下载源码 UnityPackage

1.Ray2D

让小球向右发射射线：

Ray2D ray;

void Start()
{
    // Ray2D(起点，终点)
    ray = new Ray2D(this.transform.position, Vector2.right);
    // Debug.DrawLine(起点，终点，颜色，显示时间)
    Debug.DrawLine(ray.origin, ray.direction, Color.green, 1000);
}

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2.RaycastHit2D（射线检测）

返回鼠标单击对象的名字:

  RaycastHit2D hitInfo;

    void Update()
    {
        if (Input.GetMouseButtonDown(0))
        {
            hitInfo = Physics2D.Raycast(Camera.main.ScreenToWorldPoint(Input.mousePosition), Vector2.zero);
            if (hitInfo.collider != null)
            {
                Debug.Log(hitInfo.collider.gameObject.name);
            }
        }        
    }