draco: Improve installation and packaging support.

- Fixed omission of draco_version.h when installed in static
  configurations.
- Remove DracoConfig.cmake: it was broken and we actually use
  draco-config.cmake.
- Update FindDraco.cmake so it actually has a chance of working
  properly. Fixed usage of find_path() and subsequent related errors.
- Correct the usage of CMakePackageConfigHelpers in installation target setup
  and the config template.
- Add a CMake version file.
- Normalize the Draco variables exposed in CMake.
  - draco_FOUND -> DRACO_FOUND
  - DRACO_INCLUDE_DIRS, draco_INCLUDE_DIRS -> DRACO_INCLUDE_DIR
  - DRACO_LIBRARIES, draco_LIBRARIES -> DRACO_LIBRARY
  - DRACO_LIBRARY_DIRS, draco_LIBRARY_DIRS -> DRACO_LIBRARY_DIR
  - draco_VERSION_STRING -> DRACO_VERSION
- Use full path variants of GNUInstallDirs variables to init our
  install paths.

Fixes https://github.com/google/draco/issues/764

* Add install() for draco-version.cmake.

CMakeLists.txt

@@ -35,7 +35,6 @@ if("${draco_root}" STREQUAL "${draco_build}")
                 "And re-run CMake from the draco_build directory.")
 endif()
 
-include(CMakePackageConfigHelpers)
 include(FindPythonInterp)
 include("${draco_root}/cmake/draco_build_definitions.cmake")
 include("${draco_root}/cmake/draco_cpu_detection.cmake")
@@ -347,6 +346,7 @@ list(APPEND draco_core_sources
             "${draco_src_root}/core/draco_index_type_vector.h"
             "${draco_src_root}/core/draco_types.cc"
             "${draco_src_root}/core/draco_types.h"
+            "${draco_src_root}/core/draco_version.h"
             "${draco_src_root}/core/encoder_buffer.cc"
             "${draco_src_root}/core/encoder_buffer.h"
             "${draco_src_root}/core/hash_utils.cc"

cmake/DracoConfig.cmake

@@ -1,3 +0,0 @@
-@PACKAGE_INIT@
-set_and_check(draco_INCLUDE_DIR "@PACKAGE_draco_include_install_dir@")
-set_and_check(draco_LIBRARY_DIR "@PACKAGE_draco_lib_install_dir@")

cmake/FindDraco.cmake

@@ -7,50 +7,62 @@
 #
 # draco_FOUND is set to YES only when all other variables are successfully
 # configured.
+include(GNUInstallDirs)
 
-unset(draco_FOUND)
-unset(draco_INCLUDE_DIRS)
-unset(draco_LIBRARY_DIRS)
-unset(draco_LIBRARIES)
-unset(draco_VERSION_STRING)
+unset(DRACO_FOUND)
+unset(DRACO_INCLUDE_DIR)
+unset(DRACO_LIBRARY_DIR)
+unset(DRACO_LIBRARY)
+unset(DRACO_VERSION)
 
-mark_as_advanced(draco_FOUND)
-mark_as_advanced(draco_INCLUDE_DIRS)
-mark_as_advanced(draco_LIBRARY_DIRS)
-mark_as_advanced(draco_LIBRARIES)
-mark_as_advanced(draco_VERSION_STRING)
+mark_as_advanced(DRACO_FOUND)
+mark_as_advanced(DRACO_INCLUDE_DIR)
+mark_as_advanced(DRACO_LIBRARY_DIR)
+mark_as_advanced(DRACO_LIBRARIES)
+mark_as_advanced(DRACO_VERSION)
 
-set(draco_version_file_no_prefix "draco/src/draco/core/draco_version.h")
+if(NOT DRACO_SEARCH_DIR)
+  set(DRACO_SEARCH_DIR ${CMAKE_INSTALL_FULL_INCLUDEDIR})
+endif()
 
-# Set draco_INCLUDE_DIRS
-find_path(draco_INCLUDE_DIRS NAMES "${draco_version_file_no_prefix}")
+set(draco_features_dir "${DRACO_SEARCH_DIR}/draco")
+
+# Set DRACO_INCLUDE_DIR
+find_path(
+  DRACO_INCLUDE_DIR
+  NAMES "draco_features.h"
+  PATHS "${draco_features_dir}")
+
+# The above returned "path/to/draco/", strip "draco" so that projects can
+# include draco sources using draco[/subdir]/file.h, like the draco sources.
+get_filename_component(DRACO_INCLUDE_DIR ${DRACO_INCLUDE_DIR} DIRECTORY)
 
 # Extract the version string from draco_version.h.
-if(draco_INCLUDE_DIRS)
+if(DRACO_INCLUDE_DIR)
   set(draco_version_file
-      "${draco_INCLUDE_DIRS}/draco/src/draco/core/draco_version.h")
-  file(STRINGS "${draco_version_file}" draco_version REGEX "kdracoVersion")
+      "${DRACO_INCLUDE_DIR}/draco/core/draco_version.h")
+  file(STRINGS "${draco_version_file}" draco_version REGEX "kDracoVersion")
   list(GET draco_version 0 draco_version)
-  string(REPLACE "static const char kdracoVersion[] = " "" draco_version
+  string(REPLACE "static const char kDracoVersion[] = " "" draco_version
                  "${draco_version}")
   string(REPLACE ";" "" draco_version "${draco_version}")
   string(REPLACE "\"" "" draco_version "${draco_version}")
-  set(draco_VERSION_STRING ${draco_version})
+  set(DRACO_VERSION ${draco_version})
 endif()
 
 # Find the library.
 if(BUILD_SHARED_LIBS)
-  find_library(draco_LIBRARIES NAMES draco.dll libdraco.dylib libdraco.so)
+  find_library(DRACO_LIBRARY NAMES draco.dll libdraco.dylib libdraco.so)
 else()
-  find_library(draco_LIBRARIES NAMES draco.lib libdraco.a)
+  find_library(DRACO_LIBRARY NAMES draco.lib libdraco.a)
 endif()
 
 # Store path to library.
-get_filename_component(draco_LIBRARY_DIRS ${draco_LIBRARIES} DIRECTORY)
+get_filename_component(DRACO_LIBRARY_DIR ${DRACO_LIBRARY} DIRECTORY)
 
-if(draco_INCLUDE_DIRS
-   AND draco_LIBRARY_DIRS
-   AND draco_LIBRARIES
-   AND draco_VERSION_STRING)
-  set(draco_FOUND YES)
+if(DRACO_INCLUDE_DIR
+   AND DRACO_LIBRARY_DIR
+   AND DRACO_LIBRARY
+   AND DRACO_VERSION)
+  set(DRACO_FOUND YES)
 endif()

cmake/draco-config.cmake.template

@@ -1,2 +1,4 @@
-set(DRACO_INCLUDE_DIRS "@DRACO_INCLUDE_DIRS@")
-set(DRACO_LIBRARIES "draco")
+@PACKAGE_INIT@
+set_and_check(DRACO_INCLUDE_DIR "@CMAKE_INSTALL_FULL_INCLUDEDIR@")
+set_and_check(DRACO_LIB_DIR "@CMAKE_INSTALL_FULL_LIBDIR@")
+set_and_check(DRACO_LIBRARY "draco")

cmake/draco.pc.template

@@ -1,11 +1,6 @@
-prefix=@prefix@
-exec_prefix=@exec_prefix@
-libdir=@libdir@
-includedir=@includedir@
-
 Name: @PROJECT_NAME@
 Description: Draco geometry de(com)pression library.
 Version: @DRACO_VERSION@
-Cflags: -I${includedir}
-Libs: -L${libdir} -ldraco
+Cflags: -I@includes_path@
+Libs: -L@libs_path@ -ldraco
 Libs.private: @CMAKE_THREAD_LIBS_INIT@

cmake/draco_install.cmake

@@ -17,30 +17,41 @@ if(DRACO_CMAKE_DRACO_INSTALL_CMAKE_)
 endif() # DRACO_CMAKE_DRACO_INSTALL_CMAKE_
 set(DRACO_CMAKE_DRACO_INSTALL_CMAKE_ 1)
 
+include(CMakePackageConfigHelpers)
+include(GNUInstallDirs)
+
 # Sets up the draco install targets. Must be called after the static library
 # target is created.
 macro(draco_setup_install_target)
-  include(GNUInstallDirs)
-
-  # pkg-config: draco.pc
-  set(prefix "${CMAKE_INSTALL_PREFIX}")
-  set(exec_prefix "\${prefix}")
-  set(libdir "\${prefix}/${CMAKE_INSTALL_LIBDIR}")
-  set(includedir "\${prefix}/${CMAKE_INSTALL_INCLUDEDIR}")
+  set(bin_path "${CMAKE_INSTALL_FULL_BINDIR}")
+  set(data_path "${CMAKE_INSTALL_FULL_DATAROOTDIR}")
+  set(includes_path "${CMAKE_INSTALL_FULL_INCLUDEDIR}")
+  set(libs_path "${CMAKE_INSTALL_FULL_LIBDIR}")
   set(draco_lib_name "draco")
 
+  # pkg-config: draco.pc
   configure_file("${draco_root}/cmake/draco.pc.template"
                  "${draco_build}/draco.pc" @ONLY NEWLINE_STYLE UNIX)
-  install(FILES "${draco_build}/draco.pc"
-          DESTINATION "${prefix}/${CMAKE_INSTALL_LIBDIR}/pkgconfig")
+  install(FILES "${draco_build}/draco.pc" DESTINATION "${libs_path}/pkgconfig")
 
   # CMake config: draco-config.cmake
-  set(DRACO_INCLUDE_DIRS "${prefix}/${CMAKE_INSTALL_INCLUDEDIR}")
-  configure_file("${draco_root}/cmake/draco-config.cmake.template"
-                 "${draco_build}/draco-config.cmake" @ONLY NEWLINE_STYLE UNIX)
+  set(DRACO_INCLUDE_DIR "${includes_path}")
+  configure_package_config_file(
+    "${draco_root}/cmake/draco-config.cmake.template"
+    "${draco_build}/draco-config.cmake"
+    INSTALL_DESTINATION "${data_path}/cmake")
   install(
     FILES "${draco_build}/draco-config.cmake"
-    DESTINATION "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_DATAROOTDIR}/cmake")
+    DESTINATION "${data_path}/cmake")
+
+  # CMake version: draco-version.cmake
+  write_basic_package_version_file(
+    "${draco_build}/draco-version.cmake"
+    VERSION ${DRACO_VERSION}
+    COMPATIBILITY AnyNewerVersion)
+  install(
+      FILES "${draco_build}/draco-version.cmake"
+      DESTINATION "${data_path}/cmake")
 
   foreach(file ${draco_sources})
     if(file MATCHES "h$")
@@ -48,46 +59,42 @@ macro(draco_setup_install_target)
     endif()
   endforeach()
 
+  list(REMOVE_DUPLICATES draco_api_includes)
+
   # Strip $draco_src_root from the file paths: we need to install relative to
   # $include_directory.
   list(TRANSFORM draco_api_includes REPLACE "${draco_src_root}/" "")
-  set(include_directory "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_INCLUDEDIR}")
 
   foreach(draco_api_include ${draco_api_includes})
     get_filename_component(file_directory ${draco_api_include} DIRECTORY)
-    set(target_directory "${include_directory}/draco/${file_directory}")
+    set(target_directory "${includes_path}/draco/${file_directory}")
     install(FILES ${draco_src_root}/${draco_api_include}
             DESTINATION "${target_directory}")
   endforeach()
 
   install(
     FILES "${draco_build}/draco/draco_features.h"
-    DESTINATION "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_INCLUDEDIR}/draco/")
+    DESTINATION "${includes_path}/draco/")
 
-  install(TARGETS draco_decoder DESTINATION
-                  "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_BINDIR}")
-  install(TARGETS draco_encoder DESTINATION
-                  "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_BINDIR}")
+  install(TARGETS draco_decoder DESTINATION "${bin_path}")
+  install(TARGETS draco_encoder DESTINATION "${bin_path}")
 
   if(MSVC)
-    install(TARGETS draco DESTINATION
-                    "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}")
+    install(TARGETS draco DESTINATION "${libs_path}")
   else()
-    install(TARGETS draco_static DESTINATION
-                    "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}")
+    install(TARGETS draco_static DESTINATION "${libs_path}")
+
     if(BUILD_SHARED_LIBS)
-      install(TARGETS draco_shared DESTINATION
-                      "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}")
+      install(TARGETS draco_shared DESTINATION "${libs_path}")
     endif()
   endif()
 
   if(DRACO_UNITY_PLUGIN)
-    install(TARGETS dracodec_unity DESTINATION
-                    "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}")
+    install(TARGETS dracodec_unity DESTINATION "${libs_path}")
   endif()
+
   if(DRACO_MAYA_PLUGIN)
-    install(TARGETS draco_maya_wrapper DESTINATION
-                    "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}")
+    install(TARGETS draco_maya_wrapper DESTINATION "${libs_path}")
   endif()
 
 endmacro()