/* 
Part of the ReCode Project (http://recodeproject.com)
Based on "Hex Variation" by William Kolmyjec
Originally published in "Computer Graphics and Art" vol3 no4, 1978
Copyright (c) 2012 Steve Berrick - OSI/MIT license (http://recodeproject/license).
*/

int _width = 600;
int _height = 900;
int _size = 20;     // hexagon radius

int mod = 2;

void setup() {
  
  size(_width, _height);
  noLoop();
  
  background(255);
  noFill();
  stroke(0);
  strokeWeight(2);

}

void draw() {

  // clear background
  background(255);
  
  // line length (hypotenuse)
  float h = sin(THIRD_PI) * _size;
  int r = 0;
  
  for (int i = 0; i <= _width / (_size * 3); i++) {
    for (int j = 0; j <= (_height / h) + 1; j++) {

      // reference points (centre of each hexagon)
      float x = i * _size * 3 + (_size / 2);
      float y = j * h;
      // offset each odd row
      if (j % 2 > 0) {
        x += _size * 1.5;
      }
      r++;
      
      pushMatrix();
      
      translate(x, y);
        
      // random hexagon rotation (0, 120, 240 degrees)
      rotate(r % mod * THIRD_PI);
    
      // draw line
      line(0, -h, 0, h);
  
      // draw arcs
      arc(-_size, 0, _size, _size, -THIRD_PI,     THIRD_PI);
      arc( _size, 0, _size, _size,  THIRD_PI * 2, THIRD_PI * 4); 
      
      popMatrix();

    }  
  }

}void mousePressed() {
  
  redraw();

}

void mouseMoved() {
   
  mod = (mouseX % width / (_size * 3)) + 1;
  redraw();
   
}