How should I design my particle system to make it easy to add new particle effect types?

Question

Recently I started designing a particle system for a game I develop. But I have some issues with it. I mean, it works but I have a feeling that my design isn't good enough.

So, basically I have a Particle class which contains the particle's vars and couple of functions:

class OBJECTATTRIBUTE_API Particle
{
protected:
     Vector3d position;
     Vector3d direction;
     Vector3d gravity;

     float life;
     float fade;

     float red;
     float green;
     float blue;

     bool isActive;
     bool isInit;

public:
     void Deinitialize();

     void SetPosition(Vector3d position);

     bool IsActive();
};

And I derive from that class the types of particles. Like this:

class OBJECTATTRIBUTE_API ParticleExplosion : public Particle
{
public:
    void Initialize();

    void Update();
    void Render();

    void Rejuvenate();
};

And at the end is the emitter. This is actually where I think my design fails. I make an emitter for every particle system and, at some point, I may have too much different emitters.

Here is an example of the particle emitter realisation:

// The base class
class OBJECTATTRIBUTE_API ParticleEmitter
{
protected:
    Vector3d emitterPosition;

    unsigned int particleTextureID;
    unsigned int particleCount;
    bool isEmitterStopped;

public:
    ParticleEmitter();
    ParticleEmitter(Vector3d emitterPosition);
};

// The derived emitter.
class OBJECTATTRIBUTE_API ParticleEmitter_Explosion : public ParticleEmitter
{
private:
   ParticleExplosion *particles;

public:
   void AddParticles(unsigned int particleCount);

   void Initialize();

   void Start();
   void Stop();

   void Reposition(Vector3d newPosition);
   void SetParticleTextureID(unsigned int particleTextureID);
};

And the question - Is my particle system design good? If not, what can I do to improve it?

EDIT : I was told that the question was too subjective, so I will try to add couple of specifications.

Firstly, I started making the particle system for explosion simulation and also some attack animations in my game. It works very well with that, so I think this goal is achieved.

Secondly, the performance hit is acceptable and I am OK with that.

And finally, the question was about is this design good for flexible adding of new particle effects implementation?

Answer 1

I would decouple the particle type from a specific emitter. Have a base emitter and have it work with different particles.

For instance you can derive a SprayEmitter class deriving ParticleEmitter and you pass it the particles you want it to work with. The emitter can then call Set position on the particles to move them where you want them e.t.c.

Essentially the Emitter takes care of how particles are emitted regardless of their concrete type and the particles are only concerned about updating themselves.

I guess the above would be best achieved using a function pointer in the emitter with the signature to return an abstract particle. You can have a class sitting above the emitter that will pass it a function that creates a particular concrete particle so when you call AddParticles you can call this createParticle function and add the return to your array of particles in the emitter.