colmap/share/cmake/FindFLANN.cmake

# Copyright (c) 2023, ETH Zurich and UNC Chapel Hill.
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# Author: Johannes L. Schoenberger (jsch-at-demuc-dot-de)

# Find package module for FLANN library.
#
# The following variables are set by this module:
#
#   FLANN_FOUND: TRUE if FLANN is found.
#   FLANN_INCLUDE_DIRS: Include directories for FLANN.
#   FLANN_LIBRARIES: Libraries required to link FLANN.
#
# The following variables control the behavior of this module:
#
# FLANN_INCLUDE_DIR_HINTS: List of additional directories in which to
#                              search for FLANN includes.
# FLANN_LIBRARY_DIR_HINTS: List of additional directories in which to
#                              search for FLANN libraries.

set(FLANN_INCLUDE_DIR_HINTS "" CACHE PATH "FLANN include directory")
set(FLANN_LIBRARY_DIR_HINTS "" CACHE PATH "FLANN library directory")

unset(FLANN_FOUND)
unset(FLANN_INCLUDE_DIRS)
unset(FLANN_LIBRARIES)

list(APPEND FLANN_CHECK_INCLUDE_DIRS
    ${FLANN_INCLUDE_DIR_HINTS}
    /usr/include
    /usr/local/include
    /opt/include
    /opt/local/include
)

list(APPEND FLANN_CHECK_LIBRARY_DIRS
    ${FLANN_LIBRARY_DIR_HINTS}
    /usr/lib
    /usr/local/lib
    /opt/lib
    /opt/local/lib
)

find_path(FLANN_INCLUDE_DIRS
    NAMES
    flann/flann.hpp
    PATHS
    ${FLANN_CHECK_INCLUDE_DIRS})
find_library(FLANN_LIBRARIES
    NAMES
    flann
    PATHS
    ${FLANN_CHECK_LIBRARY_DIRS})

if(FLANN_INCLUDE_DIRS AND FLANN_LIBRARIES)
    set(FLANN_FOUND TRUE)
endif()

if(FLANN_FOUND)
    message(STATUS "Found FLANN")
    message(STATUS "  Includes : ${FLANN_INCLUDE_DIRS}")
    message(STATUS "  Libraries : ${FLANN_LIBRARIES}")
else()
    if(FLANN_FIND_REQUIRED)
        message(FATAL_ERROR "Could not find FLANN")
    endif()
endif()