arkit_rotate_point

// test

var result = PointRotator.RotatePoint(new Vector2(5.0f, 0), new Vector2(0, 0), Math.PI / 2 );
Assert.IsTrue(Math.Round(result.X, 0) == 0f);
Assert.IsTrue(Math.Round(result.Y,0) == -5);


// RotatePoint method

    public static class PointRotator
    {
        public static Vector2 RotatePoint(Vector2 point, Vector2 pivot, double radians)
        {
            // this is arkit so rotate the other way around... 
            radians = radians * -1;

            var cosTheta = Math.Cos(radians);
            var sinTheta = Math.Sin(radians);

            var dx = point.X - pivot.X;
            var dy = point.Y - pivot.Y;
            var x = cosTheta * dx - sinTheta * dy + pivot.X;
            var y = sinTheta * dx + cosTheta * dy + pivot.Y;

            return new Vector2((float)x, (float)y);
        }

    }