基于cocos2dx的飞机大战学习[五]-添加三种敌机

这节完成了许多的功能：
1、添加小飞机、中等飞机、大飞机。
2、每种飞机的移动速度和血量不同。
3、飞机被子弹打击效果。
4、飞机被摧毁效果。

cocos2d提供的Sprite类不足以提供以上功能，所以我们需要新建一个Enemy类重写Sprite。

Enemy.h代码段

#ifndef __ENEMY_H__
#define __ENEMY_H__

#include "cocos2d.h"

//敌机类型
typedef enum 
{
    SMALL_ENEMY,MIDDLE_ENEMY,BIG_ENEMY
}EnemyType;

class Enemy : public cocos2d::Sprite {
public:
    Enemy();
    static Enemy* create(EnemyType);
    bool init(EnemyType);
    //碰撞
    void hit();
    //摧毁
    void down();

    EnemyType e_type;
    //敌机移动速度
    float e_step;
    //敌机血量
    int e_hp;   
};
#endif

这里的e_step、e_hp、e_type我直接public了，可以自行封装。

Enemy.cpp代码段

#include "Enemy.h" Enemy::Enemy() { this->e_type = SMALL_ENEMY; this->e_hp = 0; } Enemy* Enemy::create(EnemyType type) { auto enemy = new Enemy(); if( enemy && enemy->init(type) ) { enemy->autorelease(); return enemy; } delete enemy; enemy = NULL; return NULL; } //根据不同的敌机建立不同的图片效果 bool Enemy::init(EnemyType type) { this->e_type = type; switch (type) { case SMALL_ENEMY: this->e_hp = 1; this->e_step = 4; cocos2d::Sprite::initWithSpriteFrameName("enemy1.png"); break; case MIDDLE_ENEMY: this->e_hp = 6; this->e_step = 1; cocos2d::Sprite::initWithSpriteFrameName("enemy2.png"); break; case BIG_ENEMY: this->e_hp = 30; this->e_step = 0.5f; cocos2d::Sprite::initWithSpriteFrameName("enemy3_n1.png"); break; default: break; } return true; } //打击效果 void Enemy::hit() { auto animation = cocos2d::Animation::create(); switch (this->e_type) { case MIDDLE_ENEMY: animation->addSpriteFrame(cocos2d::SpriteFrameCache::getInstance()-> getSpriteFrameByName("enemy2_hit.png")); animation->addSpriteFrame(cocos2d::SpriteFrameCache::getInstance()-> getSpriteFrameByName("enemy2.png")); break; case BIG_ENEMY: animation->addSpriteFrame(cocos2d::SpriteFrameCache::getInstance()-> getSpriteFrameByName("enemy3_hit.png")); animation->addSpriteFrame(cocos2d::SpriteFrameCache::getInstance()-> getSpriteFrameByName("enemy3_n1.png")); break; default: break; } animation->setDelayPerUnit(0.2f); auto animate = cocos2d::Animate::create(animation); this->runAction(animate); } //摧毁效果 void Enemy::down() { auto animation = cocos2d::Animation::create(); switch(this->e_type) { case SMALL_ENEMY: for (int i = 0; i < 4; i++) { auto png = cocos2d::StringUtils::format("enemy1_down%d.png",i+1); animation->addSpriteFrame(cocos2d::SpriteFrameCache::getInstance()->getSpriteFrameByName(png)); } break; case MIDDLE_ENEMY: for (int i = 0; i < 4; i++) { auto png = cocos2d::StringUtils::format("enemy2_down%d.png",i+1); animation->addSpriteFrame(cocos2d::SpriteFrameCache::getInstance()->getSpriteFrameByName(png)); } break; case BIG_ENEMY: for (int i = 0; i < 6; i++) { auto png = cocos2d::StringUtils::format("enemy3_down%d.png",i+1); animation->addSpriteFrame(cocos2d::SpriteFrameCache::getInstance()->getSpriteFrameByName(png)); } break; default: break; } animation->setDelayPerUnit(0.1f); auto animate = cocos2d::Animate::create(animation); //CallFunc是动作，允许我们的代码作为动作执行 //Sequence是动作，作用是将多个动作按顺序依次执行 auto callFuncN = cocos2d::CallFuncN::create([](Node* node) { //Node参数是这个动作的执行者 //将自己从父容器删除并清除(定时器，动作) node->removeFromParentAndCleanup(true); }); this->runAction(cocos2d::Sequence::create(animate,callFuncN,NULL)); }

修改FlyPlane.h文件

#include "cocos2d.h"
#include "Enemy.h"

class FlyPlane : public cocos2d::Layer {
public:
    CREATE_FUNC(FlyPlane);
    bool init();
    static cocos2d::Scene* createScene();

    //定时器函数必须是void返回类型，必须有一个float类型的参数
    void update(float);
private:
    cocos2d::Point m_vec;
    //英雄子弹集合
    std::vector<cocos2d::Sprite*> h_bullets;
    //敌机集合
    std::vector<Enemy*> h_enemies;
    //创建子弹
    void createBullet(float);   
    //创建敌机
    void createSmallEnemy(float);
    void createMiddleEnemy(float);
    void createBigEnemy(float);
    void createEnemy(EnemyType);
};

修改FlyPlane.cpp文件

#include "FlyPlane.h"
#include "CommonData.h"

cocos2d::Scene* FlyPlane::createScene() {
    //1、auto是c++11的新特性，是自动根据变量的值确定变量的类型，类似var
    //2、大多数时候,cocos中的类想获取它的对象，不建议去new，而是调用它的create方法（oc语法导致）
    //调用cocos2d空间中scene类的静态create方法,返回一个cocos2d::Scene*对象给scene连接
    //‘场景’是一个自动关联的对象
    auto scene = cocos2d::Scene::create();
    auto layer = FlyPlane::create();

    //把层添加到场景里
    scene->addChild(layer);
    return scene;
}

bool FlyPlane::init() {
    //一定要先调用父类初始函数
    if( !cocos2d::Layer::init() ) {
        return false;
    }

    //使用精灵集需要两步
    //1、将美工做好的plist文件读取到缓存中
    //2、通过帧名字创建精灵并显示
    cocos2d::CCSpriteFrameCache::getInstance()->
        addSpriteFramesWithFile("shoot_background.plist");
    auto bg1 = cocos2d::Sprite::createWithSpriteFrameName("background.png");

    //把精灵bg1加到FlyPlane层中，第二个参数ZOrder表示距离用户的距离，第三个参数tag设为1
    this->addChild(bg1,-1,1);

    //默认锚点为(0.5,0.5)，只会显示一半的图，必须设置锚点为(0,0)
    bg1->setAnchorPoint(cocos2d::Point(0,0));

    //texture:纹理,通过精灵找到对应的纹理，并开启抗锯齿
    bg1->getTexture()->setAliasTexParameters();

    auto bg2 = cocos2d::Sprite::createWithSpriteFrameName("background.png");
    this->addChild(bg2,2);
    bg2->setAnchorPoint(cocos2d::Point(0,0));
    bg2->getTexture()->setAliasTexParameters();

    //添加英雄
    cocos2d::CCSpriteFrameCache::getInstance()->
        addSpriteFramesWithFile("shoot.plist");
    auto hero = cocos2d::Sprite::createWithSpriteFrameName("hero1.png");    
    hero->setPosition(VISIBLE_SIZE.width / 2,100);
    this->addChild(hero,3,3);

    //为英雄添加飞行动作，动作由动画组成，所以得到动作对象前，需要先得到动画对象
    //一、创建动画对象
    //1.1通过create得到动画对象
    auto animation = cocos2d::Animation::create();  
    //1.2添加这个动画所要用的精灵帧
    animation->addSpriteFrame(cocos2d::SpriteFrameCache::getInstance()->
        getSpriteFrameByName("hero1.png"));
    animation->addSpriteFrame(cocos2d::SpriteFrameCache::getInstance()->
        getSpriteFrameByName("hero2.png"));
    //1.3设置切换时间
    animation->setDelayPerUnit(0.2f);
    //1.4循环次数，默认为1，设为-1使其无限循环
    animation->setLoops(-1);    
    //二、根据动画对象创建动作对象
    auto animate = cocos2d::Animate::create(animation);
    //三、让hero执行这个动作
    hero->runAction(animate);


    //用单个处理事件添加鼠标监听事件
    auto listener = cocos2d::EventListenerTouchOneByOne::create();
    //用lambda表达式处理分解事件
    //Lambda表达式:
    // {} 类似于普通函数的函数体
    // () 类似于普通函数的参数列表
    // [] 默认Lambda表达式不能访问外部的变量，如果想访问外部变量，就通过中括号传进来

    listener->onTouchBegan = [=](cocos2d::Touch* touch,cocos2d::Event*) {
        auto touchPos = touch->getLocation();
        bool isContain = hero->getBoundingBox().containsPoint(touchPos);
        if(isContain) {
            m_vec = hero->getPosition() - touchPos;//my_vector,记录touchPos指向hero的向量
        }
        return isContain;
    };

    const float leftMinX = hero->getContentSize().width / 2;    //英雄的X最小值(左边界线)
    const float rightMaxX = VISIBLE_SIZE.width - hero->getContentSize().width / 2;//英雄X最大值(右边界线)
    const float downMinY = hero->getContentSize().height / 2;       //英雄Y最小值(下边界线)
    const float upMaxY = VISIBLE_SIZE.height - hero->getContentSize().height / 2; //英雄Y最大值(上边界线)

    listener->onTouchMoved = [=](cocos2d::Touch* touch,cocos2d::Event*) {      
        auto touchPos = touch->getLocation() + m_vec;
        //让英雄跟着手指动并且不超出边界
        hero->setPosition(cocos2d::Point(MAX(leftMinX,MIN(rightMaxX,touchPos.x)),MAX(downMinY,MIN(upMaxY,touchPos.y)))); 
    };

    //将监听器添加到事件分配器上
    this->getEventdispatcher()->
        addEventListenerWithSceneGraPHPriority(listener,hero);

    //定时添加子弹
    schedule(schedule_selector(FlyPlane::createBullet),0.1f);
    //定时添加不同敌机
    schedule(schedule_selector(FlyPlane::createSmallEnemy),0.8f,2);
    schedule(schedule_selector(FlyPlane::createMiddleEnemy),10,8);
    schedule(schedule_selector(FlyPlane::createBigEnemy),20,14);
    //定时器。scheduleUpdate每帧调用一次update函数
    scheduleUpdate();

    return true;
}

void FlyPlane::update(float) {  
    auto bg1 = this->getChildByTag(1);
    auto bg2 = this->getChildByTag(2);
    //bg1下落，bg2跟随
    bg1->setPositionY(bg1->getPositionY() - 5);
    bg2->setPositionY(bg1->getPositionY() + bg1->getContentSize().height);
    if(bg2->getPositionY() <= 0) {
        bg1->setPositionY(0);
    }

    //重置迭代器
    std::vector<Enemy*>::iterator it_enemy = h_enemies.begin();
    std::vector<cocos2d::Sprite*>::iterator it_bullet = this->h_bullets.begin();

    //让子弹飞
    while( it_bullet != this->h_bullets.end() ) {       
        (*it_bullet)->setPositionY((*it_bullet)->getPositionY() + 12);                              
        //如果子弹飞出游戏区则清除
        if((*it_bullet)->getPositionY() > VISIBLE_SIZE.height) {
            this->removeChild((*it_bullet));
            it_bullet = h_bullets.erase(it_bullet);         
        } else {
            ++it_bullet;
        }
    }

    //让敌机飞
    while( it_enemy != h_enemies.end() ) {
        auto enemy = (*it_enemy);
        enemy->setPositionY(enemy->getPositionY() - enemy->e_step);
        //如果敌机飞出游戏区则清除
        if(enemy->getPositionY() <= 0) { 
            this->removeChild(enemy);
            it_enemy = h_enemies.erase(it_enemy);
        } else {        
            it_enemy++;
        }
    }

    //碰撞检测
    it_enemy = h_enemies.begin();
    it_bullet = this->h_bullets.begin();
    //第一层循环遍历敌机
    while( it_enemy != h_enemies.end()) {
        it_bullet = h_bullets.begin(); //每次遍历，子弹迭代器置于起始位置
        bool isDown = false;
        //第二层循环遍历子弹
        while(it_bullet != h_bullets.end()) {
            //如果相撞
            if((*it_bullet)->getBoundingBox().intersectsRect((*it_enemy)->getBoundingBox())) {  
            //在层中与容器中清除子弹并用isDown记录相撞
                this->removeChild((*it_bullet));                                
                it_bullet = h_bullets.erase(it_bullet);                                     
                isDown = true;                              
            } else {
                ++it_bullet;
            }
        }       
        //如果相撞，运行打击动画
        if(isDown == true) {
            (*it_enemy)->hit();
            (*it_enemy)->e_hp--;    //敌机减血
            if( (*it_enemy)->e_hp <= 0 ) { // 如果为0则被摧毁
                (*it_enemy)->down();    
                it_enemy = h_enemies.erase(it_enemy);
            }
        } else {
            ++it_enemy;
        }
    }
}

void FlyPlane::createBullet(float) {
    auto hero = this->getChildByTag(3);
    auto bullet = cocos2d::Sprite::createWithSpriteFrameName("bullet1.png");//初始子弹在shoot.plist中名字叫bullet1
    bullet->setPosition(hero->getPosition() + cocos2d::Point(0,hero->getContentSize().height / 2));//子弹初始位置
    this->addChild(bullet,0); //zorder为0，高于背景层-1，低于英雄的3
    //每创建一个子弹就存在容器中
    h_bullets.push_back(bullet);
}

void FlyPlane::createEnemy(EnemyType type) {
    auto enemy = Enemy::create(type);
    float leftMinX = enemy->getContentSize().width / 2;
    float rightMaxX = VISIBLE_SIZE.width - enemy->getContentSize().width / 2;
    float x = rand() % (int)(rightMaxX - leftMinX + 1) + leftMinX;      //产生一个[leftMinX,rightMaxX]的随机数
    float y = VISIBLE_SIZE.height;
    enemy->setPosition(x,y);
    h_enemies.push_back(enemy);
    this->addChild(enemy,0);
}


void FlyPlane::createSmallEnemy(float) {
    this->createEnemy(SMALL_ENEMY);
}

void FlyPlane::createMiddleEnemy(float) {
    this->createEnemy(MIDDLE_ENEMY);
}

void FlyPlane::createBigEnemy(float) {
    this->createEnemy(BIG_ENEMY);
}

这里有三个定时器来产生三种敌机

//定时添加不同敌机
    schedule(schedule_selector(FlyPlane::createSmallEnemy),0.8f,2);
    schedule(schedule_selector(FlyPlane::createMiddleEnemy),8);
    schedule(schedule_selector(FlyPlane::createBigEnemy),14);

在update()函数中增加对子弹和敌机碰撞添加判断

//让敌机飞
    while( it_enemy != h_enemies.end() ) {
        auto enemy = (*it_enemy);
        enemy->setPositionY(enemy->getPositionY() - enemy->e_step);
        //如果敌机飞出游戏区则清除
        if(enemy->getPositionY() <= 0) { 
            this->removeChild(enemy);
            it_enemy = h_enemies.erase(it_enemy);
        } else {        
            it_enemy++;
        }
    }

    //碰撞检测
    it_enemy = h_enemies.begin();
    it_bullet = this->h_bullets.begin();
    //第一层循环遍历敌机
    while( it_enemy != h_enemies.end()) {
        it_bullet = h_bullets.begin(); //每次遍历，子弹迭代器置于起始位置
        bool isDown = false;
        //第二层循环遍历子弹
        while(it_bullet != h_bullets.end()) {
            //如果相撞
            if((*it_bullet)->getBoundingBox().intersectsRect((*it_enemy)->getBoundingBox())) {  
            //在层中与容器中清除子弹并用isDown记录相撞
                this->removeChild((*it_bullet));                                
                it_bullet = h_bullets.erase(it_bullet);                                     
                isDown = true;                              
            } else {
                ++it_bullet;
            }
        }       
        //如果相撞，运行打击动画
        if(isDown == true) {
            (*it_enemy)->hit();
            (*it_enemy)->e_hp--;    //敌机减血
            if( (*it_enemy)->e_hp <= 0 ) { // 如果为0则被摧毁
                (*it_enemy)->down();    
                it_enemy = h_enemies.erase(it_enemy);
            }
        } else {
            ++it_enemy;
        }
    }

运行后效果如图：