捏（缩放）手势不正确缩放

Question

我试图找出为什么我的缩放在我的OpenGL相机上表现得非常奇怪。 它的目的是放大和缩小，但其缩放非常随机。

继承人我的代码：

- (void)pinchDetected:(UIPinchGestureRecognizer *)pinchRecognizer 
{ 
    NSLog (@"%@", @"Pinching"); 

    if (pinchRecognizer.state == UIGestureRecognizerStateBegan || 
       pinchRecognizer.state == UIGestureRecognizerStateChanged || 
       pinchRecognizer.state == UIGestureRecognizerStateEnded) { 
     currentScale = pinchRecognizer.scale; 
    } 

    if(lastScale < currentScale) { 
     _camera.z += currentScale * 0.01f; 
     lastScale = currentScale; 
    } 

    if (lastScale > currentScale) 
    { 
     _camera.z -= currentScale * 0.01f; 
     lastScale = currentScale; 
    } 

} 

Answer 1

如果你有什么事情，是乘法，你想让它添加剂，你需要采取日志：

- (void)pinchDetected:(UIPinchGestureRecognizer *)pinchRecognizer 
{ 
    if ((gesture.state == UIGestureRecognizerStateBegan) || 
     (gesture.state == UIGestureRecognizerStateChanged) || 
     (gesture.state == UIGestureRecognizerStateEnded)) { 
     _camera.z += log(gesture.scale); // you'll probably want to multiply this by some constant 
     gesture.scale = 1.0; 
    } 
}