判斷物體是否在攝像機視野內

倆個要點：1 是判斷物體在攝像機的前面   2 是判斷物體的視口座標在（0,0）至（1,1）之間

public bool IsInView(Vector3 worldPos)
        {
            Transform camTransform = Camera.main.transform;
            Vector2 viewPos = Camera.main.WorldToViewportPoint(worldPos);
            Debug.Log("viewPos.x:" + viewPos.x);
            Debug.Log("viewPos.y:" + viewPos.y);
            Vector3 dir = (worldPos - camTransform.position).normalized;
            float dot = Vector3.Dot(camTransform.forward, dir);     //判斷物體是否在相機前面  

            if (dot > 0 && viewPos.x >= 0 && viewPos.x <= 1 && viewPos.y >= 0 && viewPos.y <= 1)
                return true;
            else
                return false;
        }

        void Update()
        {
          
            if (IsInView(transform.position))
            {
                Debug.Log("目前本物體在攝像機範圍內");
            }
            else
            {
                Debug.Log("目前本物體不在攝像機範圍內");
            }
        }