<!-- NEW6 — TEST 6 · THE FIVE SHORES · part 122 -->
n.
	 * @return {Ray} A reference to this ray.
	 */
	lookAt( v ) {

		this.direction.copy( v ).sub( this.origin ).normalize();

		return this;

	}

	/**
	 * Shift the origin of this ray along its direction by the given distance.
	 *
	 * @param {number} t - The distance along the ray to interpolate.
	 * @return {Ray} A reference to this ray.
	 */
	recast( t ) {

		this.origin.copy( this.at( t, _vector$7 ) );

		return this;

	}

	/**
	 * Returns the point along this ray that is closest to the given point.
	 *
	 * @param {Vector3} point - A point in 3D space to get the closet location on the ray for.
	 * @param {Vector3} target - The target vector that is used to store the method's result.
	 * @return {Vector3} The closest point on this ray.
	 */
	closestPointToPoint( point, target ) {

		target.subVectors( point, this.origin );

		const directionDistance = target.dot( this.direction );

		if ( directionDistance < 0 ) {

			return target.copy( this.origin );

		}

		return target.copy( this.origin ).addScaledVector( this.direction, directionDistance );

	}

	/**
	 * Returns the distance of the closest approach between this ray and the given point.
	 *
	 * @param {Vector3} point - A point in 3D space to compute the distance to.
	 * @return {number} The distance.
	 */
	distanceToPoint( point ) {

		return Math.sqrt( this.distanceSqToPoint( point ) );

	}

	/**
	 * Returns the squared distance of the closest approach between this ray and the given point.
	 *
	 * @param {Vector3} point - A point in 3D space to compute the distance to.
	 * @return {number} The squared distance.
	 */
	distanceSqToPoint( point ) {

		const directionDistance = _vector$7.subVectors( point, this.origin ).dot( this.direction );

		// point behind the ray

		if ( directionDistance < 0 ) {

			return this.origin.distanceToSquared( point );

		}

		_vector$7.copy( this.origin ).addScaledVector( this.direction, directionDistance );

		return _vector$7.distanceToSquared( point );

	}

	/**
	 * Returns the squared distance between this ray and the given line segment.
	 *
	 * @param {Vector3} v0 - The start point of the line segment.
	 * @param {Vector3} v1 - The end point of the line segment.
	 * @param {Vector3} [optionalPointOnRay] - When provided, it receives the point on this ray that is closest to the segment.
	 * @param {Vector3} [optionalPointOnSegment] - When provided, it receives the point on the line segment that is closest to this ray.
	 * @return {number} The squared distance.
	 */
	distanceSqToSegment( v0, v1, optionalPointOnRay, optionalPointOnSegment ) {

		// from https://github.com/pmjoniak/GeometricTools/blob/master/GTEngine/Include/Mathematics/GteDistRaySegment.h
		// It returns the min distance between the ray and the segment
		// defined by v0 and v1
		// It can also set two optional targets :
		// - The closest point on the ray
		// - The closest point on the segment

		_segCenter.copy( v0 ).add( v1 ).multiplyScalar( 0.5 );
		_segDir.copy( v1 ).sub( v0 ).normalize();
		_diff.copy( this.origin ).sub( _segCenter );

		const segExtent = v0.distanceTo( v1 ) * 0.5;
		const a01 = - this.direction.dot( _segDir );
		const b0 = _diff.dot( this.direction );
		const b1 = - _diff.dot( _segDir );
		const c = _diff.lengthSq();
		const det = Math.abs( 1 - a01 * a01 );
		let s0, s1, sqrDist, extDet;

		if ( det > 0 ) {

			// The ray and segment are not parallel.

			s0 = a01 * b1 - b0;
			s1 = a01 * b0 - b1;
			extDet = segExtent * det;

			if ( s0 >= 0 ) {

				if ( s1 >= - extDet ) {

					if ( s1 <= extDet ) {

						// region 0
						// Minimum at interior points of ray and segment.

						const invDet = 1 / det;
						s0 *= invDet;
						s1 *= invDet;
						sqrDist = s0 * ( s0 + a01 * s1 + 2 * b0 ) + s1 * ( a01 * s0 + s1 + 2 * b1 ) + c;

					} else {

						// region 1

						s1 = segExtent;
						s0 = Math.max( 0, - ( a01 * s1 + b0 ) );
						sqrDist = - s0 * s0 + s1 * ( s1 + 2 * b1 ) + c;

					}

				} else {

					// region 5

					s1 = - segExtent;
					s0 = Math.max( 0, - ( a01 * s1 + b0 ) );
					sqrDist = - s0 * s0 + s1 * ( s1 + 2 * b1 ) + c;

				}

			} else {

				if ( s1 <= - extDet ) {

					// region 4

					s0 = Math.max( 0, - ( - a01 * segExtent + b0 ) );
					s1 = ( s0 > 0 ) ? - segExtent : Math.min( Math.max( - segExtent, - b1 ), segExtent );
					sqrDist = - s0 * s0 + s1 * ( s1 + 2 * b1 ) + c;

				} else if ( s1 <= extDet ) {

					// region 3

					s0 = 0;
					s1 = Math.min( Math.max( - segExtent, - b1 ), segExtent );
					sqrDist = s1 * ( s1 + 2 * b1 ) + c;

				} else {

					// region 2

					s0 = Math.max( 0, - ( a01 * segExtent + b0 ) );
					s1 = ( s0 > 0 ) ? segExtent : Math.min( Math.max( - segExtent, - b1 ), segExtent );
					sqrDist = - s0 * s0 + s1 * ( s1 + 2 * b1 ) + c;

				}

			}

		} else {

			// Ray and segment are parallel.

			s1 = ( a01 > 0 ) ? - segExtent : segExtent;
			s0 = Math.max( 0, - ( a01 * s1 + b0 ) );
			sqrDist = - s0 * s0