如何使用光线投射检测我在屏幕上看到的对象？

Question

所以，我想检查一下我是否在屏幕上看到了一个对象。当然是使用光线投射。

代码：

private void SeeObject(){
  ISeeObj = false;
  if (Vector3.Dot(cam.transform.forward, (cam.transform.position - obj.transform.position).normalized) < -0.65f){
    RaycastHit hit;
    if (Physics.Raycast(cam.transform.position, (obj.transform.position - cam.transform.position).normalized, out hit, range, layerMask)){
      if (hit.transform.name == obj.name){
        ISeeObj = true;
        Debug.Log("I see an Object");
      }
    }
  }
}

我也试过使用

if (Vector3.Dot(cam.transform.forward,
(cam.transform.position - obj.transform.position).normalized) > 0 )

但是没用。

Answer 1

我建议不要为此使用Raycast。

MonoBehaviour 已经实现了两个方法 OnBecameVisible

OnBecameVisible is called when the renderer became visible by any camera.

This message is sent to all scripts attached to the renderer.

和

OnBecameInvisible

OnBecameInvisible is called when the renderer is no longer visible by any camera.

This message is sent to all scripts attached to the renderer.

(两者也可以是协程)

因此，如果您需要不断检查某个对象当前是否可见，请附加一个组件，例如

public class VisibilityChecker : MonoBehaviour
{
    // E.g. using a read-only auto-property
    public bool IsVisible{ get; private set; }

    // If you rather like to be able to also see the value in the Inspector for debugging use
    //public bool IsVisible { get { return _isVisible;}}
    //[SerializeField] private bool _isVisible;

    private void OnBecameVisible()
    {
        IsVisible = true;

        //or
        //_isVisible = true;
    }

    private void OnBecameInvisible()
    {
        IsVisible = false;

        //or
        //_isVisible = false;
    }
}

并且在另一个脚本中，例如在Update中检查它喜欢

private VisibilityChecker objVisibilityChecker;

private void Awake()
{
    objVisibilityChecker = obj.GetComponent<VisibilityChecker>();
}

private void Update()
{
    if(objVisibilityChecker.IsVisible)
    {
        // Do something
    }
    else
    {
        // Do another thing
    }
}

如何使用光线投射检测我在屏幕上看到的对象？

How can I detect an object that I see on screen using Raycasting?

c#

unity3d

raycasting