'use strict';

const linearTransform = (a, b, c, d, e, f) => point => [
    a * point[0] + b * point[1] + e,
    c * point[0] + d * point[1] + f
];

const polygonTransforms = (vertices, frac) => vertices.map(
    vertex => linearTransform(
        frac, 0, 0, frac,
        vertex[0] * (frac - 1), vertex[1] * (frac - 1)
    )
);

export const barnsley = [[
    linearTransform(0, 0, 0, 0.16, 0, 0),
    linearTransform(.85, .04, -.04, .85, 0, 1.6),
    linearTransform(.20, -.26, .23, .22, 0, 1.6),
    linearTransform(-.15, .28, .26, .24, 0, .44)
], [
    .01, .85, .07, .07
]];

export const sierpinski = [polygonTransforms([
    [.866, .5],
    [-.866, .5],
    [0, -1]
], 1 / 2), [1 / 3, 1 / 3, 1 / 3]];