getSqDist function
Code ported from (c) 2017, Vladimir Agafonkin Simplify.js, a high-performance JS polyline simplification library mourner.github.io/simplify-js
Implementation
// square distance between 2 points
double getSqDist(p1, p2) {
var dx = p1.x - p2.x, dy = p1.y - p2.y;
return dx * dx + dy * dy;
}