Allegro 5 api
#include <allegro5/allegro_direct3d.h> LPDIRECT3DTEXTURE9 al_get_d3d_system_texture(ALLEGRO_BITMAP *bitmap)
Returns the system texture (stored with the D3DPOOL_SYSTEMMEM flags). This texture is used for the render-to-texture feature set.
Returns: A pointer to the Direct3D system texture.