calculate the vertex normals of a sphere

Question

I was wondering how I could takes each sphere's vertex stored in my buffer, and calculate the normal to each of them separately. Is it possible to do it in OpenGL?

Answer 1

OpenGL is typically used to render meshes, not compute them. And normals are part of a mesh's data. It is usually the responsibility of the builder of the mesh to supply normals.

In the case of a sphere, normals are dead simple to compute perfectly. For a given vector position P on the sphere who's center is C, the normal is norm(P - C), where norm normalizes the vector.