Re: [PyOpenGL-Users] Modelview and projection matrices

[Richard J. <ric...@op...>]

On Sat, 5 Jan 2002 23:46, Jan Ekholm wrote:
> Hi,
>
> I've been trying to implement some form of view frustum culling. I found
> some interesting code on:
>
> 	http://www.markmorley.com/opengl/frustumculling.html
>
> The code is in C, so I need to translate it to Python. Central in that
> approach is the use the current modelview and projection matrices. So I
> get the using:
>
>         projection = glGetFloatv ( GL_PROJECTION_MATRIX )
>         modelview  = glGetFloatv ( GL_MODELVIEW_MATRIX )
>
> However, the Python versions return a [4][4] matrix, while the C versions
> return a [16] array. The code on the page above uses a [16] array for all
> indexing, so I'd like to translate the matrices I get from glGetFloatv to
> arrays.

Code (interchangeable python and C modules for frustum culling and octree 
storage) attached :)

You can also get this code by downloading the tarball from 
http://goanna.adroit.net/~richard/ufo/ where there is some octree code that 
uses the frustum culling too. Note that since I discovered that the code is 
_significantly_ faster when it just draws _everything_ rather than tries to 
cull, the current ufo.py doesn't actually call the frustum or octree code. In 
a nutshell, define objects like the triangle object, stuff them into the 
octree with octree.insertPolygon or octree.insertObject for each of the 
object's bounding vertexes. The call octree.render with the frustum and it 
calls each of the appropriate sub-object's render() method.

Note that I do _all_ my view projection manipulation in the projection 
matrix, so I don't include the modelview matrix. It's simple enough to 
un-comment the appropriate code though.


    Richard