While installation you have to assemble your Qt toolchain. Take the most recent version of Qt compiled with MinGW.
Although the installer provides its own bundled MinGW compiler Toolchain its recommend installing it separately because Qt is missing MSYS which is needed to compile and install OpenCV and OpenAL. Thus you can - if needed - deselect the tab "Tools".
The following steps assume that Qt is installed at "C:\Qt". If you decided to choose another location, replace corresponding parts.
Clone the repository (https://github.com/tux3/qTox.git) with your preferred Git client. [SmartGit](http://www.syntevo.com/smartgit/) is very nice for this task.
The following steps assume that you cloned the repository at "C:\qTox". If you decided to choose another location, replace corresponding parts.
Afterwards download the source archive of OpenCV from [http://opencv.org](http://opencv.org/downloads.html). It's recommended to download the Linux/Mac package because the Windows package is bloated with useless binaries. The Linux/Mac package only contains the sources and works perfectly on Windows.
Run CMake (cmake-gui) and set up the input boxes "Where is the source code:" and "Where to build the binaries" with "C:\qTox\libs\opencv-x.y.z" and "C:\qTox\libs\opencv-build". Press configure and choose "MSYS Makefiles" in the drop down menu and "Use default native compilers". To start initial configuration press Finish. Given that qTox only needs some components of OpenCV it's recommended to disable not required modules. Furthermore, this will decrease compilation time of OpenCV dramatically. Each module begins with "BUILD_opencv_" and can be disabled by deselecting its entry. Use the "Search" input box for convenience. Disable all modules except of "core", "highgui" and "imgproc" (highgui depends on imgproc and will automatically be disabled if imgproc is disabled). For maximum performance search for "CMAKE_BUILD_TYPE" and select "Release". Finally, make sure "CMAKE_INSTALL_PREFIX" points to "C:\qTox\libs\opencv-build\install" (should be by default). To update the configuration press Configure again. Afterwards press Generate to create the Makefiles.
Open a new command prompt within "C:\qTox\libs\opencv-build" (HINT: Use shift + right click on the directory within Windows explorer and use "Open command window here"). Compile and install OpenCV with the following command. It's not recommended to use -j for multicore compilation, because it freezes the terminal from time to time.
```bash
make
make install
```
After OpenCV was successfully installed to "C:\qTox\libs\opencv-build\install" copy the dlls "libopencv_core249.dll", "libopencv_highgui249.dll" and "libopencv_imgproc249.dll" located at "C:\qTox\libs\opencv-build\install\x86\mingw\bin" to "C:\qTox\libs\lib". Afterwards copy the content of the directory "C:\qTox\libs\opencv-build\install\include" to "C:\qTox\libs\include". Finally, you have to patch the file "C:\qTox\libs\include\opencv2\opencv.hpp" because it includes all modules of OpenCV regardless of your configuration.
The following steps assumes that you cloned the repository at "/home/user/qTox". If you decided to choose another location, replace corresponding parts.
Now you can either follow the instructions at https://github.com/irungentoo/toxcore/blob/master/INSTALL.md#unix or use the "bootstrap.sh" script located at "/home/user/qTox".