c++opencvcmake

Compile and link OpenCV to my project in my main CMakeLists.txt


I am new to cmake. I have a project which uses dlib and opencv. They are defined as submodules which are in third_party folder. I want to link them to my main project which is 'node' with cmake but I could not achieved. I am sharing my project tree. I did with find_package(OpenCV) and target_link_libraries(recognition-node ${OPENCV_LIBS}) way but I need to compile from source without installing anything. At last, I just want to write 'cmake . && make'

.
├── CMakeLists.txt
├── node
│   ├── build.sh
│   ├── CMakeLists.txt
│   ├── configure.sh
│   ├── findfacestask.cpp
│   ├── findfacestask.h
│   ├── main.cpp
│   ├── matrixwrapper.h
│   ├── poolcontext.cpp
│   ├── poolcontext.h
│   ├── recognition.dat
│   ├── recognizefacetask.cpp
│   ├── recognizefacetask.h
│   ├── runscript
│   ├── sp.dat
│   ├── task.cpp
│   ├── task.h
│   ├── unhandledexception.cpp
│   ├── unhandledexception.h
│   ├── webcamfeed.cpp
│   ├── webcamfeed.h
│   ├── wrapper.cpp
│   └── wrapper.h
└── third_party
    ├── dlib
    │   ├── appveyor.yml
    │   ├── CMakeLists.txt
    │   ├── dlib
    │   ├── docs
    │   ├── examples
    │   ├── MANIFEST.in
    │   ├── python_examples
    │   ├── README.md
    │   ├── setup.py
    │   └── tools
    └── opencv
        ├── 3rdparty
        ├── apps
        ├── cmake
        ├── CMakeLists.txt
        ├── CONTRIBUTING.md
        ├── data
        ├── doc
        ├── include
        ├── LICENSE
        ├── modules
        ├── platforms
        ├── README.md
        └── samples

Content of my top CMakeLists.txt

cmake_minimum_required(VERSION 2.8.12)

set (CMAKE_CXX_STANDARD 11)

add_subdirectory(node)
add_subdirectory(third_party/dlib)
add_subdirectory(third_party/opencv)

Content of node/CMakeLists.txt

cmake_minimum_required(VERSION 2.8.12)
project(recognition-node)

set(CMAKE_AUTOMOC ON)

find_package(Qt5Widgets REQUIRED)

add_executable(recognition-node main.cpp  
            webcamfeed.cpp 
            poolcontext.cpp 
            unhandledexception.cpp
            task.cpp
            findfacestask.cpp
            wrapper.cpp
            recognizefacetask.cpp)

target_link_libraries(recognition-node Qt5::Widgets)
target_link_libraries(recognition-node dlib::dlib)
target_link_libraries(recognition-node opencv::core)

It gives error in 'make' stage which is :

/home/arnes/workspace/recognition-node/node/poolcontext.h:10:28: fatal error: 
opencv2/core.hpp: No such file or directory

Solution

  • Since you insist on keeping the opencv in your project tree

    It is easier way but I just want it to do in this way.

    Here is the solution that for sure works fine with your project tree that you posted in the question and with opencv-3.4.1. For simplicity I will neglect dlib library and Qt dependency, since you didn't have any problem with it.

    Root CMakeLists.txt should have the following content:

    cmake_minimum_required(VERSION 2.8.11) # or anything higher, if you wish
    project(recognition-node CXX)
    
    add_subdirectory(node)
    

    The CMakeLists.txt under the node directory should have the following content:

    add_subdirectory(third_party)
    
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -g") # or any other additional flags
    
    # at this point you can add find_package(Qt5Widgets REQUIRED) and later link your binary against Qt5::widgets as well
    add_executable(myExec main.cpp
    # and put here all the other source files of your project ...
    )
    # for linking libs I have put additionally highgui and imgproc to check the solution against OpenCV official sample
    target_link_libraries(myExec opencv_core opencv_highgui opencv_imgproc)
    
    target_include_directories(myExec PUBLIC 
        third_party/opencv/modules/calib3d/include
        third_party/opencv/modules/core/include
        third_party/opencv/modules/cudaarithm/include
        third_party/opencv/modules/cudabgsegm/include
        third_party/opencv/modules/cudacodec/include
        third_party/opencv/modules/cudafeatures2d/include
        third_party/opencv/modules/cudafilters/include
        third_party/opencv/modules/cudaimgproc/include
        third_party/opencv/modules/cudalegacy/include
        third_party/opencv/modules/cudaobjdetect/include
        third_party/opencv/modules/cudaoptflow/include
        third_party/opencv/modules/cudastereo/include
        third_party/opencv/modules/cudawarping/include
        third_party/opencv/modules/cudev/include
        third_party/opencv/modules/dnn/include
        third_party/opencv/modules/features2d/include
        third_party/opencv/modules/flann/include
        third_party/opencv/modules/highgui/include
        third_party/opencv/modules/imgcodecs/include
        third_party/opencv/modules/imgproc/include
        third_party/opencv/modules/ml/include
        third_party/opencv/modules/objdetect/include
        third_party/opencv/modules/photo/include
        third_party/opencv/modules/shape/include
        third_party/opencv/modules/stitching/include
        third_party/opencv/modules/superres/include
        third_party/opencv/modules/ts/include
        third_party/opencv/modules/video/include
        third_party/opencv/modules/videoio/include
        third_party/opencv/modules/videostab/include
        third_party/opencv/modules/viz/include
        third_party/opencv/modules/world/include
    )
    

    The CMakeLists.txt under third_party should contain only:

    add_subdirectory(opencv)
    # add_subdirectory(dlib) # if you will use dlib, of course also add dlib
    

    The sample I used to verify the build is contours2.cpp (just copy pasted the content into main.cpp).

    However, I still think that it is a terrible idea to use this solution.

    So, my recommendation is: if you want, use this solution for scientific purpose, but just compile and install OpenCv system-wise (or locally, if you are not the admin) when you really need to use it.