import cv2
import dlib
import numpy as np
from imutils import face_utils

face_landmark_path = './model/shape_predictor_68_face_landmarks.dat'
object_pts = np.float32([[6.825897, 6.760612, 4.402142],  #33左眉左上角
                         [1.330353, 7.122144, 6.903745],  #29左眉右角
                         [-1.330353, 7.122144, 6.903745], #34右眉左角
                         [-6.825897, 6.760612, 4.402142], #38右眉右上角
                         [5.311432, 5.485328, 3.987654],  #13左眼左上角
                         [1.789930, 5.393625, 4.413414],  #17左眼右上角
                         [-1.789930, 5.393625, 4.413414], #25右眼左上角
                         [-5.311432, 5.485328, 3.987654], #21右眼右上角
                         [2.005628, 1.409845, 6.165652],  #55鼻子左上角
                         [-2.005628, 1.409845, 6.165652], #49鼻子右上角
                         [2.774015, -2.080775, 5.048531], #43嘴左上角
                         [-2.774015, -2.080775, 5.048531],#39嘴右上角
                         [0.000000, -3.116408, 6.097667], #45嘴中央下角
                         [0.000000, -7.415691, 4.070434]])#6下巴角
K = [6.5308391993466671e+002, 0.0, 3.1950000000000000e+002,
     0.0, 6.5308391993466671e+002, 2.3950000000000000e+002,
     0.0, 0.0, 1.0]
D = [7.0834633684407095e-002, 6.9140193737175351e-002, 0.0, 0.0, -1.3073460323689292e+000]
cam_matrix = np.array(K).reshape(3, 3).astype(np.float32)
dist_coeffs = np.array(D).reshape(5, 1).astype(np.float32)
reprojectsrc = np.float32([[10.0, 10.0, 10.0],
                           [10.0, 10.0, -10.0],
                           [10.0, -10.0, -10.0],
                           [10.0, -10.0, 10.0],
                           [-10.0, 10.0, 10.0],
                           [-10.0, 10.0, -10.0],
                           [-10.0, -10.0, -10.0],
                           [-10.0, -10.0, 10.0]])
line_pairs = [[0, 1], [1, 2], [2, 3], [3, 0],
              [4, 5], [5, 6], [6, 7], [7, 4],
              [0, 4], [1, 5], [2, 6], [3, 7]]

def get_head_pose(shape):
    image_pts = np.float32([shape[17], shape[21], shape[22], shape[26], shape[36],
                            shape[39], shape[42], shape[45], shape[31], shape[35],
                            shape[48], shape[54], shape[57], shape[8]])
    _, rotation_vec, translation_vec = cv2.solvePnP(object_pts, image_pts, cam_matrix, dist_coeffs)
    reprojectdst, _ = cv2.projectPoints(reprojectsrc, rotation_vec, translation_vec, cam_matrix,dist_coeffs)
    reprojectdst = tuple(map(tuple, reprojectdst.reshape(8, 2)))
    rotation_mat, _ = cv2.Rodrigues(rotation_vec)
    pose_mat = cv2.hconcat((rotation_mat, translation_vec))
    _, _, _, _, _, _, euler_angle = cv2.decomposeProjectionMatrix(pose_mat)
    return reprojectdst, euler_angle
def main():
    cap = cv2.VideoCapture(0)
    if not cap.isOpened():
        print("Unable to connect to camera.")
        return
    detector = dlib.get_frontal_face_detector()
    predictor = dlib.shape_predictor(face_landmark_path)
    while cap.isOpened():
        ret, frame = cap.read()
        if ret:
            face_rects = detector(frame, 0)
            if len(face_rects) > 0:
                shape = predictor(frame, face_rects[0])
                shape = face_utils.shape_to_np(shape)
                reprojectdst, euler_angle = get_head_pose(shape)
                pitch = format(euler_angle[0, 0])
                yaw = format(euler_angle[1, 0])
                roll = format(euler_angle[2, 0])
                print('pitch:{}, yaw:{}, roll:{}'.format(pitch, yaw, roll))
                for (x, y) in shape:
                    cv2.circle(frame, (x, y), 1, (0, 0, 255), -1)
                for start, end in line_pairs:
                    cv2.line(frame, reprojectdst[start], reprojectdst[end], (0, 0, 255))
                cv2.putText(frame, "X: " + "{:7.2f}".format(euler_angle[0, 0]), (20, 20), cv2.FONT_HERSHEY_SIMPLEX,0.75, (0, 0, 255), thickness=2)
                cv2.putText(frame, "Y: " + "{:7.2f}".format(euler_angle[1, 0]), (20, 50), cv2.FONT_HERSHEY_SIMPLEX,0.75, (0, 0, 255), thickness=2)
                cv2.putText(frame, "Z: " + "{:7.2f}".format(euler_angle[2, 0]), (20, 80), cv2.FONT_HERSHEY_SIMPLEX,0.75, (0, 0, 255), thickness=2)    
            cv2.putText(frame, "Press 'q': Quit", (20, 450),cv2.FONT_HERSHEY_SIMPLEX, 0.7, (84, 255, 159), 2)
            cv2.imshow("Head_Posture", frame)
            if cv2.waitKey(1) & 0xFF == ord('q'):
                break
    cap.release()
    cv2.destroyAllWindows()

if __name__ == '__main__':
    main()