Centroid = function (triangle, out)
{
    if (out === undefined) { out = new Point(); }

    out.x = (triangle.x1 + triangle.x2 + triangle.x3) / 3;
    out.y = (triangle.y1 + triangle.y2 + triangle.y3) / 3;

    return out;
}
Calculates the position of a Triangle's centroid, which is also its center of mass (center of gravity).

The centroid is the point in a Triangle at which its three medians (the lines drawn from the vertices to the bisectors of the opposite sides) meet. It divides each one in a 2:1 ratio.

@function Phaser.Geom.Triangle.Centroid
@since 3.0.0

@generic {Phaser.Geom.Point} O - [out,$return]

@param {Phaser.Geom.Triangle} triangle - The Triangle to use.
@param {(Phaser.Geom.Point|object)} [out] - An object to store the coordinates in.

@return {(Phaser.Geom.Point|object)} The `out` object with modified `x` and `y` properties, or a new Point if none was provided.