+ CometParticleSystem();
+ virtual ~CometParticleSystem();
+
+ void parse(const Reader& lisp);
+ void write(lisp::Writer& writer);
+
+ virtual void update(float elapsed_time);
+
+ std::string type() const
+ { return "CometParticleSystem"; }
+
+private:
+ class CometParticle : public Particle
+ {
+ public:
+ float speed;