import org.jbox2d.particle.ParticleGroup; //导入依赖的package包/类
@Override
public void mouseDrag(Vec2 p, int button) {
  super.mouseDrag(p, button);
  if (m_drawing) {
    pshape.m_p.set(p);
    pshape.m_radius = 2.0f;
    pxf.setIdentity();
    m_world.destroyParticlesInShape(pshape, pxf);
    ppd.shape = pshape;
    ppd.color = color;
    ppd.flags = m_particleFlags;
    ppd.groupFlags = m_groupFlags;
    ParticleGroup group = m_world.createParticleGroup(ppd);
    if (m_lastGroup != null && group.getGroupFlags() == m_lastGroup.getGroupFlags()) {
      m_world.joinParticleGroups(m_lastGroup, group);
    } else {
      m_lastGroup = group;
    }
    mouseTracing = false;
  }
}
 

import org.jbox2d.particle.ParticleGroup; //导入依赖的package包/类
/**
 * Create a particle group whose properties have been defined. No reference to the definition is
 * retained.
 * 
 * @warning This function is locked during callbacks.
 */
public ParticleGroup createParticleGroup(ParticleGroupDef def) {
  assert (isLocked() == false);
  if (isLocked()) {
    return null;
  }
  ParticleGroup g = m_particleSystem.createParticleGroup(def);
  return g;
}
 

import org.jbox2d.particle.ParticleGroup; //导入依赖的package包/类
/**
 * Join two particle groups.
 * 
 * @param the first group. Expands to encompass the second group.
 * @param the second group. It is destroyed.
 * @warning This function is locked during callbacks.
 */
public void joinParticleGroups(ParticleGroup groupA, ParticleGroup groupB) {
  assert (isLocked() == false);
  if (isLocked()) {
    return;
  }
  m_particleSystem.joinParticleGroups(groupA, groupB);
}
 

import org.jbox2d.particle.ParticleGroup; //导入依赖的package包/类
/**
 * Destroy particles in a group. This function is locked during callbacks.
 * 
 * @param The particle group to destroy.
 * @param Whether to call the world b2DestructionListener for each particle is destroyed.
 * @warning This function is locked during callbacks.
 */
public void destroyParticlesInGroup(ParticleGroup group, boolean callDestructionListener) {
  assert (isLocked() == false);
  if (isLocked()) {
    return;
  }
  m_particleSystem.destroyParticlesInGroup(group, callDestructionListener);
}
 

import org.jbox2d.particle.ParticleGroup; //导入依赖的package包/类
public void generteParticleColors(ParticleGroup group, int hue){
  int count = group.getParticleCount();
  int from = group.getBufferIndex();
  int to = from + count;
  
  ParticleColor[] colors = world.getParticleColorBuffer();
  Vec2[] pos = world.getParticlePositionBuffer();
  
  colorMode(HSB, 360, 100, 100, 100);
  
  for(int i = from; i < to; i++){
    float x = pos[i].x / 3f;
    float y = pos[i].y / 3f;
    float noisexy = noise(x, y, i /(float)count) * 2 - 1;
    float rand = random(-1, +1);

    float hsb_h = hue + 90 * rand * noisexy;
    float hsb_s = 100;
    float hsb_b = 100;
    float hsb_a = 50 + noisexy * 50;
    
    hsb_h = (hsb_h + 360) % 360;

    int argb = color(hsb_h, hsb_s, hsb_b, hsb_a);
    
    colors[i].set(argb);
  }
  
  colorMode(RGB, 255);
}
 

import org.jbox2d.particle.ParticleGroup; //导入依赖的package包/类
public ParticleGroup spawn(float screen_x, float screen_y){
  transform.getScreen2box(screen_x, screen_y, shape_transform.p);
  
  applyShapeTransform();
  
  // destroy particles in group_def.shape
  if(destroy_inplace_before_spawn){
    pdestroyer.destroyParticles(group_def.shape);
  }

  // spawn particles in group_def.shape
  group_old = group_new;
  group_new = world.createParticleGroup(group_def);
  
  revertShapeTransform();
  
  // result stats
  spawn_count = group_new.getParticleCount();
  spawn_begin = group_new.getBufferIndex();
  spawn_end   = spawn_begin + spawn_count;

  // join groups if its a good idea
  if(join_groups){
    if (group_old != null && group_new.getGroupFlags() == group_old.getGroupFlags()) {
      world.joinParticleGroups(group_old, group_new);
      group_new = group_old;
    }
  }
  is_active = true;
  return group_new;
}
 

import org.jbox2d.particle.ParticleGroup; //导入依赖的package包/类
@Override
public void particleGroupDestroyed(ParticleGroup group) {
  super.particleGroupDestroyed(group);
  if (group == m_lastGroup) {
    m_lastGroup = null;
  }
}
 

import org.jbox2d.particle.ParticleGroup; //导入依赖的package包/类
public ParticleGroup[] getParticleGroupBuffer() {
  return m_particleSystem.getParticleGroupBuffer();
}
 

import org.jbox2d.particle.ParticleGroup; //导入依赖的package包/类
public void reset(){
  // release old resources
  release();
  
  
  // liquid effect
  pixelflow = new DwPixelFlow(this);
  particle_fluidfx = new DwLiquidFX(pixelflow);
  
  // different render-targets for different bodies/particles/etc...
  pg_liquid = (PGraphics2D) createGraphics(width, height, P2D);
  pg_liquid.smooth(0);

  pg_prigid = (PGraphics2D) createGraphics(width, height, P2D);
  pg_prigid.smooth(0);
  
  pg_bodies = (PGraphics2D) createGraphics(width, height, P2D);
  pg_bodies.smooth(8);
  

  

  // box2d/liquidfun world
  world = new DwWorld(this, 15);
  
  // particle render settings
  
  world.particles.param.falloff_exp1 = 3f;
  world.particles.param.falloff_exp2 = 1f;
  world.particles.param.radius_scale = 2;
  
  // callback to group particles by their properties (flags)
  world.particles.setParticleRenderGroupCallback(new DwParticleRenderGroupCallback() {
    @Override
    public int getRenderGroupIndex(int particle_idx, ParticleGroup group, int particle_flag) {
      int group_flag = group.getGroupFlags();
      
      boolean is_wall  = (particle_flag & ParticleType     .b2_wallParticle      ) != 0;
      boolean is_solid = (group_flag    & ParticleGroupType.b2_solidParticleGroup) != 0;
      boolean is_rigid = (group_flag    & ParticleGroupType.b2_rigidParticleGroup) != 0;

      int group_id = 0;
      if(is_wall || is_solid || is_rigid){
        group_id = 1;
      } else {
        group_id = 0;
      }
      return group_id;
    }
  });
  

 
  setParticleSpawnProperties(spawn_type);
  
  // create scene: rigid bodies, particles, etc ...
  initScene();
}
 

import org.jbox2d.particle.ParticleGroup; //导入依赖的package包/类
public void reset(){
    // release old resources
    release();
    
    
    // liquid effect
    pixelflow = new DwPixelFlow(this);
    particle_fluidfx = new DwLiquidFX(pixelflow);
    
    // different render-targets for different bodies/particles/etc...
    pg_liquid = (PGraphics2D) createGraphics(width, height, P2D);
    pg_liquid.smooth(0);

    pg_prigid = (PGraphics2D) createGraphics(width, height, P2D);
    pg_prigid.smooth(0);
    
    pg_bodies = (PGraphics2D) createGraphics(width, height, P2D);
    pg_bodies.smooth(8);
    

    

    // box2d/liquidfun world
//    world.INIT_GL_PARTICLES = false;
    world = new DwWorld(this, 15);
    
    // particle render settings
    
    world.particles.param.falloff_exp1 = 3f;
    world.particles.param.falloff_exp2 = 1f;
    world.particles.param.radius_scale = 2;
    
    // callback to group particles by their properties (flags)
    world.particles.setParticleRenderGroupCallback(new DwParticleRenderGroupCallback() {
      @Override
      public int getRenderGroupIndex(int particle_idx, ParticleGroup group, int particle_flag) {
        int group_flag = group.getGroupFlags();
        
        boolean is_wall  = (particle_flag & ParticleType     .b2_wallParticle      ) != 0;
        boolean is_solid = (group_flag    & ParticleGroupType.b2_solidParticleGroup) != 0;
        boolean is_rigid = (group_flag    & ParticleGroupType.b2_rigidParticleGroup) != 0;

        int group_id = 0;
        if(is_wall || is_solid || is_rigid){
          group_id = 1;
        } else {
          group_id = 0;
        }
        return group_id;
      }
    });
    

   
    setParticleSpawnProperties(spawn_type);
    
    // create scene: rigid bodies, particles, etc ...
    initScene();
  }
 

import org.jbox2d.particle.ParticleGroup; //导入依赖的package包/类
@Override
public void sayGoodbye(ParticleGroup group) {
}
 

import org.jbox2d.particle.ParticleGroup; //导入依赖的package包/类
/**
 * Called when any particle group is about to be destroyed.
 */
void sayGoodbye(ParticleGroup group);
 

import org.jbox2d.particle.ParticleGroup; //导入依赖的package包/类
/**
 * Get the world particle group list. With the returned group, use ParticleGroup::GetNext to get
 * the next group in the world list. A NULL group indicates the end of the list.
 * 
 * @return the head of the world particle group list.
 */
public ParticleGroup[] getParticleGroupList() {
  return m_particleSystem.getParticleGroupList();
}
 

import org.jbox2d.particle.ParticleGroup; //导入依赖的package包/类
public int getRenderGroupIndex(int particle_idx, ParticleGroup group, int particle_flag); 

import org.jbox2d.particle.ParticleGroup; //导入依赖的package包/类
public void particleGroupDestroyed(ParticleGroup group) {}