Arrangement_Without_HE.pde

class HalfEdge {
 
  Node origin;
  Node next;
  Node prev;
  HalfEdge twin;
  Face face;
  
  public HalfEdge(Node o, Node n, Node p, HalfEdge t, Face f){
      origin = o;
      next = n;
      prev = p;
      twin = t;
      face = f;
  }
  
  
}

class Node{
  int x_coord;
  int y_coord;
  HalfEdge arbitrary_outgoing;
  
  public Node(int x, int y, HalfEdge a_o){
     x_coord = x;
     y_coord = y;
     arbitrary_outgoing = a_o;
  }
  
}

class Face{
  HalfEdge inc_edge;
  
  public Face(HalfEdge he){
      inc_edge = he;
  }
}

int num_lines = int(random(4, 8));

int[][] list_of_lines = new int[num_lines][4];




void setup(){
 size(800, 800); 
 frameRate(60);
 background(0, 0, 0);
 for(int i = 0; i < num_lines; i++){
     stroke(255, 255, 255);
     int side1 = int(random(1,5));
     int side2 = side1;
     
     while ( side2 == side1){
         side2 = int(random(1,5));
     }
     
     int x1 = int(random(0, width + 1));
     int y1 = int(random(0, height + 1));
     int x2 = int(random(0, width + 1));
     int y2 = int(random(0, height + 1));
     
     if (side1 == 1)
         y1 = 0;
         
     if (side1 == 2)
         x1 = width;
         
     if (side1 == 3)
         y1 = height;
         
     if (side1 == 4)
         x1 = 0;
         
     ///////////////////
         
     if (side2 == 1)
         y2 = 0;
         
     if (side2 == 2)
         x2 = width;
         
     if (side2 == 3)
         y2 = height;
         
     if (side2 == 4)
         x2 = 0;
         
     
     if( i == 0 ){
       
         line(x1, y1, x2, y2);
         list_of_lines[i][0] = x1;
         list_of_lines[i][1] = y1;
         list_of_lines[i][2] = x2;
         list_of_lines[i][3] = y2;
       
     }
     
     
     else{
     
         int hasIntersect = 0;
     
         for (int k = 0; k < i; k++){
     
             if (checkLineIntersect(x1, y1, x2, y2, list_of_lines[k][0], list_of_lines[k][1], list_of_lines[k][2], list_of_lines[k][3]) == true){
          
                 hasIntersect = 1;
                 break;
             }
        
          }
     
         if (hasIntersect == 1){
           
             line(x1, y1, x2, y2);
             list_of_lines[i][0] = x1;
             list_of_lines[i][1] = y1;
             list_of_lines[i][2] = x2;
             list_of_lines[i][3] = y2;
        
         }else{
        
             i--;
        
         }
     
     }
     
 }
}

boolean checkLineIntersect(int x1, int y1, int x2, int y2, int x3, int y3, int x4, int y4){
      
  int orientation1 = ccw( x1, y1, x2, y2, x3, y3);
  int orientation2 = ccw( x1, y1, x2, y2, x4, y4);
  int orientation3 = ccw( x3, y3, x4, y4, x1, y1);
  int orientation4 = ccw( x3, y3, x4, y4, x2, y2);
      
  if((orientation1 != orientation2) && (orientation3 != orientation4)){
      return true;
  }else{
      return false;
  }
}
    
int ccw(int point1_x, int point1_y, int point2_x, int point2_y, int point3_x, int point3_y){
        
  float returnVal = (float)(point2_y - point1_y)/(point2_x - point1_x) - (float)(point3_y - point2_y)/(point3_x - point2_x); //<>//
      
  if (returnVal > 0)
      return 1;
          
  else if (returnVal == 0)
      return 0;
          
  else if (returnVal < 0)
      return -1;
          
  else
      return 2;  //error code
}
    


void draw(){
 
}