MiniMapRoomTrigger.cs

using UnityEngine;

public class MiniMapRoomTrigger : MonoBehaviour
{
    MiniMapCamController m_miniMapControl;
    Renderer m_renderer;

    void Start()
    {
        m_miniMapControl = FindFirstObjectByType<MiniMapCamController>();
        m_renderer = GetComponent<Renderer>();
    }

    void OnTriggerEnter(Collider other)
    {
        if (other.CompareTag("Player") && !m_renderer.enabled)
        {
            m_renderer.enabled = true;
            m_miniMapControl.SetMapPosToThis(GetComponent<MeshFilter>());
        }
    }
    void OnTriggerExit(Collider other)
    {
        if (other.CompareTag("Player") && m_renderer.enabled)
        {
            m_renderer.enabled = false;
        }
    }
}