1gfx_capabilities(3) Allegro manual gfx_capabilities(3)
2
6 gfx_capabilities - Bitfield describing video hardware capabilities.
7 Allegro game programming library.
8
10 #include <allegro.h>
11 extern int gfx_capabilities;
14
16 Bitfield describing the capabilities of the current graphics driver and
17 video hardware. This may contain combination any of the flags:
18 GFX_CAN_SCROLL: Indicates that the scroll_screen() function may be used
20 with this driver.
21 GFX_CAN_TRIPLE_BUFFER: Indicates that the request_scroll() and
23 poll_scroll() functions may be used with this driver. If this flag is
24 not set, it is possible that the enable_triple_buffer() function may be
25 able to activate it.
26 GFX_HW_CURSOR: Indicates that a hardware mouse cursor is in use. When
28 this flag is set, it is safe to draw onto the screen without hiding the
29 mouse pointer first. Note that not every cursor graphic can be imple‐
30 mented in hardware: in particular VBE/AF only supports 2-color images
31 up to 32x32 in size, where the second color is an exact inverse of the
32 first. This means that Allegro may need to switch between hardware and
33 software cursors at any point during the execution of your program, so
34 you should not assume that this flag will remain constant for long
35 periods of time. It only tells you whether a hardware cursor is in use
36 at the current time, and may change whenever you hide/redisplay the
37 pointer.
38 GFX_SYSTEM_CURSOR Indicates that the mouse cursor is the default system
40 cursor, not Allegro's custom cursor.
41 GFX_HW_HLINE: Indicates that the normal opaque version of the hline()
43 function is implemented using a hardware accelerator. This will improve
44 the performance not only of hline() itself, but also of many other
45 functions that use it as a workhorse, for example circlefill(), trian‐
46 gle(), and floodfill().
47 GFX_HW_HLINE_XOR: Indicates that the XOR version of the hline() func‐
49 tion, and any other functions that use it as a workhorse, are imple‐
50 mented using a hardware accelerator.
51 GFX_HW_HLINE_SOLID_PATTERN: Indicates that the solid and masked pattern
53 modes of the hline() function, and any other functions that use it as a
54 workhorse, are implemented using a hardware accelerator (see note
55 below).
56 GFX_HW_HLINE_COPY_PATTERN: Indicates that the copy pattern mode of the
58 hline() function, and any other functions that use it as a workhorse,
59 are implemented using a hardware accelerator (see note below).
60 GFX_HW_FILL: Indicates that the opaque version of the rectfill() func‐
62 tion, the clear_bitmap() routine, and clear_to_color(), are implemented
63 using a hardware accelerator.
64 GFX_HW_FILL_XOR: Indicates that the XOR version of the rectfill() func‐
66 tion is implemented using a hardware accelerator.
67 GFX_HW_FILL_SOLID_PATTERN: Indicates that the solid and masked pattern
69 modes of the rectfill() function are implemented using a hardware
70 accelerator (see note below).
71 GFX_HW_FILL_COPY_PATTERN: Indicates that the copy pattern mode of the
73 rectfill() function is implemented using a hardware accelerator (see
74 note below).
75 GFX_HW_LINE: Indicates that the opaque mode line() and vline() func‐
77 tions are implemented using a hardware accelerator.
78 GFX_HW_LINE_XOR: Indicates that the XOR version of the line() and
80 vline() functions are implemented using a hardware accelerator.
81 GFX_HW_TRIANGLE: Indicates that the opaque mode triangle() function is
83 implemented using a hardware accelerator.
84 GFX_HW_TRIANGLE_XOR: Indicates that the XOR version of the triangle()
86 function is implemented using a hardware accelerator.
87 GFX_HW_GLYPH: Indicates that monochrome character expansion (for text
89 drawing) is implemented using a hardware accelerator.
90 GFX_HW_VRAM_BLIT: Indicates that blitting from one part of the screen
92 to another is implemented using a hardware accelerator. If this flag is
93 set, blitting within the video memory will almost certainly be the
94 fastest possible way to display an image, so it may be worth storing
95 some of your more frequently used graphics in an offscreen portion of
96 the video memory.
97 GFX_HW_VRAM_BLIT_MASKED: Indicates that the masked_blit() routine is
99 capable of a hardware accelerated copy from one part of video memory to
100 another, and that draw_sprite() will use a hardware copy when given a
101 sub-bitmap of the screen or a video memory bitmap as the source image.
102 If this flag is set, copying within the video memory will almost cer‐
103 tainly be the fastest possible way to display an image, so it may be
104 worth storing some of your more frequently used sprites in an offscreen
105 portion of the video memory.
106 Warning: if this flag is not set, masked_blit() and draw_sprite() will
108 not work correctly when used with a video memory source image! You must
109 only try to use these functions to copy within the video memory if they
110 are supported in hardware.
111 GFX_HW_MEM_BLIT: Indicates that blitting from a memory bitmap onto the
113 screen is being accelerated in hardware.
114 GFX_HW_MEM_BLIT_MASKED: Indicates that the masked_blit() and
116 draw_sprite() functions are being accelerated in hardware when the
117 source image is a memory bitmap and the destination is the physical
118 screen.
119 GFX_HW_SYS_TO_VRAM_BLIT: Indicates that blitting from a system bitmap
121 onto the screen is being accelerated in hardware. Note that some accel‐
122 eration may be present even if this flag is not set, because system
123 bitmaps can benefit from normal memory to screen blitting as well. This
124 flag will only be set if system bitmaps have further acceleration above
125 and beyond what is provided by GFX_HW_MEM_BLIT.
126 GFX_HW_SYS_TO_VRAM_BLIT_MASKED: Indicates that the masked_blit() and
128 draw_sprite() functions are being accelerated in hardware when the
129 source image is a system bitmap and the destination is the physical
130 screen. Note that some acceleration may be present even if this flag is
131 not set, because system bitmaps can benefit from normal memory to
132 screen blitting as well. This flag will only be set if system bitmaps
133 have further acceleration above and beyond what is provided by
134 GFX_HW_MEM_BLIT_MASKED.
135 GFX_HW_VRAM_STRETCH_BLIT: Indicates that stretched blitting of video
137 bitmaps onto the screen is implemented using hardware acceleration.
138 GFX_HW_SYS_STRETCH_BLIT: Indicates that stretched blitting of system
140 bitmaps onto the screen is implemented using hardware acceleration.
141 GFX_HW_VRAM_STRETCH_BLIT_MASKED: Indicates that masked stretched blit‐
143 ting (including stretch_sprite) of video bitmaps onto the screen is
144 implemented using hardware acceleration. NOTE: some display drivers
145 may show artifacts when this function is used. If the image does not
146 look correct try updating your video drivers.
147 GFX_HW_SYS_STRETCH_BLIT_MASKED: Indicates that masked stretched blit‐
149 ting (including stretch_sprite) of system bitmaps onto the screen is
150 implemented using hardware acceleration. NOTE: some display drivers
151 may show artefact's when this function is used. If the image does not
152 look correct try updating your video drivers.
153 Note: even if the capabilities information says that patterned drawing
155 is supported by the hardware, it will not be possible for every size of
156 pattern. VBE/AF only supports patterns up to 8x8 in size, so Allegro
157 will fall back on the original non-accelerated drawing routines when‐
158 ever you use a pattern larger than this.
159 Note2: these hardware acceleration features will only take effect when
161 you are drawing directly onto the screen bitmap, a video memory bitmap,
162 or a sub-bitmap thereof. Accelerated hardware is most useful in a page
163 flipping or triple buffering setup, and is unlikely to make any differ‐
164 ence to the classic "draw onto a memory bitmap, then blit to the
165 screen" system.
166
169 screen(3), create_video_bitmap(3), scroll_screen(3), request_scroll(3),
170 show_mouse(3), enable_triple_buffer(3), ex3buf(3), exaccel(3),
171 exsyscur(3), exupdate(3)
172Allegro version 4.2.3 gfx_capabilities(3)