000 -2.000000 
0.000000 -1.000000 -2.000000 -2.000000 
-1.000000 0.000000 0.000000 0.000000 
0.000000 2.000000 2.000000 3.000000 


-2.000000 -1.000000 0.000000 -2.000000 
-1.000000 -2.000000 0.000000 -2.000000 
0.000000 0.000000 -1.000000 0.000000 
2.000000 2.000000 0.000000 3.000000 

} } )