CMake: use system dependencies, install exports

src/CMakeLists.txt

@@ -75,7 +75,12 @@ endif()
 ### Enter subdirectories
 
 # VCGLib -- required
-if (VCGDIR) # VCGDIR exists - using custom user vcglib path
+find_package(vcglib CONFIG)
+if(TARGET vcglib::vcglib)
+	message(STATUS "- VCGLib - using system provided library")
+	add_library(vcglib ALIAS vcglib::vcglib)
+	get_target_property(VCGDIR vcglib::vcglib INTERFACE_INCLUDE_DIRECTORIES)
+elseif (VCGDIR) # VCGDIR exists - using custom user vcglib path
 	if(EXISTS ${VCGDIR})
 		add_subdirectory(${VCGDIR} {CMAKE_CURRENT_BINARY_DIR}/vcglib)
 		message(STATUS "- VCGLib - using custom VCGDIR path library")
@@ -224,6 +229,29 @@ endforeach()
 set(COPIED_FILES)
 
 if (NOT MESHLAB_BUILD_ONLY_LIBRARIES)
+	# headers
+	install(DIRECTORY common DESTINATION include FILES_MATCHING PATTERN "*.h")
+	# CMake exports
+	if(TARGET vcglib::vcglib AND TARGET GLEW::GLEW)
+		install(EXPORT meshlabTargets
+			DESTINATION lib/cmake/meshlab
+			NAMESPACE meshlab::
+			FILE meshlabTargets.cmake
+		)
+		include(CMakePackageConfigHelpers)
+		# generate the config file that includes the exports
+		configure_package_config_file(${CMAKE_CURRENT_SOURCE_DIR}/Config.cmake.in
+			"${CMAKE_CURRENT_BINARY_DIR}/meshlabConfig.cmake"
+			INSTALL_DESTINATION lib/cmake/vcglib
+			NO_SET_AND_CHECK_MACRO
+			NO_CHECK_REQUIRED_COMPONENTS_MACRO
+		)
+		install(FILES
+			"${CMAKE_CURRENT_BINARY_DIR}/meshlabConfig.cmake"
+			DESTINATION lib/cmake/meshlab
+		)
+	endif()
+
 	# shaders
 	set(SHADER_BASE_DIR "${MESHLAB_RESOURCES_DIR}/shaders")
 	file(

src/Config.cmake.in

@@ -0,0 +1,9 @@
+@PACKAGE_INIT@
+
+include(CMakeFindDependencyMacro)
+find_dependency(GLEW)
+find_dependency(OpenGL)
+find_dependency(Qt5 COMPONENTS OpenGL Xml Network)
+find_dependency(vcglib)
+
+include ( "${CMAKE_CURRENT_LIST_DIR}/meshlabTargets.cmake" )

src/common/CMakeLists.txt

@@ -198,7 +198,8 @@ endif()
 
 target_include_directories(meshlab-common
 	PUBLIC
-		${CMAKE_CURRENT_SOURCE_DIR}/..)
+		$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/..>
+		$<INSTALL_INTERFACE:include>)
 
 target_link_libraries(
 	meshlab-common
@@ -208,10 +209,19 @@ target_link_libraries(
 		Qt5::Widgets
 		Qt5::Xml
 		Qt5::Network
-		vcglib
-		external-glew
+	PRIVATE
 		external-easyexif
 )
+if(TARGET vcglib::vcglib)
+	target_link_libraries(meshlab-common PUBLIC vcglib::vcglib)
+else()
+	target_link_libraries(meshlab-common PUBLIC vcglib)
+endif()
+if(TARGET GLEW::GLEW)
+	target_link_libraries(meshlab-common PUBLIC GLEW::GLEW)
+else()
+	target_link_libraries(meshlab-common PUBLIC external-glew)
+endif()
 
 set_property(TARGET meshlab-common PROPERTY FOLDER Core)
 
@@ -234,4 +244,4 @@ endif()
 set_target_properties(meshlab-common PROPERTIES
 	INSTALL_RPATH "$ORIGIN")
 
-install(TARGETS meshlab-common DESTINATION ${MESHLAB_LIB_INSTALL_DIR})
+install(TARGETS meshlab-common EXPORT meshlabTargets DESTINATION ${MESHLAB_LIB_INSTALL_DIR})

src/external/levmar.cmake

@@ -3,8 +3,25 @@
 # SPDX-License-Identifier: BSL-1.0
 
 option(MESHLAB_ALLOW_DOWNLOAD_SOURCE_LEVMAR "Allow download and use of levmar source" ON)
+option(MESHLAB_ALLOW_SYSTEM_LEVMAR "Allow use of system-provided levmar" ON)
 
-if(MESHLAB_ALLOW_DOWNLOAD_SOURCE_LEVMAR)
+find_path(levmar_INCLUDE_DIR NAMES levmar.h PATHS ${levmar_PREFIX})
+find_library(levmar_LIBRARY NAMES levmar PATHS ${levmar_PREFIX})
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(
+	levmar
+	DEFAULT_MSG
+	levmar_LIBRARY
+	levmar_INCLUDE_DIR
+)
+mark_as_advanced(levmar_INCLUDE_DIR levmar_LIBRARY)
+
+if(MESHLAB_ALLOW_SYSTEM_LEVMAR AND levmar_FOUND)
+	message(STATUS "- levmar - using system-provided library")
+	add_library(external-levmar INTERFACE)
+	target_link_libraries(external-levmar INTERFACE ${levmar_LIBRARY})
+	target_include_directories(external-levmar INTERFACE ${levmar_INCLUDE_DIR})
+elseif(MESHLAB_ALLOW_DOWNLOAD_SOURCE_LEVMAR)
 	set(LEVMAR_VERSION "2.6.1")
 
 	set(LEVMAR_DIR "${MESHLAB_EXTERNAL_DOWNLOAD_DIR}/levmar-${LEVMAR_VERSION}")

src/external/lib3mf.cmake

@@ -22,8 +22,15 @@
 #############################################################################
 
 option(MESHLAB_ALLOW_DOWNLOAD_SOURCE_LIB3MF "Allow download and use of lib3MF source" ON)
+option(MESHLAB_ALLOW_SYSTEM_LIB3MF "Allow use of system-provided lib3MF" ON)
 
-if(MESHLAB_ALLOW_DOWNLOAD_SOURCE_LIB3MF)
+find_package(lib3mf)
+
+if(MESHLAB_ALLOW_SYSTEM_LIB3MF AND TARGET lib3mf::lib3mf)
+  message(STATUS "- Lib3MF - using system-provided library")
+  add_library(external-lib3mf INTERFACE)
+  target_link_libraries(external-lib3mf INTERFACE lib3mf::lib3mf)
+elseif(MESHLAB_ALLOW_DOWNLOAD_SOURCE_LIB3MF)
   set(LIB3MF_VERSION "2.4.1")
 
   set(LIB3MF_DIR ${MESHLAB_EXTERNAL_DOWNLOAD_DIR}/lib3mf-${LIB3MF_VERSION})

src/external/libigl.cmake

@@ -3,10 +3,17 @@
 # SPDX-License-Identifier: BSL-1.0
 
 option(MESHLAB_ALLOW_DOWNLOAD_SOURCE_LIBIGL "Allow download and use of LibIGL source" ON)
+option(MESHLAB_ALLOW_SYSTEM_LIBIGL "Allow use of system-provided LibIGL" ON)
 
 set(LIBIGL_VER 2.4.0)
 
-if(MESHLAB_ALLOW_DOWNLOAD_SOURCE_LIBIGL)
+find_path(libigl_INCLUDE_DIR NAMES igl_inline.h PATH_SUFFIXES igl PATHS ${libigl_PREFIX})
+
+if(MESHLAB_ALLOW_SYSTEM_LIBIGL AND libigl_INCLUDE_DIR)
+	message(STATUS "- LibIGL - using system-provided library")
+	add_library(external-libigl INTERFACE)
+	target_include_directories(external-libigl INTERFACE ${libigl_INCLUDE_DIR})
+elseif(MESHLAB_ALLOW_DOWNLOAD_SOURCE_LIBIGL)
 	set(LIBIGL_DIR "${MESHLAB_EXTERNAL_DOWNLOAD_DIR}/libigl-${LIBIGL_VER}")
 	set(LIBIGL_CHECK "${LIBIGL_DIR}/include/igl/igl_inline.h")
 

src/external/nexus.cmake

@@ -3,11 +3,18 @@
 # SPDX-License-Identifier: BSL-1.0
 
 option(MESHLAB_ALLOW_DOWNLOAD_SOURCE_NEXUS "Allow download and use of nexus source" ON)
+option(MESHLAB_ALLOW_SYSTEM_NEXUS "Allow use of system-provided nexus and corto" ON)
 
 set(CORTO_VER 2025.07)
 set(NEXUS_VER 2025.05)
 
-if(MESHLAB_ALLOW_DOWNLOAD_SOURCE_NEXUS)
+find_package(nexus CONFIG)
+
+if(MESHLAB_ALLOW_SYSTEM_NEXUS AND TARGET nexus::nexus)
+	message(STATUS "- nexus - using system-provided library")
+	add_library(external-nexus INTERFACE)
+	target_link_libraries(external-nexus INTERFACE nexus::nexus)
+elseif(MESHLAB_ALLOW_DOWNLOAD_SOURCE_NEXUS)
 	set(NEXUS_DIR "${MESHLAB_EXTERNAL_DOWNLOAD_DIR}/nexus-${NEXUS_VER}")
 	set(NEXUS_CHECK "${NEXUS_DIR}/CMakeLists.txt")
 	set(CORTO_DIR "${NEXUS_DIR}/src/corto")

src/meshlabplugins/io_base/CMakeLists.txt

@@ -27,4 +27,4 @@ set(SOURCES
 
 add_meshlab_plugin(io_base ${SOURCES} ${HEADERS})
 
-target_link_libraries(io_base PRIVATE OpenGL::GLU)
+target_link_libraries(io_base PRIVATE OpenGL::GLU external-easyexif)