Examples: Renaming opengl_example/ to opengl2_example/ for clarity (1/2 because git)

examples/sdl_opengl2_example/imgui_impl_sdl.h

@@ -0,0 +1,19 @@
+// ImGui SDL2 binding with OpenGL
+// In this binding, ImTextureID is used to store an OpenGL 'GLuint' texture identifier. Read the FAQ about ImTextureID in imgui.cpp.
+
+// 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_ImplSdl_Init(SDL_Window* window);
+IMGUI_API void        ImGui_ImplSdl_Shutdown();
+IMGUI_API void        ImGui_ImplSdl_NewFrame(SDL_Window* window);
+IMGUI_API bool        ImGui_ImplSdl_ProcessEvent(SDL_Event* event);
+
+// Use if you want to reset your rendering device without losing ImGui state.
+IMGUI_API void        ImGui_ImplSdl_InvalidateDeviceObjects();
+IMGUI_API bool        ImGui_ImplSdl_CreateDeviceObjects();