const p = {
  agentCount: 1000,
  agentSize: 3,
  agentAlpha: 1,
  minStepSize: 0.2,
  maxStepSize: 4,
  timeIntervalBetweenUpdates: 300
}

let agents
let timeOfLastUpdate

function setup() {
  createCanvas(540, 540)
  agents = []
  let a
  for (let i = p.agentCount - 1; i >= 0; i--) {
    a = new Agent()
    a.stepSize = random(p.minStepSize, p.maxStepSize)
    agents.push(a)
  }
  background(255)
  timeOfLastUpdate = millis()
}

function draw() {
  let currentTime = millis()
  // Mise à jour de la position
  if (currentTime - timeOfLastUpdate > p.timeIntervalBetweenUpdates) {
    timeOfLastUpdate = currentTime
    agents.forEach(a => {
      a.angle = random(0, TWO_PI)
    })
    agentAngle = random(0, TWO_PI)
  }

  agents.forEach(a => {
    a.updatePosition()
  })

  // Dessin
  background(255, 255, 255, 3)
  stroke(23, p.agentAlpha)
  strokeWeight(p.agentSize)
  noFill()
  agents.forEach(a => {
    line(a.previousPosition.x, a.previousPosition.y, a.position.x, a.position.y)
  })
}