RE: [Visualpython-users] proposed mesh object

[David S. <dsc...@vy...>]

I thought about this (in fact, I did it once).  It might not be a bad
idea.  However, note that my faces.index proposal would take care of the
inefficiency and perhaps some of the difficulty of use (a wrapper could
set up the index array for a mesh, and then you would just use the same
[x,y,0:3] position array.

The sample code I wrote for constructing triangles is absurdly slow; I
didn't intend anyone to do anything useful with it.  It's basically
intended as a tutorial on how triangle rendering and shading work.
Realistic applications can probably do the same things in parallel with
Numeric.

Dave

> -----Original Message-----
> From: vis...@li... 
> [mailto:vis...@li...] On 
> Behalf Of Ari Heitner
> Sent: Wednesday, July 25, 2001 5:14 PM
> To: vis...@li...
> Subject: [Visualpython-users] proposed mesh object
> 
> 
> 
> Playing with Scherer's Mesh class based on the faces object, 
> I realized that drawing heightfield meshes might be a pretty 
> common application. Right now faces is extremely poorly 
> optimized for this (using the Mesh class anyhow): vertices 
> are not correctly shared between polygons, and setting up the 
> mesh from the data is extremely slow (since it turns the Mesh 
> into polygons one vertex at a time in Python, for a 30x30 
> Mesh that's 900 polys and 3600 vertices in the inner loop.
> 
> This was by far the most expensive part of a heightfield demo 
> I wrote; by comparison calculating fractals heightfield data 
> is very cheap.
> 
> A mesh object would be pretty easy to write that took a 
> rectangular x 3 matrix (i.e. a rectangular matrix of 
> vectors). This would be faster to render as well as faster to 
> construct.
> 
> Any thoughts/requests?
> 
> 
> Ari
> 
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