int num =20;       // number in each dimension of the array
int multi = 20;    // number of pixels wide each cell will be
float[][] cord;
int feel = 210;    // hue value
int power = 500;   // how strong the mouse input is. numbers over 100 spread further.


void setup(){
  ellipseMode(CORNERS);
  colorMode(HSB, 360,100,100);
  frameRate(60);

  size(400, 400);     // set the size to number of cells * pixel size of each cell

  background(255);
  smooth();
  noStroke();

  cord = new float[num][num];     // create cordiate array
  for(int i=0; i<num; i++) {      // run through every cell to set its value
    for(int j=0; j<num; j++) {
    cord[j][i] = 50;               // initial cell value
    }
  }

}



void draw(){
  rec();           // draw squares
  diffuser();      // average each cell with all its neighbors
  userinput();     // check mouse for new values
//  emmiters();      // points that emit light
  circ();          // draw circles with new values

}


void emmiters(){
  cord[5][10] = power;
  cord[15][10] = -power;
}

void userinput(){
  if(mousePressed==true && mouseButton==LEFT){
  cord[mouseX/multi][mouseY/multi] = power;
  }
  if(mousePressed==true && mouseButton==RIGHT){
  cord[mouseX/multi][mouseY/multi] = -power;
  }

}


void rec(){
  for(int i=0; i<num; i++) {
    for(int j=0; j<num; j++) {
      fill(feel,90,cord[j][i]);
      rect(j*multi,i*multi,(j)*multi+multi,(i)*multi+multi);
      }
    }
}

void circ(){
  for(int i=0; i<num; i++) {
    for(int j=0; j<num; j++) {
      fill(feel,80,cord[j][i]);
      ellipse(j*multi,i*multi,(j)*multi+multi,(i)*multi+multi);
      }
    }
}

void diffuser(){
  for(int i=2; i<num-2; i++) {
    for(int j=2; j<num-2; j++) {
      cord[j][i] = ((cord[j][i]
                        +cord[j-1][i]+cord[j+1][i]
                        +cord[j][i-1]+cord[j][i+1]
                        +cord[j-1][i-1]+cord[j-1][i+1]
                        +cord[j+1][i-1]+cord[j+1][i+1])
                        *.111111111111111);
}
  }
}