cocos2dx 3.2 事件机制

一个sprite的情况

// oneSprite
void HelloWorld::touchableSpriteTestOne()
{
    Vec2 origin = Director::getInstance()->getVisibleOrigin();
    Size size = Director::getInstance()->getVisibleSize();

    auto sprite1 = Sprite::create("Images/CyanSquare.png");
    sprite1->setPosition(160, 240);
    addChild(sprite1,0,100);

    // Make sprite1 touchable
    auto listener1 = EventListenerTouchOneByOne::create();
    listener1->setSwallowTouches(true);//设置是否想下传递触摸

    listener1->onTouchBegan = [=](Touch* touch, Event* event){
        auto target = static_cast<Sprite*>(event->getCurrentTarget());

        log("target.x.y: %f %f tag:%d isSprite1:%d width:%f,height:%f", target->getPosition().x, target->getPosition().y,
            target->getTag(), target == sprite1, target->getContentSize().width, target->getContentSize().height);

        Vec2 locationInNode = target->convertToNodeSpace(touch->getLocation());
        log("locationInNode %f %f", locationInNode.x, locationInNode.y);
        Size s = target->getContentSize();
        Rect rect = Rect(0, 0, s.width, s.height);
        if (rect.containsPoint(locationInNode))
        {
            log("sprite began... x = %f, y = %f tag:%d", locationInNode.x, locationInNode.y, target->getTag());
            target->setOpacity(180);
            return true;
        }
        return false;
    };

    listener1->onTouchMoved = [](Touch* touch, Event* event){
        log("%s", "onTouchMoved");
        auto target = static_cast<Sprite*>(event->getCurrentTarget());
        target->setPosition(target->getPosition() + touch->getDelta());
    };

    listener1->onTouchEnded = [=](Touch* touch, Event* event){
        auto target = static_cast<Sprite*>(event->getCurrentTarget());
        log("sprite onTouchesEnded.. ");
        target->setOpacity(255);
        
    };
    //onTouchBegan 随便点个地方都触发，onTouchMoved onTouchEnded 是点到sprite1才触发，
    _eventDispatcher->addEventListenerWithSceneGraphPriority(listener1, sprite1);

}

1、onTouchBegan无论点哪里都触发。只有在点中了sprite1，onTouchBegan return true的时候onTouchMoved ，onTouchEnded才会触发

2、Vec2 locationInNode = target->convertToNodeSpace(touch->getLocation()); 这个touch->getLocation是整个GL的坐标，整个屏幕相对于左下角的坐标

转换为target的本地坐标 矩形是原点为(0,0)，长宽，原点是左下角，锚点是中心，addchild的时候是孩子的锚点对准自己的原点，自己的原点是左下角。
3、点击屏幕的每个地方 target都是最上层的那个target，通过转换为target的矩形范围，来判断是点击了哪个sprite.

4、

 设备是把屏幕上的点击通过坐标告诉你，所以begin必定触发 

 begin返回true，表示你要处理这个点击，才会触发后面的move和end 

5、摸监听listener的创建方式有两种，一种是：EventListenerTouchOneByOne，另一种是：EventListenerTouchAllAtOnce，顾名思义，EventListenerTouchOneByOne的意思单点触摸，EventListenerTouchAllAtOnce，是多点触摸，而不需要再用设置Delegate的方式来做了。3.0触摸机制还有个不同的地方，只要是放在最上面的那个精灵，那它的触摸优先级就最高。我们用的按钮Menu 就是用这种方式设置触摸优先级的。

二：两个sprite 互相包含的情况：

// TouchableSpriteTest
void HelloWorld::touchableSpriteCont()
{
	Vec2 origin = Director::getInstance()->getVisibleOrigin();
	Size size = Director::getInstance()->getVisibleSize();

	auto sprite2 = Sprite::create("Images/MagentaSquare.png");
	sprite2->setPosition(origin + Vec2(size.width / 2, size.height / 2));

	addChild(sprite2, 20, 200);
	log("1sprite2.width,sprite2.height: %f %f", sprite2->getContentSize().width, sprite2->getContentSize().height);
	//锚点确定精灵自己在父节点的加载位置,原点始终在左下角为0,0  addchild的时候是孩子的锚点对准 自己的原点。
	//并不是你点精灵的区域才响应 是精灵所在的那一层范围都能响应
	auto sprite3 = Sprite::create("Images/YellowSquare.png");
	sprite3->setPosition(0, 0);

	sprite2->addChild(sprite3, 1, 300);
	log("layer.width,layer.height: %f %f",this->getContentSize().width,this->getContentSize().height);
	log("2sprite2.width,height:%f %f", sprite2->getContentSize().width, sprite2->getContentSize().height);

	// Make sprite1 touchable
	auto listener1 = EventListenerTouchOneByOne::create();
	listener1->setSwallowTouches(true);

	listener1->onTouchBegan = [=](Touch* touch, Event* event){
		auto target = static_cast<Sprite*>(event->getCurrentTarget());
		log("target.x.y: %f %f tag:%d width:%f,height:%f", target->getPosition().x, target->getPosition().y,
			target->getTag(), target->getContentSize().width, target->getContentSize().height);

		Vec2 locationInNode = target->convertToNodeSpace(touch->getLocation());
		Size s = target->getContentSize();
		Rect rect = Rect(0, 0, s.width, s.height);
		log("locationInNode.x= %f ,y= %f,contentW= %f,contentH= %f", locationInNode.x, locationInNode.y, s.width, s.height);
		if (rect.containsPoint(locationInNode))
		{
			log("dist began... x = %f, y = %f tag:%d", locationInNode.x, locationInNode.y, target->getTag());
			target->setOpacity(180);
			return true;
		}
		return false;
	};

	listener1->onTouchMoved = [](Touch* touch, Event* event){
		log("%s", "onTouchMoved");
		auto target = static_cast<Sprite*>(event->getCurrentTarget());
		target->setPosition(target->getPosition() + touch->getDelta());
	};

	listener1->onTouchEnded = [=](Touch* touch, Event* event){
		auto target = static_cast<Sprite*>(event->getCurrentTarget());
		log("sprite onTouchesEnded.. ");
		target->setOpacity(255);
	
	};
	_eventDispatcher->addEventListenerWithSceneGraphPriority(listener1->clone(), sprite2);
}