particle_system.h

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//            Copyright (C) 2004-2007 by The Allacrost Project
//                         All Rights Reserved
//
// This code is licensed under the GNU GPL version 2. It is free software 
// and you may modify it and/or redistribute it under the terms of this license.
// See http://www.gnu.org/copyleft/gpl.html for details.

/*!****************************************************************************
 * \file    particle_system.h
 * \author  Raj Sharma, roos@allacrost.org
 * \brief   Header file for particle system
 *
 * This file contains two classes: ParticleSystemDef, and ParticleSystem.
 *
 * ParticleSystemDef is a "definition" class, meaning that it holds information 
 * about a particle system, like its lifetime, the emitter, and other properties.
 *
 * ParticleSystem is an "instance" class, meaning that it holds information about
 * a particle system which is currently being drawn on screen.
 *
 * This way, if you have 100 explosions for example, the properties of the
 * effect are stored only once, and the only thing that gets repeated 100 times
 * is instance-specific stuff like positions of vertices, etc.
 *****************************************************************************/

#ifndef __PARTICLE_SYSTEM_HEADER__
#define __PARTICLE_SYSTEM_HEADER__

#include "defs.h"
#include "utils.h"
#include "particle.h"
#include "particle_emitter.h"
#include "video.h"

namespace hoa_video
{

namespace private_video
{


/*!***************************************************************************
 *  \brief when we change a property of an effect, it affects all of the
 *         systems contained within that effect. So, this structure contains
 *         any relevant parameters that particle systems need to know about.
 *****************************************************************************/

class EffectParameters
{
public:

  float orientation;
  
  float attractor_x, attractor_y;
};


class ParticleSystemDef
{
public:


  bool enabled;
  
  ParticleEmitter emitter;
  
  std::vector <ParticleKeyframe *> keyframes;

  int32 blend_mode;
  
  float system_lifetime;
  
  float particle_lifetime;
  
  float particle_lifetime_variation;
  
  int32 max_particles;
  
  float damping;  
  
  float damping_variation;
  
  float acceleration_x;
  float acceleration_y;
  
  float acceleration_variation_x;
  float acceleration_variation_y;
  
  float wind_velocity_x;
  float wind_velocity_y;
  
  float wind_velocity_variation_x;
  float wind_velocity_variation_y;
    
  bool  wave_motion_used;
  
  float wave_length;
  
  float wave_length_variation;
  
  float wave_amplitude;
  
  float wave_amplitude_variation;
    
  float tangential_acceleration;
  
  float tangential_acceleration_variation;
  
  float radial_acceleration;
  
  float radial_acceleration_variation;

  bool user_defined_attractor;
  
  float attractor_falloff;  
      
  bool rotation_used; 
  
  bool rotate_to_velocity;
  
  
  bool speed_scale_used;
  
  
  float speed_scale;
  

  float min_speed_scale;


  float max_speed_scale;

  
  bool smooth_animation;

  bool modify_stencil;
  
  
  VIDEO_STENCIL_OP stencil_op;
  
  
  bool use_stencil;


  float scene_lighting;

  
  bool random_initial_angle;

  
  std::vector <int32>       animation_frame_times;
  

  std::vector <std::string> animation_frame_filenames;
  
}; // class ParticleSystemDef



class ParticleSystem
{
public:

  ParticleSystem();
  

  bool Create(const ParticleSystemDef *sys_def);


  bool Draw();
  

  bool Update(float frame_time, const EffectParameters &params);
  
  
  void Destroy();


  bool IsAlive() const;
  

  bool IsStopped() const;
  
  
  void Stop();


  int32 GetNumParticles() const;


  float GetAge() const;

private:


  void _UpdateParticles(float t, const EffectParameters &params);
  

  void _KillParticles(int32 &num_particles, const EffectParameters &params);
  
  
  void _EmitParticles(int32 num_particles, const EffectParameters &params);
  

  void _MoveParticle(int32 src, int32 dest);
  
  
  void _RespawnParticle(int32 i, const EffectParameters &params);


  const ParticleSystemDef *_system_def;

  hoa_video::AnimatedImage _animation;

  int32 _max_particles;
  
  int32 _num_particles;

  std::vector <ParticleVertex>   _particle_vertices;
  std::vector <Color>            _particle_colors;
  std::vector <ParticleTexCoord> _particle_texcoords;
  
  std::vector <Particle>     _particles;
  
  bool _stopped;
  
  bool _alive;
  
  float _age;
  
  float _last_update_time;
  
}; // class ParticleSystem

}  // namespace private_video
}  // namespace hoa_video

#endif

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