const { PI, cos, sin } = Math;


function reflectVector(
        θm: number,
        v: number[],
        p: number[]): number[] {

    const cx = v[0];
    const cy = v[1];

    const vx = p[0] - cx;
    const vy = p[1] - cy;

    const cosθ = cos(θm*PI/12);
    const sinθ = sin(θm*PI/12);

    return [
        cosθ*vx + sinθ*vy + cx,
        sinθ*vx - cosθ*vy + cy
    ];
}


export { reflectVector }