I tried to build OpenCV 3.1.0 on my Raspberry Pi 2B. Unfortunetly, when I trying:
cmake -D CMAKE_BUILD_TYPE=RELEASE \ -D CMAKE_INSTALL_PREFIX=/usr/local \ -D INSTALL_C_EXAMPLES=OFF \ -D INSTALL_PYTHON_EXAMPLES=OFF /home/pi/Downloads/opencv-3.1.0
CMake Error: The source "/home/pi/Downloads/opencv-3.1.0/CMakeLists.txt" does not match the source "/home/pi/Downloads/opencv-3.1.0/modules/CMakeLists.txt" used to generate cache. Re-run cmake with a different source directory.
First, I hope you do run CMake outside your sources, in a separate directory. Not doing that is really not recommended
To understand the error message you have to know a little bit on how CMake works.
Basically, when you run
cd /path/to/opencv mkdir build cd build cmake ..
CMake generates a cache in the build dir (It's a simple file named
CMakeCache.txt). This file contains some information like:
If you ever re-run CMake and change one of these values, (by re-running cmake with different arguments, setting an other generotor or moving files), CMake will complain with this kind of message.
A good solution is then to delete the CMakeCache, or even the whole build dir to be safe.