Demonstration of snow falling (the number of crystals is fixed) /雪の降下アニメーション (雪の結晶の個数固定）

snowfalling1.pde

class Crystal {
  float x, y, phi;
  
  Crystal(float x0, float y0, float phi0) {
    x = x0;
    y = y0;
    phi = phi0;
  }
  
  void fall() {
    y += 1;
  }
  
  void show() {
    noStroke();
    ellipse(x, y, phi, phi);
  }
}

Crystal[] crystals = new Crystal[100];

void setup() {
  size(500, 500);

  for (int i = 0; i < crystals.length; i++) {
    crystals[i] = new Crystal(random(width), random(height), 20);
  }
}

void draw() {
  background(180);
  for (int i = 0; i < crystals.length; i++) {
    crystals[i].fall();
    crystals[i].show();
  }
}