This file contains in-depth information for building with the CMake build system.
Want to build it fast?
Required tools and dependencies:
- CMake 3.20 or higher.
- A working toolchain, e.g. Visual Studio on Windows or the
build-essentialspackage on Ubuntu Linux. - Main OpenGL libraries and development files.
- The
GLEWLibrary on Windows.
To use the library in other projects, it is required to install it. Use CMAKE_INSTALL_PREFIX to specify the
installation directory.
From the project root, execute:
mkdir build
cd build
cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/path/to/install-dir
cmake --build . --target install --config ReleaseIf the build succeeded, you should now have the projectM libraries and include files in the specified install dir.
To use the library in other CMake projects, simply point the build to your install dir by adding it
to CMAKE_PREFIX_PATH and call find_package(libprojectM) in the other project's CMakeLists.txt.
If you use other build systems, you have to specify the include and library paths manually.
Building libprojectM does not require any specific CMake generator. It should work with any available generator, single- and multi-config.
To specify a CMake generator, use the -G switch, followed by the generator name. Some newer generators take an
additional architecture using the -A switch. To list all available generators available on your current platform,
leave out the generator name:
cmake -GAdditional information on the supported generators can be found in the CMake documentation.
By default, CMake will use the Unix Makefiles
generator on Linux and macOS, which is a good choice and should work. Yet in some circumstances, you might want to
generate project files for a specific build tool or IDE:
cmake -G "Unix Makefiles" -S /path/to/source/dir -B /path/to/build/dirA common alternative is the Ninja generator, which
requires ninja to be installed. It is mostly a make
replacement with less overhead and should work equally well. It is supported on all major platforms, including Windows:
cmake -G Ninja -S /path/to/source/dir -B /path/to/build/dirOn macOS, CMake also supports the Xcode generator. It will
create an .xcodeproj bundle which you can open in Xcode. It also adds support for automatic code signing, which might
be required if your application using projectM needs to be notarized for store deployment.
cmake -G Xcode -S /path/to/source/dir -B /path/to/build/dirIf you develop on Windows, you will possibly use Visual Studio. While recent visual Studio versions have CMake support
built-in, you can still pre-generate the solution and project files and open the .sln file from the build directory.
CMake provides a separate generator for each Visual Studio release. For Visual Studio 2019 you would use
the Visual Studio 16 2019 generator
and provide an additional architecture parameter:
cmake -G "Visual Studio 16 2019" -A "X64" -S /path/to/source/dir -B /path/to/build/dirIt is not possible to generate multi-arch solutions with CMake though. You need to create separate build directories and
use the respective -A switch for each.
CMake has no built-in way of printing all available configuration options. You can either refer to the
top-level CMakeLists.txt which contains a block of option and cmake_dependent_option commands, or use one of the
available CMake UIs which will display the options after configuring the project once.
The following table also gives you an overview of important build options and their defaults. All options accept a
boolean
value (YES/NO, TRUE/FALSE, ON/OFF or 1/0) and can be provided on the configuration-phase command line
using the -D switch.
| CMake option | Default | Required dependencies | Description |
|---|---|---|---|
BUILD_TESTING |
OFF |
Builds the unit tests. | |
BUILD_SHARED_LIBS |
ON |
Build projectM as shared libraries. If OFF, build static libraries. |
|
ENABLE_PLAYLIST |
ON |
Builds and installs the playlist library. | |
ENABLE_EMSCRIPTEN |
OFF |
Emscripten |
Build for the web using Emscripten. Only supports build as a static library and using GLES. |
ENABLE_GLES |
OFF |
GLES |
Use OpenGL ES 3 profile for rendering instead of the Core profile. |
Note that ENABLE_GLES will be forcibly set to ON for Emscripten and Android builds, making it mandatory.
The following table contains a list of build options which are only useful in special circumstances, e.g. when developing libprojectM, trying experimental features or building the library for a special use-case/environment.
| CMake option | Default | Required dependencies | Description |
|---|---|---|---|
ENABLE_SDL_UI |
ON |
SDL2 |
Builds the SDL-based test application. Only used for development testing, will not be installed. |
ENABLE_INSTALL |
OFF |
Building as a CMake subproject | Enable projectM install targets when built as a subproject via add_subdirectory(). |
ENABLE_DEBUG_POSTFIX |
ON |
Adds d (by default) to the name of any binary file in debug builds. |
|
ENABLE_SYSTEM_GLM |
OFF |
Builds against a system-installed GLM library. | |
ENABLE_CXX_INTERFACE |
OFF |
Exports symbols for the ProjectM and PCM C++ classes and installs the additional the headers. Using the C++ interface is not recommended and unsupported. |
There are also a few textual parameters that can be used to fine-tune the installation directories. Relative paths in
the following options are appended to the value
of CMAKE_INSTALL_PREFIX (which, on most UNIX
platforms, defaults to /usr/local):
| CMake option | Default | Description |
|---|---|---|
CMAKE_INSTALL_PREFIX |
(OS dependent) | Base directory where the projectM libraries, includes and support files will be installed. |
PROJECTM_BIN_DIR |
bin |
Directory where executables (e.g. the SDL standalone application) are installed. |
PROJECTM_LIB_DIR |
lib[64] |
Directory where libprojectM is installed. |
PROJECTM_INCLUDE_DIR |
include |
Directory where the libprojectM include files will be installed under. |
Various other options for specific needs.
| CMake option | Default | Description |
|---|---|---|
CMAKE_DEBUG_POSTFIX |
d (if ENABLE_DEBUG_POSTFIX is set) |
Postfix appended to debug libraries. |
CMAKE_INSTALL_BINDIR |
bin |
Another way to specify the binary installation directory. Used as default value for PROJECTM_BIN_DIR. |
CMAKE_INSTALL_LIBDIR |
lib or lib64 |
Another way to specify the library installation directory. Used as default value for PROJECTM_LIB_DIR. |
CMAKE_INSTALL_INCLUDEDIR |
include |
Another way to specify the include file installation directory. Used as default value for PROJECTM_INCLUDE_DIR. |
Most classic IDEs and build systems directly make use of the source tree and create project files, temporary build artifacts (e.g. object files) and the final binaries in the same directory structure as the source files. An advantage of this approach is that you can find all compiled binaries side-by-side with their sources and generated headers are already in the same directories as the source files including them. This approach has some drawbacks though:
- Only a single build configuration is supported as files are overwritten in-place.
- A lot of noise is created in the source directory, making it hard to distinguish between generated and original source files.
- A very large
.gitignorefile is required to cover all unwanted files. - Mistakes in the build scripts can overwrite source files, causing errors and destroy uncommitted work.
Some of these can be mitigated by providing additional targets (make clean and make distclean) or creating
subdirectories for Debug/Release build configurations.
While CMake also supports in-tree builds, it is "discouraged" in the official documentation, for the above reasons. Building out-of-tree allows it to create multiple build directories with different configurations which do not influence each other in any way. If a build directory contains unwanted artifacts, and you want to start fresh, simply delete and recreate the whole directory - no work is lost.
This project follow this principle by treating the original source tree as read-only and avoiding potential conflicts:
- Everything under
CMAKE_SOURCE_DIRmust only be read, never changed or written to. - Everything under
CMAKE_BINARY_DIRis temporary and related to the current build configuration. - When generating configuration-dependent files,
use
CMAKE_CONFIGURATION_TYPESandCMAKE_BUILD_TYPEto create non-conflicting files in the build tree.
While this project will not force you to build out-of-tree, there is no mechanism to clean up the generated files after running cmake in-tree.
If you are new to CMake, the way of how CMake creates the build directory and where it creates the build targets might be confusing. Here is a summary of what's in the build directory and how it is structured in general.
It is generally not good practice to directly take binaries and other files from the build tree for packaging, for several reasons:
- The directory structure is generated by CMake and depends on the generator used. The layout might change between CMake versions, even for the same generator.
- On platforms with RPATH support, CMake will store absolute paths in executables and shared libraries which point to the absolute paths of any linked dependencies, either from the build tree or external libraries as well. These binaries are not relocatable and will most certainly not work if run on any other computer (or even on the same after deleting the build directory).
- For some configurations, even Release build artifacts may contain debug symbols until they are installed.
It is fine to build and run executables from the build directory for development and debugging. For packaging or using
libprojectM in other projects, always use the install target and copy files from there.
In the top-level build directory, CMake creates a few files that are present on any platform:
CMakeCache.txt: This file contains all variables and build settings CMake needs to remember from the first configuration run. This file can be edited on demand either manually or using a CMake UI to change any values. On the next build, CMake will regenerate the project files if this file has been modified.cmake_install.cmake: Contains generated install-related settings.install_manifest.txt: After installing the project, this file contains a list with absolute filenames of all installed files. It can be used for packaging or deleting installed files as CMake doesn't define anuninstalltarget.- The top-level project file for use with the selected build toolset, e.g.
Makefile,build.ninja,projectm.slnorprojectm.xcodeproj, plus additional toolset-specific files.
The projectM build files generate additional files used in the build and install phases. These are scattered over the build tree, but installed into the proper directories. Do not try and gather these files yourself from the build tree.
The rest of the directory structure generally resembles the source tree. Source directories containing
a CMakeLists.txt file will also be created in the build tree with the same relative path. Each of these subdirectories
contains a CMakeFiles directory with CMake-internal data, generated project files for the select toolset, e.g.
makefiles and any temporary compile artifacts.
The directory structure is created by CMake and may change depending on the generator and CMake version used.
Build targets - shared/static libraries and executables - are created in the same subdirectory in the build tree as
the CMakeLists.txt file that defines the target in the source tree (which, in most cases, resides in the same
directory as the source files). Depending on the generator used, the binaries are created directly in the directory for
single-configuration generators (like Unix Makefiles or Ninja) and in a subdirectory with the configuration name,
e.g. Debug or Release, for multi-configuration generators like Xcode or Visual Studio 16 2019.
You may also find additional files and symbolic links in the same location depending on the platform, e.g. .pdb files
on Windows.
The projectM library can be used as a static library or shared library in other CMake-based projects to provide embedded audio visualization. It is highly recommended to build projectM as shared libraries for maximum compatibility and LGPL compliance.
The build directory is not structured in a way that other projects can make use of it. Use the install target to copy
all required files to the configured installation prefix. You can customize the subdirectories for libraries, includes
and binaries using the PROJECTM_<X>>_DIR variables when configuring the CMake project.
This approach is not recommended, but can be useful for projects that either require more in-depth access to the projectM library files, especially to headers that are not installed as part of the public API. This might cause issues if the internal headers change, but gives a broader set of features and more control to the developer.
Please refer to the ExternalProject CMake module
documentation on how to set up the libprojectM build system for use in another project.
This is the recommended and supported way of importing libprojectM in your project. This project installs a set of CMake
files in <PREFIX>/<LIBDIR>/cmake/projectM4, containing target definitions, version and dependency checks as well as
any additional libraries required for linking. Other projects then use CMake's find_package command to search for
these files in different locations.
In the case projectM libraries and headers are not installed in any system search path, you need to add either the
install prefix path (the top-level install dir) or the directory containing the libraries (the lib dir by default) to
the CMAKE_PREFIX_PATH list.
If the package was found, you can then link against libprojectM by using the libprojectM::projectM target.
Depending on how the package was built, targets might be available for multiple configurations or only Release. CMake
will automatically select the most appropriate one to link.
Include dirs, additional link dependencies and possible compiler options will be propagated to any target the library is linked to.
If you want to use the optional playlist library, you need to specifically request it as a component:
find_package(projectM4 COMPONENTS Playlist)You can either use REQUIRED to force a fatal error if the component cannot be found or check if the target exists
using:
if(TARGET libprojectM::playlist)
# ...
endif()If you link the playlist library, the main libprojectM::projectM target will be linked automatically as a dependency.
Searches for projectM and the playlist library and links both to the application:
find_package(projectM4 REQUIRED COMPONENTS Playlist)
add_executable(MyApp main.cpp)
target_link_libraries(MyApp PRIVATE
libprojectM::playlist
)