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gfx_capabilities(3)		Allegro	manual		   gfx_capabilities(3)

NAME
       gfx_capabilities	- Bitfield describing video hardware capabilities. Al-
       legro game programming library.

SYNOPSIS
       #include	<allegro.h>

       extern int gfx_capabilities;

DESCRIPTION
       Bitfield	describing the capabilities of the current graphics driver and
       video hardware. This may	contain	combination any	of the flags:

       GFX_CAN_SCROLL: Indicates that the scroll_screen() function may be used
       with this driver.

       GFX_CAN_TRIPLE_BUFFER:	Indicates   that   the	 request_scroll()  and
       poll_scroll() functions may be used with	this driver. If	this  flag  is
       not set,	it is possible that the	enable_triple_buffer() function	may be
       able to activate	it.

       GFX_HW_CURSOR:  Indicates  that a hardware mouse	cursor is in use. When
       this flag is set, it is safe to draw onto the screen without hiding the
       mouse pointer first. Note that not every	cursor graphic can  be	imple-
       mented  in  hardware: in	particular VBE/AF only supports	2-color	images
       up to 32x32 in size, where the second color is an exact inverse of  the
       first.  This means that Allegro may need	to switch between hardware and
       software	cursors	at any point during the	execution of your program,  so
       you  should not assume that this	flag will remain constant for long pe-
       riods of	time. It only tells you	whether	a hardware cursor is in	use at
       the current time,  and  may  change  whenever  you  hide/redisplay  the
       pointer.

       GFX_SYSTEM_CURSOR Indicates that	the mouse cursor is the	default	system
       cursor, not Allegro's custom cursor.

       GFX_HW_HLINE:  Indicates	 that the normal opaque	version	of the hline()
       function	is implemented using a hardware	accelerator. This will improve
       the performance not only	of hline() itself,  but	 also  of  many	 other
       functions  that use it as a workhorse, for example circlefill(),	trian-
       gle(), and floodfill().

       GFX_HW_HLINE_XOR: Indicates that	the XOR	version	of the	hline()	 func-
       tion,  and  any	other functions	that use it as a workhorse, are	imple-
       mented using a hardware accelerator.

       GFX_HW_HLINE_SOLID_PATTERN: Indicates that the solid and	masked pattern
       modes of	the hline() function, and any other functions that use it as a
       workhorse, are implemented using	a hardware accelerator (see  note  be-
       low).

       GFX_HW_HLINE_COPY_PATTERN:  Indicates that the copy pattern mode	of the
       hline() function, and any other functions that use it as	 a  workhorse,
       are implemented using a hardware	accelerator (see note below).

       GFX_HW_FILL:  Indicates that the	opaque version of the rectfill() func-
       tion, the clear_bitmap()	routine, and clear_to_color(), are implemented
       using a hardware	accelerator.

       GFX_HW_FILL_XOR:	Indicates that the XOR version of the rectfill() func-
       tion is implemented using a hardware accelerator.

       GFX_HW_FILL_SOLID_PATTERN: Indicates that the solid and masked  pattern
       modes  of  the rectfill() function are implemented using	a hardware ac-
       celerator (see note below).

       GFX_HW_FILL_COPY_PATTERN: Indicates that	the copy pattern mode  of  the
       rectfill()  function  is	 implemented using a hardware accelerator (see
       note below).

       GFX_HW_LINE: Indicates that the opaque mode line()  and	vline()	 func-
       tions are implemented using a hardware accelerator.

       GFX_HW_LINE_XOR:	 Indicates  that  the  XOR  version  of	the line() and
       vline() functions are implemented using a hardware accelerator.

       GFX_HW_TRIANGLE:	Indicates that the opaque mode triangle() function  is
       implemented using a hardware accelerator.

       GFX_HW_TRIANGLE_XOR:  Indicates	that the XOR version of	the triangle()
       function	is implemented using a hardware	accelerator.

       GFX_HW_GLYPH: Indicates that monochrome character expansion  (for  text
       drawing)	is implemented using a hardware	accelerator.

       GFX_HW_VRAM_BLIT:  Indicates  that blitting from	one part of the	screen
       to another is implemented using a hardware accelerator. If this flag is
       set, blitting within the	video memory  will  almost  certainly  be  the
       fastest	possible  way  to display an image, so it may be worth storing
       some of your more frequently used graphics in an	offscreen  portion  of
       the video memory.

       GFX_HW_VRAM_BLIT_MASKED:	 Indicates  that  the masked_blit() routine is
       capable of a hardware accelerated copy from one part of video memory to
       another,	and that draw_sprite() will use	a hardware copy	when  given  a
       sub-bitmap  of the screen or a video memory bitmap as the source	image.
       If this flag is set, copying within the video memory will  almost  cer-
       tainly  be  the	fastest	possible way to	display	an image, so it	may be
       worth storing some of your more frequently used sprites in an offscreen
       portion of the video memory.

       Warning:	if this	flag is	not set, masked_blit() and draw_sprite()  will
       not work	correctly when used with a video memory	source image! You must
       only try	to use these functions to copy within the video	memory if they
       are supported in	hardware.

       GFX_HW_MEM_BLIT:	 Indicates that	blitting from a	memory bitmap onto the
       screen is being accelerated in hardware.

       GFX_HW_MEM_BLIT_MASKED:	 Indicates   that   the	  masked_blit()	   and
       draw_sprite()  functions	 are  being  accelerated  in hardware when the
       source image is a memory	bitmap and the	destination  is	 the  physical
       screen.

       GFX_HW_SYS_TO_VRAM_BLIT:	 Indicates  that blitting from a system	bitmap
       onto the	screen is being	accelerated in hardware. Note that some	accel-
       eration may be present even if this flag	is  not	 set,  because	system
       bitmaps can benefit from	normal memory to screen	blitting as well. This
       flag will only be set if	system bitmaps have further acceleration above
       and beyond what is provided by GFX_HW_MEM_BLIT.

       GFX_HW_SYS_TO_VRAM_BLIT_MASKED:	Indicates  that	 the masked_blit() and
       draw_sprite() functions are being  accelerated  in  hardware  when  the
       source  image  is  a  system bitmap and the destination is the physical
       screen. Note that some acceleration may be present even if this flag is
       not set,	because	system bitmaps	can  benefit  from  normal  memory  to
       screen  blitting	 as well. This flag will only be set if	system bitmaps
       have  further  acceleration  above  and	beyond	what  is  provided  by
       GFX_HW_MEM_BLIT_MASKED.

       GFX_HW_VRAM_STRETCH_BLIT:  Indicates  that  stretched blitting of video
       bitmaps onto the	screen is implemented using hardware acceleration.

       GFX_HW_SYS_STRETCH_BLIT:	Indicates that stretched  blitting  of	system
       bitmaps onto the	screen is implemented using hardware acceleration.

       GFX_HW_VRAM_STRETCH_BLIT_MASKED:	 Indicates that	masked stretched blit-
       ting (including stretch_sprite) of video	bitmaps	onto the screen	is im-
       plemented using hardware	acceleration.  NOTE: some display drivers  may
       show  artifacts when this function is used.  If the image does not look
       correct try updating your video drivers.

       GFX_HW_SYS_STRETCH_BLIT_MASKED: Indicates that masked  stretched	 blit-
       ting  (including	 stretch_sprite)  of system bitmaps onto the screen is
       implemented using hardware acceleration.	 NOTE:	some  display  drivers
       may  show artefact's when this function is used.	 If the	image does not
       look correct try	updating your video drivers.

       Note: even if the capabilities information says that patterned  drawing
       is supported by the hardware, it	will not be possible for every size of
       pattern.	 VBE/AF	 only  supports	patterns up to 8x8 in size, so Allegro
       will fall back on the original non-accelerated drawing  routines	 when-
       ever you	use a pattern larger than this.

       Note2:  these hardware acceleration features will only take effect when
       you are drawing directly	onto the screen	bitmap,	a video	memory bitmap,
       or a sub-bitmap thereof.	Accelerated hardware is	most useful in a  page
       flipping	or triple buffering setup, and is unlikely to make any differ-
       ence  to	 the  classic  "draw  onto  a  memory bitmap, then blit	to the
       screen" system.

SEE ALSO
       screen(3), create_video_bitmap(3), scroll_screen(3), request_scroll(3),
       show_mouse(3),	 enable_triple_buffer(3),    ex3buf(3),	   exaccel(3),
       exsyscur(3), exupdate(3)

Allegro				 version 4.4.3		   gfx_capabilities(3)

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