用手指在Cocos2d中旋转精灵

问题描述：

我需要帮助确定用手指旋转精灵。精灵旋转得很好，但是在初始触摸我的手指时，它本身以某种方式旋转了几度。用手指在Cocos2d中旋转精灵

此外，旋转仅在手指围绕精灵中心旋转时才起作用。

我试图模拟自行车车轮，并有一个齿轮精灵和一个踏板精灵作为齿轮精灵的孩子。当我触碰踏板并旋转它时，我想让自行车轮旋转。我还没有那么远。现在我正试图弄清楚如何摆脱这种装备的初始转变。

下面是完整的代码

#import "BicycleScene.h" 

@implementation BicycleScene 

+(id) scene 
{ 
    // 'scene' is an autorelease object. 
    CCScene *scene = [CCScene node]; 

    // 'layer' is an autorelease object. 
    BicycleScene *layer = [BicycleScene node]; 

    // add layer as a child to scene 
    [scene addChild: layer]; 

    // return the scene 
    return scene; 
} 

-(id) init 
{ 
    if ((self=[super init])) { 

     CGSize winSize = [[CCDirector sharedDirector] winSize]; 

     //place the bicycle sprite 
     bicycleSprite = [CCSprite spriteWithFile:@"bike_gear.png"]; 
     bicycleSprite.position = ccp(bicycleSprite.contentSize.width/2 + 100, winSize.height/2); 
     [self addChild:bicycleSprite z:1]; 

     //place the pedal sprite 
     pedalSprite = [CCSprite spriteWithFile:@"bike_pedal.png"]; 
     [bicycleSprite addChild:pedalSprite z:1]; 

     pedalSprite.position = ccp(150, 15); 

     //enable touch 
     self.isTouchEnabled = YES; 

     [self schedule:@selector(gameLoop:) interval:.1/100]; 

    } 

    return self; 
} 

-(void) ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{ 

    NSLog(@"Touch begun"); 

} 

-(void)gameLoop:(ccTime) dt{ 

    bicycleSprite.rotation = cocosAngle; 
} 

-(void) ccTouchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{ 

    NSLog(@"Touch moved"); 

    UITouch *touch = [touches anyObject]; 
    CGPoint location = [touch locationInView:[touch view]]; 
    CGPoint previousLocation = [touch previousLocationInView:[touch view]]; 

    CGPoint touchingPoint = [[CCDirector sharedDirector] convertToGL:location]; 
    CGPoint previousTouchingPoint = [[CCDirector sharedDirector] convertToGL:previousLocation]; 

    CGPoint vector = ccpSub(touchingPoint, bicycleSprite.position); 
    CGFloat rotateAngle = -ccpToAngle(vector); 

    previousAngle = cocosAngle; 
    cocosAngle = CC_RADIANS_TO_DEGREES(rotateAngle); 

    //bicycleSprite.rotation = cocosAngle; 
} 

@end

我稍微感到困惑，如果行：

CGPoint vector = ccpSub(touchingPoint, bicycleSprite.position);

实际上应该是：

CGPoint vector = ccpSub(touchingPoint, previousTouchingPoint);

我试过，很好，但它没没有工作。

我还上传了我的完整xcodeproj到4shared的人谁愿意到这里看看：http://www.4shared.com/file/5BaeW4oe/Healthy.html

当您使用previousTouchingPoint而不是bicycleSprite.position时会发生什么？同样的行为？没有？ – lins314159 2011-03-15 07:25:25

当我使用previousTouchingPoint而不是bicycleSprite.position时，齿轮也会跳跃很多，并且齿轮缓慢旋转时也会出现很多闪烁现象。 – tbag 2011-03-15 15:43:53

我刚刚测试了上面的代码，它完成了我期望的操作。问题是touchBegan没有移到正确的角度？或者它在初始移动时跳跃而不是逐渐移动到一个角度？ – lins314159 2011-03-16 08:40:13

答

@interface MainScene : CCLayer { 
    CCSprite *dial; 

    CGFloat dialRotation; 

} 

+ (id)scene; 

@end 
--------------------------------- 
@implementation MainScene 

+ (id)scene 
{ 
    CCScene *scene = [CCScene node]; 
    CCLayer *layer = [MainScene node]; 
    [scene addChild:layer]; 

    return scene; 
} 

- (id)init 
{ 
    if((self = [super init])) { 
     CCLOG(@"MainScene init"); 

     CGSize size = [[CCDirector sharedDirector]winSize]; 

     dial = [CCSprite spriteWithFile:@"dial.png"]; 
     dial.position = ccp(size.width/2,dial.contentSize.height/2); 
      [self addChild:dial]; 

     self.isTouchEnabled = YES; 
     [self scheduleUpdate]; 

    } 
    return self; 
} 

- (void)dealloc 
{ 
    [super dealloc]; 
} 

- (void)update:(ccTime)delta 
{ 
    dial.rotation = dialRotation; 
} 

- (void)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event 
{ 

} 

- (void)ccTouchesMoved:(NSSet *)touches withEvent:(UIEvent *)event 
{ 
    UITouch *touch = [touches anyObject]; 

    //acquire the previous touch location 
    CGPoint firstLocation = [touch previousLocationInView:[touch view]]; 
    CGPoint location = [touch locationInView:[touch view]]; 

    //preform all the same basic rig on both the current touch and previous touch 
    CGPoint touchingPoint = [[CCDirector sharedDirector] convertToGL:location]; 
    CGPoint firstTouchingPoint = [[CCDirector sharedDirector] convertToGL:firstLocation]; 

    CGPoint firstVector = ccpSub(firstTouchingPoint, dial.position); 
    CGFloat firstRotateAngle = -ccpToAngle(firstVector); 
    CGFloat previousTouch = CC_RADIANS_TO_DEGREES(firstRotateAngle); 

    CGPoint vector = ccpSub(touchingPoint, dial.position); 
     CGFloat rotateAngle = -ccpToAngle(vector); 
    CGFloat currentTouch = CC_RADIANS_TO_DEGREES(rotateAngle); 

    //keep adding the difference of the two angles to the dial rotation 
    dialRotation += currentTouch - previousTouch; 
} 

- (void)ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event 
{ 

}

编辑：我很抱歉，我不能让这个留在代码模式。但这是解决方案，应该很容易在代码中实现。干杯！

要将文本格式设置为代码，请选择所需文本，然后单击带花括号的按钮。 – lins314159 2011-03-28 22:03:40

不错 - 谢谢 – Chev 2011-07-06 10:42:06

答

在ccTouchesBegan，使用相同的代码，你在ccTouchesMoved已经得到了确定角度，然后移动使用CCRotateTo到那个角度。您需要一些处理用户移动他的手指，而CCRotateTo处于活动状态，可能会停止当前操作并踢开另一个移动到新角度。

用手指在Cocos2d中旋转精灵

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