Worm Coral

Today, I’m going to work on using [worms](https://blog.jverkamp.com/2020/11/17/p5js-worms/ to generate coral, similar to what I did way back when I was generating omnichromatic images.

In a nutshell:

  • Spawn n worms
  • On each tick:
    • Each worm tries to randomly move one direction
    • If it cannot, increment that worm’s stuck counter
    • If it can, restart the stuck counter
    • If a worm is stuck long enough, kill it off and spawn a new worm

Eventually, we’ll fill the entire space with colors that end up looking a bit like coral. I’ll probably extend this later, since there are a lot of cool tweaks you can do with this general idea.

let gui;
let params = {
  pointCount: 10,
  maxAge: 0,
  maxStuck: 10,
};

let visited;
let points;

function setup() {
  createCanvas(400, 400);
  gui = createGuiPanel();
  gui.addObject(params);
  gui.setPosition(420, 0);

  reset();
}

function reset() {
  clear();
  background(0);
  
  visited = [];
  for (var x = 0; x < width; x++) {
    visited[x] = [];
    for (var y = 0; y < height; y++) {
      visited[x][y] = false;
    }
  }
  
  points = [];
}

function draw() {
  while (points.length < params.pointCount) {
    points.push({
      x: int(random(width)),
      y: int(random(height)),
      c: color(random(256), random(256), random(256)),
      age: 0,
      stuck: 0,
    })
  }

  for (var i = 0; i < points.length; i++) {
    var point = points[i];
    point.age++;
    
    fill(point.c);
    noStroke();
    rect(point.x, point.y, 1, 1);
    
    // Try to move each point
    var newX = point.x + random([-1, 0, 1]);
    var newY = point.y + random([-1, 0, 1]);
    
    if (newX == point.x && newY == point.y) {
      continue;
    } else if (newX < 0 || newX >= width || newY < 0 || newY >= height || visited[newX][newY]) {
      point.stuck++;
    } else {
      point.x = newX;
      point.y = newY;
      visited[newX][newY] = true;
    }
    
    // Remove old points
    if (params.maxAge > 0 && point.age > params.maxAge) {
      points.splice(i, 1);
      i--;
    }

    // Remove 'stuck' points
    if (params.maxStuck > 0 && point.stuck > params.maxStuck) {
      points.splice(i, 1);
      i--;
    }
  }
}

Pretty cool!

I’ve also updated my p5js Hugo shortcode with a bit of a neat trick to add the save and clear buttons:

{{ $additionalScript := `
var oldSetup = setup;
setup = () => {
    oldSetup();
    
    createButton("play/pause").mousePressed(() => {
      if (isLooping()) {
        noLoop();
      } else {
        loop();
      }
    });

    createButton("save").mousePressed(() => {
        saveCanvas('photo', 'png')
    });

    createButton("clear").mousePressed(() => {
        if (typeof reset !== 'undefined') {
            reset();
        } else {
            clear();
        }
    });
}
`}}

<iframe 
    width="{{ $width }}" height="{{ $height }}" frameBorder="0"
    srcdoc="{{ $header }}<script>{{ .Inner }}{{ $additionalScript }}</script>{{ $footer }}"
></iframe>

So after the script that I’m embedding I will be overwriting the script provided setup function with one that can add the buttons:

  • play/pause will stop the p5js loop or start it again
  • save will call the built in saveCanvas to generate a PNG and export it
  • clear will call the custom reset function if defined (to do additional work, like resetting the worms in this case), the built in clear if not

And because I’m modifying the shortcode, this will apply to all previous sketches as well. Woot.