Initial import.

cmake/imgui.cmake

@@ -0,0 +1,39 @@
+find_package(SDL2 REQUIRED)
+find_package(OpenGL REQUIRED)
+find_package(Freetype)
+if (DEFINED FREETYPE_INCLUDE_DIRS)
+    add_definitions(-DIMGUI_ENABLE_FREETYPE)
+    set(FREETYPE_SOURCES
+            ext/imgui/misc/freetype/imgui_freetype.cpp
+            ext/imgui/misc/freetype/imgui_freetype.h)
+endif()
+
+add_library(imgui STATIC
+        # Main Imgui files
+        ext/imgui/imgui.cpp
+        ext/imgui/imgui.h
+        ext/imgui/imgui_draw.cpp
+        ext/imgui/imgui_tables.cpp
+        ext/imgui/imgui_widgets.cpp
+        ext/imgui/imgui_demo.cpp
+
+        ext/imgui/backends/imgui_impl_sdl2.cpp
+        ext/imgui/backends/imgui_impl_sdl2.h
+        ext/imgui/backends/imgui_impl_opengl3.cpp
+        ext/imgui/backends/imgui_impl_opengl3.h
+
+        $<IF:$<TARGET_EXISTS:Freetype::Freetype>,${FREETYPE_SOURCES},>)
+add_library(imgui::imgui ALIAS imgui)
+target_link_libraries(imgui
+        PUBLIC
+        OpenGL::GL
+        $<IF:$<TARGET_EXISTS:Freetype::Freetype>,Freetype::Freetype,>
+        $<TARGET_NAME_IF_EXISTS:SDL2::SDL2main>
+        $<IF:$<TARGET_EXISTS:SDL2::SDL2>,SDL2::SDL2,SDL2::SDL2-static>)
+target_include_directories(imgui PUBLIC
+        ext/imgui/
+        ext/imgui/backends/
+        ext/imgui/misc/freetype
+        $<IF:$<TARGET_EXISTS:Freetype::Freetype>,${FREETYPE_INCLUDE_DIRS},>)
+
+include_directories(ext/ ${SDL2_INCLUDE_DIRS})