Feature: Simplex Noise Generator

Using a fill layer, you can now generate a simplex gradient noise texture. This noise can be looped seamlessly, distorted in two dimensions, and given a string of text to use as an optional custom seed value.

This new generator plugin makes use of a C port of Kurt Spencer's
permissive, open source, and patent-free OpenSimplex noise implementation.

If no custom seed string is given, a seed number will be chosen
randomly.

In order to achieve seamless looping without distortion we generate
noise in 4-dimensions, and sample each pixel from a toroidal
(doughnut-shaped) pattern. In order to keep the look of the noise
consistent between looping and non-looping modes, both are sampled from
4-dimensions.

• Eoin and Emmet O'Neill.