cellular automata - OpenProcessing

mySketch
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// make accessible to DPD 2025: Complexity I
// schien@mail.ncku.edu.tw
​
// adding comments to line 45, 48
​
// Cellular Automata (CA) in P5js
// demo for autonomy in Pearson (2011)
// schien@mail.ncku.edu.tw, Fall 2018
// updated revision
// schien@mail.ncku.edu.tw, Spring 2023
​
let _cellArray = []; // this will be a 2D array
let _numX, _numY;
let _cellSize = 10;
​
function setup() {
  createCanvas(windowWidth, windowHeight);
  //frameRate(4);
  _numX = floor(width / _cellSize);
  _numY = floor(height / _cellSize);
  restart();
}
​
function draw() {
  background(255);
  for (let x = 0; x < _numX; x++) {
    for (let y = 0; y < _numY; y++) {
      _cellArray[x][y].calcNextState();
    }
  }
  for (let x = 0; x < _numX; x++) {
    for (let y = 0; y < _numY; y++) {
      _cellArray[x][y].drawMe();
    }
  }
}
​
function mousePressed() {
  restart();
}
​
function restart() {
  // first, create a grid of cells
  for (let x = 0; x < _numX; x++) {
    _cellArray[x] = [];       // initialize the _cellArray[0], _cellArray[1], ..., _cellArray[_numX-1]
    for (let y = 0; y < _numY; y++) {
      let newCell = new Cell(x, y);
      _cellArray[x].push(newCell);  // adding cells into _cellArray[x] to form _cellArray[x][0], _cellArray[x][1], ..., _cellArray[x][_numY-1]
    }
  }
  // setup the neighbors of each cell
  for (let x = 0; x < _numX; x++) {
    for (let y = 0; y < _numY; y++) {
      let above = y - 1;
      let below = y + 1;
      let left = x - 1;
      let right = x + 1;
      if (above < 0) {
        above = _numY - 1;
      }
      if (below === _numY) {
        below = 0;
      }
      if (left < 0) {
        left = _numX - 1;
      }
      if (right === _numX) {
        right = 0;
      }
      _cellArray[x][y].addNeighbour(_cellArray[left][above]);
      _cellArray[x][y].addNeighbour(_cellArray[left][y]);
      _cellArray[x][y].addNeighbour(_cellArray[left][below]);
      _cellArray[x][y].addNeighbour(_cellArray[x][below]);
      _cellArray[x][y].addNeighbour(_cellArray[right][below]);
      _cellArray[x][y].addNeighbour(_cellArray[right][y]);
      _cellArray[x][y].addNeighbour(_cellArray[right][above]);
      _cellArray[x][y].addNeighbour(_cellArray[x][above]);
    }
  }
}
​
// ====== Cell Class ====== //
class Cell {
  constructor (ex, why) { // constructor
    this.x = ex * _cellSize;
    this.y = why * _cellSize;
    if (random(2) > 1) {
      this.nextState = true;
    } else {
      this.nextState = false;
    }
    this.state = this.nextState;
    this.neighbours = [];
  }
​
  addNeighbour (cell) {
    this.neighbours.push(cell);
  }
​
  calcNextState () {
    let liveCount = 0;
    for (let i = 0; i < this.neighbours.length; i++) {
      if (this.neighbours[i].state) {
        liveCount++;
      }
    }
    if (this.state) {
      if ((liveCount === 2) || (liveCount === 3)) {
        this.nextState = true;
      } else {
        this.nextState = false;
      }
    } else {
      if (liveCount === 3) {
        this.nextState = true;
      } else {
        this.nextState = false;
      }
    }
  }
​
  drawMe () {
    this.state = this.nextState;
    //stroke(0);
    noStroke();
    if (this.state) {
      fill(0, 100);
    } else {
      fill(255);
    }
    circle(this.x, this.y, _cellSize);
  }
}