update method

void update(double dt)

Implementation

void update(double dt) {
  age += dt;
  radius += speed * dt;
  double progress = (age / maxAge).clamp(0.0, 1.0);
  amplitude = (1.0 - progress) * (1.0 - progress);

  for (var p in particles) {
    p.update(dt);
  }
  particles.removeWhere((p) => p.life <= 0);
}