Cocos2d-x如何控製動作速度

基本動作和組合動作實現了針對精靈的各種運動和動畫效果的改變。但這樣的改變速度勻速的、線性的。通過ActionEase及其的派生類和Speed 類我們可以使精靈以非勻速或非線性速度運動這樣看起了效果更加逼真。

ActionEase的類圖如下圖所示。

下麵我們通過一個實例介紹一下這些動作中速度的控製的使用這個實例如下圖所示上圖是一個操作菜單場景選擇菜單可以進入到下圖動作場景在下圖動作場景中點擊Go按鈕可以執行我們選擇的動作效果點擊Back按鈕可以返回到菜單場景。

下麵我們再看看具體的程序代碼首先看一下看HelloWorldScene.h文件它的代碼如下

#ifndef __HELLOWORLD_SCENE_H__
#define __HELLOWORLD_SCENE_H__
 
#include "cocos2d.h"
#include "MyActionScene.h"
 
typedef enum                                                                                                                                         ①
{
    kEaseIn = 1
   ,kEaseOut
   ,kEaseInOut
   ,kEaseSineIn
   ,kEaseSineOut
   ,kEaseSineInOut
   ,kEaseExponentialIn
   ,kEaseExponentialOut
   ,kEaseExponentialInOut
   ,kSpeed
   
} ActionTypes;                                                                                                                             ②
 
 
class HelloWorld : public cocos2d::Layer
{
public:
   static cocos2d::Scene* createScene();
   virtual bool init(); 
   void OnClickMenu(cocos2d::Ref* pSender);
   
   CREATE_FUNC(HelloWorld);
};
 
#endif // __HELLOWORLD_SCENE_H__

上述代碼第①~②是定義個枚舉類型ActionTypes枚舉類型ActionTypes中定義了10個常量這10個常量對應10個菜單項。

HelloWorldScene的實現代碼HelloWorldScene.ccp文件它的主要代碼如下

bool HelloWorld::init()
{
    if( !Layer::init() )
    {
         returnfalse;
    }
 
    SizevisibleSize = Director::getInstance()->getVisibleSize();
    Pointorigin = Director::getInstance()->getVisibleOrigin();
 
    autobg = Sprite::create("background.png");
    bg->setPosition(Point(visibleSize.width/2,visibleSize.height /2));
    this->addChild(bg);
 
    autopItmLabel1 = Label::createWithBMFont("fonts/fnt2.fnt","EaseIn");
    autopItmMenu1 = MenuItemLabel::create(pItmLabel1,
              CC_CALLBACK_1(HelloWorld::OnClickMenu, this));
    pItmMenu1->setTag(kEaseIn);
 
    autopItmLabel2 = Label::createWithBMFont("fonts/fnt2.fnt","EaseOut");
    autopItmMenu2 = MenuItemLabel::create(pItmLabel2,
             CC_CALLBACK_1(HelloWorld::OnClickMenu,this));
    pItmMenu2->setTag(kEaseOut);
 
    autopItmLabel3 = Label::createWithBMFont("fonts/fnt2.fnt","EaseInOut");
    autopItmMenu3 = MenuItemLabel::create(pItmLabel3,
             CC_CALLBACK_1(HelloWorld::OnClickMenu,this));
    pItmMenu3->setTag(kEaseInOut);
 
    autopItmLabel4 = Label::createWithBMFont("fonts/fnt2.fnt","EaseSineIn");
    autopItmMenu4 = MenuItemLabel::create(pItmLabel4,
             CC_CALLBACK_1(HelloWorld::OnClickMenu,this));
    pItmMenu4->setTag(kEaseSineIn);
 
    autopItmLabel5 = Label::createWithBMFont("fonts/fnt2.fnt", "EaseSineOut");
    autopItmMenu5 = MenuItemLabel::create(pItmLabel5,
             CC_CALLBACK_1(HelloWorld::OnClickMenu,this));
    pItmMenu5->setTag(kEaseSineOut);
 
    autopItmLabel6 = Label::createWithBMFont("fonts/fnt2.fnt","EaseSineInOut");
    autopItmMenu6 = MenuItemSprite::create(pItmLabel6,
             CC_CALLBACK_1(HelloWorld::OnClickMenu,this));
    pItmMenu6->setTag(kEaseSineInOut);
 
    autopItmLabel7 = Label::createWithBMFont("fonts/fnt2.fnt","EaseExponentialIn");
    autopItmMenu7 = MenuItemSprite::create(pItmLabel7,
             CC_CALLBACK_1(HelloWorld::OnClickMenu,this));
    pItmMenu7->setTag(kEaseExponentialIn);
 
    autopItmLabel8 = Label::createWithBMFont("fonts/fnt2.fnt","EaseExponentialOut");
    autopItmMenu8 = MenuItemLabel::create(pItmLabel8,
             CC_CALLBACK_1(HelloWorld::OnClickMenu,this));
    pItmMenu8->setTag(kEaseExponentialOut);
 
    autopItmLabel9 = Label::createWithBMFont("fonts/fnt2.fnt","EaseExponentialInOut");
    autopItmMenu9 = MenuItemLabel::create(pItmLabel9,
             CC_CALLBACK_1(HelloWorld::OnClickMenu,this));
    pItmMenu9->setTag(kEaseExponentialInOut);
 
    autopItmLabel10 = Label::createWithBMFont("fonts/fnt2.fnt","Speed");
    autopItmMenu10 = MenuItemLabel::create(pItmLabel10,
             CC_CALLBACK_1(HelloWorld::OnClickMenu,this));
    pItmMenu10->setTag(kSpeed);
 
    automn = Menu::create(pItmMenu1,pItmMenu2,pItmMenu3,pItmMenu4,pItmMenu5,
         pItmMenu6,pItmMenu7,pItmMenu8,pItmMenu9,pItmMenu10,NULL);
 
    mn->alignItemsInColumns(2,2, 2, 2, 2, NULL);
 this->addChild(mn);
 
    returntrue;
}
 
void HelloWorld::OnClickMenu(Ref* pSender)
{
    MenuItem*nmitem = (MenuItem*)pSender;
 
    auto  sc = Scene::create();
    auto  layer = MyAction::create();
    layer->setTag(nmitem->getTag());
 
    sc->addChild(layer);
 
    autoreScene = TransitionSlideInR::create(1.0f, sc);
    Director::getInstance()->replaceScene(reScene);
}

在上訴代碼大家比較熟悉了我們這裏就不再介紹了。下麵我們再看看下一個場景MyActionScene它的MyActionScene.ccp它的主要代碼如下

void MyAction::goMenu(Ref* pSender)
{  
    log("Tag = %i",this->getTag());
   FiniteTimeAction * ac1 = (FiniteTimeAction *)MoveBy::create(2,Point(200, 0));
   FiniteTimeAction * ac2 = ((FiniteTimeAction *)ac1)->reverse();
   
   ActionInterval * ac = Sequence::create(ac1, ac2, NULL);
   
   switch (this->getTag()) {
       case kEaseIn:
           sprite->runAction(EaseIn::create(ac, 3));                                                                        ①
            break;
       case kEaseOut:
           sprite->runAction(EaseOut::create(ac, 3));                                                            ②
            break;
       case kEaseInOut:
            sprite->runAction(EaseInOut::create(ac,3));                                                         ③
            break;
       case kEaseSineIn:
           sprite->runAction(EaseSineIn::create(ac));                                                           ④
            break;
       case kEaseSineOut:
           sprite->runAction(EaseSineOut::create(ac));                                                                  ⑤
            break;
       case kEaseSineInOut:
           sprite->runAction(EaseSineInOut::create(ac));                                                              ⑥
            break;
       case kEaseExponentialIn:
           sprite->runAction(EaseExponentialIn::create(ac));                                                       ⑦
            break;
       case kEaseExponentialOut:
           sprite->runAction(EaseExponentialOut::create(ac));                                                     ⑧
            break;
       case kEaseExponentialInOut:
           sprite->runAction(EaseExponentialInOut::create(ac));                                        ⑨
            break;
       case kSpeed:
           sprite->runAction(Speed::create(ac, (CCRANDOM_0_1() * 5)));                                  ⑩
            break;
   }
}

第①行代碼sprite->runAction(EaseIn::create(ac, 3))是以3倍速度由慢至快。第②代碼sprite->runAction(EaseOut::create(ac, 3))是以3倍速度由快至慢。第③代碼sprite->runAction(EaseInOut::create(ac, 3))是以3倍速度由慢至快再由快至慢。

第④代碼sprite->runAction(EaseSineIn::create(ac))是采用正弦變換速度由慢至快。第⑤代碼sprite->runAction(EaseSineOut::create(ac))是采用正弦變換速度由快至慢。第⑥代碼sprite->runAction(EaseOut::create(ac, 3)) 是采用正弦變換速度由慢至快再由快至慢。

第⑦代碼sprite->runAction(EaseExponentialIn::create(ac))采用指數變換速度由慢至快。第⑧代碼sprite->runAction(EaseExponentialOut::create(ac))采用指數變換速度由快至慢。第⑨代碼sprite->runAction(EaseExponentialInOut::create(ac)) 采用指數變換速度由慢至快再由快至慢。

第⑩代碼sprite->runAction(Speed::create(ac, (CCRANDOM_0_1() * 5))) 隨機設置變換速度。

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