z-axis-rotation 的调试不是 0，而在检查器中它是 0 [英] Debug of z-axis-rotation is not 0, while in inspector it is 0

问题描述

在检查器中，我的变换的 z 轴旋转为 0.

In the inspector the z-axis rotation of my transform is 0.

但是当我使用这些代码行调试它时:

But when i debug this using these lines of code:

Debug.Log("local-Euler-z: " + transform.localEulerAngles.z);
Debug.Log("global-Euler-z: " + transform.eulerAngles.z);
Debug.Log("local-rot-z: " + transform.localRotation.z);
Debug.Log("global-rot-z: " + transform.rotation.z);

你可以在我的截图中看到我没有得到 0 作为值.

you can see in my screenshot that i don't get 0 as value.

推荐答案

首先，您获得的价值确实很小.xE+/-y 是一个 指数浮点数字表示.

First of all, values you're getting are really small. xE+/-y is an exponential floating point number representation.

所以实际上你有这样的东西:6.349661E-05 == 0.00006349661，它非常接近实际的零.

So in reality you have something like this: 6.349661E-05 == 0.00006349661 which is quite close to actual zero.

这个问题来自浮点数精度，因为在编程中浮点数实际上有 2 个零 (-0 & +0) - 这就是事情的工作原理.如果您想阅读有关浮点数的内容，我不想让这个答案超载 - 上面的链接是一个很好的起点.

This problem comes from float numbers precision and because there's actually 2 zeros (-0 & +0) for float numbers in programming - that's just how things work. I don't want to overload this answer, if you want to read something about floats - the link above is a good starting point.

由于这个 float 数字的问题，相同的数字可以用接近但仍然不同的 float 类型表示来表示.float->int 对于您想要比较的情况并不是很好，比如说，非整数度，而且您不能像这样比较 Quaternion 数字 -它的组件 (x, y, z, w) 的值介于 0 和 1 之间.要解决这个问题，您要么需要手动比较"浮点数与机器零，这对新手来说有点复杂，另一个解决方案是使用 Mathf.Approximately 来自 UnityAPI.

Because of this float numbers' problem same number can be represented by close but still different float type representation. float->int is not really good for cases where you want to compare, let's say, non-int degrees, plus you can't compare Quaternion numbers like that - its components (x, y, z, w) have values between 0 and 1. To solve this problem you either need to manualy "compare" floats with machine zero which is kinda complicated for a novice, another solution is to use Mathf.Approximately from Unity API.

顺便说一下，变换检查器会显示纯零，因为它只是丢弃了旋转向量的这些不影响数字.

By the way, transform inspector shows you pure zero because it just discards such non-affecting digits of the rotation vector.

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