1. Install prerequisites

1.1. MinGW-W64

MinGW64 can be downloaded from here.
Note
At the time this tutorial was created, we downloaded the latest UCRT runtime Win64 Zip archive Version "GCC 13.1.0 (with POSIX threads) + LLVM/Clang/LLD/LLDB 16.0.5 + MinGW-w64 11.0.0 (UCRT) - release 5 (LATEST)" that brings winlibs-x86_64-posix-seh-gcc-13.1.0-llvm-16.0.5-mingw-w64ucrt-11.0.0-r5.zip file.
After downloading, you should unzip the file to a folder. We recommend to unzip in to C:\ root drive.
At this point, in C:\mingw64 folder you should have something similar to
Then you have to set up path. For that follow these steps:
- Open settings
- Search for Edit environment variables for your account
- Choose path variable and then select edit
- Select New and add the path to Mingw-w64 bin folder. In our case, you may add C:\mingw64\bin
- Select OK to save the updated path
- Now reopen your cmd and check if everything is good by typing:
```
C:\> gcc --version
gcc (MinGW-W64 x86_64-ucrt-posix-seh, built by Brecht Sanders) 13.1.0
Copyright (C) 2023 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
```

1.2. CMake

CMake could be download from http://www.cmake.org. Download the latest release for Windows win64-x64 platform (at the time this tutorial was written it was the file cmake-3.26.4-win64-x64.msi). To install just double click on the msi file.

1.3. Git

Install Git for Windows from https://git-for-windows.github.io/. This installation allows then to use git in a cmd Command Prompt.

2. Create a workspace

If not already done, create a workspace that will contain all ViSP source, build, data set and optional 3rd parties. This workspace is here set to C:\visp-ws folder, but it could be set to any other location.

To create the workspace, open a cmd Command Prompt (a fast way to launch this window is to press the Win + R keys on your keyboard. Then, type cmd or cmd.exe and press Enter or click/tap OK) and run the following to create a workspace environment var named VISP_WS:

C:\> setx VISP_WS "C:\visp-ws"
C:\> exit

Open a new cmd Command Prompt and create the corresponding folder

C:\> mkdir %VISP_WS%
C:\> exit

3. Quick ViSP installation

In this section, we give minimal instructions to build ViSP from source just to try ViSP without entering in

Advanced ViSP installation

.

Open a new cmd Command Prompt and get ViSP source code in the workspace

C:\> cd %VISP_WS%
C:\> git clone https://github.com/lagadic/visp.git

Create a build directory

C:\> mkdir %VISP_WS%\visp-build-mingw
C:\> cd %VISP_WS%\visp-build-mingw

Run CMake in build directory (here the generator is chosen for Visual Studio 15 2017 and 64 bits hardware):
```
C:\> cmake -G "MinGW Makefiles" %VISP_WS%\visp
```
Build and install ViSP (installation doesn't need administrator privileges)
```
C:\> cmake --build . --config Release --target install -j4
```
ViSP is now installed in %VISP_WS%\visp-build-mingw\install folder
Modify the Path var to add %VISP_WS%\visp-build-mingw\install\x64\mingw\bin corresponding to the path to ViSP libraries. To modify Path environment variable do the following:
- Open the Start Search, type in "env", and choose "Edit environment variables for your account"
- Click the "Environment Variables..." button
- Under the "User Variables" section (the upper half), find the row with "Path" in the first column, and click edit
- The "Edit environment variable" UI will appear.
- Click "New" button to add a new line with %VISP_WS%\visp-build-mingw\install\x64\mingw\bin

Set VISP_DIR var to help CMake to find ViSP as a 3rd party

C:\> setx VISP_DIR "%VISP_WS%\visp-build-mingw\install"
C:\> exit

To have a trial, just jump to

Install ViSP data set

before running some binaries that you just build or jump to

Next tutorial

. You can later come back to the

Advanced ViSP installation

.

4. Advanced ViSP installation

4.1. Install 3rd parties

ViSP is interfaced with several 3rd party libraries. Follow the link to see the complete list of Supported Third-Party Libraries. We recommend to install 4.1.2. Eigen3, 4.1.1. OpenCV and 4.1.3. Nlohmann JSON in the workspace.

4.1.1. OpenCV

4.1.1.1. Get OpenCV

First you have to get OpenCV:

From https://opencv.org/releases/ download the latest OpenCV for Windows. In our case we got opencv-4.8.0-windows.exe Win pack installer. The same procedure could be applied with all the previous OpenCV releases starting from 3.4.0 version.
Extract the content of the archive in your workspace %VISP_WS%\3rdparty.
The installer extract all the material in %VISP_WS%\3rdparty\opencv.
We strongly recommend to rename this folder to a name that contain OpenCV version like %VISP_WS%\3rdparty\opencv-4.8.0.

Note: OpenCV 4.7.0 win pack installer contains prebuild OpenCV libraries build with Visual Studio 16 2019 (vc16) but there is no build for MinGW. That's why you need to build yourself OpenCV from source and install the libraries in %VISP_WS%\3rdparty\opencv-4.8.0\build\x64\mingw.

4.1.1.2. Configure, build and install OpenCV from source

Open a cmd Command Prompt and create a build folder

C:\> cd %VISP_WS%\3rdparty\opencv-4.8.0
C:\> mkdir build-mingw
C:\> cd build-mingw

Run CMake in build directory and set the install dir to %VISP_WS%\3rdparty\opencv-4.8.0\build. We disable also tests build in order to speed up the build process:
```
C:\> cmake -G "MinGW Makefiles" ..\sources -DCMAKE_INSTALL_PREFIX=%VISP_WS%\3rdparty\opencv-4.8.0\build -DBUILD_TESTS=OFF -DBUILD_PERF_TESTS=OFF
```
Build and install OpenCV for MinGW (installation doesn't need administrator privileges)
```
C:\> cmake --build . --config Release --target install -j4
```
OpenCV is now installed in %VISP_WS%\opencv-4.8.0\build folder

Note: - With OpenCV 4.7.0 and 4.8.0 if you don't set WITH_OBSENSOR=OFF during cmake configuration you will get an 7.1. OpenCV 4.7.0 and 4.8.0 compilation problem in obsensor_stream_channel_msmf.cpp.; - With OpenCV 4.5.0 if you don't set OPENCV_ENABLE_ALLOCATOR_STATS=OFF you will get an 7.2. OpenCV 4.5.0 compilation problem gcc: error: long: No such file or directory.; - With OpenCV 4.1.0 if you don't set WITH_OPENCL_D3D11_NV=OFF you will get an 7.3. OpenCL D3D11 build failure.; - Using OpenCV older versions you may encounter the following issues, for which we propose work arounds; 7.9. windres.exe invalid option –W, 7.10. Build error in cap_dshow.cpp, 7.7. OpenCV build error: struct has virtual functions and accessible non-virtual destructor, 7.5. OpenCV build error: cannot build with tiff support, or 7.6. OpenCV link error: cannot find -lRunTmChk.

4.1.1.3. Complete OpenCV installation

Now you have to complete OpenCV installation setting some environment vars:

In order that ViSP detects OpenCV you have to set OpenCV_DIR environment variable. Start up a cmd Command Prompt and enter:
```
C:\> setx OpenCV_DIR "%VISP_WS%\3rdparty\opencv-4.8.0\build"
C:\> exit
```
where %VISP_WS%\3rdparty\opencv-4.8.0\build is where you have installed OpenCV. Inside this folder you should have a file named OpenCVConfig.cmake.
You have also to add the location of OpenCV libraries corresponding to MinGW usage in the Path environment variable. Open the "Edit environment variable" UI, and modify Path to add a new line with %VISP_WS%\3rdparty\opencv-4.8.0\build\x64\mingw\bin.

4.1.2. Eigen3

Even if Eigen3 is designed as a template we recommend to install the library with MinGW.

4.1.2.1. Get Eigen3

Download the latest Eigen3 release from http://eigen.tuxfamily.org. At the time this tutorial was written we downloaded eigen-3.4.0.zip archive corresponding to Eigen 3.4.0.
Extract the content of the archive in %VISP_WS%\3rdparty.
Once unzipped, you should have Eigen in %VISP_WS%\3rdparty\eigen-3.4.0

4.1.2.2. Build and install Eigen3 from source

Create a build directory

C:\> cd %%VISP_WS%\3rdparty\eigen-3.4.0
C:\> mkdir build-mingw
C:\> cd build-mingw

Run CMake in build directory (here the generator is chosen for MinGW and installation folder is set to %VISP_WS%\3rdparty\eigen-3.4.0\build-mingw\install folder):
```
C:\> cmake -G "MinGW Makefiles" .. -DCMAKE_INSTALL_PREFIX=%VISP_WS%\3rdparty\eigen-3.4.0\build-mingw\install
```
Build and install Eigen3 (installation doesn't need administrator privileges)
```
C:\> cmake --build . --config Release --target install -j4
```
Eigen3 is now installed in %VISP_WS%\3rdparty\eigen-3.4.0\build-mingw\install folder.

4.1.2.3. Complete Eigen3 installation

Now you have to complete Eigen3 installation setting some environment vars:

In order that ViSP detects eigen you have to set EIGEN_DIR environment variable. Start up a cmd Command Prompt and enter:
```
C:\> setx Eigen3_DIR "%VISP_WS%\3rdparty\eigen-3.4.0\build-mingw\install\share\eigen3\cmake"
C:\> exit
```
where %VISP_WS%\3rdparty\eigen-3.4.0\build-mingw\install is where you have installed Eigen3. Inside the folder %VISP_WS%\3rdparty\eigen-3.4.0\build-mingw\install\share\eigen3\cmake you should have a file named Eigen3Config.cmake.
There is no need to set Path environment var since Eigen3 is a template that has no library.

4.1.3. Nlohmann JSON

JSON for modern C++ installation need to be installed from source for MinGW.

Open a cmd Command Prompt and follow the instructions below
```
C:\> cd %VISP_WS%\3rdparty
C:\> git clone https://github.com/nlohmann/json.git
C:\> cd json && mkdir build-mingw && cd build-mingw
C:\> cmake -G "MinGW Makefiles" .. -DCMAKE_INSTALL_PREFIX=%VISP_WS%\3rdparty\json\build-mingw\install -DBUILD_TESTING=OFF -DJSON_BuildTests=OFF
C:\> cmake --build . --config Release --target install
```
JSON is now installed in %VISP_WS%\3rdparty\json\build-mingw\install folder. Now in order that ViSP detects JSON you have to set nlohmann_json_DIR environment variable. Start up a cmd Command Prompt and enter:
```
C:\> setx nlohmann_json_DIR "%VISP_WS%\3rdparty\json\build-mingw\install\share\cmake\nlohmann_json"
C:\> exit
```
where %VISP_WS%\3rdparty\json\build-mingw\install is where you have installed JSON. Inside the folder %VISP_WS%\3rdparty\json\build-mingw\install\share\cmake\nlohmann_json you should have a file named nlohmann_jsonConfig.cmake. There is no need to set Path environment var since JSON has only a header and no library.

4.2. Get ViSP source code

There are different ways to get ViSP source code.

You can download the latest release as a zip or a tarball. Once visp-x.y.z.tar.gz or visp-x.y.z.zip is downloaded, uncompress the file in %VISP_WS%\visp\visp-x.y.z using for example WinRAR.
You can also download a daily snapshot. Once visp-snapshot-yyyy-mm-dd.tar.gz is downloaded, uncompress the file in %VISP_WS%\visp\visp-x.y.z using for example WinRAR.
Or you get the cutting-edge ViSP from GitHub repository using the git command line tool:
```
C:\> cd %VISP_WS%
C:\> git clone https://github.com/lagadic/visp.git
```

We suppose now that ViSP source is in %VISP_WS%\visp.

4.3. Configure ViSP from source

The goal of the configuration step is now to use CMake to produce a Visual Studio C++ solution file that will be located in %VISP_WS%/visp-build-mingw.

Launch CMake (cmake-gui) and complete the source code and binaries location as in the next image.
Click then on "Configure" button.
Click on "Yes" to create the %VISP_WS%/visp-build-mingw folder.
Select then your compiler "MinGW Makefiles" and click on "Finish" button.
This will start CMake configuration. As shown in the next image, Eigen3, GDI, JSON, OpenCV and OpenMP 3rd parties are automatically detected.

Note
- If OpenCV is not detected, you may encounter the following issue 7.8. OpenCV not detected with Mingw build.

- Installation folder is set to %VISP_WS%/visp-build-mingw/install. If you want to change the installation folder to C:/Program Files (x86)/ViSP, make sure that you have administrator privileges to write in that folder before modifying CMAKE_INSTALL_PREFIX.
Click then on "Configure" button. All the red lines should disappear.
Note
The default configuration lead to the creation of a shared library (with .dll extension). This is the default configuration that is recommended. If you want to create rather a static library (with .lib extension) you have to uncheck the BUILD_SHARED_LIBS option to disable DLL creation.
To finish the configuration, click on "Generate" button.
Once the generation is done, in %VISP_WS%/visp-build-mingw folder you have the Makefile file that will be used by MinGW to build the whole project.

4.4. Build and install ViSP

To build ViSP, open a cmd Command Prompt, change to %VISP_WS%\visp-build-mingw folder and run mingw32-make:
```
C:\> cd %VISP_WS%\visp-build-mingw
C:\> mingw32-make -j4
```
Now to install ViSP, in the same cmd Command Prompt run:
```
C:\> mingw32-make -j4 install
```
At the end, in %VISP_WS%/visp-build-mingw/install/x64/mingw/bin folder you will find ViSP DLL libraries corresponding to the build modules.

Note: When CMAKE_BUILD_TYPE is set to Debug, the library names are suffixed by "d".

4.5. Build ViSP documentation

To build ViSP documentation, you have first to install Doxygen:

Download binary distribution for Windows. At the time this tutorial was written, we downloaded doxygen-1.8.20-setup.exe
Run the installer following default options
Open a new cmd Command Prompt and enter build directory
```
C:\> cd %VISP_WS%\visp-build-mingw
```

Run CMake in build directory:

C:\> cmake -G "MinGW Makefiles" %VISP_WS%\visp

Build documentation using:

C:\> cmake --build . --config Release --target visp_doc

The generated documentation is then available in $VISP_WS/visp-build-mingw/doc/html/index.html

Note

To speed up generating online doc, particularly around formula rendering, you can use MatJax. To this end, install first npm LTS version following these instructions, then install MathJax and build doc using:
```
C:\> npm install mathjax
C:\> cmake -G "MinGW Makefiles" %VISP_WS%\visp -DUSE_MATHJAX=ON
C:\> cmake --build . --config Release --target visp_doc
```
It is also possible to generate a more complete documentation that includes also all the internal classes. This could be achieved setting CMake var ENABLE_FULL_DOC to ON like:
```
C:\> cmake -G "MinGW Makefiles" %VISP_WS%\visp -DENABLE_FULL_DOC=ON
C:\> cmake --build . --config Release --target visp_doc
```

4.6. Set Path environment var

Modify the Path var to add the path to ViSP dll libraries. To this end open the "Edit environment variable" UI, and modify Path to add a new line with %VISP_WS%\visp-build-mingw\install\x64\mingw\bin.

4.7. Set VISP_DIR environment var

In order to ease ViSP detection by CMake when ViSP is used as a 3rd party in an external project, like the one described in the Tutorial: How to create and build a project that uses ViSP and CMake on Unix or Windows, you may set VISP_DIR environment variable with the path to the VISPConfig.cmake file:

C:\> setx VISP_DIR "%VISP_WS%\visp-build-mingw\install"
C:\> exit

5. Install ViSP data set

Some ViSP examples and tests require a dataset that contains images, video, models that is not part of ViSP source code. This dataset is available in Github (https://github.com/lagadic/visp-images) or as a release in a separate archive named visp-images-x.y.z.zip. This archive could be downloaded from https://visp.inria.fr/download page. Note that ViSP tutorials are not using ViSP data set.

We give hereafter the two ways to get this data set:

5.1. Get data set release

Download the latest dataset release from https://visp.inria.fr/download and uncompress it in your workspace %VISP_WS%. At the time this tutorial was written, the latest release was visp-images-3.6.0.zip.
Once downloaded, you need to set VISP_INPUT_IMAGE_PATH environment variable to help ViSP examples and tests to detect automatically the location of the requested data. In our case, this variable should be set to %VISP_WS%\visp-images-3.6.0. Open a cmd Command Prompt and run
```
C:\> setx VISP_INPUT_IMAGE_PATH %VISP_WS%\visp-images-3.6.0
C:\> exit
```

5.2. Get data set from github

Use git to get the data set latest version:

C:\> cd %VISP_WS%
C:\> git clone https://github.com/lagadic/visp-images.git

Once cloned, you need to set VISP_INPUT_IMAGE_PATH environment variable to help ViSP examples and tests to detect automatically the location of the requested data. In our case, this variable should be set to %VISP_WS%\visp-images. Open a cmd Command Prompt and run
```
C:\> setx VISP_INPUT_IMAGE_PATH %VISP_WS%\visp-images
C:\> exit
```

5.3. Test data set usage

From now, you can try to run ViSP examples and tests. For example, if you want to run %VISP_WS%\visp-build-mingw\example\device\display\displayOpenCV.exe, open a cmd Command Prompt, enter in the right folder and run:

C:\> cd %VISP_WS%\visp-build-mingw\example\device\display
C:\> displayOpenCV.exe

A click to close the windows...

A click to display a cross...
Cross position: 392, 306

A click to exit the program...
Bye

6. Tips and tricks

6.1. How to take into account a newly installed 3rd party

Since all 3rd parties are optional you may have started to install only some of them. Imagine that you just installed a new third-party, or that you upgraded the version of this 3rd party. The next step is to go back to the build folder, configure ViSP with CMake to detect the newly installed third-party library and build again ViSP. This could be achieved with:

$ cd $VISP_WS/visp-build-mingw
$ cmake ../visp

Here you can check the content of the ViSP-third-party.txt file and see if the newly installed 3rd party is well detected.

Finally, you need to rebuild ViSP with:

$ mingw32-make

6.2. How to uninstall ViSP

After ViSP installation, you can remove installed material using:

$ cd $VISP_WS/visp-build-mingw
$ mingw32-make uninstall

6.3. How to build only ViSP libraries

If you want to build only ViSP modules libraries, nor the examples, tutorials and tests:

$ cd $VISP_WS%/visp-build-mingw
$ mingw32-make visp_modules

6.4. How to build a ViSP specific module

If you want to build a given module and all the dependencies:

$ cd $VISP_WS%/visp-build-mingw
$ mingw32-make visp_<module_name>

For example to build the model-based tracker module named mbt, run:

$ cd $VISP_WS%/visp-build-mingw
$ mingw32-make visp_mbt

6.5. Which are the 3rd party libraries that are used in ViSP ?

To see which are the optional 3rd parties that are found during the configuration stage and that will be used by ViSP during the build you can have a look to the text file named ViSP-third-party.txt and located in %VISP_WS%/visp-build-mingw. We provide hereafter an example of a possible content of this file that contains also build info.

$ type %VISP_WS%/visp-build-mingw/ViSP-third-party.txt

==========================================================
General configuration information for ViSP 3.5.1

  Version control:               08a979a03-dirty

  Platform:
    Timestamp:                   2023-07-06T14:34:24Z
    Host:                        Windows 10.0.19044 AMD64
    CMake:                       3.26.4
    CMake generator:             MinGW Makefiles
    CMake build tool:            C:/mingw64/bin/mingw32-make.exe
    Configuration:               Release

  System information:
    Number of CPU logical cores: 4
    Number of CPU physical cores: 4
    Total physical memory (in MiB): 16057
    OS name:                     Windows
    OS release:                  Professional
    OS version:                  (Build 19044)
    OS platform:                 AMD64
    CPU name:                    Pentium II (0.25 micron)
    Is the CPU 64-bit?           yes
    Does the CPU have FPU?       yes
    CPU optimization:            SSE2 SSE3 SSSE3

  C/C++:
    Built as dynamic libs?:      yes
    C++ Compiler:                C:/mingw64/bin/c++.exe  (ver 13.1.0)
    C++ flags (Release):         -Wall -Wextra -fopenmp -std=c++17 -fvisibility=hidden -msse2 -msse3 -mssse3 -O3 -DNDEBUG
    C++ flags (Debug):           -Wall -Wextra -fopenmp -std=c++17 -fvisibility=hidden -msse2 -msse3 -mssse3 -g
    C Compiler:                  C:/mingw64/bin/gcc.exe
    C flags (Release):           -Wall -Wextra -fopenmp -std=c++17 -fvisibility=hidden -msse2 -msse3 -mssse3 -O3 -DNDEBUG
    C flags (Debug):             -Wall -Wextra -fopenmp -std=c++17 -fvisibility=hidden -msse2 -msse3 -mssse3 -g
    Linker flags (Release):
    Linker flags (Debug):
    Use cxx standard:            17

  ViSP modules:
    To be built:                 core dnn_tracker gui imgproc io java_bindings_generator klt me sensor ar blob robot visual_features vs vision detection mbt tt tt_mi
    Disabled:                    -
    Disabled by dependency:      -
    Unavailable:                 java

  Windows RT support:            no

  Python (for build):            C:/Python310/python.exe

  Java:
    ant:                         no
    JNI:                         C:/Program Files/Microsoft/jdk-11.0.16.101-hotspot/include C:/Program Files/Microsoft/jdk-11.0.16.101-hotspot/include/win32 C:/Program Files/Microsoft/jdk-11.0.16.101-hotspot/include

  Build options:
    Build deprecated:            yes
    Build with moment combine:   no

  OpenCV:
    Version:                     4.8.0
    Modules:                     calib3d core dnn features2d flann gapi highgui imgcodecs imgproc ml objdetect photo stitching video videoio
    OpenCV dir:                  C:/visp-ws/3rdparty/opencv-4.8.0/build

  Mathematics:
    Blas/Lapack:                 yes
    \- Use MKL:                  no
    \- Use OpenBLAS:             no
    \- Use Atlas:                no
    \- Use Netlib:               no
    \- Use GSL:                  no
    \- Use Lapack (built-in):    yes (ver 3.2.1)
    Use Eigen3:                  yes (ver 3.4.0)
    Use OpenCV:                  yes (ver 4.8.0)

  Simulator:
    Ogre simulator:
    \- Use Ogre3D:               no
    \- Use OIS:                  no
    Coin simulator:
    \- Use Coin3D:               no
    \- Use SoWin:                no
    \- Use SoXt:                 no
    \- Use SoQt:                 no
    \- Use Qt5:                  no
    \- Use Qt4:                  no
    \- Use Qt3:                  no

  Media I/O:
    Use JPEG:                    no
    Use PNG:                     no
    \- Use ZLIB:                 no
    Use OpenCV:                  yes (ver 4.8.0)
    Use stb_image (built-in):    yes (ver 2.27.0)
    Use TinyEXR (built-in):      yes (ver 1.0.2)

  Real robots:
    Use Afma4:                   no
    Use Afma6:                   no
    Use Franka:                  no
    Use Viper650:                no
    Use Viper850:                no
    Use ur_rtde:                 no
    Use Kinova Jaco:             no
    Use aria (Pioneer):          no
    Use PTU46:                   no
    Use Biclops PTU:             no
    Use Flir PTU SDK:            no
    Use MAVSDK:                  no
    Use Parrot ARSDK:            no
    \-Use ffmpeg:                no
    Use Virtuose:                no
    Use qbdevice (built-in):     yes (ver 2.6.0)
    Use takktile2 (built-in):    no

  GUI:
    Use X11:                     no
    Use GTK:                     no
    Use OpenCV:                  yes (ver 4.8.0)
    Use GDI:                     yes
    Use Direct3D:                no

  Cameras:
    Use DC1394-2.x:              no
    Use CMU 1394:                no
    Use V4L2:                    no
    Use directshow:              no
    Use OpenCV:                  yes (ver 4.8.0)
    Use FLIR Flycapture:         no
    Use Basler Pylon:            no
    Use IDS uEye:                no

  RGB-D sensors:
    Use Realsense:               no
    Use Realsense2:              no
    Use Occipital Structure:     no
    Use Kinect:                  no
    \- Use libfreenect:          no
    \- Use libusb-1:             no
    \- Use pthread:              no
    Use PCL:                     no
    \- Use VTK:                  no

  F/T sensors:
    Use atidaq (built-in):       no
    Use comedi:                  no
    Use IIT SDK:                 no

  Mocap:
    Use Qualisys:                no
    Use Vicon:                   no

  Detection:
    Use zbar:                    no
    Use dmtx:                    no
    Use AprilTag (built-in):     yes (ver 3.1.1)
    \- Use AprilTag big family:  no

  Misc:
    Use Clipper (built-in):      yes (ver 6.4.2)
    Use pugixml (built-in):      yes (ver 1.9.0)
    Use libxml2:                 no
    Use json (nlohmann):         yes (ver 3.11.2)

  Optimization:
    Use OpenMP:                  yes
    Use pthread:                 no
    Use pthread (built-in):      yes (ver 3.0.1)
    Use Simd (built-in):         yes (ver 4.9.109)

  DNN:
    Use CUDA Toolkit:            no
    Use TensorRT:                no

  Documentation:
    Use doxygen:                 yes
    \- Use mathjax:              no

  Tests and samples:
    Use catch2 (built-in):       yes (ver 2.13.7)
    Tests:                       yes
    Demos:                       yes
    Examples:                    yes
    Tutorials:                   yes
    Dataset found:               yes (ver 3.6.0 in C:\visp-ws\visp-images)

  Library dirs:
    Eigen3 include dir:          C:/visp-ws/3rdparty/eigen-3.4.0/build-vc17/install/share/eigen3/cmake
    OpenCV dir:                  C:/visp-ws/3rdparty/opencv-4.8.0/build

  Install path:                  C:/visp-ws/visp-build-mingw/install

==========================================================

7. Known issues

7.1. OpenCV 4.7.0 and 4.8.0 compilation problem in obsensor_stream_channel_msmf.cpp

This issue occurs with OpenCV 4.7.0 and OpenCV 4.8.0.

In file included from C:\visp-ws\3rdparty\opencv-4.7.0\sources\modules\videoio\src\cap_obsensor\obsensor_stream_channel_msmf.hpp:41,
                 from C:\visp-ws\3rdparty\opencv-4.7.0\sources\modules\videoio\src\cap_obsensor\obsensor_stream_channel_msmf.cpp:25:
C:\visp-ws\3rdparty\opencv-4.7.0\sources\modules\videoio\src\cap_obsensor\obsensor_stream_channel_msmf.hpp: In instantiation of 'class cv::obsensor::ComPtr<IMFAttributes>':
C:\visp-ws\3rdparty\opencv-4.7.0\sources\modules\videoio\src\cap_obsensor\obsensor_stream_channel_msmf.hpp:145:42:   required from here
C:\visp-ws\3rdparty\opencv-4.7.0\sources\modules\videoio\src\cap_obsensor\obsensor_stream_channel_msmf.hpp:106:27: error: could not convert template argument 'cv::obsensor::ComPtr<IMFAttributes>::__T_IID_getter' from 'const IID& (cv::obsensor::ComPtr<IMFAttributes>:()' {aka 'const GUID& (cv::obsensor::ComPtr<IMFAttributes>:()'} to 'const IID& ()' {aka 'const GUID& ()'}
  106 |     _COM_SMARTPTR_TYPEDEF(T, __uuidof(T));

The workaround is to configure OpenCV using cmake -DWITH_OBSENSOR=OFF like:

C:\> cd %VISP_WS%\opencv-4.7.0\build-mingw
C:\> C:\> cmake -G "MinGW Makefiles" ..\sources -DCMAKE_INSTALL_PREFIX=%VISP_WS%\3rdparty\opencv-4.7.0\build -DBUILD_TESTS=OFF -DBUILD_PERF_TESTS=OFF -DWITH_OBSENSOR=OFF
C:\> cmake --build . --config Release --target install -j4

Note: Previous instructions need to be adapted to your OpenCV version.

7.2. OpenCV 4.5.0 compilation problem gcc: error: long: No such file or directory

This issue occurs with OpenCV 4.5.0 and is referenced here.

C:\>cmake --build . --config Release --target install
...
[ 44%] Building RC object modules/core/CMakeFiles/opencv_core.dir/vs_version.rc.obj
gcc: error: long: No such file or directory
C:\PROGRA~1\MINGW-~1\X86_64~1.0-P\mingw64\bin\windres.exe: preprocessing failed.
mingw32-make.exe[2]: *** [modules\core\CMakeFiles\opencv_core.dir\build.make:1494: modules/core/CMakeFiles/opencv_core.dir/vs_version.rc.obj] Error 1
mingw32-make.exe[1]: *** [CMakeFiles\Makefile2:1770: modules/core/CMakeFiles/opencv_core.dir/all] Error 2
mingw32-make.exe: *** [Makefile:181: all] Error 2

The workaround is to configure OpenCV using cmake -DOPENCV_ENABLE_ALLOCATOR_STATS=OFF like:

C:\> cd %VISP_WS%\opencv-4.5.0\build-mingw
C:\> cmake -G "MinGW Makefiles" ..\sources -DCMAKE_INSTALL_PREFIX=%VISP_WS%\opencv-4.5.0\build \
     -DBUILD_TESTS=OFF -DBUILD_PERF_TESTS=OFF -DWITH_OPENCL_D3D11_NV=OFF -DOPENCV_ENABLE_ALLOCATOR_STATS=OFF
C:\> cmake --build . --config Release --target install -j4

7.3. OpenCL D3D11 build failure

This issue occurs with OpenCV 4.1.1 and is referenced here.

If you encounter the following issue during OpenCV build:

you have to disable OpenCL D3D11 support and restart a new build:

C:\> cd %VISP_WS%\opencv-4.1.1\build-mingw
C:\> cmake -G "MinGW Makefiles" ..\sources -DCMAKE_INSTALL_PREFIX=%VISP_WS%\opencv-4.1.1\build \
    -DWITH_OPENCL_D3D11_NV=OFF
C:\> cmake --build . --config Release --target install

7.4. OpenCV endianness failure during CMake configuration

Note: This issue occurs with OpenCV 2.4.10, 2.3.0-beta and 2.3.0 releases.

If you encounter the following issue during CMake configuration

Edit %VISP_WS%\opencv-2.y.z\sources\CMakeLists.txt file, and line 464 replace:

test_big_endian(WORDS_BIGENDIAN)

by:

#test_big_endian(WORDS_BIGENDIAN)
set(WORDS_BIGENDIAN 0)

7.5. OpenCV build error: cannot build with tiff support

Note: This issue occurs with OpenCV 2.4.10, 2.3.0-beta and 2.3.0 releases.

If you encounter a build issue during libtiff build as given in the next image:

Open CMake GUI on OpenCV, turn BUILD_TIFF=OFF and also WITH_TIFF=OFF
Click on "Configure" button, and then on "Generate" one.

Build again OpenCV using

cd %VISP_WS%\opencv-2.y.z\sources\build-mingw
C:\> mingw32-make

7.6. OpenCV link error: cannot find -lRunTmChk

Note: This issue occurs with OpenCV 2.3.0-beta and 2.3.0 releases.

The following image shows the link issue that may appear when building OpenCV with MinGW:

A work around is to configure OpenCV without ipp support turning WITH_IPP=OFF and then trying to build again.

7.7. OpenCV build error: struct has virtual functions and accessible non-virtual destructor

This error that occurs with OpenCV 3.0.0 during cap_dshow.cpp build is known and reported as an issue in https://github.com/Itseez/opencv/pull/5282/commits.

The fix consists in modifying modules/videoio/src/cap_dshow.cpp by adding near line 96:

#ifdef __MINGW32__
// MinGW does not understand COM interfaces
#pragma GCC diagnostic ignored "-Wnon-virtual-dtor"
#endif

7.8. OpenCV not detected with Mingw build

Note: This issue occurs with OpenCV 2.4.9, 2.4.10 and 2.3.0-beta.

To fix this issue, edit %VISP_WS%\opencv-2.y.z\sources\cmake\OpenCVConfig.cmake, and line 89 replace:
```
  if(CMAKE_OPENCV_GCC_TARGET_MACHINE MATCHES "64")
```
by:
```
  if(OPENCV_GCC_TARGET_MACHINE MATCHES "64")
```

Then open a new cmd Command Prompt to build and install OpenCV again:

C:\> cd %VISP_WS%\opencv-2.y.z\sources\build-mingw
C:\> mingw32-make install

7.9. windres.exe invalid option –W

Note: This issue occurs with OpenCV 3.3.0.

When running mingw32-make if you get the following issue:

the workaround consists in:

opening cmake-gui and turning ENABLE_PRECOMPILED_HEADERS cmake var OFF:
in cmake-gui press "Configure" button, then press "Generate" button
then in the cmd Command Prompt run again mingw32-make

7.10. Build error in cap_dshow.cpp

Note: This issue occurs with OpenCV 3.3.0.