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//Created by Dave Elfving (www.aught.io) in conversation with chatGPT-4, for the Wattis Institute for Contemporary Arts at CCA (www.wattis.org). 

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//This simulation models four distinct "strains" of bacteria on a virtual petri dish. The bacteria replicate and form colonies of 1,000,000 individual bacterium. The resulting generative patterns are inspired by bacterial cultures created by Anicka Yi (https://www.artforum.com/features/portfolio-4-223119/). 

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// GlOBAL VARIABLES

let bacteria = [];

const MAX_BACTERIA = 1000000; 

let simulationActive = true; 

let generationCount = 0; 

const maxGenerations = 4; 

const colors = [ // Color and alpha for each strain – try different values!

  [220, 133, 25, 1.7],

  [113, 57, 23, 1.4],

  [167, 79, 29, 1.6],

  [241, 164, 21, 1.7],

];

let strainColor; 

let fadeOut = false; 

​

//SETUP

function setup() {

  createCanvas(windowWidth, windowHeight);

  noStroke();

  initializeSimulation(); 

}

​

//DRAW

function draw() {

  if (simulationActive && !fadeOut) {

    bacteria.forEach(b => {

      b.divide();

      b.display();

    });

​

    if (bacteria.length >= MAX_BACTERIA) {

      simulationActive = false; 

      setTimeout(() => {

        clearBacteria(); 

        generationCount++;

        if (generationCount < maxGenerations) {

          strainColor = color(...colors[generationCount]); 

          populateBacteria(random(3, 13), strainColor);

          simulationActive = true; 

        } else {

          fadeOut = true; 

        }

      }, 1500); 

    }

  }

​

  if (fadeOut) {

    applyFadeOutEffect(); 

  }

}

​

​

//INITIALIZE SIMULATION

function initializeSimulation() {

  background(255); 

  drawPetriDish(); 

  generationCount = 0; 

  strainColor = color(...colors[generationCount]); 

  populateBacteria(random(3, 13), strainColor); // Initial bacteria - try different values!

  simulationActive = true; 

}

​

​

//POPULATE BACTERIA

function populateBacteria(count, color) {

  for (let i = 0; i < count; i++) {

    let x = random(width / 2 - 240, width / 2 + 240);

    let y = random(height / 2 - 240, height / 2 + 240);

    if (dist(x, y, width / 2, height / 2) < 240) {

      let divisionRate = random(2, 9); // Variable division rates - try changing these!

      bacteria.push(new Bacterium(x, y, divisionRate, color));

    }

  }

}

​

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//CLEAR BACTERIA

function clearBacteria() {

  bacteria = [];

}

​

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//PETRI DISH FOR FADE

function drawPetriDish() {

  fill(242, 239, 222); 

  ellipse(width / 2, height / 2, 480, 480);

}

​

​

//FADE TRANSITION

function applyFadeOutEffect() {

  fill(242, 239, 222, 15); 

  ellipse(width / 2, height / 2, 480, 480); 

  if (frameCount % 60 === 0 && frameCount > 60) { 

    initializeSimulation(); 

    fadeOut = false; 

  }

}

​

//RESIZE

function windowResized() {

  resizeCanvas(windowWidth, windowHeight);

}

​

​

//BACTERIUM CLASS

class Bacterium {

  constructor(x, y, divisionRate, color) {

    this.x = x;

    this.y = y;

    this.size = 1; // Fixed size of 1 pixel - try changing this!

    this.color = color;

    this.divisionRate = divisionRate;

    this.age = 0;

  }

​

  display() {

    fill(this.color);

    ellipse(this.x, this.y, this.size, this.size);

  }

​

  divide() {

    this.age++;

    if (this.age >= this.divisionRate && bacteria.length < MAX_BACTERIA) {

      this.age = 0;

      let angle = random(TWO_PI);

      let distance = random(2, 17); // Random distance for new bacteria – try changing this!

      let newX = this.x + cos(angle) * distance;

      let newY = this.y + sin(angle) * distance;

      if (dist(newX, newY, width / 2, height / 2) < 240) {

        bacteria.push(new Bacterium(newX, newY, this.divisionRate, this.color));

      }

    }

  }

}

​