NAME¶
gfx_capabilities - Bitfield describing video hardware capabilities. Allegro 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 implemented 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 periods 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(), triangle(), and floodfill().
GFX_HW_HLINE_XOR: Indicates that the XOR version of the hline() function,
and any other functions that use it as a workhorse, are implemented 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 below).
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()
function, 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()
function 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 accelerator
(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() functions
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 certainly 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 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.
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 blitting
(including stretch_sprite) of video bitmaps onto the screen is implemented
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 blitting
(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 whenever 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 difference to the classic
"draw onto a memory bitmap, then blit to the screen" system.
SEE ALSO¶
screen(3alleg4),
create_video_bitmap(3alleg4),
scroll_screen(3alleg4),
request_scroll(3alleg4),
show_mouse(3alleg4),
enable_triple_buffer(3alleg4),
ex3buf(3alleg4),
exaccel(3alleg4),
exsyscur(3alleg4),
exupdate(3alleg4)