import numpy as np
import matplotlib.pyplot as plt
import cv2
import glob

# termination criteria
criteria = (cv2.TERM_CRITERIA_EPS + cv2.TERM_CRITERIA_MAX_ITER, 30, 0.001)

# prepare object points, like (0,0,0), (1,0,0), (2,0,0) ....,(6,5,0)
objp = np.zeros((7*7, 3), np.float32)
objp[:, :2] = np.mgrid[0:7, 0:7].T.reshape(-1, 2)

# Arrays to store object points and image points from all the images.
objpoints = []  # 3d point in real world space
imgpoints = []  # 2d points in image plane.

images = glob.glob('./chessboard/*.jpg')

scale_size = 6
rotMat = np.zeros((3, 3))
camera_center = np.zeros((3, 1))
mtx = np.array([[626.23949494, 0., 211.21608234], [0., 626.22136938, 162.64737962], [0., 0., 1.]])
dist = np.array([[-5.82531846e-01, 2.49567823e-01, 3.59964573e-03, -1.10895344e-04, -3.18090306e-01]])
i = 0
f = open("date1.ply", 'w')

for fname in images:
    img = cv2.imread(fname)
    img = cv2.resize(img, (img.shape[1]//scale_size, img.shape[0]//scale_size))
    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

    # Find the chess board corners
    what = ret, corners = cv2.findChessboardCorners(gray, (7, 7), None)

    # If found, add object points, image points (after refining them)
    if ret == True:
        objpoints.append(objp)
        corners2 = cv2.cornerSubPix(
            gray, corners, (11, 11), (-1, -1), criteria)
        imgpoints.append(corners2)
        # Draw and display the corners
        img = cv2.drawChessboardCorners(img, (7, 7), corners2, ret)
        ret, mtx1, dist1, rvecs, tvecs = cv2.calibrateCamera(
            objpoints, imgpoints, gray.shape[::-1], None, None)

        imgp = imgpoints[i][:, 0]
        objp = np.array(objpoints)[i]
        retval, rvecs[i], tvecs[i]=cv2.solvePnP(objp, np.array(imgp), mtx, dist)
        cv2.Rodrigues(np.array(rvecs[i]), rotMat)
        camera_postion =np.dot(rotMat.T, - tvecs[i])
        f.write(str(camera_postion[0])+" "+str(camera_postion[1])+" "+str(camera_postion[2])+"\n")
        i = i + 1
        cv2.waitKey(500)

f.close()
k = cv2.waitKey(0) & 0xff
if k == 27:
    cv2.destroyAllWindows()
