Fix CMake config to allow using imnodes as sub project (#182)

* Fix compile with latest ImGui

IMGUI_DEFINE_MATH_OPERATORS now needs to be defined before #include <imgui.h>

* Fix CMake config to allow using imnodes as sub project, option for building examples, custom imgui linking

* Fix comment typo

CMakeLists.txt

@@ -5,8 +5,25 @@ project(imnodes)
 set(CMAKE_CXX_STANDARD 11)
 set(CMAKE_CXX_STANDARD_REQUIRED True)
 
-find_package(imgui CONFIG REQUIRED)
-find_package(SDL2 CONFIG REQUIRED)
+
+# determine whether this is a standalone project or included by other projects
+if (NOT DEFINED IMNODES_STANDALONE_PROJECT)
+ if (CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
+ set(IMNODES_STANDALONE_PROJECT ON)
+ else()
+ set(IMNODES_STANDALONE_PROJECT OFF)
+ endif ()
+endif()
+
+# cmake options
+option(IMNODES_EXAMPLES "Build examples" ${IMNODES_STANDALONE_PROJECT})
+
+# allow custom imgui target name since this can vary because imgui doesn't natively include a CMakeLists.txt
+if(NOT DEFINED IMNODES_IMGUI_TARGET_NAME)
+ find_package(imgui CONFIG REQUIRED)
+ set(IMNODES_IMGUI_TARGET_NAME imgui::imgui)
+endif()
+
 
 if(MSVC)
  add_compile_definitions(SDL_MAIN_HANDLED)
@@ -22,59 +39,63 @@ target_sources(imnodes PRIVATE
  imnodes.h
  imnodes_internal.h
  imnodes.cpp)
-target_include_directories(imnodes PUBLIC ${CMAKE_SOURCE_DIR})
-target_link_libraries(imnodes PUBLIC imgui::imgui)
+target_include_directories(imnodes PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+target_link_libraries(imnodes PUBLIC ${IMNODES_IMGUI_TARGET_NAME})
 
 # Example projects
+if(IMNODES_EXAMPLES)
 
-add_executable(colornode
- ${CMAKE_SOURCE_DIR}/imnodes.cpp
- ${CMAKE_SOURCE_DIR}/example/main.cpp
- ${CMAKE_SOURCE_DIR}/example/color_node_editor.cpp)
-target_link_libraries(colornode imnodes SDL2::SDL2)
-if (APPLE)
- target_link_libraries(colornode "-framework OpenGL")
-elseif(MSVC)
- target_link_libraries(colornode "opengl32")
-else()
- target_link_libraries(colornode X11 Xext GL)
-endif()
+ find_package(SDL2 CONFIG REQUIRED)
 
-add_executable(multieditor
- ${CMAKE_SOURCE_DIR}/imnodes.cpp 
- ${CMAKE_SOURCE_DIR}/example/main.cpp
- ${CMAKE_SOURCE_DIR}/example/multi_editor.cpp)
-target_link_libraries(multieditor imnodes SDL2::SDL2)
-if (APPLE)
- target_link_libraries(multieditor "-framework OpenGL")
-elseif(MSVC)
- target_link_libraries(multieditor "opengl32")
-else()
- target_link_libraries(multieditor X11 Xext GL)
-endif()
+ add_executable(colornode
+  ${CMAKE_CURRENT_SOURCE_DIR}/imnodes.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/example/main.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/example/color_node_editor.cpp)
+ target_link_libraries(colornode imnodes SDL2::SDL2)
+ if (APPLE)
+  target_link_libraries(colornode "-framework OpenGL")
+ elseif(MSVC)
+  target_link_libraries(colornode "opengl32")
+ else()
+  target_link_libraries(colornode X11 Xext GL)
+ endif()
 
-add_executable(saveload
- ${CMAKE_SOURCE_DIR}/imnodes.cpp
- ${CMAKE_SOURCE_DIR}/example/main.cpp
- ${CMAKE_SOURCE_DIR}/example/save_load.cpp)
-target_link_libraries(saveload imnodes SDL2::SDL2)
-if (APPLE)
- target_link_libraries(saveload "-framework OpenGL")
-elseif(MSVC)
- target_link_libraries(saveload "opengl32")
-else()
- target_link_libraries(saveload X11 Xext GL)
-endif()
+ add_executable(multieditor
+  ${CMAKE_CURRENT_SOURCE_DIR}/imnodes.cpp 
+  ${CMAKE_CURRENT_SOURCE_DIR}/example/main.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/example/multi_editor.cpp)
+ target_link_libraries(multieditor imnodes SDL2::SDL2)
+ if (APPLE)
+  target_link_libraries(multieditor "-framework OpenGL")
+ elseif(MSVC)
+  target_link_libraries(multieditor "opengl32")
+ else()
+  target_link_libraries(multieditor X11 Xext GL)
+ endif()
 
-add_executable(hello
- ${CMAKE_SOURCE_DIR}/imnodes.cpp
- ${CMAKE_SOURCE_DIR}/example/main.cpp
- ${CMAKE_SOURCE_DIR}/example/hello.cpp)
-target_link_libraries(hello imnodes SDL2::SDL2)
-if (APPLE)
- target_link_libraries(hello "-framework OpenGL")
-elseif(MSVC)
- target_link_libraries(hello "opengl32")
-else()
- target_link_libraries(hello X11 Xext GL)
-endif()
+ add_executable(saveload
+ ${CMAKE_CURRENT_SOURCE_DIR}/imnodes.cpp
+ ${CMAKE_CURRENT_SOURCE_DIR}/example/main.cpp
+ ${CMAKE_CURRENT_SOURCE_DIR}/example/save_load.cpp)
+ target_link_libraries(saveload imnodes SDL2::SDL2)
+ if (APPLE)
+ target_link_libraries(saveload "-framework OpenGL")
+ elseif(MSVC)
+ target_link_libraries(saveload "opengl32")
+ else()
+ target_link_libraries(saveload X11 Xext GL)
+ endif()
+
+ add_executable(hello
+ ${CMAKE_CURRENT_SOURCE_DIR}/imnodes.cpp
+ ${CMAKE_CURRENT_SOURCE_DIR}/example/main.cpp
+ ${CMAKE_CURRENT_SOURCE_DIR}/example/hello.cpp)
+ target_link_libraries(hello imnodes SDL2::SDL2)
+ if (APPLE)
+ target_link_libraries(hello "-framework OpenGL")
+ elseif(MSVC)
+ target_link_libraries(hello "opengl32")
+ else()
+ target_link_libraries(hello X11 Xext GL)
+ endif()
+endif()