@Override
public void computeArea(ConvexHull convexHull) {
GeometricPoint[] closedPolygonFromHull = getClosedPolygonFromHull(convexHull);
// init area to zero
double area = 0;
// sum up the cross products around each vertex of the hull
for (int i = 0; i < closedPolygonFromHull.length - 1; i++) {
double xUp = closedPolygonFromHull[i].getX();
double yDown = closedPolygonFromHull[i + 1].getY();
double yUp = closedPolygonFromHull[i].getY();
double xDown = closedPolygonFromHull[i + 1].getX();
area += (xUp * yDown) - (yUp * xDown);
}
convexHull.setArea(area / 2);
}
