BetweenPoints = function (point1, point2)
{
    return Math.atan2(point2.y - point1.y, point2.x - point1.x);
}
Find the angle of a segment from (point1.x, point1.y) -> (point2.x, point2.y).

Calculates the angle of the vector from the first point to the second point.

@function Phaser.Math.Angle.BetweenPoints
@since 3.0.0

@param {Phaser.Types.Math.Vector2Like} point1 - The first point.
@param {Phaser.Types.Math.Vector2Like} point2 - The second point.

@return {number} The angle in radians.