Probably this question has been asked already but does anyone know the
equation for cylindrical mapping ?
Advanced Animation & Rendering Techniques doesn’t satisfy me:
He defined cylinder as:
I: ( x, y, z ) = ( r * cos(PHI), r * sin PHI), hz )
For the u and v texels he said:
II: ( u, v ) = ( phi / 2 * PI, z )
For PHI I get:
III: PHI = arccos ( x / r) and IV: PHI = arcsin( y / r )
If I set only one equation (III or IV) in II the mapping goes wrong.
My question is now: How do I get the correct equation ?