我正在使用以下几行旋转 SCNNode:

 let rotate = SCNAction.rotateByAngle(CGFloat(M_PI), aroundAxis:SCNVector3Make(0, 1, 0), duration: NSTimeInterval(10.0))
    let repeat = SCNAction.repeatActionForever(rotate)
    node.runAction(repeat)

我在渲染方法中打印节点的 eulerAngles.y:
let rad = Double(node.eulerAngles.y)
var angleInDegrees = fmodf(360.0 + -Float(rad) * (180.0 / Float(M_PI)), 360.0)
println("eulerAngles.y rad:\(rad) degree:\(angleInDegrees)")

但我在旋转过程中得到奇怪的值,如下所示:
...
eulerAngles.y rad:-1.38788688182831 degree:79.5201
eulerAngles.y rad:-1.40567290782928 degree:80.5391
eulerAngles.y rad:-1.4227991104126 degree:81.5204
eulerAngles.y rad:-1.44030773639679 degree:82.5236
eulerAngles.y rad:-1.45790004730225 degree:83.5315
eulerAngles.y rad:-1.47438871860504 degree:84.4763
eulerAngles.y rad:-1.49130213260651 degree:85.4453
eulerAngles.y rad:1.57079637050629 degree:270.0
eulerAngles.y rad:1.57079637050629 degree:270.0
eulerAngles.y rad:1.57079637050629 degree:270.0
eulerAngles.y rad:1.57079637050629 degree:270.0
eulerAngles.y rad:1.57079637050629 degree:270.0
eulerAngles.y rad:1.57079637050629 degree:270.0
eulerAngles.y rad:1.57079637050629 degree:270.0
eulerAngles.y rad:1.57079637050629 degree:270.0
eulerAngles.y rad:-1.49359321594238 degree:85.5766
eulerAngles.y rad:-1.47716772556305 degree:84.6355
...

我不明白为什么要打印 270。你能解释我或者有另一种方式吗
获得正确的节点角度?

最佳答案

这就是欧拉角的工作原理。他们有两个怪癖(我将 xyz 分别称为 pitchyawroll ):

  • rollyaw从0逆时针旋转增加到π(180度)然后跳到-π(-180度),随着旋转完成一圈继续增加到0;但是 pitch 增加到 π/2(90 度)然后减少到 0,然后减少到 -π/2(-90 度)并增加到 0。
  • 值在某些方向上变得不准确。特别是当pitch为±90度时,rollyaw变得不稳定。请参阅 wikipedia article on gimbal lock
  • 关于swift - SceneKit euler 旋转期间角度奇怪的值,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/32126632/

    10-12 14:43
    查看更多