cocos2d－基本概念(3)-Actions: Ease緩沖動作

Actions: Ease

ease 不知道怎麼翻譯，暫時翻譯成緩沖操作吧。這個chapter大概的意思就是對移動等動作進行封裝路線的變化，或者是從原來的在總的持續時間不變的前提下，變成了非勻速的運動。需要說名的一點就是，這個wiki裡面提到的部分內容，現在最新版本的cocos2d裡面已經找不到了，函數的說明變了。。。對於找不到的，暫時不翻譯，反正也比較簡單，照貓畫虎把。哈哈。

緩沖操作是一個特殊的復雜操作，可以改變inner 動作的時間。在Flash裡面，它們經常被稱作Tweening 或者Easing 動作。

它們雖然改變了運動的速度，但是並沒有改變總體時間，如果整個的action持續5秒鐘，那麼整個的時間仍然會持續5秒鐘。

The Ease actions alter the　linearity　of the time.

例如它們可以對inner的action進行加速或者是減速。

這些action可以被分成3類：

In actions: action開始的時候加速

Out actions: action結束的時候加速

InOut actions: action開始，結束的時候加速

For more information about　easing　or　tweening　actions, visit any of these pages:

http://hosted.zeh.com.br/tweener/docs/en-us/misc/transitions.html

http://www.robertpenner.com/easing/easing_demo.html

Ease actions

這些內部的action是按著如下進行加速的:

-(void)　update:(ccTime)　t
{
　　 [inner　update:　powf(t,rate)];
}

rate 這個參數就是增加的速率

以下舉了幾個例子說明的分別的動作的開始，結束，和開始或者結束的時候加速。

Example:

//　acceleration　at　the　beginning
　　　　　　　　 id　action　=　[MoveTo　actionWithDuration:2　position:ccp(100,100)];
　 id　ease　=　[EaseIn　actionWithAction:action　rate:2];
　 [sprite　runAction:　ease];

　 //　acceleration　at　the　end
　 id　action　=　[MoveTo　actionWithDuration:2　position:ccp(100,100)];
　 id　ease　=　[EaseIn　actionWithAction:action　rate:2];
　 [sprite　runAction:　ease];

　 //　acceleration　at　the　beginning　/　end
　 id　action　=　[MoveTo　actionWithDuration:2　position:ccp(100,100)];
　 id　ease　=　[EaseInOut　actionWithAction:action　rate:2];
　 [sprite　runAction:　ease];

EaseExponential actions 指數緩沖動作

EaseExponentialIn

EaseExponentialOut

EaseExponentialInOut

EaseSine actions 塞因緩沖

EaseSineIn

EaseSineOut

EaseSineInOut

接下來的幾個Ease的action，在最新版本的cocos2d裡面找不到了，貌似已經干掉了。不理解了。。可以我從xcode拿出來的code，就知道了，以下的這幾個關鍵字已經不變色了。。

就剩下一個rate的了。

[EaseRateAction actionWithAction:<#(IntervalAction *)action#> rate:<#(float)rate#>];

EaseElastic actions 彈性緩沖

These actions alters the time simulating an elastic. Elastic actions will use　time　values greater than 1 and lower than 0, so the inner action should be prepared to handle this special values.

Also some values will be triggered more than once (this function is not bijective), so again, the　inner　action should be prepared to handle this values. Simple actions like　MoveBy,　ScaleBy,　RotateBy　work OK with　EaseElastic　actions, but the　Sequence　or　Spawnactions might have unexpected results.

Available since v0.8.2

Available elastic actions:

EaseElasticIn

EaseElasticOut

EaseElasticInOut

Examples:

//　'period'　is　how　elastic　is　the　action.
　 //　recommended　values:　between　0.3　and　0.45

　 //　Elastic　at　the　beginning
　 id　move　=　[MoveBy　actionWithDuration:3　position:ccp(350,0)];
　 id　action　=　[EaseElasticIn　actionWithAction:move　period:0.3f];
　 [sprite　runAction:　action];

　 //　Elastic　at　the　end
　 id　move　=　[MoveBy　actionWithDuration:3　position:ccp(350,0)];
　 id　action　=　[EaseElasticOut　actionWithAction:move　period:0.3f];
　 [sprite　runAction:　action];

　 //　Elastic　at　the　beginning　and　at　the　end
　 id　move　=　[MoveBy　actionWithDuration:3　position:ccp(350,0)];
　 id　action　=　[EaseElasticInOut　actionWithAction:move　period:0.3f];
　 [sprite　runAction:　action];

EaseBounce actions 跳躍緩沖

EaseBounce actions simulates a bouncing effect.

Some　time　values will be triggered more than once (this function is not bijective), so the　inner　action should be prepared to handle this values. Simple actions like　MoveBy,　ScaleBy,　RotateBy　work OK with　EaseBounce　actions, but the　Sequence　or　Spawn　actions might have unexpected results.

Available since v0.8.2

Available bounce actions:

EaseBounceIn

EaseBounceOut

EaseBounceInOut

Examples:

//　Bounce　at　the　beginning
　 id　move　=　[MoveBy　actionWithDuration:3　position:ccp(350,0)];
　 id　action　=　[EaseBounceIn　actionWithAction:move];
　 [sprite　runAction:　action];

　 //　Bounce　at　the　end
　 id　move　=　[MoveBy　actionWithDuration:3　position:ccp(350,0)];
　 id　action　=　[EaseBounceOut　actionWithAction:move];
　 [sprite　runAction:　action];

　 //　Bounce　at　the　beginning　and　at　the　end
　 id　move　=　[MoveBy　actionWithDuration:3　position:ccp(350,0)];
　 id　action　=　[EaseBounceInOut　actionWithAction:move];
　 [sprite　runAction:　action];

EaseBack actions

Some　time　values will be triggered more than once (this function is not bijective), so the　inner　action should be prepared to handle this values. Simple actions like　MoveBy,　ScaleBy,　RotateBy　work OK with　EaseBack　actions, but the　Sequence　or　Spawn　actions might have unexpected results.

Available since v0.8.2

Available bounce actions:

EaseBackIn

EaseBackOut

EaseBackInOut

Examples:

//　Back　at　the　beginning
　 id　move　=　[MoveBy　actionWithDuration:3　position:ccp(350,0)];
　 id　action　=　[EaseBackIn　actionWithAction:move];
　 [sprite　runAction:　action];

　 //　Back　at　the　end
　 id　move　=　[MoveBy　actionWithDuration:3　position:ccp(350,0)];
　 id　action　=　[EaseBackOut　actionWithAction:move];
　 [sprite　runAction:　action];

　 //　Back　at　the　beginning　and　at　the　end
　 id　move　=　[MoveBy　actionWithDuration:3　position:ccp(350,0)];
　 id　action　=　[EaseBackInOut　actionWithAction:move];
　 [sprite　runAction:　action];

Actions: Speed

Speed action

The　Speed　action modifies the duration of the inner action.

id　move　=　[MoveBy　actionWithDuration:3　position:ccp(350,0)];
　 id　action　=　[Speed　actionWithAction:　move　speed:1.0f];　　　//　no　speed　modification

　 //　but　you　can　modify　the　speed　later
　 [action　setSpeed:　2.5f];　//　speed　is　2.5　faster

　 [action　setSpeed:　0.5f];　//　speed　is　0.5　faster　(it　means　2　times　slower)

出處：http://alexliu.cnblogs.com/