[人工智能]SLAM十四讲第二版ch7位姿估计实践的编译问题

在看ch7中遇到了g2o::OptimizableGraph::Vertex::clone() const’未定义的引用的问题。为了方便以后复现，记录如下:

我的环境配置

Pangolin 0.5
Opencv 3.4.16
cere 1.14
g2o 在slambook2的3rdparty中获取的
cmake 3.22.20211211
eigen3.3.7
sophus 0.9.5
//注意不用git clone。直接下载zip压缩包。
//安装流程网上都有，基本上都是CMake工程。

遇到问题：

[ 83%] Linking CXX executable pose_estimation_3d2d
CMakeFiles/pose_estimation_3d2d.dir/pose_estimation_3d2d.cpp.o:(.rodata._ZTVN3g2o10BaseVertexILi6EN6Sophus8SE3GroupIdLi0EEEEE[_ZTVN3g2o10BaseVertexILi6EN6Sophus8SE3GroupIdLi0EEEEE]+0x30)：对‘g2o::OptimizableGraph::Vertex::clone() const’未定义的引用
CMakeFiles/pose_estimation_3d2d.dir/pose_estimation_3d2d.cpp.o:(.rodata._ZTV10VertexPose[_ZTV10VertexPose]+0x30)：对‘g2o::OptimizableGraph::Vertex::clone() const’未定义的引用
CMakeFiles/pose_estimation_3d2d.dir/pose_estimation_3d2d.cpp.o:(.rodata._ZTVN3g2o8BaseEdgeILi2EN5Eigen6MatrixIdLi2ELi1ELi0ELi2ELi1EEEEE[_ZTVN3g2o8BaseEdgeILi2EN5Eigen6MatrixIdLi2ELi1ELi0ELi2ELi1EEEEE]+0x30)：对‘g2o::OptimizableGraph::Edge::clone() const’未定义的引用
CMakeFiles/pose_estimation_3d2d.dir/pose_estimation_3d2d.cpp.o:(.rodata._ZTVN3g2o13BaseUnaryEdgeILi2EN5Eigen6MatrixIdLi2ELi1ELi0ELi2ELi1EEE10VertexPoseEE[_ZTVN3g2o13BaseUnaryEdgeILi2EN5Eigen6MatrixIdLi2ELi1ELi0ELi2ELi1EEE10VertexPoseEE]+0x30)：对‘g2o::OptimizableGraph::Edge::clone() const’未定义的引用
CMakeFiles/pose_estimation_3d2d.dir/pose_estimation_3d2d.cpp.o:(.rodata._ZTV14EdgeProjection[_ZTV14EdgeProjection]+0x30)：对‘g2o::OptimizableGraph::Edge::clone() const’未定义的引用
collect2: error: ld returned 1 exit status
CMakeFiles/pose_estimation_3d2d.dir/build.make:141: recipe for target 'pose_estimation_3d2d' failed
make[2]: *** [pose_estimation_3d2d] Error 1
CMakeFiles/Makefile2:196: recipe for target 'CMakeFiles/pose_estimation_3d2d.dir/all' failed
make[1]: *** [CMakeFiles/pose_estimation_3d2d.dir/all] Error 2
Makefile:90: recipe for target 'all' failed
make: *** [all] Error 2

具体是什么原因没搞懂，但是估计跟g2o有关，换了很多版本都不行，有可能跟ros的g2o冲突的问题，后面在看了issues后做如下修改：

CMakeLists.txt中

//这里Opencv版本写自己安装的版本，不过这一步好像没有影响，用ros中的opencv是3.3.1,也可以
find_package(OpenCV 3.4.16 REQUIRED)

//第二步 g2o那行换掉，Sophus这里有人遇到fmt的问题，所以我就加上了，不过我去掉了也可以运行
add_executable(pose_estimation_3d2d pose_estimation_3d2d.cpp)
target_link_libraries(pose_estimation_3d2d  ${Sophus_LIBRARIES})
target_link_libraries(pose_estimation_3d2d
        ${G2O_CORE_LIBRARY} ${G2O_STUFF_LIBRARY}
        ${OpenCV_LIBS})

cmake/FindG2O.cmake中

//加入NO_DEFAULT_PATH
# Find the header files

FIND_PATH(G2O_INCLUDE_DIR g2o/core/base_vertex.h
  ${G2O_ROOT}/include
  $ENV{G2O_ROOT}/include
  $ENV{G2O_ROOT}
  /usr/local/include
  /usr/include
  /opt/local/include
  /sw/local/include
  /sw/include
  NO_DEFAULT_PATH
  )

# Macro to unify finding both the debug and release versions of the
# libraries; this is adapted from the OpenSceneGraph FIND_LIBRARY
# macro.

MACRO(FIND_G2O_LIBRARY MYLIBRARY MYLIBRARYNAME)

  FIND_LIBRARY("${MYLIBRARY}_DEBUG"
    NAMES "g2o_${MYLIBRARYNAME}_d"
    PATHS
    ${G2O_ROOT}/lib/Debug
    ${G2O_ROOT}/lib
    $ENV{G2O_ROOT}/lib/Debug
    $ENV{G2O_ROOT}/lib
    NO_DEFAULT_PATH
    )

  FIND_LIBRARY("${MYLIBRARY}_DEBUG"
    NAMES "g2o_${MYLIBRARYNAME}_d"
    PATHS
    ~/Library/Frameworks
    /Library/Frameworks
    /usr/local/lib
    /usr/local/lib64
    /usr/lib
    /usr/lib64
    /opt/local/lib
    /sw/local/lib
    /sw/lib
    NO_DEFAULT_PATH
    )
  
  FIND_LIBRARY(${MYLIBRARY}
    NAMES "g2o_${MYLIBRARYNAME}"
    PATHS
    ${G2O_ROOT}/lib/Release
    ${G2O_ROOT}/lib
    $ENV{G2O_ROOT}/lib/Release
    $ENV{G2O_ROOT}/lib
    NO_DEFAULT_PATH
    )

  FIND_LIBRARY(${MYLIBRARY}
    NAMES "g2o_${MYLIBRARYNAME}"
    PATHS
    ~/Library/Frameworks
    /Library/Frameworks
    /usr/local/lib
    /usr/local/lib64
    /usr/lib
    /usr/lib64
    /opt/local/lib
    /sw/local/lib
    /sw/lib
    NO_DEFAULT_PATH
    )

然后在build中cmake和make就可以了。