3 \ \ \L\ \\//\ \ \//\ \ __ __ _ __ ___
4 \ \ __ \ \ \ \ \ \ \ /'__`\ /'_ `\/\`'__\/ __`\
5 \ \ \/\ \ \_\ \_ \_\ \_/\ __//\ \L\ \ \ \//\ \L\ \
6 \ \_\ \_\/\____\/\____\ \____\ \____ \ \_\\ \____/
7 \/_/\/_/\/____/\/____/\/____/\/___L\ \/_/ \/___/
12 A game programming library
14 By Shawn Hargreaves, 1994/97
18 #include <std_disclaimer.h>
20 "I do not accept responsibility for any effects, adverse or otherwise,
21 that this code may have on you, your computer, your sanity, your dog,
22 and anything else that you can think of. Use it at your own risk."
26 ======================================
27 ============ Introduction ============
28 ======================================
30 Allegro is a library of functions for use in computer games, written for
31 the djgpp compiler in a mixture of C and assembly language. This is
32 version 3.0: see the NEWS file for a list of differences from the
35 According to the Oxford Companion to Music, Allegro is the Italian for
36 "quick, lively, bright". Once upon a time it was also an acronym for
37 "Atari Low Level Game Routines", but it is a long time since I did any
38 programming on the Atari, and the name is pretty much the only thing left
39 of the original Atari code.
43 ==================================
44 ============ Features ============
45 ==================================
47 Supports VGA mode 13h, mode-X (twenty two tweaked VGA resolutions plus
48 unchained 640x400 Xtended mode), and SVGA modes with 8, 15, 16, 24, and
49 32 bit color depths. Uses VESA 2.0 linear framebuffers if they are
50 available, and also contains register level drivers for ATI, Cirrus,
51 Paradise, S3, Trident, Tseng, and Video-7 cards.
53 Drawing functions including putpixel, getpixel, lines, rectangles, flat
54 shaded, gouraud shaded, and texture mapped polygons, circles, floodfill,
55 bezier splines, patterned fills, masked, run length encoded, and compiled
56 sprites, blitting, bitmap scaling and rotation, translucency/lighting,
57 and text output with proportional fonts. Supports clipping, and can draw
58 directly to the screen or to memory bitmaps of any size.
60 Hardware scrolling, mode-X split screens, and palette manipulation.
62 FLI/FLC animation player.
64 Plays background MIDI music and up to 32 simultaneous sound effects.
65 Samples can be looped (forwards, backwards, or bidirectionally), and the
66 volume, pan, pitch, etc, can be adjusted while they are playing. The MIDI
67 player responds to note on, note off, main volume, pan, pitch bend, and
68 program change messages, using the General MIDI patch set and drum
69 mappings. Currently supports Adlib, SB, SB Pro, SB16, AWE32, MPU-401, and
70 software wavetable MIDI.
72 Easy access to the mouse, keyboard, joystick, and high resolution timer
73 interrupts, including a vertical retrace interrupt simulator.
75 Routines for reading and writing LZSS compressed files.
77 Multi-object data files and a grabber utility.
79 Math functions including fixed point arithmetic, lookup table trig, and
80 3d vector/matrix manipulation.
82 GUI dialog manager and file selector.
86 ===================================
87 ============ Copyright ============
88 ===================================
90 Allegro is swap-ware. You may use, modify, redistribute, and generally
91 hack it about in any way you like, but if you do you must send me
92 something in exchange. This could be a complimentary copy of a game, an
93 addition or improvement to Allegro, a bug report, some money (this is
94 particularly encouraged if you use Allegro in a commercial product), or
95 just a copy of your autoexec.bat if you don't have anything better. If
96 you redistribute parts of Allegro or make a game using it, it would be
97 nice if you mentioned me somewhere in the credits, but if you just want
98 to pinch a few routines that is OK too. I'll trust you not to rip me off.
102 ============================================
103 ============ Supported hardware ============
104 ============================================
106 The bare minimum you need to use Allegro is a 386 with a VGA graphics
107 card, but a 486 is strongly recommended. To get into SVGA modes you will
108 need a compatible SVGA card, which means either one of the cards that is
109 supported directly, or a card with a working VESA driver. If you have a
110 VESA 2.0 implementation such as UniVBE (which you can get from the
111 Display Doctor link on http://www.scitechsoft.com/), you are fine just
112 using that. If you don't, beware. For one thing, everything will be much
113 slower if Allegro can't use the sexy VBE 2.0 features. For another, I
114 could go on all day telling horror stories about the buggy and generally
115 just pathetic VESA implementations that I've come across. If you are
116 having trouble with the SVGA modes, try getting a copy of UniVBE and see
117 if that clears things up (it probably will: SciTech usually get these
120 On the sound front, Allegro supports sample playback on the SB (mono),
121 the SB Pro (stereo), and the SB16. It has MIDI drivers for the OPL2 FM
122 synth (Adlib and SB cards), the OPL3 (Adlib Gold, SB Pro-II and above),
123 the pair of OPL2 chips found in the SB Pro-I, the AWE32 EMU8000 chip, the
124 raw SB MIDI output, and the MPU-401 interface, plus it can emulate a
125 wavetable MIDI synth in software, running on top of any of the supported
126 digital soundcards. If you feel like coming up with drivers for any other
127 hardware, they would be much appreciated.
129 You may notice that this release contains some code for building a Linux
130 version, but don't bother trying this: it won't work! A _lot_ more work
131 is needed before Allegro will be usable under Linux.
133 There is also the first part of a VBE/AF driver in this package. VBE/AF
134 is an extension to the VBE 2.0 API which provides a standard way of
135 accessing hardware accelerator features. My driver implements all the
136 basic mode set and bank switch functions, so it works as well as the
137 regular VESA drivers, but it doesn't yet support any accelerated drawing
138 operations. This is because SciTech have, so far, only implemented VBE/AF
139 on the ATI Mach64 chipset, and I don't have access to a Mach64. I'll
140 finish the driver as soon as they implement VBE/AF on the Matrox Mystique.
144 ============================================
145 ============ Installing Allegro ============
146 ============================================
148 To conserve space I decided to make this a source-only distribution, so
149 you will have to compile Allegro before you can use it. To do this you
152 - Go to wherever you want to put your copy of Allegro (your main djgpp
153 directory would be fine, but you can put it somewhere else if you
154 prefer), and unzip everything. Allegro contains several subdirectories,
155 so you must specify the -d flag to pkunzip.
157 - If you are using PGCC, uncomment the definition of PGCC at the top of
158 the makefile, or set the environment variable "PGCC=1".
160 - Type "cd allegro", followed by "make". Then go do something
161 interesting while everything compiles. If all goes according to plan
162 you will end up with a bunch of test programs, some tools like the
163 grabber, and the library itself, liballeg.a.
165 If you have any trouble with the build, look at faq.txt for the
166 solutions to some of the more common problems.
168 - If you want to use the sound routines or a non-US keyboard layout, it
169 is a good idea to set up an allegro.cfg file: see below.
171 - If you want to read the Allegro documentation with the Info viewer
172 or the Rhide online help system, edit the file djgpp\info\dir, and in
173 the menu section add the lines:
175 * Allegro: (allegro.inf).
176 The Allegro game programming library
178 - If you want to create the HTML documentation as one large allegro.html
179 file rather than splitting it into sections, edit docs\allegro._tx,
180 remove the @multiplefiles statement from line 8, and run make again.
182 To use Allegro in your programs you should:
184 - Put the following line at the beginning of all C or C++ files that use
189 - If you compile from the command line or with a makefile, add '-lalleg'
190 to the end of the gcc command, eg:
192 gcc foo.c -o foo.exe -lalleg
194 - If you are using Rhide, go to the Options/Libraries menu, type 'alleg'
195 into the first empty space, and make sure the box next to it is checked.
197 See allegro.txt for details of how to use the Allegro functions, and how
198 to build a debug version of the library.
202 =======================================
203 ============ Configuration ============
204 =======================================
206 When Allegro initialises the keyboard and sound routines it reads
207 information about your hardware from a file called allegro.cfg or sound.cfg.
208 If this file doesn't exist it will autodetect (ie. guess :-) You can write
209 your config file by hand with a text editor, or you can use the setup
212 Normally setup.exe and allegro.cfg will go in the same directory as the
213 Allegro program they are controlling. This is fine for the end user, but it
214 can be a pain for a programmer using Allegro because you may have several
215 programs in different directories and want to use a single allegro.cfg for
216 all of them. If this is the case you can set the environment variable
217 ALLEGRO to the directory containing your allegro.cfg, and Allegro will look
218 there if there is no allegro.cfg in the current directory.
220 The mapping tables used to store different keyboard layouts are stored in a
221 file called keyboard.dat. This must either be located in the same directory
222 as your Allegro program, or in the directory pointed to by the ALLEGRO
223 environment variable. If you want to support different international
224 keyboard layouts, you must distribute a copy of keyboard.dat along with your
227 See allegro.txt for details of the config file format.
231 ================================================
232 ============ Notes for the musician ============
233 ================================================
235 The OPL2 synth chip can provide either nine voice polyphony or six voices
236 plus five drum channels. How to make music sound good on the OPL2 is left as
237 an exercise for the reader :-) On an SB Pro or above you will have eighteen
238 voices, or fifteen plus drums. Allegro decides whether to use drum mode
239 individually for each MIDI file you play, based on whether it contains any
240 drum sounds or not. If you have an orchestral piece with just the odd cymbal
241 crash, you might be better removing the drums altogether as that will let
242 Allegro use the non-drum mode and give you an extra three notes polyphony.
244 When Allegro is playing a MIDI file in looped mode, it jumps back to the
245 start of the file when it reaches the end of the piece. To control the exact
246 loop point, you may need to insert a dummy marker event such as a controller
247 message on an unused channel.
249 All the OPL chips have very limited stereo capabilities. On an OPL2,
250 everything is of course played in mono. On the SB Pro-I, sounds can only be
251 panned hard left or right. With the OPL3 chip in the SB Pro-II and above,
252 they can be panned left, right, or centre. I could use two voices per note
253 to provide more flexible panning, but that would reduce the available
254 polyphony and I don't want to do that. So don't try to move sounds around
255 the stereo image with streams of pan controller messages, because they will
256 jerk horribly. It is also worth thinking out the panning of each channel so
257 that the music will sound ok on both SB Pro-I and OPL3 cards. If you want a
258 sound panned left or right, use a pan value less than 48 or greater than 80.
259 If you want it centred, use a pan value between 48 and 80, but put it
260 slightly to one side of the exactly central 64 to control which speaker will
261 be used if the central panning isn't possible.
263 The DIGMID wavetable driver uses standard GUS format .pat files, and you
264 will need a collection of such instruments before you can use it. This can
265 either be in the standard GUS format (a set of .pat files and a default.cfg
266 index), or a patches.dat file as produced by the pat2dat utility. You can
267 also use pat2dat to convert AWE32 SoundFont banks into the patches.dat
268 format, and if you list some MIDI files on the command line it will filter
269 the sample set to only include the instruments that are actually used by
270 those tunes, so it can be useful for getting rid of unused instruments when
271 you are preparing to distribute a game. See the Allegro website for some
272 links to suitable sample sets.
274 The DIGMID driver normally only loads the patches needed for each song when
275 the tune is first played. This reduces the memory usage, but can result in a
276 longish delay the first time you play each MIDI file. If you prefer to load
277 the entire patch set in one go, call the load_midi_patches() function.
279 The CPU sample mixing code can support between 1 and 32 voices, going up in
280 powers of two (ie. either 1, 2, 4, 8, 16, or 32 channels). By default it
281 provides 8 digital voices, or 8 digital plus 24 MIDI voices (a total of 32)
282 if the DIGMID driver is in use. But the more voices, the lower the output
283 volume and quality, so you may wish to change this by calling the
284 reserve_voices() function or setting the digi_voices and midi_voices
285 parameters in allegro.cfg.
289 ======================================
290 ============ Contact info ============
291 ======================================
293 WWW: http://www.talula.demon.co.uk/allegro/
295 Mailing list: allegro@canvaslink.com. To add or remove yourself,
296 write to listserv@canvaslink.com with the text
297 "subscribe allegro yourname" or "unsubscribe
298 allegro" in the body of your message.
300 Usenet: Try the djgpp newsgroup, comp.os.msdos.djgpp
302 IRC: #allegro channel on EFnet
304 My email: shawn@talula.demon.co.uk
306 Snail mail: Shawn Hargreaves,
312 Telephone: UK 01630 654346
314 On Foot: Coming down Shrewsbury Road from the town centre,
315 turn off down Salisbury Road and it is the first
318 If all else fails: 52 deg 54' N
321 The latest version of Allegro can always be found on the Allegro
322 homepage, http://www.talula.demon.co.uk/allegro/.