BezierCurve

BezierCurve.js

function BezierCurve(p1x, p1y, p2x, p2y, t) {
  let mt = 1 - t;
  let mt2 = mt * mt,
    t2 = t * t,
    a,
    b,
    c,
    d = 0;
  let p0x = 0, p0y = 0;
  let p3x = 100, p3y = 100;

  a = mt2 * mt;
  b = mt2 * t * 3;
  c = mt * t2 * 3;
  d = t * t2;
  const ret = {
    x: a * p0x + b * p1x + c * p2x + d * p3x,
    y: a * p0y + b * p1y + c * p2y + d * p3y,
    t: t,
  };
  return ret;
}


// TEST
let t= 0.9;
let p1x = 30, p1y = 30, p2x = 90, p2y=90;

BezierCurve(p1x, p1y, p2x, p2y, t)

for (var i = 0; i < 100; i++) {
    (function(i){
        setTimeout(function(){
            var x = BezierCurve(p1x, p1y, p2x, p2y, i/100);
            console.log(x);
        }, i * 50)
    })(i);
}