// Sept 2008 
// http://www.abandonedart.org
// http://www.zenbullets.com
//
// This work is licensed under a Creative Commons 3.0 License.
// (Attribution - NonCommerical - ShareAlike)
// http://creativecommons.org/licenses/by-nc-sa/3.0/
// 
// This basically means, you are free to use it as long as you:
// 1. give http://www.zenbullets.com a credit
// 2. don't use it for commercial gain
// 3. share anything you create with it in the same way I have
//
// These conditions can be waived if you want to do something groovy with it 
// though, so feel free to email me via http://www.zenbullets.com


//================================= global vars

int nextNum = 1;   // keeps track fo current figure
float xstart1, xstart2, xstart3;

//================================= init

void setup() {
  size(500,300);
  frameRate(60);
  smooth();
  clearBackground();
  xstart1 = 1 * width/4;
  xstart2 = 2 * width/4;
  xstart3 = 3 * width/4;
  create();
  create();
  create();
}

void create() {
  float x1, x2, y1, y2;
  stroke(140, 120, 60, 200);
  strokeWeight(1);
  
  float xpos = xstart1;
  if (nextNum == 2) {
    xpos = xstart2;
  } else if (nextNum == 3) {
    xpos = xstart3;
  } 
  
  int ytop = 20;
  int ybottom = height - 20;
  
  float step = 5 + (random(4) - 4);
  
  // straight line
  x1 = xpos;
  y1 = ytop;
  for (float y = ytop; y < ybottom; y+= step) {
    y2 = y;
    x2 = x1 + (random(1) - 0.5);
    
    // draw line to it
    line(x1, y1, x2, y2);
    x1 = x2; y1 = y2;
  }
  
  if (x1 > width) { 
    x1 = 0; 
  } else if (x1 < 0) {
    x1 = width;
  } 
  if (nextNum == 1) {
    xstart1 = x1;
  } else if (nextNum == 2) {
    xstart2 = x1;
  } else if (nextNum == 3) {
    xstart3 = x1;
  } 
  
  // spiral noise
  spiralScratch(xpos, random(ybottom) + ytop);
  
  
  // move to next figure for next drawing
  nextNum++;
  if (nextNum > 3) { nextNum = 1; }
}


void spiralScratch(float xpos, float ypos) {
  float x1, x2, y1, y2;
  float step = 5 + (random(4) - 4);
  strokeWeight(1);
  stroke(200, 160, 60, 70);
  float radius = 5;
  float rad = radians(90);
  x1 = xpos;
  y1 = ypos;
  for (int x = 0; x < (360 * 4); x+= step) {
    radius += (1 + (random(4) - 2));
    
    rad = radians(x + step);
    x2 = xpos + (radius * cos(rad))  + (random(4) - 2);
    y2 = ypos + (radius * sin(rad))  + (random(4) - 2);
    // draw line to it
   line(x1, y1, x2, y2);
   x1 = x2; y1 = y2;
  } 
}


void clearBackground() {
  background(255);
  // graph paper
  int gap = 10;
  strokeWeight(1);
  stroke(140, 40);
  for (int x=0;x<width;x+=gap) {
     line(x, 0, x, height);
  }
  for (int y=0;y<height;y+=gap) {
    line(0, y, width, y);
  } 
}

//================================= frame loop

void draw() {
  // clearBackground();
  create();
}

//================================= interaction

void mousePressed() { 
  clearBackground();
  // create();
  xstart1 = 1 * width/4;
  xstart2 = 2 * width/4;
  xstart3 = 3 * width/4;
}

//================================= objects