使用旋转触摸精灵数据

问题描述：

所以我有一个精灵节点，我想通过跟踪用户的触摸旋转它... 这是我做过什么：使用旋转触摸精灵数据

- (void)calculateAngleAndRotateSelectedCellForThouchPoint:(CGPoint)tPoint withDuration:(NSTimeInterval) duration 
{ 
    CGPoint cellPoint = self.currentlySelectedCell.position; 
    // math here 
    if (!CGPointEqualToPoint(tPoint, previousTouchPoint)) { 
     float rotationAngle = radiansFromSlope(slopeDifference(cellPoint, tPoint, cellPoint, previousTouchPoint)); 
     SKAction *rotateForAimingAction = [SKAction rotateByAngle:rotationAngle duration:duration]; 
     [self.currentlySelectedPlayer runAction:rotateForAimingAction]; 
    } 
} 

    #pragma mark - Trigonometric calculations (C functions) 

    static inline float slopeBetweenPoints(CGPoint p1, CGPoint p2) 
    { 
     return ((p2.y-p1.y)/(p2.x-p1.x)); 
    } 

    static inline float slopeDifference(CGPoint pl1_1, CGPoint pl1_2, CGPoint pl2_1, CGPoint pl2_2) 
    { 
     return (slopeBetweenPoints(pl1_1, pl1_2) - slopeBetweenPoints(pl2_1, pl2_2)); 
    } 

    static inline float radiansFromSlope(float slope) 
    { 
     return atanf(slope); 
    } 

    - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event 
    { 
     touchStartTime = event.timestamp; 
     crtIntervalPrev = event.timestamp; 
    } 

    - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event 
    { 
     NSTimeInterval crtThouchDuration = event.timestamp - touchStartTime; 

     if (crtThouchDuration > TAP_TIMEOUT) { 
      /// rotate the selected player sprite 
      currentTouchPoint = [[touches anyObject] locationInView:self.view]; 
      NSTimeInterval time_delta = event.timestamp - crtIntervalPrev; 
      [self calculateAngleAndRotateSelectedCellForThouchPoint:currentTouchPoint withDuration:time_delta]; 
      crtIntervalPrev = event.timestamp; 
     } 
     } 

     - (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event 
     { 
      [self resetTouchTimes]; 
      [self resetTouchPoints]; 
      [self deselectAllCells]; 
     } 

     - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event 
     { 
      touchEndTime = event.timestamp; 
      NSTimeInterval touchDuration = touchEndTime - touchStartTime; 

      if (touchDuration < TAP_TIMEOUT) { 
       // it's a tap ... so deselect the selected cell 
       [self deselectAllCells]; 
      } 
      [self resetTouchPoints]; 
      [self resetTouchTimes]; 
     }

这是旋转的，但方式太快...任何线索为什么？

对于题外话题很抱歉，但是当p2.x == p1.x'时'slopeBetweenPoints（CGPoint p1，CGPoint p2）'中的0问题除外。 – RaffAl

是的，这是真的......谢谢指出。 – user1028028

你是否尝试过增加持续时间，比如说2 *持续时间 – santhu

答

我认为问题出在calculateAngleAndRotateSelectedCellForThouchPoint方法中。而不是运行动作，只分配旋转角度。

- (void)calculateAngleAndRotateSelectedCellForThouchPoint:(CGPoint)tPoint withDuration:(NSTimeInterval) duration 
{ 
    CGPoint cellPoint = self.currentlySelectedCell.position; 
    // math here 
    if (!CGPointEqualToPoint(tPoint, previousTouchPoint)) { 
     float rotationAngle = radiansFromSlope(slopeDifference(cellPoint, tPoint, cellPoint, previousTouchPoint)); 

     self.currentlySelectedPlayer.zRotation = rotationAngle; 
    } 
}

仍然无法正常工作，但效果会好很多。我在某个时间点轮换跳跃......可能是有人注意到的零点划分 – user1028028

答

基于一些答案，我发现在这里（在这个问题上的边栏）解决办法：

- (void)calculateAngleAndRotateSelectedCellForThouchPoint:(CGPoint)tPoint 
{ 
    CGPoint cellPoint = self.currentlySelectedCell.position; 
    // math here 
    if (!CGPointEqualToPoint(tPoint, previousTouchPoint)) { 

     float dy = cellPoint.y - tPoint.y; 
     float dx = cellPoint.x - tPoint.x; 

      self.currentlySelectedCell.zRotation = - (atan2(dy,dx) - DEGREES_TO_RADIANS(90)); 
    } 
}

这比我想象的简单。

使用旋转触摸精灵数据

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