捏（縮放）手勢不正確縮放

Question

我試圖找出爲什麼我的縮放在我的OpenGL相機上表現得非常奇怪。 它的目的是放大和縮小，但其縮放非常隨機。

繼承人我的代碼：

- (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

如果你有什麼事情，是乘法，你想讓它添加劑，你需要採取日誌：

- (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; 
    } 
}