Introduce doxygen documentation

CMakeLists.txt

@@ -133,7 +133,11 @@ endif()
 # DOCUMENTATION
 #----------------------------------
 
-# TODO Build doxygen
+option(BUILD_DOC "Build documentation" ON)
+
+if(BUILD_DOC)
+    add_subdirectory("${CMAKE_SOURCE_DIR}/doc")
+endif()
 
 #----------------------------------
 # CMAKE CONFIG & PACKAGE CONFIG

doc/CMakeLists.txt

@@ -0,0 +1,17 @@
+# Building doxygen documentation
+
+find_package(Doxygen)
+
+if(DOXYGEN_FOUND)
+    configure_file(${CMAKE_CURRENT_SOURCE_DIR}/Doxyfile.in ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile @ONLY)
+
+    add_custom_target(doc
+        COMMAND ${DOXYGEN_EXECUTABLE} ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile
+        WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
+        COMMENT "Generating API documentation with Doxygen"
+        VERBATIM)
+
+    install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/html DESTINATION ${CMAKE_INSTALL_DOCDIR})
+else()
+    message(WARNING "Documentation enabled, but Doxygen cannot be found")
+endif()