Cocos2d-x学习笔记（十一）动作

动作类Action是一切动作的祖先类。它有三个直接继承子类：

1. FiniteTimeAction受时间限制的动作；
2. Follow精灵跟随精灵的动作；
3. Speed运动速度控制；

而FiniteTimeAction又有两个直接子类：分别是ActionInstant和ActionInterval，顾类名而思意。

瞬时动作即立即执行动作，下边是其使用示例：

void MyAction::goMenu(cocos2d::Ref *pSender)
{
    log("Tag = %i", this->getTag());
    Size size = Director::getInstance()->getVisibleSize();
    Vec2 p = Vec2(CCRANDOM_0_1()*size.width, CCRANDOM_0_1()*size.height);

    switch (this->getTag())
    {
        case PLACE_TAG:
            sprite->runAction(Place::create(p));// Places the node in a certain position
            break;
        case FLIPX_TAG:
            sprite->runAction(FlipX::create(true));// Flips the sprite horizontally
            break;
        case FLIPY_TAG:
            sprite->runAction(FlipY::create(true));// Flips the sprite vertically
            break;
        case HIDE_SHOW_TAG:
            if (hiddenFlag)
            {
                sprite->runAction(Hide::create());// Hide the node
                hiddenFlag = false;
            }
            else
            {
                sprite->runAction(Show::create());// Show the node
                hiddenFlag = true;
            }
            break;
        case TOGGLE_TAG:
            sprite->runAction(ToggleVisibility::create());// Toggles the visibility of a node
            break;
        default:
            break;
    }
}
    
void MyAction::backMenu(cocos2d::Ref *pSender)
{
    auto sc = HelloWorld::createScene();
    // Slide in the incoming scene from the left border.
    auto reScene = TransitionSlideInL::create(1.0f, sc);
    Director::getInstance()->replaceScene(reScene);
}

在goMenu()函数中的动作类都是ActionInstant的子类；

void HelloWorld::OnClickMenu(cocos2d::Ref *pSender)
{
    MenuItem *nmitem = (MenuItem*)pSender;

    auto sc = Scene::create();
    auto layer = MyAction::create();
    layer->setTag(nmitem->getTag());// set layer's tag, and this should be the most important part in this func.

    sc->addChild(layer);

    auto reScene = TransitionSlideInR::create(1.0f, sc);
    Director::getInstance()->replaceScene(reScene);
}

运行结果：

图1 HelloWorld层

图2 MyAction层

注意：这里的聚焦貌似没那么准确。

以下为间隔动作的使用示例：

void MyAction::goMenu(cocos2d::Ref *pSender)
{
    log("Tag = %i", this->getTag());
    Size size = Director::getInstance()->getVisibleSize();

    ccBezierConfig bezier;

    switch (this->getTag())
    {
        case kMoveTo:
            // 第一个参数为移动持续时间，第二个参数为目标位置
            sprite->runAction(MoveTo::create(2,Vec2(size.width-50, size.height-50)));
            break;
        case kMoveBy:
            sprite->runAction(MoveBy::create(2,Vec2(-50, -50)));
            break;
        case kJumpTo:
            // 第一个参数为持续时间，第二个参数为目标位置，第三个参数为高度，第四个参数为跳跃次数
            sprite->runAction(JumpTo::create(2,Vec2(150, 50), 30, 5));
            break;
        case kJumpBy:
            sprite->runAction(JumpBy::create(2,Vec2(100, 100),30,5));
            break;
        case kBezierBy:
            bezier.controlPoint_1 = Vec2(0, size.height/2);
            bezier.controlPoint_2 = Vec2(300, -size.height/2);
            bezier.endPosition = Vec2(100, 100);
            sprite->runAction(BezierBy::create(3, bezier));
            break;
        case kScaleTo:
            // 第一个参数为持续时间，第二个参数为缩放比例
            sprite->runAction(ScaleTo::create(2, 4));
            break;
        case kScaleBy:
            sprite->runAction(ScaleBy::create(2, 0.5));
            break;
        case kRotateTo:
            // 第一个参数为持续时间，第二参数为旋转角度
            sprite->runAction(RotateTo::create(2, 180));
            break;
        case kRotateBy:
            sprite->runAction(RotateBy::create(2, -180));
            break;
        case kBlink:
            // 第一个参数为持续时间，第二个参数为闪烁次数
            sprite->runAction(Blink::create(3, 5));
            break;
        case kTintTo:
            // 第一个参数为持续时间，剩余参数对应RGB
            sprite->runAction(TintTo::create(2, 255, 0, 0));
            break;
        case kTintBy:
            sprite->runAction(TintBy::create(0.5, 0, 255, 255));
            break;
        case kFadeTo:
            // 第一个参数为持续时间，第二个参数为不透明度（百分数）
            sprite->runAction(FadeTo::create(1, 80));
            break;
        case kFadeIn:
            sprite->setOpacity(10);// 0~255，0位完全透明
            // 参数为持续时间
            sprite->runAction(FadeIn::create(1));
            break;
        case kFadeOut:
            sprite->runAction(FadeOut::create(1));
            break;
        default:
            break;
    }
}

动作的速度控制示例：

void MyAction::goMenu(Ref* pSender)
{   
    log("Tag = %i",this->getTag());
    FiniteTimeAction * ac1 = (FiniteTimeAction *)MoveBy::create(2, Vec2(200, 0));
    FiniteTimeAction * ac2 = ((FiniteTimeAction *)ac1)->reverse();
    
    ActionInterval * ac = Sequence::create(ac1, ac2, NULL);
    
    switch (this->getTag()) {
        case kEaseIn:
            // 3倍速度由慢至快
            sprite->runAction(EaseIn::create(ac, 3));
            break;
        case kEaseOut:
            sprite->runAction(EaseOut::create(ac, 3));
            break;
        case kEaseInOut:
            sprite->runAction(EaseInOut::create(ac, 3));
            break;
        case kEaseSineIn:
            // 采用正弦变换由慢至快
            sprite->runAction(EaseSineIn::create(ac));
            break;
        case kEaseSineOut:
            sprite->runAction(EaseSineOut::create(ac));
            break;
        case kEaseSineInOut:            
            sprite->runAction(EaseSineInOut::create(ac));
            break;
        case kEaseExponentialIn:
            // 采用指数变换速度由慢至快
            sprite->runAction(EaseExponentialIn::create(ac));
            break;
        case kEaseExponentialOut:
            sprite->runAction(EaseExponentialOut::create(ac));
            break;
        case kEaseExponentialInOut:
            sprite->runAction(EaseExponentialInOut::create(ac));
            break;
        case kSpeed:
            // 随机变换速度
            sprite->runAction(Speed::create(ac, (CCRANDOM_0_1() * 5)));
            break;
    }
}