Re: [Closed REQ 6216]: Geomview

[daemons <daemon>]

> 1 - Is it possible to have external modules running on the parallel
> nodes, supply data to geomview running on the host?

Yes.  Although geomview can't take data from TCP/IP sockets at present
(though that'll be in the next release!), it can read from named pipes.

The program "togeomview" may be the easiest interface to this.
"togeomview" creates a named pipe (if none exists), and invokes a copy
of geomview reading commands or geometric data from that named pipe
(if no such copy of geomview is already running).

If, say, the parallel processor runs something like UNIX, and supports
rsh (remote shell), you could write C code like the following on the
parallel machine to send data to geomview:

  FILE *f;

  f = popen("rsh graphicsmachine  env DISPLAY=:0 togeomview -c", "w");

  ...
  /* Now send GCL commands down the pipe to rsh, which sends them across
   * the network to togeomview, which in turn writes them to a named pipe
   * for geomview to read.
   */
  fprintf(f, "(geometry Blob  { OFF ...
  ...
  fprintf(f, "})\n");
  fflush(f);   /* Remember to fflush() after sending a batch of updates,
		* to ensure geomview receives the complete message,
		* lest it hang waiting for the matching close parenthesis!
		*/

  ...
  fprintf(f, "(geometry Blob { ... })");
  fflush(f);


This should work well so long as there's just one such stream running at
a time; if several processes are running "togeomview" concurrently,
they'll all use the same named pipe, and will screw up.  It'd be possible
to handle that, but not as simply as the above.

If this isn't practical for your parallel machine, let us know what it can
do, and maybe something can be worked out.

> 2 - If we decide to build the Visualization tool from scratch, can we
> look at some of the source code from Geomview?

Sure -- it's not documented much, but it's all there, at
  ftp://geom.umn.edu/pub/software/geomview/geomview-1.6.1-src.tar.gz

> 3 - Will Geomview run on SparcStation 20 using Xgl?

No.  However, if you can find an OpenGL implementation for the Sparc 20,
you'd be able to compile geomview there; and if the OpenGL libraries could
take advantage of hardware graphics acceleration, then so would geomview.


  Stuart Levy