sample_normal

float  sample_normal(float u)

float  sample_normal(float mean, float stddev, float u)

float  sample_normal(float origmean, float origstddev, float minvalue, float maxvalue, float u)

vector2  sample_normal(vector2 u)

vector  sample_normal(vector u)

vector4  sample_normal(vector4 u)

u

A number, or multiple numbers, in the range [0,1).

mean

The mean of the distribution, or 0 if not specified.

origmean

The mean the distribution would have, were it not for minvalue and maxvalue, limiting the range.

stddev

The standard deviation (scale) of the distribution, or 1 if not specified.

origstddev

The standard deviation (scale) the distribution would have, were it not for minvalue and maxvalue, limiting the range.

minvalue,maxvalue

When given, instead of sampling the full normal distribution, the distribution with its range limited to [minvalue,maxvalue] will be sampled.

Samples the normal distribution with the specified mean and stddev, optionally with a minvalue and maxvalue. Given uniform random u values in [0,1), this will return normally distributed random numbers. The return value will be monotone increasing with respect to u.

The vector2, vector, and vector4 versions return multiple samples with mean 0 and standard deviation 1. The distribution of these vectors is naturally isotropic, i.e. rotating the distribution won’t change it, which can be useful in simulations. To add a maximum distance from the origin, while keeping the distribution isotropic, use:

sample_normal(0,1,0,maxdist,u.x) * sample_direction_uniform(set(u.y,u.z))