如何从hit.normal中找到对撞机的哪一侧？

Question

在 Unity3d 中，我可以使用 hit.normal 获取对撞机碰撞的表面的法线，但是有没有办法找到哪一面被击中了 Unity3d 提供的东西？

一种解决方案是查看法线的方向，对于静态对象应该很好，但是对于方向发生变化的动态和移动对象呢？

Answer 1

function OnCollisionEnter(collision : Collision)
{
    var relativePosition = transform.InverseTransformPoint(collision.contacts);

    if(relativePosition.x > 0) 
    {
        print(“The object is to the right”);
    } 
    else 
    {
        print(“The object is to the left”);
    }

    if(relativePosition.y > 0) 
    {
        print(“The object is above.”);
    } 
    else 
    {
        print(“The object is below.”);
    }

    if(relativePosition.z > 0) 
    {
        print(“The object is in front.”);
    } 
    else 
    {
        print(“The object is behind.”);
    }
}

Answer 2

void OnCollisionEnter(Collision collision)
{            
    Vector3 dir = (collision.gameObject.transform.position - gameObject.transform.position).normalized;

    if(Mathf.Abs(dir.z) < 0.05f)
    {
        if (dir.x > 0)
        {
            print ("RIGHT");    
        }
        else if (dir.x < 0)
        {
            print ("LEFT");             
        }
    }
    else
    {
        if(dir.z > 0)
        {
            print ("FRONT");
        }
        else if(dir.z < 0)
        {
            print ("BACK");
        }
    }
}

Answer 3

这行得通：

function OnCollisionEnter(collision: Collision) {
    var relativePosition = transform.InverseTransformPoint(collision.transform.position);

    if (relativePosition.x > 0) 
    {
        print ("The object is to the right");
    }
    else 
    {
        print ("The object is to the left");
    }

    if (relativePosition.y > 0) 
    {
        print ("The object is above.");
    } 
    else 
    {
        print ("The object is below.");
    }

    if (relativePosition.z > 0) {
        print ("The object is in front.");
    }
    else 
    {
        print ("The object is behind.");
    }
}