To make a simple transformation like a rotation I want to use linear algebra -multiplying the
vec4 vertex_position by a
alpha is the angle of rotation, then the
mat4 is structured like this:
|first |second |third |forth| |cos(alpha) |sin(alpha)|0 |0 | |sin(alpha) |cos(alpha)|0 |0 | |0 |0 |0 |0 | |0 |0 |0 |0 |
This matrix represents a rotation in the xy plane.
The transformation doesn't work though - can anyone spot my mistake?