Obsoleted the io.RenderDrawListsFn callback, you can call your graphics engine render function after ImGui::Render(). Use ImGui::GetDrawData() to retrieve the ImDrawData* to display..(#1599)

Examples: Updated examples.

examples/sdl_opengl2_example/main.cpp

@@ -122,6 +122,7 @@ int main(int, char**)
         glClear(GL_COLOR_BUFFER_BIT);
         //glUseProgram(0); // You may want this if using this code in an OpenGL 3+ context where shaders may be bound
         ImGui::Render();
+        ImGui_ImplSdlGL2_RenderDrawData(ImGui::GetDrawData());
         SDL_GL_SwapWindow(window);
     }