Not sure how to build OpenCV for MinGW

Question

TL;DR;

I am trying to build OpenCV for MinGW. cmake keeps complaining about no sane CXX compiler, although I can compile sample code with g++.exe.

Answer 1

I tried everthing mentioned here and CMAKE_MAKE_PROGRAM not found but nothing helped. Then restarted the computer and it works.

Answer 2

1. cleanup! delete all previous build attempts, CmakeFile.cache, etc.

2. have MingW/bin on the path

3. make a folder within the opencv dir, called build_mingw, cd there

4. cmake -G "MinGW Makefiles" -D CMAKE_CXX_COMPILER=mingw32-g++.exe -D CMAKE_MAKE_PROGRAM=mingw32-make.exe .. # <-- note the dots at the end

5. mingw32-make

6. mingw32-make install