[CMake] use a custom module for assimp

Because using its .pc would not work on Windows, and its -config.cmake
is broken.

While here remove switch for assimp < 2.0, as assimp v3 is from 2014.

CMakeLists.txt

@@ -61,6 +61,10 @@ include(cmake/hpp.cmake)
 include(cmake/apple.cmake)
 include(cmake/ide.cmake)
 
+SET(CMAKE_MODULE_PATH
+  ${CMAKE_SOURCE_DIR}/cmake-modules/
+  ${CMAKE_MODULE_PATH})
+
 # If needed, fix CMake policy for APPLE systems
 APPLY_DEFAULT_APPLE_CONFIGURATION()
 
@@ -116,7 +120,7 @@ if(HPP_FCL_HAS_QHULL)
     )
 endif()
 
-ADD_PROJECT_DEPENDENCY(assimp REQUIRED PKG_CONFIG_REQUIRES "assimp >= 2.0.0")
+FIND_PACKAGE(assimp REQUIRED)
 
 SET(${PROJECT_NAME}_HEADERS
   include/hpp/fcl/collision_data.h

cmake-modules/Findassimp.cmake

+#
+#   Copyright 2020 CNRS
+#
+#   Author: Guilhem Saurel
+#
+
+# Try to find assimp in standard prefixes and in ${assimp_PREFIX}
+# Once done this will define
+#  assimp_FOUND - System has assimp
+#  assimp_INCLUDE_DIR - The assimp include directories
+#  assimp_LIBRARY - The libraries needed to use assimp
+
+FIND_PATH(assimp_INCLUDE_DIR
+  NAMES assimp/defs.h
+  PATHS ${assimp_PREFIX} ${assimp_PREFIX}/include
+  )
+
+FIND_LIBRARY(assimp_LIBRARY
+  NAMES libassimp.so
+  PATHS ${assimp_PREFIX} ${assimp_PREFIX}/lib
+  )
+
+INCLUDE(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(assimp DEFAULT_MSG assimp_LIBRARY assimp_INCLUDE_DIR)
+mark_as_advanced(assimp_INCLUDE_DIR assimp_LIBRARY)

src/CMakeLists.txt

@@ -156,21 +156,22 @@ add_library(${LIBRARY_NAME}
 ADD_SOURCE_GROUP(${LIBRARY_NAME}_SOURCES)
 ADD_HEADER_GROUP(PROJECT_HEADERS_FULL_PATH)
 
-FIND_LIBRARY(ASSIMP_FULL_LIB NAMES assimp PATHS ${ASSIMP_LIBRARY_DIRS} NO_DEFAULT_PATH)
-MESSAGE(STATUS "assimp: ${ASSIMP_FULL_LIB}")
-
 TARGET_LINK_LIBRARIES(${LIBRARY_NAME}
   PUBLIC
   ${Boost_THREAD_LIBRARY}
   ${Boost_DATE_TIME_LIBRARY}
   ${Boost_SYSTEM_LIBRARY}
-  ${ASSIMP_FULL_LIB}
-#  assimp::assimp # Not working
 #  Boost::thread
 #  Boost::date_time
 #  Boost::system
   )
 
+TARGET_LINK_LIBRARIES(${LIBRARY_NAME}
+  PRIVATE
+  ${assimp_LIBRARY}
+  # assimp::assimp # Not working
+  )
+
 if(HPP_FCL_HAS_QHULL)
   target_compile_definitions(${LIBRARY_NAME} PRIVATE -DHPP_FCL_HAS_QHULL)
   target_include_directories(${LIBRARY_NAME} SYSTEM PRIVATE
@@ -182,7 +183,7 @@ target_include_directories(${LIBRARY_NAME}
   SYSTEM PUBLIC
   ${EIGEN3_INCLUDE_DIR}
   ${Boost_INCLUDE_DIRS}
-  ${ASSIMP_INCLUDE_DIRS}
+  ${assimp_INCLUDE_DIR}
   )
 
 target_include_directories(${LIBRARY_NAME}
@@ -190,12 +191,6 @@ target_include_directories(${LIBRARY_NAME}
   $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
   )
 
-if (NOT ${ASSIMP_VERSION} VERSION_LESS "2.0.1150")
-  target_compile_definitions(${LIBRARY_NAME} PRIVATE -DHPP_FCL_USE_ASSIMP_UNIFIED_HEADER_NAMES)
-  message(STATUS "Assimp version has unified headers")
-else()
-  message(STATUS "Assimp version does not have unified headers")
-endif()
 IF(octomap_FOUND)
   target_include_directories(${LIBRARY_NAME} SYSTEM PUBLIC ${OCTOMAP_INCLUDE_DIRS})
   target_link_libraries(${LIBRARY_NAME} PUBLIC ${OCTOMAP_LIBRARIES})

src/mesh_loader/assimp.cpp

@@ -45,21 +45,12 @@
   #define AI_NO_EXCEPT
 #endif
 
-#ifdef HPP_FCL_USE_ASSIMP_UNIFIED_HEADER_NAMES
-  #include <assimp/DefaultLogger.hpp>
-  #include <assimp/IOStream.hpp>
-  #include <assimp/IOSystem.hpp>
-  #include <assimp/Importer.hpp>
-  #include <assimp/postprocess.h>
-  #include <assimp/scene.h>
-#else
-  #include <assimp/DefaultLogger.h>
-  #include <assimp/assimp.hpp>
-  #include <assimp/IOStream.h>
-  #include <assimp/IOSystem.h>
-  #include <assimp/aiPostProcess.h>
-  #include <assimp/aiScene.h>
-#endif
+#include <assimp/DefaultLogger.hpp>
+#include <assimp/IOStream.hpp>
+#include <assimp/IOSystem.hpp>
+#include <assimp/Importer.hpp>
+#include <assimp/postprocess.h>
+#include <assimp/scene.h>
 
 namespace hpp
 {