[Visualpython-users] Disable pixel shaders to improve performance

[Aaron M. <ajm...@al...>]

Hello VPython Folks,

As I work toward a greater implementation of using VPython in my
courses this fall, I have run into some trouble with the new rendering
engine.  We have ~35 <1yr old Tablet PCs that will be used in class
and in lab and I am working on developing vpython exercises and demos
along these lines.

I have found that the tablets seem to have no pixel shader rendering
in hardware, so under the new vpython 5 (Python 2.6.2, VPython
2.6-5.11), my simulations are extremely slow (few frames per second
instead of >15).  Although I don't know what units the measurement is
in, if I set the show_rendertime property of the scene to True I see
"cycle" reported in the 200s and "render" around 70.

If I subsequently set the enable_shaders property to False, everything
works just like with previous versions of vpython and the "cycle"
changes to ~40 and "render" to 6 or 7.

Furthermore, with the shaders enabled pythonw crashes on closing the
display window, whereas disabled pythonw closes just fine.

So, here is my question:  For now, I think it best for me to disable
shaders by default, so students don't have to deal with this in their
code.  Where is the best place to put the command to disable these
shaders?

Thank you,
Aaron

------------------------------------------------------
Aaron J. Miller, Ph.D.
Department of Physics
328 Palenske Hall
Albion College, Albion, MI 49224

ajm...@al...
517-629-0684 phone
517-629-0264 fax