cocos2dx打飞机项目笔记四：Enemy类和EnemyLayer类

Enemy类没什么内容，就create和init方法，根据参数来创建不同的敌机，头文件代码如下：

 //飞机的类型
 enum planeType {smallPlane, midPlane, bigPlane};

 class Enemy : public CCSprite
 {

 public:

     void loseLife();

     CC_SYNTHESIZE(float, m_speed, Speed);
     CC_SYNTHESIZE(int, m_life, Life);
     CC_SYNTHESIZE(int, m_score, Score);
     CC_SYNTHESIZE(planeType, m_type, Type);

     ~Enemy();
     virtual bool init(planeType type, CCTexture2D* texture);
     static Enemy* create(planeType type, CCTexture2D* texture);

 };

create和init方法实现如下：

Enemy* Enemy::create(planeType type, CCTexture2D* texture)
{
    Enemy *pRet = new Enemy();
    if (pRet && pRet->init(type, texture))
    {
        pRet->autorelease();
        return pRet;
    }
    else
    {
        delete pRet;
        pRet = NULL;
        return NULL;
    }
}

bool Enemy::init(planeType type, CCTexture2D* texture)
{
    bool bRet = false;
    do
    {
        const char* fileName;
        float score = ;
        int life = ;
        float speed = ;

        int random_speed = rand() %  + ;

        switch (type)
        {
        case bigPlane:
            fileName = "enemy3_n1.png";
            life = ;
            score = ;
            break;

        case midPlane:
            fileName = "enemy2.png";
            life = ;
            score = ;
            break;

        case smallPlane:
            fileName = "enemy1.png";
            life = ;
            score = ;
            break;

        default:
            break;
        }
;
        CC_BREAK_IF(!CCSprite::initWithSpriteFrameName(fileName));

        this->m_score = score;
        this->m_life = life;
        this->m_speed = *random_speed;
        this->m_type = type;
        bRet = true;

    } while ();

    return bRet;
}

EnemyLayer类则负责敌机除了创建之外的所有工作，包括开始启动创建方法、停止创建、移除敌机、敌机爆炸等。头文件：

 class EnemyLayer : public cocos2d::CCLayer
 {

 protected:

     CCSize designResolutionSize;
     CCSpriteBatchNode* batchNode;

 public:

     CCArray *m_enemys;

     EnemyLayer(void);
     ~EnemyLayer(void);
     virtual bool init();

     void startTakeEnemys(float dt);
     void stopTakeEnemy(void);

     void EnemyMoveToFinish(CCNode* pSender);
     void removeEnemy(CCNode* pTarget, void* enemy);
     void removeAllEnmeys();

     void addEnemy(float dt);

     void bomb(CCNode* pSender);

     CREATE_FUNC(EnemyLayer);
 };

敌机的创建和子弹不同，还记得子弹的创建我是保证屏幕上只有一粒子弹的吧，敌机则不然，固定每隔多少时间就会创建

 void EnemyLayer::startTakeEnemys(float dt)
 {

     float delay = 1.0f;//多少秒后调用
     float interval = 0.3f;//调用时间间隔
     this->schedule(schedule_selector(EnemyLayer::addEnemy), interval, kCCRepeatForever, delay);
 }

addEnemy和bomb方法实现：

 void EnemyLayer::addEnemy(float dt)
 {
     if (true)
     {
         int seed = ;
         int random_planeType = rand() % seed + ;//1~19
         planeType type;

         Enemy* enemy = NULL;

         //按概率随机生成大中小三种敌机，或者不产生
         //big
         if (random_planeType %  == )
         {
             type = bigPlane;
             SimpleAudioEngine::sharedEngine()->playEffect("music/big_spaceship_flying.wav",false);
         }
         //mid
         else if(random_planeType %  == )
         {
             type = midPlane;
         }
         //small
         else if(random_planeType %  == )
         {
             type = smallPlane;
         }
         // no
         else
         {
             return;
         }

         enemy = Enemy::create(type, this->batchNode->getTexture());

         //初始位置(随机)
         CCSize winSize = CCDirector::sharedDirector()->getWinSize();
         float x = rand() % (int)(winSize.width - (int)enemy->boundingBox().size.width * ) + enemy->boundingBox().size.width;
         float y = winSize.height - enemy->boundingBox().size.height/;

         CCPoint position = ccp(x,y);

         enemy->setPosition(position);
         this->m_enemys->addObject(enemy);
         batchNode->addChild(enemy);

         //敌机的运动轨迹CCDirector::sharedDirector()->getWinSize()
         float length = enemy->getContentSize().height + designResolutionSize.height;//飞行距离，超出屏幕即结束
         float velocity = /;//飞行速度：420pixel/sec
         float realMoveDuration = length/enemy->getSpeed();//飞行时间

         CCFiniteTimeAction* actionMove = CCMoveTo::create(realMoveDuration,ccp(x, -enemy->getContentSize().height));
         CCFiniteTimeAction* actionDone = CCCallFuncN::create(this,callfuncN_selector(EnemyLayer::EnemyMoveToFinish));//回调一个敌机结束处理函数

         CCSequence* sequence = CCSequence::create(actionMove,actionDone,NULL);

         enemy->runAction(sequence);

     }

 }

 void EnemyLayer::bomb(CCNode* pSender)
 {

     CCAnimation *animationBomb = NULL;
     Enemy *enemy = (Enemy*) pSender;
     char bombMusciName[];

     if (enemy->getType() == bigPlane)
     {
         sprintf(bombMusciName, "music/enemy3_down.wav");
         animationBomb = CCAnimationCache::sharedAnimationCache()->animationByName("animation_Enemy3Bomb");
     }
     else if(enemy->getType() == midPlane)
     {
         sprintf(bombMusciName, "music/enemy2_down.wav");
         animationBomb = CCAnimationCache::sharedAnimationCache()->animationByName("animation_Enemy2Bomb");
     }
     else if(enemy->getType() == smallPlane)
     {
         sprintf(bombMusciName, "music/enemy1_down.wav");
         animationBomb = CCAnimationCache::sharedAnimationCache()->animationByName("animation_Enemy1Bomb");
     }

     SimpleAudioEngine::sharedEngine()->playEffect(bombMusciName, false);//开始播放背景音效，false表示不循环 

     CCActionInterval *action = CCScaleTo::create(0.5f, pSender->getScale() + 0.05f);
     CCCallFuncND *funcND = CCCallFuncND::create(this,callfuncND_selector(EnemyLayer::removeEnemy),(void*)pSender);
     CCFiniteTimeAction* seq = CCSequence::create(CCAnimate::create(animationBomb), funcND, NULL);

     pSender->stopAllActions();
     pSender->runAction(seq);

 }

可以看得出，这两个方法其实放到Enemy类里也很正常完全没问题的，这个要看coder想怎么写了。另外，敌机飞出屏幕外时的删除和被子弹打中时爆炸的回收是不同，差一个爆炸效果，而子弹在这两种情况的处理是一样的。