phaser/wip/vec2/Project.js
2018-01-09 22:12:16 +00:00

14 lines
245 B
JavaScript

// Project vector b onto vector a and return a
export default function (a, b) {
const dot = a[0] * b[0] + a[1] * b[1];
const lenV = b[0] * b[0] + b[1] * b[1];
const s = dot / lenV;
a[0] *= s;
a[1] *= s;
return a;
}