import numpy as np
import cv2
import glob

def draw(img, corners, imgpts):
    corner = tuple(corners[0].ravel())
    img = cv2.line(img, corner, tuple(imgpts[0].ravel()), (255,0,0), 5)
    img = cv2.line(img, corner, tuple(imgpts[1].ravel()), (0,255,0), 5)
    img = cv2.line(img, corner, tuple(imgpts[2].ravel()), (0,0,255), 5)
    return img

# 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((6*7,3), np.float32) # used 7 x 6 grid, so it is composed of 42 points with 3 coordinates
objp[:,:2] = np.mgrid[0:7,0:6].T.reshape(-1,2)  # assign value to x,y keep z = 0

# 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('/home/airscan/stereo/calib_imgs/*.jpg')
ctr = 0
for fname in images:
    img = cv2.imread(fname)
    #cv2.imshow('img',img)
    gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)


    # Find the chess board corners
    ret, corners = cv2.findChessboardCorners(gray, (7,6),None)

    # If found, add object points, image points (after refining them)
    if ret == True:
        objpoints.append(objp)
        ctr = ctr + 1
        print(ctr)
        corners2 = cv2.cornerSubPix(gray,corners,(11,11),(-1,-1),criteria)
        imgpoints.append(corners2)

        # Draw and display the corners
        img = cv2.drawChessboardCorners(img, (7,6), corners2,ret)
        h,  w = img.shape[:2]
        print(h)
        print(w)
        cv2.imshow('img',img)
        cv2.waitKey(500)

cv2.destroyAllWindows()

ret, mtx, dist, rvecs, tvecs = cv2.calibrateCamera(objpoints, imgpoints, gray.shape[::-1],None,None)

criteria = (cv2.TERM_CRITERIA_EPS + cv2.TERM_CRITERIA_MAX_ITER, 30, 0.001)
objp2 = np.zeros((6*7,3), np.float32)
objp2[:,:2] = np.mgrid[0:7,0:6].T.reshape(-1,2)

axis = np.float32([[3,0,0], [0,3,0], [0,0,-3]]).reshape(-1,3)

for fname in glob.glob('/home/airscan/stereo/calib_imgs/left*.jpg'):
    img = cv2.imread(fname)
    gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
    ret, corners = cv2.findChessboardCorners(gray, (7,6),None)

    if ret == True:
        corners2 = cv2.cornerSubPix(gray,corners,(11,11),(-1,-1),criteria)

        # Find the rotation and translation vectors.
        _, r, t, inliers = cv2.solvePnPRansac(objp2, corners2, mtx, dist) #changed from rvecs to r etc
        print(r)
        print(t)
        
        # project 3D points to image plane
        imgpts, jac = cv2.projectPoints(axis, r, t, mtx, dist)

        img = draw(img,corners2,imgpts)
        cv2.imshow('img',img)
        k = cv2.waitKey(0) & 0xff
        if k == 's':
            cv2.imwrite(fname[:6]+'.png', img)

cv2.destroyAllWindows()
