更改Sprite Anchorpoint而不移動它？

Question

我正在嘗試更改我的Sprite錨點，以便旋轉0.0f，0.0f的錨點。起初，我的對象是在默認錨點（0.5f，0.5f）的旋轉。不過後來我需要它旋轉0.0,0.0 AnchorPoint。

問題是我無法更改錨點並相應地更改位置，因此它保持在相同的位置，而不顯示對象快速移動並重新定位到其原始點。

有沒有一種方法可以一次設置我的Sprite的錨點和位置，而不會移動它？謝謝。

-Oscar

Answer 1

這是一個很好的問題，我不知道全部答案。

正如您可能已經注意到的那樣，在不影響比例和旋轉的情況下，不能更改anchorPoint。

調整後的精靈：

你必須同時改變anchorPoint和你的精靈的位置。見this question for a hint

對於旋轉精靈：

直覺說，你需要同時改變anchorPoint，旋轉和位置。 （我不知道如何計算這一點。）

注：我還在學習圖形編程，所以我不是100％能夠計算這個東西呢。

Answer 2

我找到了解決這個與一個UIView其他地方，並改寫了它的cocos2d：

- (void)setAnchorPoint:(CGPoint)anchorPoint forSprite:(CCSprite *)sprite 
{ 
    CGPoint newPoint = CGPointMake(sprite.contentSize.width * anchorPoint.x, sprite.contentSize.height * anchorPoint.y); 
    CGPoint oldPoint = CGPointMake(sprite.contentSize.width * sprite.anchorPoint.x, sprite.contentSize.height * sprite.anchorPoint.y); 

    newPoint = CGPointApplyAffineTransform(newPoint, [sprite nodeToWorldTransform]); 
    oldPoint = CGPointApplyAffineTransform(oldPoint, [sprite nodeToWorldTransform]); 

    CGPoint position = sprite.position; 

    position.x -= oldPoint.x; 
    position.x += newPoint.x; 

    position.y -= oldPoint.y; 
    position.y += newPoint.y; 

    sprite.position = position; 
    sprite.anchorPoint = anchorPoint; 
} 

Answer 3

我需要這幾次並決定爲CCNode一個擴展，測試了升技和似乎工作正常。可以真的有用:)

它用1.x測試，但它應該在2.x也很好。支持轉換節點和HD。

只需將其添加到您的項目並在需要時隨時導入 - 它將被添加到從CCNode派生的所有類中。 （CCSprite，CCLayer）

接口

#import "cocos2d.h" 

@interface CCNode (Extensions) 

// Returns the parent coordinate for an anchorpoint. Useful for aligning nodes with different anchorpoints for instance 
-(CGPoint)positionOfAnchorPoint:(CGPoint)anchor; 

// As above but using anchorpoint in points rather than percentage 
-(CGPoint)positionOfAnchorPointInPoints:(CGPoint)anchor; 

//Sets the anchorpoint, to not move the node set lockPosition to `YES`. Setting it to `NO` is equal to setAnchorPoint, I thought this would be good for readability so you always know what you do when you move the anchorpoint 
-(void)setAnchorPoint:(CGPoint)a lockPosition:(BOOL)lockPosition; 

@end 

實施

#import "CCNode+AnchorPos.h" 

@implementation CCNode (Extensions) 

-(CGPoint)positionOfAnchorPoint:(CGPoint)anchor 
{ 
    float x = anchor.x * self.contentSizeInPixels.width; 
    float y = anchor.y * self.contentSizeInPixels.height; 

    CGPoint pos = ccp(x,y); 

    pos = CGPointApplyAffineTransform(pos, [self nodeToParentTransform]); 

    return ccpMult(pos, 1/CC_CONTENT_SCALE_FACTOR()); 
} 

-(CGPoint)positionOfAnchorPointInPoints:(CGPoint)anchor; 
{ 
    CGPoint anchorPointInPercent = ccp(anchor.x/self.contentSize.width, anchor.y/self.contentSize.height); 
    return [self positionOfAnchorPoint:anchorPointInPercent]; 
} 

-(void)setAnchorPoint:(CGPoint)a lockPosition:(BOOL)lockPosition 
{ 
    CGPoint tempPos = [self positionOfAnchorPoint:a]; 
    self.anchorPoint = a; 

    if(lockPosition) 
    { 
     self.position = tempPos; 
    } 
} 

@end 

Answer 4

的Cocos2D-X +固定規模

YourClass.h

virtual cocos2d::Vec2 positionFromSprite(cocos2d::Vec2 newAnchorPoint, cocos2d::Sprite *sprite); 

YourClass。m

Vec2 YourClass::positionFromSprite(Vec2 newAnchorPoint, cocos2d::Sprite *sprite) { 
    Rect rect = sprite->getSpriteFrame()->getRect(); 
    Vec2 oldAnchorPoint = sprite->getAnchorPoint(); 
    float scaleX = sprite->getScaleX(); 
    float scaleY = sprite->getScaleY(); 

    Vec2 newPoint = Vec2(rect.size.width * newAnchorPoint.x * scaleX, rect.size.height * newAnchorPoint.y * scaleY); 
    Vec2 oldPoint = Vec2(rect.size.width * oldAnchorPoint.x * scaleX, rect.size.height * oldAnchorPoint.y * scaleY); 

    Vec2 position = sprite->getPosition(); 

    position.x -= oldPoint.x; 
    position.x += newPoint.x; 

    position.y -= oldPoint.y; 
    position.y += newPoint.y; 

    return position; 
}