gfx_capabilities(3) Allegro manual gfx_capabilities(3)NAMEgfx_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 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
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(), 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
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() 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
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() 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
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 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 ALSOscreen(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 4.4.2 gfx_capabilities(3)
