2008-08-30  Colin D Bennett <address@hidden>

	VBE smart double buffering using page flipping or blitting.

	* include/grub/video.h (GRUB_VIDEO_RENDER_TARGET_FRONT_BUFFER):
	Removed.
	(GRUB_VIDEO_RENDER_TARGET_BACK_BUFFER): Removed.

	* video/i386/pc/vbe.c (framebuffer): Added is_double_buffered field.
	(doublebuf_state): New struct.
	(double_buffering_init): New function.
	(grub_video_vbe_init): Clear doublebuf_state.
	(grub_video_vbe_fini): Destroy doublebuf_state.
	(grub_video_vbe_setup): Call double_buffering_init to initialize
	double buffering.
	(doublebuf_pageflipping_commit): New function.
	(doublebuf_pageflipping_update_screen): New function.
	(doublebuf_pageflipping_destroy): New function.
	(doublebuf_pageflipping_init): New function.
	(doublebuf_blit_update_screen): New function.
	(doublebuf_blit_destroy): New function.
	(doublebuf_blit_init): New function.
	(doublebuf_null_update_screen): New function.
	(doublebuf_null_destroy): New function.
	(doublebuf_null_init): New function.
	(double_buffering_init): New function.
	(grub_video_vbe_swap_buffers): Implement buffer swapping.
	(grub_video_vbe_set_active_render_target): Handle special target
	GRUB_VIDEO_RENDER_TARGET_DISPLAY and neither
	GRUB_VIDEO_RENDER_TARGET_FRONT_BUFFER nor
	GRUB_VIDEO_RENDER_TARGET_BACK_BUFFER.