Examples: Possibly clarified the intent of imgui_impl_* files.

examples/opengl3_example/imgui_impl_glfw_gl3.cpp

@@ -1,4 +1,7 @@
 // ImGui GLFW binding with OpenGL3 + shaders
+// You can copy and use unmodified imgui_impl_* files in your project. 
+// If you use this binding you'll need to call 4 functions: ImGui_ImplXXXX_Init(), ImGui_ImplXXXX_NewFrame(), ImGui::Render() and ImGui_ImplXXXX_Shutdown().
+// See main.cpp for an example of using this.
 // https://github.com/ocornut/imgui
 
 #include <imgui.h>

examples/opengl3_example/imgui_impl_glfw_gl3.h

@@ -1,4 +1,7 @@
 // ImGui GLFW binding with OpenGL3 + shaders
+// You can copy and use unmodified imgui_impl_* files in your project. 
+// If you use this binding you'll need to call 4 functions: ImGui_ImplXXXX_Init(), ImGui_ImplXXXX_NewFrame(), ImGui::Render() and ImGui_ImplXXXX_Shutdown().
+// See main.cpp for an example of using this.
 // https://github.com/ocornut/imgui
 
 struct GLFWwindow;