Re-add the glm interface library in cmake

Also re-work the main cmakelists to make the project more easily embeddable

CMakeLists.txt

@@ -4,6 +4,13 @@ cmake_policy(VERSION 3.2)
 set(GLM_VERSION "0.9.9")
 project(glm VERSION ${GLM_VERSION} LANGUAGES CXX)
 
+add_subdirectory(glm)
+
+add_library(glm::glm ALIAS glm)
+
+if(${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_CURRENT_SOURCE_DIR})
+
+add_subdirectory(test)
 enable_testing()
 
 option(GLM_QUIET "No CMake Message" OFF)
@@ -232,8 +239,4 @@ elseif(CMAKE_CXX_COMPILER_ID MATCHES "MSVC")
 	add_definitions(-D_CRT_SECURE_NO_WARNINGS)
 endif()
 
-include_directories("${PROJECT_SOURCE_DIR}")
-
-add_subdirectory(glm)
-add_subdirectory(test)
-
+endif(${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_CURRENT_SOURCE_DIR})

glm/CMakeLists.txt

@@ -42,7 +42,8 @@ source_group("SIMD Files" FILES ${SIMD_SOURCE})
 source_group("SIMD Files" FILES ${SIMD_INLINE})
 source_group("SIMD Files" FILES ${SIMD_HEADER})
 
-include_directories(${CMAKE_CURRENT_SOURCE_DIR}/..)
+add_library(glm INTERFACE)
+target_include_directories(glm INTERFACE ../)
 
 if(BUILD_STATIC_LIBS)
 add_library(glm_static STATIC ${ROOT_TEXT} ${ROOT_MD} ${ROOT_NAT}
@@ -52,6 +53,8 @@ add_library(glm_static STATIC ${ROOT_TEXT} ${ROOT_MD} ${ROOT_NAT}
 	${GTC_SOURCE}     ${GTC_INLINE}     ${GTC_HEADER}
 	${GTX_SOURCE}     ${GTX_INLINE}     ${GTX_HEADER}
 	${SIMD_SOURCE}    ${SIMD_INLINE}    ${SIMD_HEADER})
+	target_link_libraries(glm_static PUBLIC glm)
+	add_library(glm::glm_static ALIAS glm_static)
 endif()
 
 if(BUILD_SHARED_LIBS)
@@ -62,5 +65,6 @@ add_library(glm_shared SHARED ${ROOT_TEXT} ${ROOT_MD} ${ROOT_NAT}
 	${GTC_SOURCE}     ${GTC_INLINE}     ${GTC_HEADER}
 	${GTX_SOURCE}     ${GTX_INLINE}     ${GTX_HEADER}
 	${SIMD_SOURCE}    ${SIMD_INLINE}    ${SIMD_HEADER})
+	target_link_libraries(glm_shared PUBLIC glm)
+	add_library(glm::glm_shared ALIAS glm_shared)
 endif()
-