Getting started » Usage with CMake

Guide how to find and use Magnum with CMake build system.

Magnum uses CMake build system for both building and integration into your projects. The logic is in module FindMagnum.cmake distributed with the engine in modules/ directory, you are encouraged to copy it along with FindCorrade.cmake into your project and add path to the files to CMAKE_MODULE_PATH. Otherwise, if CMake won't be able to find this file in predefined locations, it will error out even if Magnum might be installed on the system. If you plan to use Magnum on OpenGL ES, you may also need FindOpenGLES2.cmake or FindOpenGLES3.cmake and in some cases also FindEGL.cmake.

Note that the module files are updated as the library evolves, you are encouraged to update your copies from time to time to avoid strange building issues.

If you installed the library or its dependencies to non-standard location (other than /usr, e.g. /home/xyz/projects), set CMAKE_PREFIX_PATH to that directory to help CMake find it. You can enter more different dirs if you separate them with semicolons.

Basic usage is:

find_package(Magnum REQUIRED)

This module tries to find base Magnum library and then defines:

  • Magnum_FOUND — Whether the library was found
  • Magnum::Magnum — Base library imported target
  • MAGNUM_DEPLOY_PREFIX — Prefix where to put final application executables, defaults to .. If a relative path is used, it's relative to CMAKE_INSTALL_PREFIX.
  • MAGNUM_INCLUDE_INSTALL_PREFIX — Prefix where to put platform-independent include and other files, defaults to .. If a relative path is used, it's relative to CMAKE_INSTALL_PREFIX.
  • MAGNUM_PLUGINS_DEBUG_DIR — Base directory with dynamic plugins for debug builds, defaults to magnum-d/ subdirectory of dir where Magnum library was found
  • MAGNUM_PLUGINS_RELEASE_DIR — Base directory with dynamic plugins for release builds, defaults to magnum/ subdirectory of dir where Magnum library was found
  • MAGNUM_PLUGINS_DIR — Base directory with dynamic plugins, defaults to MAGNUM_PLUGINS_RELEASE_DIR in release builds and multi-configuration builds or to MAGNUM_PLUGINS_DEBUG_DIR in debug builds. You can modify all three variable (e.g. set them to . when deploying on Windows with plugins stored relatively to the executable), the following MAGNUM_PLUGINS_*_DIR variables depend on it.
  • MAGNUM_PLUGINS_FONT[|_DEBUG|_RELEASE]_DIR — Directory with dynamic font plugins
  • MAGNUM_PLUGINS_FONTCONVERTER[|_DEBUG|_RELEASE]_DIR — Directory with dynamic font converter plugins
  • MAGNUM_PLUGINS_IMAGECONVERTER[|_DEBUG|_RELEASE]_DIR — Directory with dynamic image converter plugins
  • MAGNUM_PLUGINS_IMPORTER[|_DEBUG|_RELEASE]_DIR — Directory with dynamic importer plugins
  • MAGNUM_PLUGINS_AUDIOIMPORTER[|_DEBUG|_RELEASE]_DIR — Directory with dynamic audio importer plugins

However, this command will try to find only the base library, not the optional components. The base library depends on Using Corrade with CMake Corrade and OpenGL libraries (or OpenGL ES libraries). Additional dependencies are specified by the components. The optional components are:

Platform namespace is split into more components:

For manual context creation (without application wrappers) there are also platform-specific context libraries (see Using custom platform toolkits for more information):

  • CglContext — CGL context
  • EglContext — EGL context
  • GlxContext — GLX context
  • WglContext — WGL context

There are also extensions to Corrade::TestSuite::Tester for testing GPU code:

The library also contains a set of plugins for importing essential file formats. Additional plugins are provided in separate plugin repository, see Plugin usage with CMake for more information. If you are going to use dynamic plugins (the default) via plugin manager, they don't need to be handled via CMake. The manager will look for them at runtime at specified location and loads them dynamically. However, if they are built as static (see Downloading and building plugins for more information), they need to be linked into the executable and then explicitly imported. Also if you are going to use them as dependencies, you need to find the dependency and then link to it.

Lastly, a few utility executables are available:

Note that each namespace, all Platform libraries and each plugin class contain more detailed information about dependencies, availability on particular platform and also guide how to enable given library in build and use it with CMake.

Example usage with specifying additional components is:

find_package(Magnum REQUIRED Trade MeshTools Primitives Sdl2Application)

For each component is then defined:

  • Magnum_*_FOUND — Whether the component was found
  • Magnum::* — Component imported target

If exactly one *Application or exactly one Windowless*Application component is requested and found, its target is available in convenience alias Magnum::Application / Magnum::WindowlessApplication to simplify porting. Similarly, if exactly one *Context component is requested and found, its target is available in convenience alias Magnum::Context.

The package is found if either debug or release version of each requested library (or plugin) is found. If both debug and release libraries (or plugins) are found, proper version is chosen based on actual build configuration of the project (i.e. Debug build is linked to debug libraries, Release build to release libraries). Note that this autodetection might fail for the MAGNUM_PLUGINS_DIR variable, especially on multi-configuration build systems. You can make use of CORRADE_IS_DEBUG_BUILD preprocessor variable along with MAGNUM_PLUGINS_*_DEBUG_DIR / MAGNUM_PLUGINS_*_RELEASE_DIR variables to decide in preprocessing step.

Features of found Magnum library are exposed in these CMake variables, they are also available as preprocessor variables if including Magnum/Magnum.h:

  • MAGNUM_BUILD_DEPRECATED — Defined if compiled with deprecated APIs included
  • MAGNUM_BUILD_STATIC — Defined if compiled as static libraries. Default are shared libraries.
  • MAGNUM_BUILD_MULTITHREADED — Defined if compiled in a way that allows having multiple thread-local Magnum contexts. The default.
  • MAGNUM_TARGET_GLES — Defined if compiled for OpenGL ES
  • MAGNUM_TARGET_GLES2 — Defined if compiled for OpenGL ES 2.0
  • MAGNUM_TARGET_GLES3 — Defined if compiled for OpenGL ES 3.0
  • MAGNUM_TARGET_DESKTOP_GLES — Defined if compiled with OpenGL ES emulation on desktop OpenGL
  • MAGNUM_TARGET_WEBGL — Defined if compiled for WebGL
  • MAGNUM_TARGET_HEADLESS — Defined if compiled for headless machines. See MAGNUM_TARGET_HEADLESS documentation for more information.

Workflows without imported targets are deprecated and the following variables are included just for backwards compatibility and only if MAGNUM_BUILD_DEPRECATED is enabled:

  • MAGNUM_LIBRARIES — Expands to Magnum::Magnum target. Use Magnum::Magnum target directly instead.
  • MAGNUM_*_LIBRARIES — Expands to Magnum::* target. Use Magnum::* target directly instead.
  • MAGNUM_APPLICATION_LIBRARIES / MAGNUM_WINDOWLESSAPPLICATION_LIBRARIES — Expands to Magnum::Application / Magnum::WindowlessApplication target. Use Magnum::Application / Magnum::WindowlessApplication target directly instead.
  • MAGNUM_CONTEXT_LIBRARIES — Expands to Magnum::Context target. Use Magnum::Context target directly instead.

Corrade library provides also its own set of CMake macros and variables, see its documentation for more information. Plugins repository, Integration repository and Extras repository have also their own CMake modules.

Other CMake modules

The modules/ directory contains more useful CMake modules:

  • FindOpenAL.cmake — CMake module for finding OpenAL. This is a forked version of the upstream module that works properly with Emscripten. Copy this to your module directory if you want to use the Audio library on Emscripten.
  • FindGLFW.cmake — CMake module for finding GLFW. Copy this to your module directory if you want to use Platform::GlfwApplication.
  • FindEGL.cmake — CMake module for finding EGL. Copy this to your module directory if you want to target embedded platforms such as iOS, Android, Windows RT or Emscripten or if you want to use EGL instead of GLX/WGL/CGL on a desktop platform.
  • FindOpenGLES2.cmake, FindOpenGLES3.cmake — CMake module for finding OpenGL ES 2.0 / 3.0 library. Copy this to your module directory if you want to target OpenGL ES.
  • FindSDL2.cmake — CMake module for finding SDL 2. Copy this to your module directory if you want to use Platform::Sdl2Application.