saving image from tkgllua buffer

[Siome Klein Goldenstein <siome@...>]

I'm trying to save images from the openGL canvas
under tklua and gllua. 

I'm using some C code a friend gave me
to do it,  but I'm always getting all blacks.

I tryed a combination of different things,
in the hope that it was just trying to grab
the image before openGL was done drawing.
I used glFlush(), glFinish,  even
(canvas)::makecurrent().

basically my last attempt was:

   setframe(i)
   tkupdate("idletasks")
   glFlush()
   glFinish()
   canvas:makecurrent()
   WriteImage (fname, wcvs, hcvs)

where setframe(i) draws the i^th frame
of my animation,  issues a glFlush() and
a canvas::swapbuffers()  
(where canvas is my openGL canvas handle, fname 
is the filename and wcvs/hcvs are the dimensions
of the canvas)

I'm sure I'm missing something obvious...

Thanks
Siome
-- 
----------------------------
Siome Klein Goldenstein
siome@cis.upenn.edu
http://www.cis.upenn.edu/~siome