Re: [Visualpython-users] Philosophical question

[Ari H. <ahe...@an...>]

On Tue, 12 Dec 2000, Dethe Elza wrote:

> I'm curious why VPython is written as a C-extension, rather than on top of
> pyOpenGL.  Is it strictly a performance thing?  Since pyOpenGL is already a
> C-extension, the performance shouldn't be a problem, but that could be my
> own ignorance speaking.  I'm mainly curious because the more an extension
> relys on C the less portable it becomes, and as a pedagical tool I prefer
> Python code to C code.
> 

It's a speed thing. The first couple of versions of Visual were written
purely in Python, for ease of prototyping/modification. But when the interfaces
were pretty well finalized, it was rewritten in C for speed. The performance
issue is nothing other than that the core Python language is rather slow. There
are a couple of features in Visual that were just very slow in the pure-Python
version.

That said, I don't see

a) why Python should be more portable than C. Python is written in C. Beyond
that, PyOpenGL relies on a working OpenGL implementation. Which is exactly what
Visual needs (well, C++ really). I have yet to hear of the platform that had a
working Python interpreter before it had a working C compiler.

b) why it should matter "as a pedagogical tool" how Visual is implemented. If
the internals were one extremely long PERL line, it shouldn't matter. The main
thing is the friendly Python API.



Ari Heitner