ma**********@gmail.com wrote:

Hi,

I've having a *small* problem with a small simulation/game I'm trying

to write in C++ using OpenGL.

It's really hard to help much here except to tell you how I would do it.

To go from one co-ordinate space to another you need to peform the

reverse which usually means multiplication by the inverse matrix. I you

have an unit orthonormal 3x3 matrix, this is just the matrix transpose.

If you have a homogenous 4x4 matrix then I would do a real matrix

invert (which can be quite efficiently done in for a 4x4).

It's mean many many years since I did much opengl so I don't know what

the latest API advances look like but if I were on the opengl committee

I would have added some apis like a 4x4 invert for example.

G