sample_sphere_cone

vector  sample_sphere_cone(vector center, float maxangle, vector u)

center

Direction in the center of the cone. This does not need to be normalized.

maxangle

Maximum angle, in radians, away from center that any sample of the cone will be, so long as all u values are between 0 and 1.

u

Three numbers between 0 and 1.

Returns a vector of length < 1, based on u. Given uniform random u vectors of three values in [0,1), the returned vectors will be uniform random and continuous with respect to u inside the unit sphere, in the volume within maxangle of the direction indicated by center.