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_opengl3_example/main.cpp

@@ -121,6 +121,7 @@ int main(int, char**)
         glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w);
         glClear(GL_COLOR_BUFFER_BIT);
         ImGui::Render();
+        ImGui_ImplSdlGL3_RenderDrawData(ImGui::GetDrawData());
         SDL_GL_SwapWindow(window);
     }