CMakeLists.txt

cmake_minimum_required(VERSION 3.14)

# LCG sets CPATH, which gets treated like -I by the compiler. We want to ignore
# warnings from libraries, by unsetting it here, it gets processed by the usual
# target_include_directories call, resulting in the desired -isystem flag.
unset(ENV{CPATH})

# must be set before project(...) call; version module is needed before
list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake)

# determine project version; sets _acts_version and _acts_commit_hash
include(ActsRetrieveVersion)

project(Acts VERSION ${_acts_version} LANGUAGES CXX)

# policy settings

# Steers how project() handles the VERSION option
cmake_policy(SET CMP0048 NEW)

# the `<project_name>_VERSION` variables set by `setup(... VERSION ...)` have
# only local scope, i.e. they are not accessible her for dependencies added
# via `add_subdirectory`. this overrides the `project(...)` function for
# sub-projects such that the resulting `<project_name>_VERSION` has
# global scope and is accessible within the main project later on.
macro(project)
    _project(${ARGN})
    set(${PROJECT_NAME}_VERSION "${${PROJECT_NAME}_VERSION}" CACHE INTERNAL "")
endmacro()

# Controls the way python is located
if(POLICY CMP0094)
    cmake_policy(SET CMP0094 NEW)
endif()

# Controls behavior of DOWNLOAD_EXTRACT_TIMESTAMP
if(POLICY CMP0135)
    cmake_policy(SET CMP0135 NEW)
endif()

# Use boost's cmake config files
if(POLICY CMP0167)
    cmake_policy(SET CMP0167 NEW)
endif()

# build options

# all options and compile-time parameters must be defined here for clear
# visibility and to make them available everywhere
#
# NOTE if you are adding a new option make sure that is defined in such a way
#   that it is off/empty by default. if you think that is not possible, then
#   it probably is not an optional component.
# core related options
# Formatting needs to be preserved here for parsing
# gersemi: off
set(ACTS_PARAMETER_DEFINITIONS_HEADER "" CACHE FILEPATH "Use a different (track) parameter definitions header")
set(ACTS_SOURCELINK_SBO_SIZE "" CACHE STRING "Customize the SBO size used by SourceLink")
option(ACTS_FORCE_ASSERTIONS "Force assertions regardless of build type" OFF)
# external library options
option(ACTS_USE_SYSTEM_LIBS "Use system libraries by default" OFF)
# plugins related options
option(ACTS_USE_SYSTEM_ACTSVG "Use the ActSVG system library" ${ACTS_USE_SYSTEM_LIBS})
option(ACTS_USE_SYSTEM_COVFIE "Use a system-provided covfie installation" ${ACTS_USE_SYSTEM_LIBS})
option(ACTS_USE_SYSTEM_DETRAY "Use a system-provided detray installation" ${ACTS_USE_SYSTEM_LIBS})
option(ACTS_USE_SYSTEM_TRACCC "Use a system-provided traccc installation" ${ACTS_USE_SYSTEM_LIBS})
option(ACTS_USE_SYSTEM_VECMEM "Use a system-provided vecmem installation" ${ACTS_USE_SYSTEM_LIBS})
option(ACTS_USE_SYSTEM_ALGEBRAPLUGINS "Use a system-provided algebra-plugins installation" ${ACTS_USE_SYSTEM_LIBS})
option(ACTS_USE_SYSTEM_NLOHMANN_JSON "Use nlohmann::json provided by the system instead of the bundled version" ${ACTS_USE_SYSTEM_LIBS})
option(ACTS_USE_SYSTEM_PYBIND11 "Use a system installation of pybind11" ${ACTS_USE_SYSTEM_LIBS} )
option(ACTS_USE_SYSTEM_EIGEN3 "Use a system-provided eigen3" ON)

option(ACTS_BUILD_PLUGIN_ACTSVG "Build SVG display plugin" OFF)
option(ACTS_BUILD_PLUGIN_CUDA "Build CUDA plugin" OFF)
option(ACTS_BUILD_PLUGIN_DD4HEP "Build DD4hep plugin" OFF)
option(ACTS_BUILD_PLUGIN_PODIO "Build Podio plugin" OFF)
option(ACTS_BUILD_PLUGIN_EDM4HEP "Build EDM4hep plugin" OFF)
option(ACTS_BUILD_PLUGIN_FPEMON "Build FPE monitoring plugin" OFF)
option(ACTS_BUILD_PLUGIN_GEOMODEL "Build GeoModel plugin" OFF)
option(ACTS_BUILD_PLUGIN_TRACCC "Build Traccc plugin" OFF)
option(ACTS_BUILD_PLUGIN_GEANT4 "Build Geant4 plugin" OFF)
option(ACTS_BUILD_PLUGIN_EXATRKX "Build the Exa.TrkX plugin" OFF)
option(ACTS_EXATRKX_ENABLE_ONNX "Build the Onnx backend for the exatrkx plugin" OFF)
option(ACTS_EXATRKX_ENABLE_TORCH "Build the torchscript backend for the exatrkx plugin" ON)
option(ACTS_EXATRKX_ENABLE_CUDA "Enable CUDA for the exatrkx plugin" OFF)
option(ACTS_BUILD_PLUGIN_JSON "Build json plugin" OFF)
option(ACTS_BUILD_PLUGIN_LEGACY "Build legacy plugin" OFF)
option(ACTS_BUILD_PLUGIN_ONNX "Build ONNX plugin" OFF)
option(ACTS_BUILD_PLUGIN_TGEO "Build TGeo plugin" OFF)
option(ACTS_SETUP_ANNOY "Explicitly set up Annoy for the project" OFF)
option(ACTS_BUILD_PLUGIN_HASHING "Build Hashing plugin" OFF)
# fatras related options
option(ACTS_BUILD_FATRAS "Build FAst TRAcking Simulation package" OFF)
option(ACTS_BUILD_FATRAS_GEANT4 "Build Geant4 Fatras package" OFF)
# alignment related options
option(ACTS_BUILD_ALIGNMENT "Build Alignment package" OFF)
# examples related options
option(ACTS_BUILD_EXAMPLES_DD4HEP "Build DD4hep-based code in the examples" OFF)
option(ACTS_BUILD_EXAMPLES_EDM4HEP "Build EDM4hep-based code in the examples" OFF)
option(ACTS_BUILD_EXAMPLES_EXATRKX "Build the Exa.TrkX example code" OFF)
option(ACTS_BUILD_EXAMPLES_GEANT4 "Build Geant4-based code in the examples" OFF)
option(ACTS_BUILD_EXAMPLES_HEPMC3 "Build HepMC3-based code in the examples" OFF)
option(ACTS_BUILD_EXAMPLES_HASHING "Build Hashing-based code in the examples" OFF)
option(ACTS_BUILD_EXAMPLES_PYTHIA8 "Build Pythia8-based code in the examples" OFF)
option(ACTS_BUILD_EXAMPLES_PYTHON_BINDINGS "Build python bindings for the examples" OFF)
option(ACTS_BUILD_ANALYSIS_APPS "Build Analysis applications in the examples" OFF)
# test related options
option(ACTS_BUILD_BENCHMARKS "Build benchmarks" OFF)
option(ACTS_BUILD_INTEGRATIONTESTS "Build integration tests" OFF)
option(ACTS_BUILD_UNITTESTS "Build unit tests" OFF)
if(ACTS_BUILD_UNITTESTS AND ACTS_BUILD_EXAMPLES)
  set(_default_examples_unit_tests ON)
else()
  set(_default_examples_unit_tests OFF)
endif()
option(ACTS_BUILD_EXAMPLES_UNITTESTS "Build unit tests" ${_default_examples_unit_tests}) # default: ACTS_BUILD_UNITTESTS AND ACTS_BUILD_EXAMPLES
option(ACTS_BUILD_NONCOMPILE_TESTS "Build tests that check build failure invariants" OFF)
option(ACTS_RUN_CLANG_TIDY "Run clang-tidy static analysis" OFF)
# other options
option(ACTS_BUILD_DOCS "Build documentation" OFF)
option(ACTS_SETUP_BOOST "Explicitly set up Boost for the project" ON)
option(ACTS_SETUP_EIGEN3 "Explicitly set up Eigen3 for the project" ON)
option(ACTS_BUILD_ODD "Build the OpenDataDetector" OFF)
# profiling related options
option(ACTS_ENABLE_CPU_PROFILING "Enable CPU profiling using gperftools" OFF)
option(ACTS_ENABLE_MEMORY_PROFILING "Enable memory profiling using gperftools" OFF)
set(ACTS_GPERF_INSTALL_DIR "" CACHE STRING "Hint to help find gperf if profiling is enabled")

option(ACTS_ENABLE_LOG_FAILURE_THRESHOLD "Enable failing on log messages with level above certain threshold" OFF)
set(ACTS_LOG_FAILURE_THRESHOLD "" CACHE STRING "Log level above which an exception should be automatically thrown. If ACTS_ENABLE_LOG_FAILURE_THRESHOLD is set and this is unset, this will enable a runtime check of the log level.")
# gersemi: on

# handle option inter-dependencies and the everything flag
# NOTE: ordering is important here. dependencies must come before dependees
include(ActsOptionHelpers)

# any examples component activates the general examples option
set_option_if(
  ACTS_BUILD_EXAMPLES
  ACTS_BUILD_EXAMPLES_DD4HEP
  OR ACTS_BUILD_EXAMPLES_EDM4HEP
  OR ACTS_BUILD_EXAMPLES_GEANT4
  OR ACTS_BUILD_EXAMPLES_HEPMC3
  OR ACTS_BUILD_EXAMPLES_HASHING
  OR ACTS_BUILD_EXAMPLES_PYTHIA8
  OR ACTS_BUILD_EXAMPLES_EXATRKX
  OR ACTS_BUILD_EXAMPLES_PYTHON_BINDINGS
)
# core plugins might be required by examples or depend on each other

set_option_if(
  ACTS_BUILD_PLUGIN_DD4HEP
  ACTS_BUILD_EXAMPLES_DD4HEP OR
  ACTS_BUILD_EXAMPLES_EDM4HEP
)
set_option_if(
  ACTS_BUILD_PLUGIN_EDM4HEP
  ACTS_BUILD_EXAMPLES_EDM4HEP
)
set_option_if(
  ACTS_BUILD_PLUGIN_PODIO
  ACTS_BUILD_EXAMPLES_EDM4HEP
)
set_option_if(
    ACTS_BUILD_PLUGIN_GEANT4
    ACTS_BUILD_EXAMPLES_GEANT4
)
set_option_if(
  ACTS_BUILD_PLUGIN_TGEO
  ACTS_BUILD_PLUGIN_DD4HEP OR
  ACTS_BUILD_EXAMPLES
)
set_option_if(
  ACTS_BUILD_PLUGIN_IDENTIFICATION
  ACTS_BUILD_PLUGIN_TGEO OR
  ACTS_BUILD_PLUGIN_PODIO OR
  ACTS_BUILD_EXAMPLES
)
set_option_if(
  ACTS_BUILD_PLUGIN_JSON
  ACTS_BUILD_EXAMPLES
)
set_option_if(
  ACTS_BUILD_FATRAS
  ACTS_BUILD_EXAMPLES
)
set_option_if(
  ACTS_BUILD_PLUGIN_EXATRKX
  ACTS_BUILD_EXAMPLES_EXATRKX
)
set_option_if(
  ACTS_BUILD_PLUGIN_FPEMON
  ACTS_BUILD_EXAMPLES
)
set_option_if(
  ACTS_BUILD_PLUGIN_JSON
  ACTS_BUILD_PLUGIN_TRACCC
)
set_option_if(
  ACTS_BUILD_PLUGIN_ACTSVG
  ACTS_BUILD_PLUGIN_TRACCC
)
set_option_if(
  ACTS_BUILD_PLUGIN_HASHING
  ACTS_BUILD_EXAMPLES_HASHING
)

# feature tests
include(CheckCXXSourceCompiles)

# function that tests if the root installation is compatible
function(check_root_compatibility)
    get_target_property(
        ROOT_INCLUDE_DIR
        ROOT::Core
        INTERFACE_INCLUDE_DIRECTORIES
    )
    set(CMAKE_REQUIRED_INCLUDES ${ROOT_INCLUDE_DIR})
    #yolo
    #check_cxx_source_compiles(" #include <string>\n #include <TString.h>\nint main(){}" ROOT_COMPATIBILITY_CHECK)
    #if(NOT ROOT_COMPATIBILITY_CHECK)
    #  message(FATAL_ERROR "Root installation is misconfigured. Ensure that your Root installation was compiled.")
    #endif()
endfunction()

# additional configuration and tools
include(GNUInstallDirs) # GNU-like installation paths, e.g. lib/, include/, ...
include(ActsCompilerOptions) # default compile options
include(ActsComponentsHelpers) # handle components via add_..._if commands
include(ActsStaticAnalysis)

# place build products in `<build>/bin` and `<build>/lib` for simple use
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY
    "${PROJECT_BINARY_DIR}/${CMAKE_INSTALL_BINDIR}"
)
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY
    "${PROJECT_BINARY_DIR}/${CMAKE_INSTALL_LIBDIR}"
)

# This needs to happen before we set up any targets
if(ACTS_FORCE_ASSERTIONS)
    message(
        STATUS
        "Injecting headers to force assertions. This can have side-effects, USE WITH CAUTION!"
    )
    include_directories(
        BEFORE
        SYSTEM
        ${CMAKE_CURRENT_SOURCE_DIR}/cmake/assert_include
    )
endif()

# minimal dependency versions. they are defined here in a single place so
# they can be easily upgraded, although they might not be used if the
# dependency is included via `add_subdirectory(...)`.
set(_acts_actsvg_version 0.4.50)
set(_acts_boost_version 1.71.0)
set(_acts_dd4hep_version 1.21)
set(_acts_geant4_version 11.1.3)
set(_acts_edm4hep_version 0.7)
set(_acts_eigen3_version 3.4.0)
set(_acts_podio_version 1.0.1) # will try this first
set(_acts_podio_fallback_version 0.16) # if not found, will try this one
set(_acts_doxygen_version 1.9.4)
set(_acts_hepmc3_version 3.2.1)
set(_acts_nlohmanjson_version 3.10.5)
set(_acts_onnxruntime_version 1.12.0)
set(_acts_root_version 6.20)
set(_acts_tbb_version 2020.1)
set(_acts_pythia8_version 8.309)
set(_acts_pybind11_version 2.13.1)
set(_acts_detray_version 0.75.3)
set(_acts_traccc_version 0.16.0)
set(_acts_covfie_version 0.10.0)
set(_acts_vecmem_version 1.4.0)
set(_acts_algebraplugins_version 0.22.0)
set(_acts_annoy_version 1.17.3)

# recommended dependency version. if there is an opportunity to reach
# this version we will try so.
set(_acts_boost_recommended_version 1.78.0)

# Include the sources for the external dependencies.
include(ActsExternSources)

# required packages
if(ACTS_SETUP_BOOST)
    # Enable both program_options and unit_test_framework to reduce complexity
    # Also Cuda tests seem to use program_options
    if(
        ACTS_BUILD_ANALYSIS_APPS
        OR ACTS_BUILD_UNITTESTS
        OR ACTS_BUILD_INTEGRATIONTESTS
        OR ACTS_BUILD_BENCHMARKS
    )
        find_package(
            Boost
            ${_acts_boost_version}
            REQUIRED
            COMPONENTS program_options unit_test_framework
        )
    else()
        find_package(Boost ${_acts_boost_version} REQUIRED COMPONENTS)
    endif()

    if(Boost_VERSION VERSION_LESS _acts_boost_recommended_version)
        message(
            WARNING
            "Found Boost ${Boost_VERSION} - recommended is at least ${_acts_boost_recommended_version}"
        )
    endif()

    if(Boost_VERSION VERSION_EQUAL "1.85.0")
        set(_boost_version_severity WARNING)
        if(ACTS_BUILD_EXAMPLES)
            set(_boost_version_severity FATAL_ERROR)
        endif()
        message(
            ${_boost_version_severity}
            "Boost 1.85.0 is known to be broken (https://github.com/boostorg/container/issues/273). Please use a different version."
        )
    endif()
endif()

if(ACTS_SETUP_EIGEN3)
    if(ACTS_USE_SYSTEM_EIGEN3)
        find_package(Eigen3 ${_acts_eigen3_version} REQUIRED CONFIG)
    else()
        add_subdirectory(thirdparty/eigen3)
    endif()
endif()

find_package(Filesystem REQUIRED)

# CUDA settings are collected here in a macro, so that they can be reused by different plugins
macro(enable_cuda)
    enable_language(CUDA)
    set(CMAKE_CUDA_STANDARD 14 CACHE STRING "CUDA C++ standard to use")
    set(CMAKE_CUDA_STANDARD_REQUIRED
        ON
        CACHE BOOL
        "Force the C++ standard requirement"
    )
    if(NOT CMAKE_CUDA_ARCHITECTURES)
        set(CMAKE_CUDA_ARCHITECTURES
            "35;52;75"
            CACHE STRING
            "CUDA architectures to generate code for"
        )
    endif()
    set(CMAKE_CUDA_FLAGS_DEBUG "${CMAKE_CUDA_FLAGS_DEBUG} -g -G")
    set(CMAKE_CUDA_FLAGS "${CMAKE_CUDA_FLAGS} --extended-lambda")
endmacro()

# optional packages
#
# find packages explicitly for each component even if this means searching for
# the same package twice. This avoids having complex if/else trees to sort out
# when a particular package is actually needed.
if(ACTS_BUILD_PLUGIN_ACTSVG)
    if(ACTS_USE_SYSTEM_ACTSVG)
        find_package(actsvg ${_acts_actsvg_version} REQUIRED CONFIG)
    else()
        add_subdirectory(thirdparty/actsvg)
    endif()
endif()
if(ACTS_BUILD_PLUGIN_CUDA)
    enable_cuda()
endif()
if(ACTS_BUILD_PLUGIN_DD4HEP)
    # Explicitly find python so we can more easily override the version
    find_package(Python 3.8 REQUIRED COMPONENTS Interpreter Development)
    find_package(
        DD4hep
        ${_acts_dd4hep_version}
        REQUIRED
        CONFIG
        COMPONENTS DDCore DDDetectors
    )
endif()
if(ACTS_BUILD_PLUGIN_JSON)
    if(ACTS_USE_SYSTEM_NLOHMANN_JSON)
        find_package(nlohmann_json ${_acts_nlohmanjson_version} REQUIRED CONFIG)
    else()
        add_subdirectory(thirdparty/nlohmann_json)
    endif()
endif()
if(ACTS_BUILD_PLUGIN_GEOMODEL)
    find_package(GeoModelCore CONFIG)
    if(NOT GeoModelCore_FOUND)
        message(
            FATAL_ERROR
            "GeoModel not found. Please install GeoModel or set ACTS_BUILD_PLUGIN_GEOMODEL to OFF."
        )
    endif()

    set(_gm_ver_min 6.3.0)

    if(GeoModelCore_VERSION VERSION_LESS _gm_ver_min)
        message(
            FATAL_ERROR
            "GeoModel version ${GeoModelCore_VERSION} is insufficient. Please install GeoModel version ${_gm_ver_min} or newer."
        )
    endif()
    # find other GeoModel components of EXACT same version
    find_package(GeoModelIO ${GeoModelCore_VERSION} REQUIRED EXACT CONFIG)
endif()
if(ACTS_BUILD_PLUGIN_TGEO)
    find_package(
        ROOT
        ${_acts_root_version}
        REQUIRED
        CONFIG
        COMPONENTS Geom Graf
    )
    check_root_compatibility()
endif()
if(ACTS_BUILD_ANALYSIS_APPS)
    find_package(
        ROOT
        ${_acts_root_version}
        REQUIRED
        CONFIG
        COMPONENTS Geom Graf
    )
    check_root_compatibility()
endif()
if(ACTS_BUILD_PLUGIN_EXATRKX)
    find_package(Torch REQUIRED)
    if(ACTS_EXATRKX_ENABLE_CUDA)
        find_package(CUDAToolkit REQUIRED)
        enable_cuda()
        add_subdirectory(thirdparty/FRNN)
        message(STATUS "Build Exa.TrkX plugin with CUDA")
    else()
        message(STATUS "Build Exa.TrkX plugin for CPU only")
    endif()
    if(NOT (ACTS_EXATRKX_ENABLE_ONNX OR ACTS_EXATRKX_ENABLE_TORCH))
        message(
            FATAL_ERROR
            "When building the Exa.TrkX plugin, at least one of ACTS_EXATRKX_ENABLE_ONNX \
      and ACTS_EXATRKX_ENABLE_TORCHSCRIPT must be enabled."
        )
    endif()
    if(ACTS_EXATRKX_ENABLE_TORCH)
        find_package(TorchScatter REQUIRED)
    endif()
endif()
if(ACTS_BUILD_PLUGIN_ONNX OR ACTS_EXATRKX_ENABLE_ONNX)
    find_package(OnnxRuntime ${_acts_onnxruntime_version} REQUIRED)
endif()
if(ACTS_BUILD_PLUGIN_EDM4HEP OR ACTS_BUILD_PLUGIN_PODIO)
    find_package(podio ${_acts_podio_version} CONFIG)
    if(NOT podio_FOUND)
        message(
            STATUS
            "Podio not found, trying ${_acts_podio_fallback_version} version"
        )
        find_package(podio ${_acts_podio_fallback_version} CONFIG REQUIRED)
    endif()
    find_package(ROOT ${_acts_root_version} REQUIRED CONFIG COMPONENTS Core)
endif()
if(ACTS_BUILD_PLUGIN_EDM4HEP)
    find_package(EDM4HEP ${_acts_edm4hep_version} REQUIRED CONFIG)
endif()
if(ACTS_BUILD_PLUGIN_GEANT4)
    find_package(Geant4 ${_acts_geant4_version} REQUIRED CONFIG COMPONENTS gdml)
endif()

if(ACTS_BUILD_PLUGIN_TRACCC)
    if(ACTS_USE_SYSTEM_ALGEBRAPLUGINS)
        find_package(algebra-plugins ${_acts_algebraplugins_version} REQUIRED)
    else()
        add_subdirectory(thirdparty/algebra-plugins)
    endif()

    if(ACTS_USE_SYSTEM_DETRAY)
        find_package(detray ${_acts_detray_version} REQUIRED CONFIG)
    else()
        add_subdirectory(thirdparty/detray)
    endif()

    if(ACTS_USE_SYSTEM_VECMEM)
        find_package(vecmem ${_acts_vecmem_version} REQUIRED)
    else()
        add_subdirectory(thirdparty/vecmem)
        # Make the "VecMem language code" available for the whole project.
        include("${VECMEM_LANGUAGE_DIR}/vecmem-check-language.cmake")
    endif()

    if(ACTS_USE_SYSTEM_COVFIE)
        find_package(covfie ${_acts_covfie_version} REQUIRED CONFIG)
    else()
        add_subdirectory(thirdparty/covfie)
    endif()

    # traccc also depends on vecmem and covfie, but those plugins should always
    # be enabled if traccc is.
    if(ACTS_USE_SYSTEM_TRACCC)
        find_package(traccc ${_acts_traccc_version} REQUIRED CONFIG)
    else()
        add_subdirectory(thirdparty/traccc)
    endif()
endif()
if(ACTS_SETUP_ANNOY OR ACTS_BUILD_PLUGIN_HASHING)
    add_subdirectory(thirdparty/Annoy)
endif()

# examples dependencies
if(ACTS_BUILD_EXAMPLES)
    set(THREADS_PREFER_PTHREAD_FLAG ON)
    find_package(Threads REQUIRED)
    # for simplicity always request all potentially required components.
    find_package(
        ROOT
        ${_acts_root_version}
        REQUIRED
        CONFIG
        COMPONENTS Core Geom Graf GenVector Hist Tree TreePlayer
    )
    check_root_compatibility()
endif()
if(ACTS_BUILD_EXAMPLES_PYTHON_BINDINGS)
    find_package(Python 3.8 REQUIRED COMPONENTS Interpreter Development)
    if(ACTS_USE_SYSTEM_PYBIND11)
        find_package(pybind11 CONFIG REQUIRED)
    else()
        add_subdirectory(thirdparty/pybind11)
    endif()
endif()
if(ACTS_BUILD_EXAMPLES_DD4HEP AND ACTS_BUILD_EXAMPLES_GEANT4)
    find_package(
        DD4hep
        ${_acts_dd4hep_version}
        REQUIRED
        CONFIG
        COMPONENTS DDCore DDG4 DDDetectors
    )
elseif(ACTS_BUILD_EXAMPLES_DD4HEP)
    find_package(
        DD4hep
        ${_acts_dd4hep_version}
        REQUIRED
        CONFIG
        COMPONENTS DDCore DDDetectors
    )
endif()
if(ACTS_BUILD_EXAMPLES_HEPMC3)
    find_package(HepMC3 ${_acts_hepmc3_version} REQUIRED CONFIG)
endif()
if(ACTS_BUILD_EXAMPLES_PYTHIA8)
    find_package(Pythia8 ${_acts_pythia8_version} REQUIRED)
endif()
# other dependencies
if(ACTS_BUILD_DOCS)
    find_package(Doxygen ${_acts_doxygen_version} REQUIRED)
    find_package(Sphinx REQUIRED)
endif()

# core library, core plugins, and other components
add_component(Core Core)
add_subdirectory(Plugins)
add_component_if(Fatras Fatras ACTS_BUILD_FATRAS)
add_component_if(Alignment Alignment ACTS_BUILD_ALIGNMENT)

if(ACTS_BUILD_ODD)
    if(
        EXISTS
            "${CMAKE_CURRENT_LIST_DIR}/thirdparty/OpenDataDetector/CMakeLists.txt"
    )
        add_subdirectory_if(thirdparty/OpenDataDetector ACTS_BUILD_ODD)
    else()
        message(
            FATAL_ERROR
            "ODD build was requested, but the ODD directory seems not to be present. "
            "Did you init and update the submodule?"
        )
    endif()
endif()

# examples
add_subdirectory_if(Examples ACTS_BUILD_EXAMPLES)

# automated tests and benchmarks
if(ACTS_BUILD_BENCHMARKS OR ACTS_BUILD_INTEGRATIONTESTS OR ACTS_BUILD_UNITTESTS)
    enable_testing() # must be set in the main CMakeLists.txt
    add_subdirectory(Tests)
endif()

# documentation
add_subdirectory_if(docs ACTS_BUILD_DOCS)

# create cmake configuration files and environment setup script
include(ActsCreatePackageConfig)
include(ActsCreateSetup)