Check point in triangle

in-triangle.js

var inUV = function (uv, point) {
    var x = point.x - uv[0].x;
    var y = point.y - uv[0].y;
    var s = (uv[1].x - uv[0].x) * y - (uv[1].y - uv[0].y) * x > 0;
    if ((uv[2].x - uv[0].x) * y - (uv[2].y - uv[0].y) * x > 0 === s) {
        return false;
    }
    return (uv[2].x - uv[1].x) * (point.y - uv[1].y) - (uv[2].y - uv[1].y) * (point.x - uv[1].x) > 0 === s;
};