Compilation issues and solutions

[petern3]

I have come across various compilation issues and solved them, so I'll put the process here for everyone else. I may not have the same problems as other people, but hopefully this is helpful!

Operating System: Windows 10, 64 bit Compiler: Visual Studio 2015

Half of the changes are to support more recent libraries such as OpenCV3 and Eigen3. I think these are all the changes I made:

(1) g2o can't find BLAS and LAPACK. The original ORB_SLAM2 g2o CMakeLists.txt file has removed the following two lines, and it seems to work:

-    FIND_PACKAGE(BLAS REQUIRED)
-    FIND_PACKAGE(LAPACK REQUIRED)

I also removed the g2o cmake_modules folder, since it apparently isn't needed either. I think it works because BLAS and LAPACK are in Eigen3?

(2) Every time there was an OpenCV dependency, I changed the following lines to support OpenCV3. This is only necessary if you use 3:

  -    find_package(OpenCV 2.4.3 REQUIRED)
  +    find_package(OpenCV 3.0 QUIET)
  +    if(NOT OpenCV_FOUND)
  +       find_package(OpenCV 2.4.3 REQUIRED)
  +    endif()

(3) I also had to change line 56 of linear_solver_eigen.h to support eigen3.3 (g2o will compile without this change, ORB_SLAM2 may not):

-    typedef Eigen::PermutationMatrix<Eigen::Dynamic, Eigen::Dynamic, SparseMatrix::Index> PermutationMatrix;
+    typedef Eigen::PermutationMatrix<Eigen::Dynamic, Eigen::Dynamic> PermutationMatrix;

(4) When configuring ORB_SLAM2 itself, I had another issue in PangolinConfig.cmake, so I've fixed by removing:

-    add_library(_libjpeg STATIC IMPORTED)
-    set_target_properties(_libjpeg PROPERTIES
-        IMPORTED_LOCATION C:/Program Files/Pangolin/build/external/libjpeg/lib/jpeg.lib
-    )

Important: I also put quotes around all of directories in that file.

(5) If the linker can't find anything such as "_libjpeg", go into Project -> Properties -> Linker -> Input, and into Additional Dependencies. Double check all the values in there. As for _libjpeg.lib, I replaced it with C:/Program Files/Pangolin/build/external/libjpeg/lib/jpeg.lib (or the relevant location).

(6) It also complained about a runtime library mismatch. The two options are:

1. RECOMMENDED: recompile Pangolin as a DLL (check BUILD_SHARED_LIBS is ON and MSVC_USE_STATIC_CRT to OFF in CMake).
2. Go into ORB_SLAM2 Project -> Properties -> C/C++ -> Code Generation, set Runtime Library from Multi-threaded DLL (/MD) to Multi-threaded (/MT). You may need to do this for each individual project. I didn't get this method to work, because it would involve a lot of recompiling.

Also make sure that each time you compile something, the Debug/Release mode is consistent.

[petern3]

Okay, things are getting a bit hacky now. To use ORB_SLAM2 in my own program with CMake, I have used

set(ORB_SLAM2 "C:/Program Files/ORB_SLAM2/build/Release/ORB_SLAM2.lib")
include_directories("C:/Program Files/ORB_SLAM2/include")

set(DBOW2 "C:/Program Files/ORB_SLAM2/Thirdparty/DBoW2/bin/Release/dbow2.lib")
include_directories("C:/Program Files/ORB_SLAM2/Thirdparty/DBoW2/dbow2")

set(G2O "C:/Program Files/ORB_SLAM2/Thirdparty/g2o/bin/Release/g2o.lib")
include_directories("C:/Program Files/ORB_SLAM2/Thirdparty/g2o")

I also had to change the following line in LoopClosing.h:

-    #include "Thirdparty/g2o/g2o/types/types_seven_dof_expmap.h"
+    #include "g2o/types/types_seven_dof_expmap.h"

and copy the g2o config file into the g2o subfolder.