     ______   ___    ___
    /\  _  \ /\_ \  /\_ \
    \ \ \L\ \\//\ \ \//\ \      __     __   _ __   ___ 
     \ \  __ \ \ \ \  \ \ \   /'__`\ /'_ `\/\`'__\/ __`\
      \ \ \/\ \ \_\ \_ \_\ \_/\  __//\ \L\ \ \ \//\ \L\ \
       \ \_\ \_\/\____\/\____\ \____\ \____ \ \_\\ \____/
        \/_/\/_/\/____/\/____/\/____/\/___L\ \/_/ \/___/
                                       /\____/
                                       \_/__/     Version 4.2.2


                A game programming library.

             By Shawn Hargreaves, Jul 22, 2007.

                See the AUTHORS file for a
               complete list of contributors.


#include <std_disclaimer.h>

   "I do not accept responsibility for any effects, adverse or otherwise, 
    that this code may have on you, your computer, your sanity, your dog, 
    and anything else that you can think of. Use it at your own risk."




======================================
============ Introduction ============
======================================

   Allegro is a cross-platform library intended for use in computer games 
   and other types of multimedia programming. It was initially conceived on 
   the Atari ST, but that platform sadly died during childbirth. After a 
   brief stay with Borland C, it was adopted by the fantastic djgpp 
   compiler, where it grew to maturity. In the fullness of time it gave 
   birth to children of its own, who went to live in such exotic locations 
   as DirectX and the X Server, but the entire family is now back together 
   again, living in harmony as a single portable entity. How about that for 
   a mixture of metaphors? :-)

   A wide range of extension packages and add-on modules are also available, 
   which can be found in the "Library Extensions" section of the Allegro.cc
   website, http://www.allegro.cc/.

   According to the Oxford Companion to Music, Allegro is the Italian for 
   "quick, lively, bright". It is also a recursive acronym which stands for 
   "Allegro Low Level Game Routines".



=============================================
============ Supported platforms ============
=============================================

   For instructions on how to install Allegro, how to link your programs 
   with it, and any additional information specific to each of the supported 
   platforms, see one of the files included in the distribution package:

   DOS/djgpp         - see docs/build/djgpp.txt
   DOS/Watcom        - see docs/build/watcom.txt
   Windows/MSVC      - see docs/build/msvc.txt
   Windows/MinGW     - see docs/build/mingw32.txt
   Windows/Cygwin    - see docs/build/mingw32.txt
   Windows/Borland   - see docs/build/bcc32.txt
   Linux (console)   - see docs/build/linux.txt
   Unix (X11)        - see docs/build/unix.txt
   Darwin (X11)      - see docs/build/darwin.txt
   BeOS              - see docs/build/beos.txt
   QNX               - see docs/build/qnx.txt
   MacOS X           - see docs/build/macosx.txt

   General API information can be found in the main manual, usually referred
   to as docs/txt/allegro.txt, allegro.txt or simply "The Allegro manual"
   throughout this document. The Allegro manual source is available as a set
   of files in the docs/src directory. During the build process of the
   library, these source files will be converted to HTML, TexInfo, and RTF
   formats (among others) and placed in their respective doc/FORMAT
   directory.

   Information about changes in the API and deprecated features can be found
   in docs/txt/api.txt (also available in HTML, TexInfo, and RTF format as
   part of the Allegro manual).



==================================
============ Features ============
==================================

   Cross-platform support for DOS, Windows, Unix, BeOS, QNX and MacOS X
   systems.

   Drawing functions including putpixel, getpixel, lines, rectangles, flat 
   shaded, gouraud shaded, texture mapped, and z-buffered polygons, circles,
   floodfill, bezier splines, patterned fills, masked, run length encoded,
   and compiled sprites, blitting, bitmap scaling and rotation,
   translucency/lighting, and text output with proportional fonts. Supports
   clipping, and can draw directly to the screen or to memory bitmaps of any
   size.

   DOS graphics drivers for VGA mode 13h, mode-X (twenty three tweaked VGA
   resolutions plus unchained 640x400 Xtended mode), and SVGA modes with 8, 
   15, 16, 24, and 32 bit color depths, taking full advantage of VBE 2.0 
   linear framebuffers and the VBE/AF hardware accelerator API if they are 
   available. Additional video hardware support is available from the 
   FreeBE/AF project (http://www.talula.demon.co.uk/freebe/).

   Windows graphics drivers using DirectX in fullscreen and windowed modes,
   plus routines for drawing onto GDI device contexts.

   Unix graphics drivers for X, DGA2, fbcon, SVGAlib, VBE/AF, mode-X, and
   standard VGA.

   BeOS graphics drivers using BWindowScreen in fullscreen and BDirectWindow
   in windowed modes.

   MacOS X native graphics drivers using CGDirectDisplay API for direct 
   fullscreen gfx access and QuickDraw in a Cocoa window in windowed mode.

   Hardware scrolling and triple buffering (where available), mode-X split
   screens, and palette manipulation.

   FLI/FLC animation player.

   Plays background MIDI music and up to 64 simultaneous sound effects, and
   can record sample waveforms and MIDI input. Samples can be looped 
   (forwards, backwards, or bidirectionally), and the volume, pan, pitch, 
   etc, can be adjusted while they are playing. The MIDI player responds to 
   note on, note off, main volume, pan, pitch bend, and program change 
   messages, using the General MIDI patch set and drum mappings. DOS version 
   currently supports Adlib, SB, SB Pro, SB16, AWE32, MPU-401, ESS 
   AudioDrive, Ensoniq Soundscape, and Windows Sound System. Windows version 
   supports WaveOut and DirectSound interfaces and the system MIDI drivers. 
   Unix version supports OSS, ESD, and ALSA sound drivers. BeOS version 
   supports BSoundPlayer and BMidiSynth interfaces. MacOS X native version 
   supports CoreAudio, Carbon Sound Manager and QuickTime Note Allocator 
   interfaces. All versions provide software wavetable MIDI playback.

   Easy access to the mouse, keyboard, joystick, and high resolution timer
   interrupts, including a vertical retrace interrupt simulator in the DOS 
   version.

   Routines for reading and writing LZSS compressed files.

   Multi-object data files and a grabber utility.

   Math functions including fixed point arithmetic, lookup table trig, and
   3d vector/matrix/quaternion manipulation.

   GUI dialog manager and file selector.

   Built-in support for 16-bit and UTF-8 format Unicode characters.



===================================
============ Copyright ============
===================================

   Allegro is gift-ware. It was created by a number of people working in 
   cooperation, and is given to you freely as a gift. You may use, modify, 
   redistribute, and generally hack it about in any way you like, and you do 
   not have to give us anything in return. However, if you like this product 
   you are encouraged to thank us by making a return gift to the Allegro 
   community. This could be by writing an add-on package, providing a useful 
   bug report, making an improvement to the library, or perhaps just 
   releasing the sources of your program so that other people can learn from 
   them. If you redistribute parts of this code or make a game using it, it 
   would be nice if you mentioned Allegro somewhere in the credits, but you 
   are not required to do this. We trust you not to abuse our generosity.

   Disclaimer:

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
   SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
   FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
   ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   DEALINGS IN THE SOFTWARE.

=======================================
============ Configuration ============
=======================================

   Allegro reads information about your hardware from a file called 
   allegro.cfg. If this file doesn't exist it will autodetect (ie. guess :-) 
   You can write your config file by hand with a text editor, or you can use 
   the setup utility program (located in the setup directory).

   Normally the setup program and allegro.cfg will go in the same directory 
   as the Allegro program they are controlling. This is fine for the end 
   user, but it can be a pain for a programmer using Allegro because you may 
   have several programs in different directories and want to use a single 
   allegro.cfg for all of them. If this is the case you can set the 
   environment variable ALLEGRO to the directory containing your 
   allegro.cfg, and Allegro will look there if there is no allegro.cfg in 
   the current directory.

   The mapping tables used to store different keyboard layouts are stored in 
   a file called keyboard.dat. This must either be located in the same 
   directory as your Allegro program, or in the directory pointed to by the 
   ALLEGRO environment variable. If you want to support different 
   international keyboard layouts, you must distribute a copy of 
   keyboard.dat along with your program.

   Various translations of things like the system error messages are stored 
   in a file called language.dat. This must either be located in the same 
   directory as your Allegro program, or in the directory pointed to by the 
   ALLEGRO environment variable. If you want to support non-English versions 
   of these strings, you must distribute a copy of language.dat along with 
   your program.

   Under Unix, BeOS and MacOS X, the config file routines also check for
   ~/allegro.cfg, ~/.allegrorc, /etc/allegro.cfg, and /etc/allegrorc, in
   that order, and the keyboard and language files can be stored in your 
   home directory or in /etc/. If under MacOS X, the application bundle
   Contents/Resources directory, if any, is also scanned first.

   See docs/txt/allegro.txt for details of the config file format.



===========================================
============ Notes about sound ============
===========================================

   The DIGMID wavetable driver uses standard GUS format .pat files, and you 
   will need a collection of such instruments before you can use it. This 
   can either be in the standard GUS format (a set of .pat files and a 
   default.cfg index), or a patches.dat file as produced by the pat2dat 
   utility. You can also use pat2dat to convert AWE32 SoundFont banks into 
   the patches.dat format, and if you list some MIDI files on the command 
   line it will filter the sample set to only include the instruments that 
   are actually used by those tunes, so it can be useful for getting rid of 
   unused instruments when you are preparing to distribute a game. See the 
   Allegro website for some links to suitable sample sets.

   The DIGMID driver normally only loads the patches needed for each song 
   when the tune is first played. This reduces the memory usage, but can 
   result in a longish delay the first time you play each MIDI file. If you 
   prefer to load the entire patch set in one go, call the 
   load_midi_patches() function.

   The CPU sample mixing code can support between 1 and 64 voices, going up 
   in powers of two (ie. either 1, 2, 4, 8, 16, 32, or 64 channels). By 
   default it provides 8 digital voices, or 8 digital plus 24 MIDI voices (a 
   total of 32) if the DIGMID driver is in use. But the more voices, the 
   lower the output volume and quality, so you may wish to change this by 
   calling the reserve_voices() function or setting the digi_voices and 
   midi_voices parameters in allegro.cfg.



======================================
============ Contact info ============
======================================

   The latest version of Allegro can always be found on the Allegro 
   homepage, http://alleg.sourceforge.net/.

   There are three mailing lists for Allegro-related discussion, each with a
   slightly different purpose.

   [AL] - Allegro main -
   http://lists.sourceforge.net/lists/listinfo/alleg-main/.

      This list is for any kind of discussion about Allegro, questions about 
      Allegro, reports of problems with Allegro, suggestions for new 
      features, announcements of programs written using Allegro, etc. 
      General rule: if it has to do with Allegro, you can post it here. If 
      not, go somewhere else (for example comp.os.msdos.djgpp, comp.lang.c, 
      or the online forums at http://www.allegro.cc/).

   [AD] - Allegro developers -
   http://lists.sourceforge.net/lists/listinfo/alleg-developers/.

      This list is for the people currently working on Allegro, who use it to
      coordinate their efforts. You can use this address if you need to 
      contact the developers directly, for example to submit some new code 
      that you have written or to report a bug.

      Unlike the other lists, we will be really rude to people who post
      inappropriate material here, so please don't do that! Do not send
      tech-support questions to this list. Don't post bug reports here unless
      you are 100% certain they aren't your fault (if you are in any doubt,
      use the main Allegro list instead, which is read by most of the same
      people who are subscribed here).

      The Allegro development is a completely open process, and everyone is
      welcome to drop by, have a listen, and start contributing code patches.
      This list is for working rather than talking, though, so please don't
      do anything that might get in our way.

   [Alleg5] - Allegro 5 -
   http://lists.sourceforge.net/mailman/listinfo/alleg-bigfive.

      This list was once available for discussing the next major version of
      Allegro, when it was too noisy to do so on [AD]. This is no longer the
      case so the list has been shut down. However, its archives are still
      valuable.

   To subscribe to one of the three lists, simply go to it's web page and use
   the online forms to subscribe yourself. You can remove yourself from a
   list going to the same page above, which can be used to remind you of your
   password too, in case you have forgotten it.

   To send a message to one of the lists, write to
   alleg-main@lists.sourceforge.net or
   alleg-developers@lists.sourceforge.net. You don't need to be subscribed to
   these mailing lists before you can post there, but it is a good idea to
   subscribe in order to see the replies.

   Before posting tech-support questions to the Allegro list, please take a
   moment to read the guidelines in docs/txt/help.txt. See docs/txt/ahack.txt
   for information about the style of code we use, and how to create your
   patches.

   If you want to search through the archives of any of those mailing lists,
   you will have to check the available options at
   http://alleg.sourceforge.net/maillist.html.

   Please don't send messages in HTML format. The increased size places an
   unnecessary load on the server, and many subscribers have a hard time
   reading these posts.

   Please do not crosspost between these lists. Choose the most appropriate
   one for your message, and then send it only to that list.

   Please don't send large binary attachments to any of the lists, they will
   be rejected by the size limit filter, which is set to 100KB for the
   developers mailing list, and 40KB for the others. Upload your files to a
   website and then post the URL, or if you can't do that, post an
   announcement asking people to write to you privately, and then send the
   file by individual email to whoever responded.
   
   Please use English in your messages. You could eventually post messages in
   whatever language you prefer, but that would terribly limit the chances of
   getting a useful answer.
   
   Remember that the RFC 1855: netiquette guidelines
   (http://www.rfc-editor.org/rfc/rfc1855.txt) describes other general
   guidelines you should follow as a correct internet user (in mailing lists
   and other places as well), and provides more verbose descriptions and
   explanations about why you should follow the above guidelines.

   One of the important guidelines you should be aware of is how to quote
   correctly the message you are replying to. The previous RFC doesn't really
   explain how to do it, so you might want to read the document "How do I
   quote correctly in Usenet?" at
   http://www.netmeister.org/news/learn2quote.html. Quoting correctly is
   easier to say than to do, especially for users of Microsoft Outlook. If
   you are such a user, you can help yourself using the Outlook-QuoteFix
   extension written by Dominik Jain, which you can find at
   http://home.in.tum.de/~jain/software/outlook-quotefix/.

