示例代码4-4 由体系构成的体系
ArrayList<articleSystem> systems;void setup() { size(640,360); systems = new ArrayList<articleSystem>();}void draw() { background(255); for (ParticleSystem ps: systems) { ps.run(); ps.addParticle(); } fill(0); text("click mouse to add particle systems",10,height-30);}void mousePressed() { systems.add(new ParticleSystem(1,new PVector(mouseX,mouseY)));}一旦鼠标被点击，一个新的粒子体系对象将会被创建并放入ArrayList中.
ParticleSystem .pde
class ParticleSystem { ArrayList<article> particles; // An arraylist for all the particles PVector origin; // An origin point for where particles are birthed ParticleSystem(int num, PVector v) { particles = new ArrayList<article>(); // Initialize the arraylist origin = v.get(); // Store the origin point for (int i = 0; i < num; i++) { particles.add(new Particle(origin)); // Add "num" amount of particles to the arraylist } } void run() { for (int i = particles.size()-1; i >= 0; i--) { Particle p = particles.get(i); p.run(); if (p.isDead()) { particles.remove(i); } } } void addParticle() { particles.add(new Particle(origin)); } // A method to test if the particle system still has particles boolean dead() { if (particles.isEmpty()) { return true; } else { return false; } }}3、运行效果
articleSystem> systems;void setup() { size(640,360); systems = new ArrayList<
