How to build

部分国家用户建议使用代理, 非正常网络环境可能导致错误. 中文

Preparation

Get MinGW-W64 from https://www.mingw-w64.org/downloads/#mingw-builds. Select the version you need. Download, unzip and add mingw64/bin/ to PATH.

Get CMake from https://cmake.org/download/.

Clone and Modify

git clone OpenCV and allback to the commit of the release.

git clone https://github.com/opencv/opencv.git
cd opencv
git reset --hard 725e440d278aca07d35a5e8963ef990572b07316

Configure and Generate

Open cmake-gui.exe, choose where your source code is and where to build the binaries.

Click Configure.

Choose MinGW Makefiles, Use default native compilers.

Click Finish and wait a while.

Check

BUILD_opencv_world

and uncheck

ENABLE_PRECOMPILED_HEADERS
WITH_MSMF
WITH_OBSENSOR

if exists. That's why: https://forum.opencv.org/t/opencv-cmake-opencv-building-error/11566/11.

If you only what the C/C++ dependency library, uncheck

BUILD_JAVA
BUILD_PERF_TESTS
BUILD_TESTS
BUILD_opencv_apps
BUILD_opencv_java_bindings_generator
BUILD_opencv_js
BUILD_opencv_js_bindings_generator
BUILD_opencv_objc_bindings_generator
BUILD_opencv_python3
BUILD_opencv_python_bindings_generator
BUILD_opencv_python_tests
BUILD_opencv_ts

to speed things up.

Click Generate and wait a while.

Build

mkdir -p build
cd build
mingw32-make -j 32
mingw32-make install

Choose the number of threads (after -j) according to your computer's performance.

Then all the files you want are in the build\install folder.

More

The compile command will look like this:

g++ "a.cpp" -o "a.exe" -I "$Env:OPENCV470\include" -I "$Env:OPENCV470\include\opencv2" -L "$Env:OPENCV470\x64\mingw\lib" -llibopencv_world470

where $Env:OPENCV470 is the build\install folder.

Then when you run a.exe, the libopencv_world470.dll (in build\install\x64\mingw\bin) should in the PATH or .\.