Get Tangent Vectors On Cubic Bezier Curve

class Example extends Phaser.Scene
{
    create ()
    {
        const graphics = this.add.graphics();

        const p0 = new Phaser.Math.Vector2(100, 500);
        const p1 = new Phaser.Math.Vector2(50, 100);
        const p2 = new Phaser.Math.Vector2(600, 100);
        const p3 = new Phaser.Math.Vector2(700, 500);

        const curve = new Phaser.Curves.CubicBezier(p0, p1, p2, p3);

        const max = 16;
        const points = [];
        const tangents = [];

        for (let c = 0; c <= max; c++)
        {
            const t = curve.getUtoTmapping(c / max);

            points.push(curve.getPoint(t));
            tangents.push(curve.getTangent(t));
        }

        const tempVec = new Phaser.Math.Vector2();

        //  Draw the points
        graphics.fillStyle(0xff0000, 1);

        for (let i = 0; i < points.length; i++)
        {
            const p = points[i];

            graphics.fillCircle(p.x, p.y, 6);

            //  Draw the tangent vector
            tempVec.copy(tangents[i]).scale(32).add(p);

            graphics.lineStyle(1, 0x00ff00, 1);
            graphics.lineBetween(p.x, p.y, tempVec.x, tempVec.y);

            //  Draw the right-hand tangent vector
            tempVec.copy(tangents[i]).normalizeRightHand().scale(-32).add(p);

            graphics.lineStyle(1, 0xff00ff, 1);
            graphics.lineBetween(p.x, p.y, tempVec.x, tempVec.y);
        }
    }
}

const config = {
    type: Phaser.AUTO,
    width: 800,
    height: 600,
    backgroundColor: '#2d2d2d',
    parent: 'phaser-example',
    scene: Example
};

const game = new Phaser.Game(config);
                        

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