setVertices(vertices, index = 0, clear = true) {
		const polygon = this.getShape(index);
		if (polygon instanceof Polygon) {
			polygon.setShape(0, 0, vertices);
		} else {
			// this will replace any other non polygon shape type if defined
			this.shapes[index] = pointPool.get(0, 0, vertices);
		}

		// update the body bounds to take in account the new vertices
		this.bounds.add(this.shapes[index].points, clear);

		if (typeof this.onBodyUpdate === "function") {
			this.onBodyUpdate(this);
		}
	}
set the body vertices to the given one
@param {Vector2d[]} vertices - an array of me.Vector2d points defining a convex hull
@param {number} [index=0] - the shape object for which to set the vertices
@param {boolean} [clear=true] - either to reset the body definition before adding the new vertices