Ios 使用平移手势上下左右旋转相机

我想上下左右旋转相机来观察对象（360度视图），使用opengl lookat功能进行平移手势，我使用swift和Metal（在本例中Metal=opengl es）。代码如下：

lookat功能（该功能位于另一个ViewController中，该ViewController继承自具有viewDidLoad和pan手势功能的主ViewController）：

viewDidLoad和var：

 var ktarget = V3f()
 var up = V3f()
 let location =V3f()

override func viewDidLoad() {
        super.viewDidLoad()        
        location = V3f(0.0, 0.0, -2.0)
        ktarget = V3f(0.0, 0.0, 0.0)
        up = V3f(0.0, 1.0, 0.0)
}

平移手势：

    func pan(panGesture: UIPanGestureRecognizer){
       up = V3f(0.0, 1.0, 0.0).Normalized()
       forward = (ktarget + -location).Normalized()
       right = Cross(forward, b: up).Normalized()

            if panGesture.state == UIGestureRecognizerState.Changed{  
               let pointInView = panGesture.locationInView(self.view)
               let xDelta = (lastPanLocation.x - pointInView.x)/self.view.bounds.width * panSensivity
               let yDelta = (lastPanLocation.y - pointInView.y)/self.view.bounds.height * panSensivity
            //        To rotate left or right, rotate the forward around up and then use a cross product between forward and up to get the right vector.
               forward = rotationM3f(up, angle: Float(xDelta)) * forward.Normalized()
               right = Cross(forward, b: up).Normalized()
            //        To rotate up or down, rotate forward vector around right vector and use a cross product between the right and forward to get the new up vector.
               forward = rotationM3f(right, angle: Float(yDelta)) * forward.Normalized()
               up = V3f(0.0, 1.0, 0.0).Normalized()
               ktarget = location + forward
               lastPanLocation = pointInView
            } else if panGesture.state == UIGestureRecognizerState.Began {
               ktarget = location + forward
               lastPanLocation = panGesture.locationInView(self.view)
            }
        }

---

但是平移相机，我设置上方向向量总是=（0,1,0），使人们只能垂直看到180度。如果用户在相机上下查看（最大值）时仍进行平移，屏幕将翻转，目标的实际值x和z将在每帧中一点一点地改变（非常小的数值，例如0.0000somenumber），因此绘制功能将在每帧中绘制差异非常小的对象。有人知道如何修理翻转吗？谢谢~~~

这不是问题所在，但是：永远不要规范化位置，只有基向量。当您调用“normalized”方法时，很可能是a=a.normalized（）或者没有可见的结果。此时您的结果是什么？我希望闪烁，因为我相信它应该是向上=交叉（右，向前），而不是交叉（向前，右）？无论如何，如果这是正确的，那么我看到结果（0,0,0）的唯一方式是因为没有对基向量进行归一化。嗯…当我平移时，对象将消失@请输入一个断点，查看哪些向量发生了剧烈的变化，以及您现在发布的值太大了。可能是溢油？将这些向量规格化为up=Cross（a，b）

    func pan(panGesture: UIPanGestureRecognizer){
       up = V3f(0.0, 1.0, 0.0).Normalized()
       forward = (ktarget + -location).Normalized()
       right = Cross(forward, b: up).Normalized()

            if panGesture.state == UIGestureRecognizerState.Changed{  
               let pointInView = panGesture.locationInView(self.view)
               let xDelta = (lastPanLocation.x - pointInView.x)/self.view.bounds.width * panSensivity
               let yDelta = (lastPanLocation.y - pointInView.y)/self.view.bounds.height * panSensivity
            //        To rotate left or right, rotate the forward around up and then use a cross product between forward and up to get the right vector.
               forward = rotationM3f(up, angle: Float(xDelta)) * forward.Normalized()
               right = Cross(forward, b: up).Normalized()
            //        To rotate up or down, rotate forward vector around right vector and use a cross product between the right and forward to get the new up vector.
               forward = rotationM3f(right, angle: Float(yDelta)) * forward.Normalized()
               up = V3f(0.0, 1.0, 0.0).Normalized()
               ktarget = location + forward
               lastPanLocation = pointInView
            } else if panGesture.state == UIGestureRecognizerState.Began {
               ktarget = location + forward
               lastPanLocation = panGesture.locationInView(self.view)
            }
        }