Prevent overlap/edge crosses when moving a vertex

gamedata.cpp

@@ -101,6 +101,16 @@ void GameData::handle_click(int x, int y)
 	if (current == NULL) return;
 	int dist = MathUtils::distance(current->x, current->y, current->z,
 				       x, y, 0);
+
+	Vertex* temp = new Vertex(x, y, 0, NODE_RADIUS);
+	if (crosses_edge(current, temp) ||
+	    vertex_would_overlap(x, y, 0, NODE_RADIUS))
+	{
+	    delete temp;
+	    return;
+	}
+	delete temp;
+
 	if (dist <= get_range())
 	{
 	    if (turn->spend_energy(dist))