mirror

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Mirror : MonoBehaviour
{
    [SerializeField] private Renderer m_PlaneRenderer;
    [SerializeField] private Camera m_PlayerCamera;
    private Camera m_MirrorCamera;
    private RenderTexture m_MirrorViewTexture;

    private void Awake()
    {
        // Get references
        m_MirrorCamera = GetComponentInChildren<Camera>();
    }

    private void Update()
    {
        // Mirror virtual camera's position with player's camera
        UpdateMirrorCameraTransform();

        // Render virtual camera's view to render texture
        RenderVirtualCamera();
    }

    /// <summary>
    /// Will update the mirror's virtual camera to be mirrored
    /// to the players camera relative to the plane/mirror.
    /// </summary>
    private void UpdateMirrorCameraTransform()
    {
        // Use trick to calculate new position and rotation, see https://www.youtube.com/watch?v=xXUVP6sN-tQ

        // Flip mirror/screen plane
        Vector3 planeScale = m_PlaneRenderer.transform.localScale;
        m_PlaneRenderer.transform.localScale = new Vector3(planeScale.x, planeScale.y * -1, planeScale.z);

        // Set the virtual camera's position and rotaion to the player camera
        m_MirrorCamera.transform.position = m_PlayerCamera.transform.position;
        m_MirrorCamera.transform.rotation = Quaternion.Euler(m_MirrorCamera.transform.rotation.eulerAngles.x, m_PlayerCamera.transform.rotation.eulerAngles.y, m_MirrorCamera.transform.rotation.eulerAngles.z);
        Debug.Log($"Player cam rotation: {m_PlayerCamera.transform.rotation.eulerAngles}");
        Debug.Log($"Mirror cam rotation: {m_MirrorCamera.transform.rotation.eulerAngles}");

        // Flip mirror/screen plane back to where it was before
        Vector3 newPlaneScale = m_PlaneRenderer.transform.localScale;
        m_PlaneRenderer.transform.localScale = new Vector3(newPlaneScale.x, newPlaneScale.y * -1, newPlaneScale.z);

        // Rotate the camera so its not upside down
        Quaternion mirrorRot = m_MirrorCamera.transform.localRotation;
        // m_MirrorCamera.transform.localRotation = Quaternion.Euler(mirrorRot.x - 90, mirrorRot.y, mirrorRot.z);


    }

    private void RenderVirtualCamera()
    {
        // Create mirrored view texture
        CreateMirroredTexture();

        m_MirrorCamera.Render();
    }

    /// <summary>
    /// Creates a new RenderTexture that the mirror's virtual camera
    /// will render to. Then it applies this texture to the Renderer
    /// on the object which will display the mirrored view.
    /// </summary>
    private void CreateMirroredTexture()
    {
        // If it's already created we don't care
        if (m_MirrorViewTexture != null)
            return;

        // Create new render texture with identical width and height as the screen
        m_MirrorViewTexture = new RenderTexture(Screen.width, Screen.height, 0);

        // Render the view from the mirror camera in to the texture
        m_MirrorCamera.targetTexture = m_MirrorViewTexture;

        // Apply the mirrored view texture to the screen/mirror
        m_PlaneRenderer.material.mainTexture = m_MirrorViewTexture;
    }
}