sample_hypersphere_cone

vector4  sample_hypersphere_cone(vector4 center, float maxangle, vector4 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

Four numbers between 0 and 1.

Returns a vector4 of length < 1, based on u. Given uniform random u vectors of four values in [0,1), the returned vectors will be uniform random and continuous with respect to u inside the unit hypersphere, in the hypervolume within maxangle of the direction indicated by center.