How does "struct PacketMotionData" work?

[jules-deponte]

Good afternoon ladies and gents.

I am trying to build a Python script to process the data coming in from F1 2021. The struct PacketHeader and struct CarMotionData UDP specifications work nicely. But I don't understand how the struct PacketMotionData works. Is this part of the Motion Data packet (with Index 0 in the Packet Header)? If so, how do you access/unpack it?

For the moment, I am creating Python lists of each of the fields, just to investigate what they look like. Like I said, for the CarMotionData, this works well. In the code below, d is a single packet; indexed from position 24 (which is just after the header). Doing the same thing as the code below for the PacketMotionData does not work. Any help will be appreciated. Thank you.

df_car_motion_data = pd.DataFrame()

ls_m_world_position_x     = []
ls_m_world_position_y     = []
ls_m_world_position_z     = []
ls_m_world_velocity_x     = []
ls_m_world_velocity_y     = []
ls_m_world_velocity_z     = []
ls_m_world_forward_dir_x  = []
ls_m_world_forward_dir_y  = []
ls_m_world_forward_dir_z  = []
ls_m_world_right_dir_x    = []
ls_m_world_right_dir_y    = []
ls_m_world_right_dir_z    = []
ls_m_g_force_lateral      = []
ls_m_g_force_longitudinal = []
ls_m_g_force_vertical     = []
ls_m_yaw                  = []
ls_m_pitch                = []
ls_m_roll                 = []

for i in range(len(data)):
    
    d = data_b[i]
    

    m_motion = CarMotionData.from_buffer_copy(d[24:])
    
    m_world_position_x     = m_motion.m_world_position_x
    m_world_position_y     = m_motion.m_world_position_y
    m_world_position_z     = m_motion.m_world_position_z
    m_world_velocity_x     = m_motion.m_world_velocity_x
    m_world_velocity_y     = m_motion.m_world_velocity_y
    m_world_velocity_z     = m_motion.m_world_velocity_z
    m_world_forward_dir_x  = m_motion.m_world_forward_dir_x
    m_world_forward_dir_y  = m_motion.m_world_forward_dir_y
    m_world_forward_dir_z  = m_motion.m_world_forward_dir_z
    m_world_right_dir_x    = m_motion.m_world_right_dir_x
    m_world_right_dir_y    = m_motion.m_world_right_dir_y
    m_world_right_dir_z    = m_motion.m_world_right_dir_z
    m_g_force_lateral      = m_motion.m_g_force_lateral
    m_g_force_longitudinal = m_motion.m_g_force_longitudinal
    m_g_force_vertical     = m_motion.m_g_force_vertical
    m_yaw                  = m_motion.m_yaw
    m_pitch                = m_motion.m_pitch
    m_roll                 = m_motion.m_roll
    
    ls_m_world_position_x.append(m_world_position_x)
    ls_m_world_position_y.append(m_world_position_y)
    ls_m_world_position_z.append(m_world_position_z)
    ls_m_world_velocity_x.append(m_world_velocity_x)
    ls_m_world_velocity_y.append(m_world_velocity_y)
    ls_m_world_velocity_z.append(m_world_velocity_z)
    ls_m_world_forward_dir_x.append(m_world_forward_dir_x)
    ls_m_world_forward_dir_y.append(m_world_forward_dir_y)
    ls_m_world_forward_dir_z.append(m_world_forward_dir_z)
    ls_m_world_right_dir_x.append(m_world_right_dir_x)
    ls_m_world_right_dir_y.append(m_world_right_dir_y)
    ls_m_world_right_dir_z.append(m_world_right_dir_z)
    ls_m_g_force_lateral.append(m_g_force_lateral)
    ls_m_g_force_longitudinal.append(m_g_force_longitudinal)
    ls_m_g_force_vertical.append(m_g_force_vertical)
    ls_m_yaw.append(m_yaw)
    ls_m_pitch.append(m_pitch)
    ls_m_roll.append(m_roll)
    

df_car_motion_data['m_world_position_x']     = ls_m_world_position_x
df_car_motion_data['m_world_position_y']     = ls_m_world_position_y
df_car_motion_data['m_world_position_z']     = ls_m_world_position_z
df_car_motion_data['m_world_velocity_x']     = ls_m_world_velocity_x
df_car_motion_data['m_world_velocity_y']     = ls_m_world_velocity_y
df_car_motion_data['m_world_velocity_z']     = ls_m_world_velocity_z
df_car_motion_data['m_world_forward_dir_x']  = ls_m_world_forward_dir_x
df_car_motion_data['m_world_forward_dir_y']  = ls_m_world_forward_dir_y
df_car_motion_data['m_world_forward_dir_z']  = ls_m_world_forward_dir_z
df_car_motion_data['m_world_right_dir_x']    = ls_m_world_right_dir_x
df_car_motion_data['m_world_right_dir_y']    = ls_m_world_right_dir_y
df_car_motion_data['m_world_right_dir_z']    = ls_m_world_right_dir_z
df_car_motion_data['m_g_force_lateral']      = ls_m_g_force_lateral
df_car_motion_data['m_g_force_longitudinal'] = ls_m_g_force_longitudinal
df_car_motion_data['m_g_force_vertical']     = ls_m_g_force_vertical
df_car_motion_data['m_yaw']                  = ls_m_yaw
df_car_motion_data['m_pitch']                = ls_m_pitch
df_car_motion_data['m_roll']                 = ls_m_roll
'''