// Conrol 2
// Created by Burak Arikan based on Martin Wattenberg's code for Level Sets
// July 14, 2005

color p;
float posX;
float posY;
float timeFunction; 
           
void setup() {
  size(400,300, P3D);
  colorMode(HSB,100);
    
  // these are basicly for sketching with parameters
  posX = 196; // constrain(mouseX, 1, width);  
  posY = 150; //constrain(mouseY, 1, height);  
}

void draw() {
  float h=200;

  float level = (float) 0.2*(1.8 - posY / h); 
  
  loadPixels();
  for (float x=0; x<width; x++) {
    for (float y=0; y<height; y++) {

      float z = height(x/posX-1, y/posY-1, 0.001*millis()) - level; 
      
     switch (key) {                     // Choose color scheme based on viewer's last key stroke.
        case 'c': case 'C':             // Use colors, a la weather map.
          int hue = (int)(20+z*20);       // Define a hue.
          hue = 15*(hue/15);              // Because hue is an int, the effect of this line is to force it to be a multiple of 15.
          p = color(hue, 100,90-hue/3); // Set the color using HSB. We make the blue colors darker.
          break; 
        case 'g': case 'G':             // Gray mode.
          p = color(50-z*30);
          break;
        case 'b': case 'B':             // Black / White mode.
          p = color(118-z*2000);
          break;
        default:                       // Gray mode.
          p = color(50-z*30);
          break;
      }
      
      pixels[(width*(int)y)+(int)x] = p;
    }
  }
    updatePixels();
}

float height(float x, float y , float time) {             
   return f(x, y) + ft(x, y, time);
}  


// geometry functions
float f(float x, float y){
  //return 2*(x*x + y*y);
  //return x*x - y*y;
  // return x*2-x*y-y+sin(2*x);
  // return x*x*x-x*y*y;
  // return -2*x*x*y*y+x*x+y*y;
  // return x+0.1*x*x-3*sin(x);
  // return x*x*x-3*x*y*y; //star 
  return 16*(-x*x*x*x+x*x-y*y);
  // return y/(x*x*x);
  // return 2*(-x*x*x*x + x*x - y*y);
  //  return -6*y*(x*x+y*y+1);
  // return -1*y*(x*x+y*y+1);
}

float f2(float x, float y){
return -2*x*x*y*y+x*x+y*y;
}

// time functions
float ft(float x, float y, float time){
  return 0.2*sin(y*0.3-3*time);
}