int i_tnum = 8;
tron[] ar_tron = new tron[i_tnum];

void setup(){
  size(640,360);
  for(int i=0; i < i_tnum; i++){
    ar_tron[i] = new tron();
  }
}

void loop(){
  background(255,255,255);
  float dx, dy;
  float dist;
  float col, cr, cg, cb;
  color c;
  tron tr;
  
  for(int i=0; i < i_tnum; i++){
    ar_tron[i].update();
  }
  
  for(int y=0; y < height; y+=5){
    for(int x=0; x < width; x+=5){
      col = 0;
      for(int t=0; t < i_tnum; t++){
        dist = 1200 / sqrt(sq(x-ar_tron[t].f_x) + sq(y-ar_tron[t].f_y));
        col += dist;
      }
     col = col * col*col * col *col *  0.00000005;
     
      c = color(col,col,col);
      if(col > 80){
        c = color(230,230,0);
        pixels[y*width  + x] =  c;
        pixels[y*width  + x+1] =  c;
        pixels[y*width  + x+2] =  c;
        pixels[y*width  + x+3] =  c;
        pixels[(y+1)*width  + x] =  c;
        pixels[(y+1)*width  + x+1] =  c;
        pixels[(y+1)*width  + x+2] =  c;
        pixels[(y+1)*width  + x+3] =  c;
      } else if(col > 40){
        c = color(100,100,0);
        pixels[y*width  + x] =  c;
        pixels[y*width  + x+1] =  c;
        pixels[y*width  + x+2] =  c;
        pixels[y*width  + x+3] =  c;
        pixels[(y+1)*width  + x] =  c;
        pixels[(y+1)*width  + x+1] =  c;
        pixels[(y+1)*width  + x+2] =  c;
        pixels[(y+1)*width  + x+3] =  c;
      }

    }
  }
}

class tron{
  float f_x, f_y;
  float f_vx, f_vy;
  float f_r, f_g, f_b;
  tron(){
    f_x = random(width);
    f_y = random(height);
    f_vx = random(6) - 3;
    f_vy = random(6) - 3;
    f_r = random(1) *0.5 + 0.4;
    f_g = random(1) *0.5 + 0.4;
    f_b = random(1) *0.5 + 0.4;
  }
  void update(){
    f_x += f_vx;
    f_y += f_vy;
    
    if (f_x > width){
      f_x = width;
      f_vx = -abs(f_vx);
    }else if(f_x < 0){
      f_x = 0;
      f_vx = abs(f_vx);
    }
     if (f_y > height){
      f_y = height;
      f_vy = -abs(f_vy);
    }else if(f_y < 0){
      f_y = 0;
      f_vy = abs(f_vy);
    }
  }
}