al_set_d3d_device_restore_callback - Man Page

#include <allegro5/allegro_direct3d.h>

void al_set_d3d_device_restore_callback(
   void (*callback)(ALLEGRO_DISPLAY *display))

The callback will be called whenever a D3D device that has been reset is restored. In the callback you should restore any d3d resources you have created yourself. The callback receives the affected display as a parameter.

Pass NULL to disable the callback.

5.1.0