Add Source in a subdirectory to a cmake project

Question

I have project which has not been divided into libraries, but the source is organized in a directory tree. I do not know how to tell cmake to go down a directory, then add

Answer 1

Like the second part of arrowdodger's answer says: in project/source/folder1/CMakeLists.txt:

set(SOURCE
   ${SOURCE}
   ${CMAKE_CURRENT_SOURCE_DIR}/file1.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/file2.cpp
   PARENT_SCOPE
)
set(HEADERS
   ${HEADERS}
   ${CMAKE_CURRENT_SOURCE_DIR}/file1.hpp
   ${CMAKE_CURRENT_SOURCE_DIR}/file2.hpp
   PARENT_SCOPE
)