using UnityEngine;
using UnityEngine.UI;
using UnityEngine.SceneManagement;
using System.Xml.Serialization;
using System.IO;
using System.Collections;
using System.Collections.Generic;
using OpenCVForUnity.CoreModule;
using OpenCVForUnity.ArucoModule;
using OpenCVForUnity.Calib3dModule;
using OpenCVForUnity.ImgprocModule;
using OpenCVForUnity.UnityUtils;
using OpenCVForUnity.UnityUtils.Helper;

namespace OpenCVForUnityExample
{
    /// <summary>
    /// ArUco WebCamTexture Example
    /// An example of marker-based AR view and camera pose estimation using the aruco (ArUco Marker Detection) module.
    /// Referring to https://github.com/opencv/opencv_contrib/blob/master/modules/aruco/samples/detect_markers.cpp.
    /// http://docs.opencv.org/3.1.0/d5/dae/tutorial_aruco_detection.html
    /// </summary>
    [RequireComponent (typeof(WebCamTextureToMatHelper))]
    public class ArUcoWebCamTextureExample : MonoBehaviour
    {
        /// <summary>
        /// Determines if restores the camera parameters when the file exists.
        /// </summary>
        public bool useStoredCameraParameters = true;

        /// <summary>
        /// The marker type.
        /// </summary>
        public MarkerType markerType = MarkerType.CanonicalMarker;

        /// <summary>
        /// The marker type dropdown.
        /// </summary>
        public Dropdown markerTypeDropdown;

        /// <summary>
        /// The dictionary identifier.
        /// </summary>
        public ArUcoDictionary dictionaryId = ArUcoDictionary.DICT_6X6_250;

        /// <summary>
        /// The dictionary id dropdown.
        /// </summary>
        public Dropdown dictionaryIdDropdown;
        
        /// <summary>
        /// Determines if shows rejected corners.
        /// </summary>
        public bool showRejectedCorners = false;

        /// <summary>
        /// The shows rejected corners toggle.
        /// </summary>
        public Toggle showRejectedCornersToggle;
        
        /// <summary>
        /// Determines if applied the pose estimation.
        /// </summary>
        public bool applyEstimationPose = true;

        /// <summary>
        /// Determines if refine marker detection. (only valid for ArUco boards)
        /// </summary>
        public bool refineMarkerDetection = true;

        /// <summary>
        /// The shows refine marker detection toggle.
        /// </summary>
        public Toggle refineMarkerDetectionToggle;

        [Space (10)]
        
        /// <summary>
        /// The length of the markers' side. Normally, unit is meters.
        /// </summary>
        public float markerLength = 0.1f;
        
        /// <summary>
        /// The AR game object.
        /// </summary>
        public GameObject arGameObject;
        
        /// <summary>
        /// The AR camera.
        /// </summary>
        public Camera arCamera;

        [Space (10)]

        /// <summary>
        /// Determines if request the AR camera moving.
        /// </summary>
        public bool shouldMoveARCamera = false;
        
        [Space (10)]

        /// <summary>
        /// Determines if enable low pass filter.
        /// </summary>
        public bool enableLowPassFilter;

        /// <summary>
        /// The enable low pass filter toggle.
        /// </summary>
        public Toggle enableLowPassFilterToggle;

        /// <summary>
        /// The position low pass. (Value in meters)
        /// </summary>
        public float positionLowPass = 0.005f;

        /// <summary>
        /// The rotation low pass. (Value in degrees)
        /// </summary>
        public float rotationLowPass = 2f;
        
        /// <summary>
        /// The old pose data.
        /// </summary>
        PoseData oldPoseData;

        /// <summary>
        /// The texture.
        /// </summary>
        Texture2D texture;
        
        /// <summary>
        /// The webcam texture to mat helper.
        /// </summary>
        WebCamTextureToMatHelper webCamTextureToMatHelper;
        
        /// <summary>
        /// The rgb mat.
        /// </summary>
        Mat rgbMat;
        
        /// <summary>
        /// The cameraparam matrix.
        /// </summary>
        Mat camMatrix;
        
        /// <summary>
        /// The distortion coeffs.
        /// </summary>
        MatOfDouble distCoeffs;

        /// <summary>
        /// The transformation matrix for AR.
        /// </summary>
        Matrix4x4 ARM;

        /// <summary>
        /// The identifiers.
        /// </summary>
        Mat ids;
        
        /// <summary>
        /// The corners.
        /// </summary>
        List<Mat> corners;
        
        /// <summary>
        /// The rejected corners.
        /// </summary>
        List<Mat> rejectedCorners;
        
        /// <summary>
        /// The rvecs.
        /// </summary>
        Mat rvecs;
        
        /// <summary>
        /// The tvecs.
        /// </summary>
        Mat tvecs;
        
        /// <summary>
        /// The rot mat.
        /// </summary>
        Mat rotMat;
        
        /// <summary>
        /// The detector parameters.
        /// </summary>
        DetectorParameters detectorParams;
        
        /// <summary>
        /// The dictionary.
        /// </summary>
        Dictionary dictionary;

        /// <summary>
        /// The FPS monitor.
        /// </summary>
        FpsMonitor fpsMonitor;

        Mat rvec;
        Mat tvec;
        Mat recoveredIdxs;

        // for GridBoard.
        // number of markers in X direction
        const int gridBoradMarkersX = 5;
        // number of markers in Y direction
        const int gridBoradMarkersY = 7;
        // marker side length (normally in meters)
        const float gridBoradMarkerLength = 0.04f;
        // separation between two markers (same unit as markerLength)
        const float gridBoradMarkerSeparation = 0.01f;
        // id of first marker in dictionary to use on board.
        const int gridBoradMarkerFirstMarker = 0;
        GridBoard gridBoard;

        // for ChArUcoBoard.
        //  number of chessboard squares in X direction
        const int chArUcoBoradSquaresX = 5;
        //  number of chessboard squares in Y direction
        const int chArUcoBoradSquaresY = 7;
        // chessboard square side length (normally in meters)
        const float chArUcoBoradSquareLength = 0.04f;
        // marker side length (same unit than squareLength)
        const float chArUcoBoradMarkerLength = 0.02f;
        const int charucoMinMarkers = 2;
        Mat charucoCorners;
        Mat charucoIds;
        CharucoBoard charucoBoard;

        // for ChArUcoDiamondMarker.
        // size of the chessboard squares in pixels
        const float diamondSquareLength = 0.1f;
        // size of the markers in pixels.
        const float diamondMarkerLength = 0.06f;
        // identifiers for diamonds in diamond corners.
        const int diamondId1 = 45;
        const int diamondId2 = 68;
        const int diamondId3 = 28;
        const int diamondId4 = 74;
        List<Mat> diamondCorners;
        Mat diamondIds;
        
        // Use this for initialization
        void Start ()
        {
            fpsMonitor = GetComponent<FpsMonitor> ();

            markerTypeDropdown.value = (int)markerType;
            dictionaryIdDropdown.value = (int)dictionaryId;
            showRejectedCornersToggle.isOn = showRejectedCorners;
            refineMarkerDetectionToggle.isOn = refineMarkerDetection;
            refineMarkerDetectionToggle.interactable = (markerType == MarkerType.GridBoard || markerType == MarkerType.ChArUcoBoard);
            enableLowPassFilterToggle.isOn = enableLowPassFilter;

            webCamTextureToMatHelper = gameObject.GetComponent<WebCamTextureToMatHelper> ();

            #if UNITY_ANDROID && !UNITY_EDITOR
            // Avoids the front camera low light issue that occurs in only some Android devices (e.g. Google Pixel, Pixel2).
            webCamTextureToMatHelper.avoidAndroidFrontCameraLowLightIssue = true;
            #endif
            webCamTextureToMatHelper.Initialize ();
        }

        /// <summary>
        /// Raises the webcam texture to mat helper initialized event.
        /// </summary>
        public void OnWebCamTextureToMatHelperInitialized ()
        {
            Debug.Log ("OnWebCamTextureToMatHelperInitialized");
            
            Mat webCamTextureMat = webCamTextureToMatHelper.GetMat ();
            
            texture = new Texture2D (webCamTextureMat.cols (), webCamTextureMat.rows (), TextureFormat.RGB24, false);
            
            gameObject.GetComponent<Renderer> ().material.mainTexture = texture;
            
            gameObject.transform.localScale = new Vector3 (webCamTextureMat.cols (), webCamTextureMat.rows (), 1);
            Debug.Log ("Screen.width " + Screen.width + " Screen.height " + Screen.height + " Screen.orientation " + Screen.orientation);

            if (fpsMonitor != null) {
                fpsMonitor.Add ("width", webCamTextureMat.width ().ToString ());
                fpsMonitor.Add ("height", webCamTextureMat.height ().ToString ());
                fpsMonitor.Add ("orientation", Screen.orientation.ToString ());
            }

            
            float width = webCamTextureMat.width ();
            float height = webCamTextureMat.height ();
            
            float imageSizeScale = 1.0f;
            float widthScale = (float)Screen.width / width;
            float heightScale = (float)Screen.height / height;
            if (widthScale < heightScale) {
                Camera.main.orthographicSize = (width * (float)Screen.height / (float)Screen.width) / 2;
                imageSizeScale = (float)Screen.height / (float)Screen.width;
            } else {
                Camera.main.orthographicSize = height / 2;
            }
            

            // set camera parameters.
            double fx;
            double fy;
            double cx;
            double cy;

            string loadDirectoryPath = Path.Combine (Application.persistentDataPath, "ArUcoCameraCalibrationExample");
            string calibratonDirectoryName = "camera_parameters" + width + "x" + height;
            string loadCalibratonFileDirectoryPath = Path.Combine (loadDirectoryPath, calibratonDirectoryName);
            string loadPath = Path.Combine (loadCalibratonFileDirectoryPath, calibratonDirectoryName + ".xml");
            if (useStoredCameraParameters && File.Exists (loadPath)) {
                CameraParameters param;
                XmlSerializer serializer = new XmlSerializer (typeof(CameraParameters));
                using (var stream = new FileStream (loadPath, FileMode.Open)) {
                    param = (CameraParameters)serializer.Deserialize (stream);
                }

                camMatrix = param.GetCameraMatrix ();
                distCoeffs = new MatOfDouble (param.GetDistortionCoefficients ());

                fx = param.camera_matrix [0];
                fy = param.camera_matrix [4];
                cx = param.camera_matrix [2];
                cy = param.camera_matrix [5];

                Debug.Log ("Loaded CameraParameters from a stored XML file.");
                Debug.Log ("loadPath: " + loadPath);

            } else {
                int max_d = (int)Mathf.Max (width, height);
                fx = max_d;
                fy = max_d;
                cx = width / 2.0f;
                cy = height / 2.0f;

                camMatrix = new Mat (3, 3, CvType.CV_64FC1);
                camMatrix.put (0, 0, fx);
                camMatrix.put (0, 1, 0);
                camMatrix.put (0, 2, cx);
                camMatrix.put (1, 0, 0);
                camMatrix.put (1, 1, fy);
                camMatrix.put (1, 2, cy);
                camMatrix.put (2, 0, 0);
                camMatrix.put (2, 1, 0);
                camMatrix.put (2, 2, 1.0f);

                distCoeffs = new MatOfDouble (0, 0, 0, 0);

                Debug.Log ("Created a dummy CameraParameters.");
            }
                
            Debug.Log ("camMatrix " + camMatrix.dump ());
            Debug.Log ("distCoeffs " + distCoeffs.dump ());


            // calibration camera matrix values.
            Size imageSize = new Size (width * imageSizeScale, height * imageSizeScale);
            double apertureWidth = 0;
            double apertureHeight = 0;
            double[] fovx = new double[1];
            double[] fovy = new double[1];
            double[] focalLength = new double[1];
            Point principalPoint = new Point (0, 0);
            double[] aspectratio = new double[1];
            
            Calib3d.calibrationMatrixValues (camMatrix, imageSize, apertureWidth, apertureHeight, fovx, fovy, focalLength, principalPoint, aspectratio);
            
            Debug.Log ("imageSize " + imageSize.ToString ());
            Debug.Log ("apertureWidth " + apertureWidth);
            Debug.Log ("apertureHeight " + apertureHeight);
            Debug.Log ("fovx " + fovx [0]);
            Debug.Log ("fovy " + fovy [0]);
            Debug.Log ("focalLength " + focalLength [0]);
            Debug.Log ("principalPoint " + principalPoint.ToString ());
            Debug.Log ("aspectratio " + aspectratio [0]);
            
            
            // To convert the difference of the FOV value of the OpenCV and Unity. 
            double fovXScale = (2.0 * Mathf.Atan ((float)(imageSize.width / (2.0 * fx)))) / (Mathf.Atan2 ((float)cx, (float)fx) + Mathf.Atan2 ((float)(imageSize.width - cx), (float)fx));
            double fovYScale = (2.0 * Mathf.Atan ((float)(imageSize.height / (2.0 * fy)))) / (Mathf.Atan2 ((float)cy, (float)fy) + Mathf.Atan2 ((float)(imageSize.height - cy), (float)fy));

            Debug.Log ("fovXScale " + fovXScale);
            Debug.Log ("fovYScale " + fovYScale);
            
            
            // Adjust Unity Camera FOV https://github.com/opencv/opencv/commit/8ed1945ccd52501f5ab22bdec6aa1f91f1e2cfd4
            if (widthScale < heightScale) {
                arCamera.fieldOfView = (float)(fovx [0] * fovXScale);
            } else {
                arCamera.fieldOfView = (float)(fovy [0] * fovYScale);
            }
            // Display objects near the camera.
            arCamera.nearClipPlane = 0.01f;
            
            
            rgbMat = new Mat (webCamTextureMat.rows (), webCamTextureMat.cols (), CvType.CV_8UC3);
            ids = new Mat ();
            corners = new List<Mat> ();
            rejectedCorners = new List<Mat> ();
            rvecs = new Mat ();
            tvecs = new Mat ();
            rotMat = new Mat (3, 3, CvType.CV_64FC1);
            
            
            detectorParams = DetectorParameters.create ();
            dictionary = Aruco.getPredefinedDictionary ((int)dictionaryId);

            rvec = new Mat ();
            tvec = new Mat ();
            recoveredIdxs = new Mat ();

            gridBoard = GridBoard.create (gridBoradMarkersX, gridBoradMarkersY, gridBoradMarkerLength, gridBoradMarkerSeparation, dictionary, gridBoradMarkerFirstMarker);

            charucoCorners = new Mat ();
            charucoIds = new Mat ();
            charucoBoard = CharucoBoard.create (chArUcoBoradSquaresX, chArUcoBoradSquaresY, chArUcoBoradSquareLength, chArUcoBoradMarkerLength, dictionary);

            diamondCorners = new List<Mat> ();
            diamondIds = new Mat (1, 1, CvType.CV_32SC4);
            diamondIds.put (0, 0, new int[] { diamondId1, diamondId2, diamondId3, diamondId4 });


            // if WebCamera is frontFaceing, flip Mat.
            if (webCamTextureToMatHelper.GetWebCamDevice ().isFrontFacing) {
                webCamTextureToMatHelper.flipHorizontal = true;
            }
        }

        /// <summary>
        /// Raises the webcam texture to mat helper disposed event.
        /// </summary>
        public void OnWebCamTextureToMatHelperDisposed ()
        {
            Debug.Log ("OnWebCamTextureToMatHelperDisposed");
            
            if (rgbMat != null)
                rgbMat.Dispose ();

            if (texture != null) {
                Texture2D.Destroy (texture);
                texture = null;
            }

            if (ids != null)
                ids.Dispose ();
            foreach (var item in corners) {
                item.Dispose ();
            }
            corners.Clear ();
            foreach (var item in rejectedCorners) {
                item.Dispose ();
            }
            rejectedCorners.Clear ();
            if (rvecs != null)
                rvecs.Dispose ();
            if (tvecs != null)
                tvecs.Dispose ();
            if (rotMat != null)
                rotMat.Dispose ();

            if (rvec != null)
                rvec.Dispose ();
            if (tvec != null)
                tvec.Dispose ();
            if (recoveredIdxs != null)
                recoveredIdxs.Dispose (); 

            if (gridBoard != null)
                gridBoard.Dispose ();         

            if (charucoCorners != null)
                charucoCorners.Dispose ();
            if (charucoIds != null)
                charucoIds.Dispose ();
            if (charucoBoard != null)
                charucoBoard.Dispose ();

            foreach (var item in diamondCorners) {
                item.Dispose ();
            }
            diamondCorners.Clear ();
            if (diamondIds != null)
                diamondIds.Dispose ();
        }

        /// <summary>
        /// Raises the webcam texture to mat helper error occurred event.
        /// </summary>
        /// <param name="errorCode">Error code.</param>
        public void OnWebCamTextureToMatHelperErrorOccurred (WebCamTextureToMatHelper.ErrorCode errorCode)
        {
            Debug.Log ("OnWebCamTextureToMatHelperErrorOccurred " + errorCode);
        }
        
        // Update is called once per frame
        void Update ()
        {            
            if (webCamTextureToMatHelper.IsPlaying () && webCamTextureToMatHelper.DidUpdateThisFrame ()) {
                
                Mat rgbaMat = webCamTextureToMatHelper.GetMat ();
                
                Imgproc.cvtColor (rgbaMat, rgbMat, Imgproc.COLOR_RGBA2RGB);


                // detect markers.
                Aruco.detectMarkers (rgbMat, dictionary, corners, ids, detectorParams, rejectedCorners, camMatrix, distCoeffs);

                // refine marker detection.
                if (refineMarkerDetection && (markerType == MarkerType.GridBoard || markerType == MarkerType.ChArUcoBoard)) {
                    switch (markerType) {
                    case MarkerType.GridBoard:
                        Aruco.refineDetectedMarkers (rgbMat, gridBoard, corners, ids, rejectedCorners, camMatrix, distCoeffs, 10f, 3f, true, recoveredIdxs, detectorParams);
                        break;
                    case MarkerType.ChArUcoBoard:
                        Aruco.refineDetectedMarkers (rgbMat, charucoBoard, corners, ids, rejectedCorners, camMatrix, distCoeffs, 10f, 3f, true, recoveredIdxs, detectorParams);
                        break;
                    }
                }

                // if at least one marker detected
                if (ids.total () > 0) {
                    if (markerType != MarkerType.ChArUcoDiamondMarker) {

                        if (markerType == MarkerType.ChArUcoBoard) {
                            Aruco.interpolateCornersCharuco (corners, ids, rgbMat, charucoBoard, charucoCorners, charucoIds, camMatrix, distCoeffs, charucoMinMarkers);

                            // draw markers.
                            Aruco.drawDetectedMarkers (rgbMat, corners, ids, new Scalar (0, 255, 0));
                            if (charucoIds.total () > 0) {
                                Aruco.drawDetectedCornersCharuco (rgbMat, charucoCorners, charucoIds, new Scalar (0, 0, 255));
                            }
                        } else {
                            // draw markers.
                            Aruco.drawDetectedMarkers (rgbMat, corners, ids, new Scalar (0, 255, 0));
                        }
                            
                        // estimate pose.
                        if (applyEstimationPose) {
                            switch (markerType) {
                            default:
                            case MarkerType.CanonicalMarker:
                                EstimatePoseCanonicalMarker (rgbMat);
                                break;
                            case MarkerType.GridBoard:
                                EstimatePoseGridBoard (rgbMat);
                                break;
                            case MarkerType.ChArUcoBoard:
                                EstimatePoseChArUcoBoard (rgbMat);
                                break;
                            }
                        }
                    } else {
                        // detect diamond markers.
                        Aruco.detectCharucoDiamond (rgbMat, corners, ids, diamondSquareLength / diamondMarkerLength, diamondCorners, diamondIds, camMatrix, distCoeffs);

                        // draw markers.
                        Aruco.drawDetectedMarkers (rgbMat, corners, ids, new Scalar (0, 255, 0));
                        // draw diamond markers.
                        Aruco.drawDetectedDiamonds (rgbMat, diamondCorners, diamondIds, new Scalar (0, 0, 255));

                        // estimate pose.
                        if (applyEstimationPose)
                            EstimatePoseChArUcoDiamondMarker (rgbMat);
                    }
                }

                if (showRejectedCorners && rejectedCorners.Count > 0)
                    Aruco.drawDetectedMarkers (rgbMat, rejectedCorners, new Mat (), new Scalar (255, 0, 0));
                
                
//                Imgproc.putText (rgbaMat, "W:" + rgbaMat.width () + " H:" + rgbaMat.height () + " SO:" + Screen.orientation, new Point (5, rgbaMat.rows () - 10), Imgproc.FONT_HERSHEY_SIMPLEX, 1.0, new Scalar (255, 255, 255, 255), 2, Imgproc.LINE_AA, false);

                Utils.fastMatToTexture2D (rgbMat, texture);
            }
        }

        private void EstimatePoseCanonicalMarker (Mat rgbMat)
        {
            Aruco.estimatePoseSingleMarkers (corners, markerLength, camMatrix, distCoeffs, rvecs, tvecs);

            for (int i = 0; i < ids.total (); i++) {
                using (Mat rvec = new Mat (rvecs, new OpenCVForUnity.CoreModule.Rect (0, i, 1, 1)))
                using (Mat tvec = new Mat (tvecs, new OpenCVForUnity.CoreModule.Rect (0, i, 1, 1))) {
                    // In this example we are processing with RGB color image, so Axis-color correspondences are X: blue, Y: green, Z: red. (Usually X: red, Y: green, Z: blue)
                    Aruco.drawAxis (rgbMat, camMatrix, distCoeffs, rvec, tvec, markerLength * 0.5f);

                    // This example can display the ARObject on only first detected marker.
                    if (i == 0) {
                        UpdateARObjectTransform (rvec, tvec);
                    }
                }
            }
        }

        private void EstimatePoseGridBoard (Mat rgbMat)
        {           
            int valid = Aruco.estimatePoseBoard (corners, ids, gridBoard, camMatrix, distCoeffs, rvec, tvec);

            // if at least one board marker detected
            if (valid > 0) {
                // In this example we are processing with RGB color image, so Axis-color correspondences are X: blue, Y: green, Z: red. (Usually X: red, Y: green, Z: blue)
                Aruco.drawAxis (rgbMat, camMatrix, distCoeffs, rvec, tvec, markerLength * 0.5f);

                UpdateARObjectTransform (rvec, tvec);
            }
        }

        private void EstimatePoseChArUcoBoard (Mat rgbMat)
        {
            // if at least one charuco corner detected
            if (charucoIds.total () > 0) {
                bool valid = Aruco.estimatePoseCharucoBoard (charucoCorners, charucoIds, charucoBoard, camMatrix, distCoeffs, rvec, tvec);

                // if at least one board marker detected
                if (valid) {
                    // In this example we are processing with RGB color image, so Axis-color correspondences are X: blue, Y: green, Z: red. (Usually X: red, Y: green, Z: blue)
                    Aruco.drawAxis (rgbMat, camMatrix, distCoeffs, rvec, tvec, markerLength * 0.5f);

                    UpdateARObjectTransform (rvec, tvec);
                }
            }
        }

        private void EstimatePoseChArUcoDiamondMarker (Mat rgbMat)
        {
            Aruco.estimatePoseSingleMarkers (diamondCorners, diamondSquareLength, camMatrix, distCoeffs, rvecs, tvecs);

            for (int i = 0; i < rvecs.total (); i++) {
                using (Mat rvec = new Mat (rvecs, new OpenCVForUnity.CoreModule.Rect (0, i, 1, 1)))
                using (Mat tvec = new Mat (tvecs, new OpenCVForUnity.CoreModule.Rect (0, i, 1, 1))) {
                    // In this example we are processing with RGB color image, so Axis-color correspondences are X: blue, Y: green, Z: red. (Usually X: red, Y: green, Z: blue)
                    Aruco.drawAxis (rgbMat, camMatrix, distCoeffs, rvec, tvec, diamondSquareLength * 0.5f);

                    // This example can display the ARObject on only first detected marker.
                    if (i == 0) {
                        UpdateARObjectTransform (rvec, tvec);
                    }
                }
            }
        }

        private void UpdateARObjectTransform (Mat rvec, Mat tvec)
        {
            // Convert to unity pose data.
            double[] rvecArr = new double[3];
            rvec.get (0, 0, rvecArr);
            double[] tvecArr = new double[3];
            tvec.get (0, 0, tvecArr);
            PoseData poseData = ARUtils.ConvertRvecTvecToPoseData (rvecArr, tvecArr);

            // Changes in pos/rot below these thresholds are ignored.
            if (enableLowPassFilter) {
                ARUtils.LowpassPoseData (ref oldPoseData, ref poseData, positionLowPass, rotationLowPass);
            }
            oldPoseData = poseData;

            // Convert to transform matrix.
            ARM = ARUtils.ConvertPoseDataToMatrix (ref poseData, true, true);

            if (shouldMoveARCamera) {

                ARM = arGameObject.transform.localToWorldMatrix * ARM.inverse;

                ARUtils.SetTransformFromMatrix (arCamera.transform, ref ARM);

            } else {

                ARM = arCamera.transform.localToWorldMatrix * ARM;

                ARUtils.SetTransformFromMatrix (arGameObject.transform, ref ARM);
            }
        }

        private void ResetObjectTransform ()
        {
            // reset AR object transform.
            Matrix4x4 i = Matrix4x4.identity;
            ARUtils.SetTransformFromMatrix (arCamera.transform, ref i);
            ARUtils.SetTransformFromMatrix (arGameObject.transform, ref i);
        }

        /// <summary>
        /// Raises the destroy event.
        /// </summary>
        void OnDestroy ()
        {
            webCamTextureToMatHelper.Dispose ();
        }

        /// <summary>
        /// Raises the back button click event.
        /// </summary>
        public void OnBackButtonClick ()
        {
            SceneManager.LoadScene ("OpenCVForUnityExample");
        }

        /// <summary>
        /// Raises the play button click event.
        /// </summary>
        public void OnPlayButtonClick ()
        {
            webCamTextureToMatHelper.Play ();
        }

        /// <summary>
        /// Raises the pause button click event.
        /// </summary>
        public void OnPauseButtonClick ()
        {
            webCamTextureToMatHelper.Pause ();
        }

        /// <summary>
        /// Raises the stop button click event.
        /// </summary>
        public void OnStopButtonClick ()
        {
            webCamTextureToMatHelper.Stop ();
        }

        /// <summary>
        /// Raises the change camera button click event.
        /// </summary>
        public void OnChangeCameraButtonClick ()
        {
            webCamTextureToMatHelper.requestedIsFrontFacing = !webCamTextureToMatHelper.IsFrontFacing ();
        }

        /// <summary>
        /// Raises the marker type dropdown value changed event.
        /// </summary>
        public void OnMarkerTypeDropdownValueChanged (int result)
        {
            if ((int)markerType != result) {
                markerType = (MarkerType)result;

                refineMarkerDetectionToggle.interactable = (markerType == MarkerType.GridBoard || markerType == MarkerType.ChArUcoBoard);

                ResetObjectTransform ();

                if (webCamTextureToMatHelper.IsInitialized ())
                    webCamTextureToMatHelper.Initialize ();
            }
        }

        /// <summary>
        /// Raises the dictionary id dropdown value changed event.
        /// </summary>
        public void OnDictionaryIdDropdownValueChanged (int result)
        {
            if ((int)dictionaryId != result) {
                dictionaryId = (ArUcoDictionary)result;
                dictionary = Aruco.getPredefinedDictionary ((int)dictionaryId);

                ResetObjectTransform ();

                if (webCamTextureToMatHelper.IsInitialized ())
                    webCamTextureToMatHelper.Initialize ();
            }
        }

        /// <summary>
        /// Raises the show rejected corners toggle value changed event.
        /// </summary>
        public void OnShowRejectedCornersToggleValueChanged ()
        {
            showRejectedCorners = showRejectedCornersToggle.isOn;
        }

        /// <summary>
        /// Raises the refine marker detection toggle value changed event.
        /// </summary>
        public void OnRefineMarkerDetectionToggleValueChanged ()
        {
            refineMarkerDetection = refineMarkerDetectionToggle.isOn;
        }

        
        /// <summary>
        /// Raises the enable low pass filter toggle value changed event.
        /// </summary>
        public void OnEnableLowPassFilterToggleValueChanged ()
        {
            if (enableLowPassFilterToggle.isOn) {
                enableLowPassFilter = true;
            } else {
                enableLowPassFilter = false;
            }
        }

        public enum MarkerType
        {
            CanonicalMarker,
            GridBoard,
            ChArUcoBoard,
            ChArUcoDiamondMarker
        }

        public enum ArUcoDictionary
        {
            DICT_4X4_50 = Aruco.DICT_4X4_50,
            DICT_4X4_100 = Aruco.DICT_4X4_100,
            DICT_4X4_250 = Aruco.DICT_4X4_250,
            DICT_4X4_1000 = Aruco.DICT_4X4_1000,
            DICT_5X5_50 = Aruco.DICT_5X5_50,
            DICT_5X5_100 = Aruco.DICT_5X5_100,
            DICT_5X5_250 = Aruco.DICT_5X5_250,
            DICT_5X5_1000 = Aruco.DICT_5X5_1000,
            DICT_6X6_50 = Aruco.DICT_6X6_50,
            DICT_6X6_100 = Aruco.DICT_6X6_100,
            DICT_6X6_250 = Aruco.DICT_6X6_250,
            DICT_6X6_1000 = Aruco.DICT_6X6_1000,
            DICT_7X7_50 = Aruco.DICT_7X7_50,
            DICT_7X7_100 = Aruco.DICT_7X7_100,
            DICT_7X7_250 = Aruco.DICT_7X7_250,
            DICT_7X7_1000 = Aruco.DICT_7X7_1000,
            DICT_ARUCO_ORIGINAL = Aruco.DICT_ARUCO_ORIGINAL,
        }
    }
}