Examples: Renamed imgui_impl_sdl2.cpp to imgui_impl_sdl.cpp (#1870) + changelog bits

examples/imgui_impl_sdl.h

@@ -0,0 +1,20 @@
+// ImGui Platform Binding for: SDL2
+// This needs to be used along with a Renderer (e.g. DirectX11, OpenGL3, Vulkan..)
+// (Info: SDL2 is a cross-platform general purpose library for handling windows, inputs, graphics context creation, etc.)
+
+// Missing features:
+//  [ ] SDL2 handling of IME under Windows appears to be broken and it explicitly disable the regular Windows IME. You can restore Windows IME by compiling SDL with SDL_DISABLE_WINDOWS_IME.
+
+// You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
+// If you use this binding you'll need to call 4 functions: ImGui_ImplXXXX_Init(), ImGui_ImplXXXX_NewFrame(), ImGui::Render() and ImGui_ImplXXXX_Shutdown().
+// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
+// https://github.com/ocornut/imgui
+
+struct SDL_Window;
+typedef union SDL_Event SDL_Event;
+
+IMGUI_API bool      ImGui_ImplSDL2_InitForOpenGL(SDL_Window* window, void* sdl_gl_context);
+IMGUI_API bool      ImGui_ImplSDL2_InitForVulkan(SDL_Window* window);
+IMGUI_API void      ImGui_ImplSDL2_Shutdown();
+IMGUI_API void      ImGui_ImplSDL2_NewFrame(SDL_Window* window);
+IMGUI_API bool      ImGui_ImplSDL2_ProcessEvent(SDL_Event* event);