feat: nix support

CMakeLists.txt

@@ -17,6 +17,11 @@ endif()
 
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake") # look for stuff in the /cmake directory
 include(UpdateCacheVariable)
+# Install a standard CMake config package so downstream users do not need a custom FindGeometryCentral.cmake module.
+include(GNUInstallDirs)
+include(CMakePackageConfigHelpers)
+
+set(GC_INSTALL_CMAKEDIR "${CMAKE_INSTALL_LIBDIR}/cmake/GeometryCentral")
 
 # Work with non-standard homebrew installations
 # (from ceres build system)
@@ -50,16 +55,42 @@ SET(GC_HAVE_SUITESPARSE ${GC_HAVE_SUITESPARSE} PARENT_SCOPE)
 ### Recurse to the source code
 add_subdirectory(src)
 
-# install
+# Install the library and export it as an imported target for find_package().
 install(
   TARGETS geometry-central
-  ARCHIVE DESTINATION lib
-  RUNTIME DESTINATION bin
-  LIBRARY DESTINATION lib)
+  EXPORT GeometryCentralTargets
+  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
+  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR})
 
 install(
-  DIRECTORY ${CMAKE_SOURCE_DIR}/include/
-  DESTINATION include
+  DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/include/
+  DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
   FILES_MATCHING
   PATTERN "*.h"
   PATTERN "*.ipp")
+
+# These vendored headers are referenced by installed public headers, so ship them
+# in the install tree rather than relying on downstream postInstall copy steps.
+install(
+  FILES "${CMAKE_CURRENT_SOURCE_DIR}/deps/happly/happly.h"
+  DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
+
+install(
+  FILES "${CMAKE_CURRENT_SOURCE_DIR}/deps/nanort/include/nanort/nanort.h"
+  DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/nanort")
+
+configure_package_config_file(
+  "${CMAKE_CURRENT_SOURCE_DIR}/cmake/GeometryCentralConfig.cmake.in"
+  "${CMAKE_CURRENT_BINARY_DIR}/GeometryCentralConfig.cmake"
+  INSTALL_DESTINATION "${GC_INSTALL_CMAKEDIR}")
+
+# Install the exported target definitions and the package entry point side-by-side.
+install(
+  EXPORT GeometryCentralTargets
+  NAMESPACE geometry-central::
+  DESTINATION "${GC_INSTALL_CMAKEDIR}")
+
+install(
+  FILES "${CMAKE_CURRENT_BINARY_DIR}/GeometryCentralConfig.cmake"
+  DESTINATION "${GC_INSTALL_CMAKEDIR}")

cmake/GeometryCentralConfig.cmake.in

@@ -0,0 +1,12 @@
+@PACKAGE_INIT@
+
+include(CMakeFindDependencyMacro)
+
+find_dependency(Eigen3 3.3 REQUIRED NO_MODULE)
+
+include("${CMAKE_CURRENT_LIST_DIR}/GeometryCentralTargets.cmake")
+
+# Reattach Eigen after loading the exported target so installed consumers still
+# inherit it transitively without exporting this project's local helper target.
+set_property(TARGET geometry-central::geometry-central APPEND PROPERTY
+  INTERFACE_LINK_LIBRARIES Eigen3::Eigen)

src/CMakeLists.txt

@@ -178,11 +178,22 @@ SET(HEADERS
 # Create a single library for the project
 add_library(geometry-central ${SRCS} ${HEADERS})
 
-# Includes from this project
-target_include_directories(geometry-central PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}/../include")
+# Public headers include vendored headers directly, so build-tree consumers need
+# those include roots explicitly. The install tree collapses them under the
+# single installed include directory.
+target_include_directories(geometry-central
+  PUBLIC
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../include>
+    $<BUILD_INTERFACE:${EIGEN3_INCLUDE_DIR}>
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../deps/happly>
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../deps/nanort/include>
+    $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
+  PRIVATE
+    "${CMAKE_CURRENT_SOURCE_DIR}/../deps/nanoflann/include")
 
-# Add all includes and link libraries from dependencies, which were populated in deps/CMakeLists.txt
-target_link_libraries(geometry-central PUBLIC ${GC_DEP_LIBS})
+# Keep Eigen out of the exported build-tree link interface to avoid exporting the
+# local helper target created in deps/CMakeLists.txt. The installed package adds
+# Eigen3::Eigen back after calling find_dependency(Eigen3).
 
 # Set compiler properties for the library
 target_compile_features(geometry-central PUBLIC cxx_std_11)