giving up... just sorting calculated hullpoints clockwise before connecting with lines

Display.cpp

@@ -334,11 +334,45 @@ void Display::update ()
     if (curStep != 5 || m_points.size() > 0) m_step++;
 }
 
+bool less (sf::CircleShape a, sf::CircleShape b)
+{
+    float centerx = WIDTH / 2;
+    float centery = HEIGHT / 2;
+    float ax = a.getPosition().x;
+    float ay = a.getPosition().y;
+    float bx = b.getPosition().x;
+    float by = b.getPosition().y;
+    if (ax - centerx >= 0 && bx - centerx < 0)
+        return true;
+    if (ax - centerx < 0 && bx - centerx >= 0)
+        return false;
+    if (ax - centerx == 0 && bx - centerx == 0) {
+        if (ay - centery >= 0 || by - centery >= 0)
+            return ay > by;
+        return by > ay;
+    }
+
+    // compute the cross product of vectors (center -> a) x (center -> b)
+    int det = (ax - centerx) * (by - centery) - (bx - centerx) * (ay - centery);
+    if (det < 0)
+        return true;
+    if (det > 0)
+        return false;
+
+    // points a and b are on the same line from the center
+    // check which point is closer to the center
+    int d1 = (ax - centerx) * (ax - centerx) + (ay - centery) * (ay - centery);
+    int d2 = (bx - centerx) * (bx - centerx) + (by - centery) * (by - centery);
+    return d1 > d2;
+}
+
 void Display::render (sf::RenderWindow &window)
 {
     window.clear(sf::Color::White);
 
     // draw already calculated hull points
+    std::sort(m_hullPoints.begin(), m_hullPoints.end(), less); // sort clockwise
+
     size_t elements = m_hullPoints.size();
     for (size_t i = 0; i < elements; ++i)
     {