cocos2d-x 3.x学习之多点触摸

#include "cocos2d.h"
USING_NS_CC;
class HelloWorld : public cocos2d::Layer
{
private:
double _distance;//两个触摸点之间的距离
double _deltax;//目标x轴的改变值
double _deltay;//目标y轴的改变值
Sprite* _bgSprite;//目标精灵
double _mscale;//初始地图缩放比例
public:
static cocos2d::Scene* createScene();
virtual bool init();
void menuCloseCallback(cocos2d::Ref* pSender);
void onTouchesBegan(const std::vector<Touch*>&touches,Event* event);
void onTouchesMoved(const std::vector<Touch*>&touches,Event* event);
void onTouchesEnded(const std::vector<Touch*>&touches,Event* event);
void onTouchesCancelled(const std::vector<Touch*>&touches,Event* event);
CREATE_FUNC(HelloWorld);
};

#include "HelloWorldScene.h"
USING_NS_CC;
/*
提示:如果在ios模拟器中进行测试，按着option键，屏幕上可出现两个触摸点，但是程序中始终
只能得到一个点，即vector当中只有一个触摸点，这时需要修改ios目录下的AppController.mm文件，在文件中启用多点触摸。
在AppController.mm的-(BOOL)application:(UIApplication*)application didFinishLauncing-WithOptions:(NSDictionary*)launchOptions函数最后增加
一行代码
激活多点触摸功能
[eaglView setMultipleTouchEnabled:YES]
*/
Scene* HelloWorld::createScene()
{
auto scene = Scene::create();
auto layer = HelloWorld::create();
scene->addChild(layer);
return scene;
}

bool HelloWorld::init()
{
if ( !Layer::init() )
{
return false;
}

Size visibleSize = Director::getInstance()->getVisibleSize();
Vec2 origin = Director::getInstance()->getVisibleOrigin();
auto closeItem = MenuItemImage::create(
"CloseNormal.png",
"CloseSelected.png",
CC_CALLBACK_1(HelloWorld::menuCloseCallback, this));

closeItem->setPosition(Vec2(origin.x + visibleSize.width - closeItem->getContentSize().width/2 ,
origin.y + closeItem->getContentSize().height/2));
auto menu = Menu::create(closeItem, NULL);
menu->setPosition(Vec2::ZERO);
this->addChild(menu, 1);
//标题标签
auto title = Label::createWithSystemFont("多点触摸（缩放功能）测试","", 64);
title->setPosition(visibleSize.width / 2,visibleSize.height * 0.9);
this->addChild(title);
//提示标签
auto subtitle = Label::createWithSystemFont("请用手指缩放屏幕","", 32);
subtitle->setPosition(visibleSize.width / 2,visibleSize.height * 0.8);
this->addChild(subtitle);
//使用HelloWorld.png创建一个精灵
_bgSprite = Sprite::create("HelloWorld.png");
_bgSprite->setPosition(Vec2(visibleSize.width / 2 + origin.x,visibleSize.height / 2 + origin.y));
this->addChild(_bgSprite,0);
//初始化图片缩放比例
_mscale = 1.0;
//创建多点触摸监听器
auto listener = EventListenerTouchAllAtOnce::create();
//绑定事件处理函数
listener->onTouchesBegan = CC_CALLBACK_2(HelloWorld::onTouchesBegan,this);
listener->onTouchesMoved = CC_CALLBACK_2(HelloWorld::onTouchesMoved,this);
listener->onTouchesEnded = CC_CALLBACK_2(HelloWorld::onTouchesEnded,this);
listener->onTouchesCancelled = CC_CALLBACK_2(HelloWorld::onTouchesCancelled,this);
//添加场景优先事件监听器
_eventDispatcher->addEventListenerWithSceneGraphPriority(listener, this);
return true;
}
void HelloWorld::onTouchesBegan(const std::vector<Touch *> &touches, cocos2d::Event *event){
//如果移动时触摸点的个数不少于两个
if(touches.size() >= 2){
//获得第一个触摸点
auto touch1 = touches.at(0);
Vec2 mPoint1 = Director::getInstance()->convertToGL(touch1->getLocation());
//获得第二个触摸点
auto touch2 = touches.at(1);
Vec2 mPoint2 = Director::getInstance()->convertToGL(touch2->getLocation());
//计算两个触摸点距离，开根号
_distance = sqrt((mPoint2.x-mPoint1.x) * (mPoint2.x-mPoint1.x) + (mPoint2.y - mPoint1.x) * (mPoint2.y - mPoint1.y));

}
}
void HelloWorld::onTouchesMoved(const std::vector<Touch *> &touches, cocos2d::Event *unused_event){
//如果移动时触摸点的个数不少于两个
if(touches.size() >= 2){
//获得第一个触摸点
auto touch1 = touches.at(0);
Vec2 mPoint1 = Director::getInstance()->convertToGL(touch1->getLocation());
//获得第二个触摸点
auto touch2 = touches.at(1);
Vec2 mPoint2 = Director::getInstance()->convertToGL(touch2->getLocation());
//计算两个触摸点距离，开根号
double mdistance = sqrt((mPoint2.x-mPoint1.x) * (mPoint2.x-mPoint1.x) + (mPoint2.y - mPoint1.x) * (mPoint2.y - mPoint1.y));
// 新的距离 / 老的距离 * 原来的缩放比例，即为新的缩放比例
_mscale = mdistance / _distance * _mscale;
_distance = mdistance;
//设置新的缩放比例
_bgSprite->setScale(_mscale);
}

}
void HelloWorld::onTouchesEnded(const std::vector<Touch *> &touches, cocos2d::Event *event){
}
void HelloWorld::onTouchesCancelled(const std::vector<Touch *> &touches, cocos2d::Event *event){
}
void HelloWorld::menuCloseCallback(Ref* pSender)
{
#if (CC_TARGET_PLATFORM == CC_PLATFORM_WP8) || (CC_TARGET_PLATFORM == CC_PLATFORM_WINRT)
MessageBox("You pressed the close button. Windows Store Apps do not implement a close button.","Alert");
return;
#endif

Director::getInstance()->end();

#if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)
exit(0);
#endif
}