Re: [PyOpenGL-Users] best way to set up matrices and vertex arrays?

[Ian M. <geo...@gm...>]

On Tue, Mar 9, 2010 at 2:58 AM, Kolja Kaehler <kol...@av...>wrote:

>  -          My hope was to avoid having to do my own 3D-vector- and
> matrix-classes for doing linear algebra, and just use numpy’s abilities. It
> turns out that this is not always so effortless – e.g. to multiply a matrix
> with a vector from the right, I have to make sure it’s a column vector. To
> transform a 3D vector with a 4x4 matrix, I have to append an extra 1.0
> element, do the multiplication, and then slice off the 4th element again.
> Looks like it would be cleaner to write out the whole matrix/vector
> multiplication by hand.
>
Scale and rotate matrices need only be 3x3 matrices.  Translation matrices,
which must be 4x4, can instead be expressed as simple addition: e.g.,
vertex_array += array([1,2,6])  You might also want to consider keeping your
vertices as vec4s--that's how OpenGL stores vertices interally, even if you
only define the x and y, or the x,y, and z coordinates.  You may also
consider using OpenGL's own matrix system.  It's technically deprecated--but
it's still an awes
Ian