[vox-tech] opengl: lines and points

[Peter Jay Salzman]

On Sun 30 Jan 05,  9:50 AM, Ken Bloom <kabloom at ucdavis.edu> said:
> On Sun, 30 Jan 2005 10:05:42 -0500
> p at dirac.org (Peter Jay Salzman) wrote:
> 
> > On Sat 29 Jan 05, 10:38 PM, Ken Bloom <kabloom at ucdavis.edu> said:
> > > On Sun, 30 Jan 2005 00:49:56 -0500
> > > p at dirac.org (Peter Jay Salzman) wrote:
> >  
> > [original code snipped - reposted below]
> > 
> > > I'm not sure why it shows up for you when you deleted one of the
> > > lines, but when I ran your code as written, the lines were outside
> > > the (-1.0,-1.0) to (1.0,1.0) clipping box, so they weren't getting
> > > drawn. Changing the coordinates helped, and they were both drawn.
> > 
> > Wait -- what clipping box?  I request an 800x600 window.  The camera
> > should be positioned at the origin, facing down the -z axis, and have
> > coordinates 800 by 600.
> 
> When you request an 800x600 window, the camera is positioned at the
> origin, facing down the -z axis, and has coordinates ranging from -1 to
> 1 on each axis. You didn't give me reshape() last time.
>
> Your new program works for me with both tDisplay() and xDisplay()
 
I didn't know about the coordinate system.  I pared down the code, but
didn't know my resize function resized the coordinate system as well as the
viewing window.  Otherwise I would've posted it.  Sorry.

But now I'm at a complete loss.  I tried the same code on other machines,
both testing and unstable, and it worked.  It just acts wierd on THIS
machine.

This machine must have the same GL as Richard's and my other machines, so
that's unlikely to be the problem.  The difference is the video card and
monitor.  But I've played GL games on this machine, and haven't seen any
problems before.  The video card is a well supported Voodoo 5 and a flat
screen monitor.

I give up.  I'll play with OpenGL on my other machine.  Grrrr.   I wish
there were a way to debug graphics.

Pete

-- 
The mathematics of physics has become ever more abstract, rather than more
complicated.  The mind of God appears to be abstract but not complicated.
He also appears to like group theory.  --  Tony Zee's "Fearful Symmetry"

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