@woosh/meep-engine/src/core/math/spline/spline_bezier3.js

Pure JavaScript game engine. Fully featured and production ready.

/**
 * 3-rd (cubic) degree bezier curve
 * @see https://www.youtube.com/watch?v=jvPPXbo87ds&t=234s
 * @see https://en.wikipedia.org/wiki/B%C3%A9zier_curve
 * @param {number} t factor value between 0..1
 * @param {number} p0 start point
 * @param {number} p1 control point
 * @param {number} p2 control point
 * @param {number} p3 end point
 * @returns {number}
 */
export function spline_bezier3(t, p0, p1, p2, p3) {
    // first we compute necessary factors for each point
    const nt = 1 - t;

    const nt_2 = nt * nt;

    const nt_3 = nt_2 * nt;

    const t_2 = t * t;

    const t_3 = t_2 * t;

    // combine factors with point values to produce final result
    return nt_3 * p0 + 3 * nt_2 * t * p1 + 3 * nt * t_2 * p2 + t_3 * p3;
}