I'm using the formula I've found here to map procedural texture on to a quad sphere.
For example I'm working with a 3d panoramic cube map that I've generated with a simplex noise.
Each face of the cube will be seamless. That's not the point.
My problem is that the corners of each face will have the typical distortion after mapping it onto the quad sphere.
Therefore I want to "manipulate" or prepare the texture ( in this case, the heightmap ) of each face individually with a curvilinear pincushion distortion.
- Am I assuming right that the curvilinear pincushion distortion will compensate the distortion effect on the quad sphere ?
- Can someone point me to a formula of the curvilinear distortion or the corresponding calculation of the formula I've linked ?
A: original texture. B: what my texture should look like after preparing.
note that B is only a sketch !