include(ExternalProject)

ExternalProject_Add(
    ext_nanoflann
    PREFIX nanoflann
    URL https://github.com/jlblancoc/nanoflann/archive/refs/tags/v1.5.0.tar.gz
    URL_HASH SHA256=89aecfef1a956ccba7e40f24561846d064f309bc547cc184af7f4426e42f8e65
    DOWNLOAD_DIR "${OPEN3D_THIRD_PARTY_DOWNLOAD_DIR}/nanoflann"
    UPDATE_COMMAND ""
    CONFIGURE_COMMAND ""
    BUILD_COMMAND ""
    INSTALL_COMMAND ""
)

ExternalProject_Get_Property(ext_nanoflann SOURCE_DIR)
set(NANOFLANN_INCLUDE_DIRS ${SOURCE_DIR}/include/) # "/" is critical.