Camera.ViewportPointToRay

Description

Возвращает луч, идущий от камеры через точку окна просмотра.

Resulting ray is in world space, starting on the near plane of the camera and going through position's (x,y) coordinates on the viewport (position.z is ignored).

Пространство окна просмотра нормализовано и взаимосвязано с камерой. Левая нижняя часть камеры

// Prints the name of the object camera is directly looking at
using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour
{
    Camera camera;

    void Start()
    {
        camera = GetComponent<Camera>();
    }

    void Update()
    {
        Ray ray = camera.ViewportPointToRay(new Vector3(0.5F, 0.5F, 0));
        RaycastHit hit;
        if (Physics.Raycast(ray, out hit))
            print("I'm looking at " + hit.transform.name);
        else
            print("I'm looking at nothing!");
    }
}