即使是真的，如果声明也不会起作用[重复]

Question

当 play.x 的值肯定是 1 或 -1 时，为什么不读取 if 语句？

如果您还有什么需要知道的，任何帮助都将非常感谢，我会尽力解释。

public class WhyDosntThisWork : MonoBehaviour
{
    public bool North = false;
    public bool South = false;
    public bool West = false;
    public bool East = false;
    public bool jimmy = false;
    public float x = 0;
    public float y = 0;
    public bool IsRotating = false;
    public Vector3 Player;
    public float if0trueifnotfalse = 0;

    void Start()
    {
        //Player = transform.up;// tryed here aswell still no work
    }

    void Update()
    {
        Player = transform.up;
        y = Input.GetAxisRaw("Vertical");// press arrowkey 
        x = Input.GetAxisRaw("Horizontal");// press arrowkey 
        print(" y =  " + y);
        print(" x =  " + x);
        if (y == 0)
        {
            WereAreWeLooking();// run function  should work???
            print("we are Running the Script");
        }
        if (y > 0)
        {
            print("We Presed up player.x is now 1");
            transform.eulerAngles = new Vector3(0,0,-90); // this changes player.x from -1 to 1
        }
        if (y < 0)
        {
            print("We Presed down player.x is now -1");
           // WereAreWeLooking();
            transform.eulerAngles = new Vector3(0,0,90); //this changes player.x from 1 to -1

        }
    }

    void WereAreWeLooking()
    {
        print("HI we are checking for bools Player.x  IS " + Player.x + " so why dont we change the bool");
        if (Player.x == -1)// this never runs even tho play.x is -1
        {   
            print("We Are GoingUp");
            North = true;
            South = false;
            East = false;
            West = false;
        }
        else if (Player.x == 1)
        {
            print("We Are GoingDown");
            South = true;
            North = false;
            East = false;
            West = false;
        }
        else if (Player.z == 1)
        {
            print("We Are going East");
            East = true;
            South = false;
            North = false;
            West = false;
        }
        else if (Player.z == -1)
        {
            print("We Aregoing west");
            West = true;
            East = false;
            South = false;
            North = false;
        }
        print("Thanks Checking done");
        jimmy = true;

        if (if0trueifnotfalse == 1)// this works if i change the value in the inspector
        {
            jimmy = false;
            print("jimmy is 1");
        }
    }
}

Answer 1

您正在通过相等运算符比较浮点数。

如果该值是计算出来的，那么该值很可能不会正好是 1 或 -1。它将是 1.0000000001 或 0.9999999999（例如）。

这意味着你的测试是这样的：

if (Player.x == -1)

总会失败。

您需要在测试中引入舍入：

if (Player.x + 1 < 10e-6)

这将检查Player.x 是否等于-1 到6 位小数，因此-0.999999 和-1.000001 将通过测试。您可能需要调整 epsilon 值以获得稳定的数据解决方案。

当您使用 Unity 时，您可以使用它们的内置功能 Mathf.Approximately:

if (Mathf.Approximately(Player.x, -1.0f))

即使您使用double，您仍然会得到这些舍入误差 - 尽管减少了很多。可能是您用来检查值的任何东西都在执行一些舍入，所以看起来值是 -1 或 1。