Install or Build Qt5

To build the MNE-CPP libraries Qt5.4.2 is required. You can either install or build Qt5 from scratch. Building Qt5.4.2 from scratch will give you the chance to configure Qt5.4.2 for your own needs. Please keep in mind that this will take much longer than installing Qt5 with the Qt5 Installer.

Install using the Qt5 Installer

Download and install the Qt5.4.2 offline installer from the [Qt archives](http://download.qt.io/archive/qt/5.4/5.4.2/). Depending on your locally installed Microsoft Visual Studio version, select the right version from the list. For example, if you have a 32bit Microsoft Visual Studio 2013 version installed on your computer, select "qt-opensource-windows-x86-msvc2013_opengl-5.4.2.exe". Make sure that you choose a Qt5.4.2 version with OpenGL support. If the installation was succesfull you can skip the "Build Qt5.4.2 from scratch" section below. Since the QtCreator comes with the Qt5.4.2 Installer you can also skip the next page and directly proceed to build Qt3D (as described on [page three](https://github.com/mne-tools/mne-cpp/wiki/3.-Install-Qt3D)).

Build Qt5.4.2 from scratch

To make sure everything is compatible, it is recommended to always download the source code of Qt5.4.2 and compile it from scratch. The source code is available as a single [zip (510 MB) file for Windows](http://download.qt-project.org/official_releases/qt/5.4/5.4.2/single/qt-everywhere-opensource-src-5.4.2.zip) users or as [tar.qz (408 MB) file for Linux/Mac](http://download.qt-project.org/official_releases/qt/5.4/5.4.2/single/qt-everywhere-opensource-src-5.4.2.zip) users.

After extracting the archive do the following steps (a detailed description on how to compile Qt5 can be found [here](https://wiki.qt.io/Building_Qt_5_from_Git)):

Windows

To compile Qt5.4.2 Perl and Python is required. Download (e.g. ActivePerl and Python), install and add each bin directory to the PATH. In this instruction, we presume having Microsoft Visual Studio and the Debugger of the Windows SDK installed. It's convenient to use VS2012 or VS2013 x86 Native Tools Command Prompt, which are coming with Visual Studio. Inside the command prompt navigate to qt-everywhere-opensource-src-5.4.2 folder and run following commands:

MSVC2012

configure -platform win32-msvc2012 -nomake examples -opensource -opengl desktop -mp -prefix "C:\Qt\Qt5.4.2-opengl"

MSVC2013

configure -platform win32-msvc2013 -nomake examples -opensource -opengl desktop -mp -prefix "C:\Qt\Qt5.4.2-opengl"
nmake
nmake install
[optional] nmake docs
[optional] nmake install_docs

static build

configure -platform win32-msvc2013 -static -nomake examples -opensource -opengl desktop -mp -prefix "C:\Qt\Qt5.4.2-opengl-static"
nmake
nmake install

Linux

./configure -nomake examples -opensource -opengl desktop -prefix ~/Qt/Qt5.4.2-opengl
make -j8
make install
[optional] make docs
[optional] make install_docs

Mac OS X

First install [Xcode](https://developer.apple.com/xcode/) from the Apple App Store. Then start Xcode and go to Xcode -> Preferences... -> Downloads and install the Command Line Tools

./configure -debug-and-release -opensource -opengl desktop -prefix ~/Qt/Qt5.4.2-opengl
make
make install
[optional] make docs
[optional] make install_docs