./build_ros.sh 解决报错 rospack found package “ORB_SLAM3“ at ““, but the current directory is....

同样针对ORB-SLAM2也有效：

编译ORB的ROS版本经常出现这个问题：

CMake Error at /opt/ros/melodic/share/ros/core/rosbuild/private.cmake:99 (message):
  [rosbuild] rospack found package "ORB_SLAM3" at "", but the current
  directory is "/home/tzy/ORB3/ORB_SLAM3_detailed_comments/Examples/ROS/ORB_SLAM3".
  You should double-check your ROS_PACKAGE_PATH to ensure that packages are
  found in the correct precedence order.
Call Stack (most recent call first):
  /opt/ros/melodic/share/ros/core/rosbuild/public.cmake:177 (_rosbuild_check_package_location)
  CMakeLists.txt:4 (rosbuild_init)


-- Configuring incomplete, errors occurred!
See also "/home/tzy/ORB3/ORB_SLAM3_detailed_comments/Examples/ROS/ORB_SLAM3/build/CMakeFiles/CMakeOutput.log".
See also "/home/tzy/ORB3/ORB_SLAM3_detailed_comments/Examples/ROS/ORB_SLAM3/build/CMakeFiles/CMakeError.log".
Makefile:724: recipe for target 'cmake_check_build_system' failed
make: *** [cmake_check_build_system] Error 1

而且检查发现.bashrc文件中的路径也是正确添加了，但依然报错

报错原因：

路径添加在 source ~/catkin_ws/devel/setup.bash 等之前了，导致路径被覆盖了，如下：

解决方法：

打开bashrc

gedit ~/.bashrc

将路径尽量添加在最下面（至少在 source 后），然后保存退出，

export ROS_PACKAGE_PATH=${ROS_PACKAGE_PATH}:/home/tzy/ORB3/ORB_SLAM3_detailed_comments/Examples/ROS

之后在终端source一下

source ~/.bashrc

然后再去编译就不会报错了

./build_ros.sh