SKSpriteNode旋轉不正常

Question

我想通過使用UIRrotationGestureRecognizer旋轉SKSpriteNode。我已經實現了一個代碼，但有時候，當我旋轉節點時，它跳轉到一個不是它應該是的那個旋轉。在這裏，你有代碼：

- (void) handleRotation:(UIRotationGestureRecognizer *) rotationrecognizer{ 

    CGFloat initialrotation = 0.0; 

    if (rotationrecognizer.state == UIGestureRecognizerStateBegan) { 

     CGPoint touchLocation = [rotationrecognizer locationInView:rotationrecognizer.view]; 
     touchLocation = [self convertPointFromView:touchLocation]; 
     [self selectNodeForTouch:touchLocation]; 

     initialrotation = selected.zRotation; 
    } 

    else if (rotationrecognizer.state == UIGestureRecognizerStateChanged) {   

     CGFloat angle = initialrotation + rotationrecognizer.rotation; 
     selected.zRotation = angle;  

    } 
} 

Answer 1

您在每次調用重置初始旋轉0 ...你應該，如果你需要它駐留移動這是您的觀點的伊娃。

你現在寫的方式，即設置「角度」的線是有效等於這個：

CGFloat angle = 0 + rotationrecognizer.rotation; 

相反，你應該做到以下（其中initialRotation初始定義爲私人伊娃）：

- (void) handleRotation:(UIRotationGestureRecognizer *) rotationrecognizer{ 

    if (rotationrecognizer.state == UIGestureRecognizerStateBegan) { 

     CGPoint touchLocation = [rotationrecognizer locationInView:rotationrecognizer.view]; 
     touchLocation = [self convertPointFromView:touchLocation]; 
     [self selectNodeForTouch:touchLocation]; 

     _initialrotation = selected.zRotation; 
    } 

    else if (rotationrecognizer.state == UIGestureRecognizerStateChanged) {   

     CGFloat angle = _initialrotation + rotationrecognizer.rotation; 
     selected.zRotation = angle;  

    } 
}