qzdoom-gpl/dumb/docs/faq.txt

TO DO: add question regarding set_close_button_callback vs set_window_close_hook
TO DO: add question regarding mixing of DJGPP and MinGW object files

/*  _______         ____    __         ___    ___
 * \    _  \       \    /  \  /       \   \  /   /       '   '  '
 *  |  | \  \       |  |    ||         |   \/   |         .      .
 *  |  |  |  |      |  |    ||         ||\  /|  |
 *  |  |  |  |      |  |    ||         || \/ |  |         '  '  '
 *  |  |  |  |      |  |    ||         ||    |  |         .      .
 *  |  |_/  /        \  \__//          ||    |  |
 * /_______/ynamic    \____/niversal  /__\  /____\usic   /|  .  . ibliotheque
 *                                                      /  \
 *                                                     / .  \
 * faq.txt - Frequently Asked Questions.              / / \  \
 *                                                   | <  /   \_
 * This file covers some of the common problems      |  \/ /\   /
 * and misconceptions people have with DUMB. If       \_  /  > /
 * your problem is not covered here, please             | \ / /
 * contact me. I'll do my best to help - but            |  ' /
 * don't be offended if I just direct you to the         \__/
 * manual!
 */


*****************************************************************************
* I get a lot of strange warnings and errors when I compile my projects     *
* with this release of DUMB. They work with older versions! What happened?  *
*****************************************************************************

   Some parts of DUMB's API have been deprecated. See docs/deprec.txt for
   full details, including an explanation as to why your compiler warnings
   and errors are so unfriendly, and information on how to fix each warning
   or error.


*****************************************************************************
* When I try to compile DUMB with Allegro, it complains that it cannot find *
* 'internal/alconfig.h'! What's wrong?                                      *
*****************************************************************************

   In Allegro 4.0.1, and quite likely some other versions of Allegro, the
   msvcmake batch file does not install Allegro properly. I believe this was
   fixed in Allegro 4.0.2, but don't take my word for it. Some include files
   are neglected, including alconfig.h. The fix is quite easy; you need to
   copy all of Allegro's include files to your compiler's directory. The
   following should do this for you (alter it accordingly depending on where
   MSVC and Allegro are installed):

      cd\progra~1\msvc\include
      xcopy/s \allegro\include\*.*

   You can safely tell it to overwrite all files.


*****************************************************************************
* When I build a project that uses DUMB, I get an error that it doesn't     *
* find -laldmbd! What's wrong?                                              *
*****************************************************************************

   See the notes for DUMB v0.8 in release.txt; the existence of libaldmbd.a
   in DUMB v0.7 was due to a mistake in the makefiles. It should be
   libaldmd.a, in order to maintain DOS compatibility. All subsequent
   releases get it right, but you will have to change your project files to
   allow for the change. If this is someone else's project, please let them
   know that it needs changing.


*****************************************************************************
* When I build a project that uses DUMB, I get some linker errors about     *
* _free, _malloc, etc. already being defined in LIBC.lib! What's wrong?     *
*****************************************************************************

   MSVC offers three different implementations of the standard libraries.
   When you link statically with a library, you have to use the same
   implementation that the library uses. You need the multithreaded DLL
   implementation, which you can select by passing /MD when you compile (not
   when you link). See howto.txt for details.


*****************************************************************************
* I created an IT file with Impulse Tracker, but DUMB won't play it! Why?   *
*****************************************************************************

   You probably created some patterns but didn't give any information on the
   order in which they should be played. Impulse Tracker will also fail to
   play your music if you press F5. Press F11 and you will have an
   opportunity to create an order list, required for playback.


*****************************************************************************
* I created an IT file with ModPlug Tracker and I have it fading out at the *
* end. Why won't it loop when I play it with DUMB?                          *
*****************************************************************************

   It loops at zero volume. This is what Impulse Tracker itself does. Fix the
   IT file by setting the global volume explicitly (Vxx in the effects
   column), either at the start, or right at the end before looping. Also see
   the next two questions.


*****************************************************************************
* My module plays too loud and distorts badly with DUMB! What can I do?     *
*****************************************************************************

   This problem is most often caused by ModPlug Tracker, which has a complete
   lack of regard for the playback volume of the original tracker. See the
   next question for DUMB's official position with regard to ModPlug Tracker.
   If you wrote your module with ModPlug Tracker, please try loading it with
   the original tracker and see if it distorts there too. If it does, reduce
   the volume. If not, then it's a problem with DUMB; please let me know.

   If for whatever reason you cannot modify the module file itself, you can
   make it sound better by reducing the volume passed to al_start_duh().


*****************************************************************************
* I created a music module with ModPlug Tracker, and DUMB doesn't play it   *
* right!                                                                    *
*****************************************************************************

   DUMB cannot and will not support ModPlug Tracker. Please see
   docs/modplug.txt for details. The original trackers, which DUMB is
   designed to mimic as closely as possible, are listed in readme.txt.
   If you find DUMB plays your module differently from the original tracker,
   then please contact me.


*****************************************************************************
* My program crashes as soon as I try to load anything with DUMB!           *
*****************************************************************************

   Please take my advice and use the debugging build of DUMB, not the
   optimised build. Then you'll probably find it aborts instead of crashing.
   In this case you probably forgot to register a DUMBFILE system; this is
   necessary for loading stand-alone files, though not for loading Allegro
   datafiles with embedded music. Follow the instructions in docs/howto.txt
   carefully and you shouldn't have this problem.

   If DUMB crashes with a specific music module, please let me know.


*****************************************************************************
* I want to use the stdio file access functions to load stand-alone music   *
* files, but I also want to load datafiles containing music files. The docs *
* say I shouldn't call both dumb_register_stdfiles() and                    *
* dumb_register_packfiles(). What shall I do?                               *
*****************************************************************************

   When you register a DUMBFILE system, it only applies to files opened with
   dumbfile_open(), i.e. separate files. When a file is embedded in a
   datafile, dumbfile_open_ex() is used to read it, enabling it to use
   PACKFILEs regardless of which DUMBFILE system is registered. In short, you
   do not need to call dumb_register_packfiles() in order to load datafiles
   with embedded music. See the section on "Sequential File Input" in
   docs/dumb.txt if you're interested in how all this works.


*****************************************************************************
* I want to read a specific object in a datafile using Allegro's            *
* "demo.dat#MY_MUSIC" syntax. Why won't it work?                            *
*****************************************************************************

   Did you call dumb_register_packfiles(), or did you call
   dumb_register_stdfiles()? It will only work if you use the former.


*****************************************************************************
* My program runs, but no music plays! What am I doing wrong?               *
*****************************************************************************

   There are a number of possible causes for this. The most likely reason is
   that you aren't calling al_poll_duh(); see docs/howto.txt for further
   information.

   Other possible causes are as follows:

   - The speakers are turned down (duh)
   - The volume of some system mixer is turned down
   - Another program is using the sound card (not a problem for most modern
     systems)
   - You didn't initialise Allegro's sound system; see install_sound() in
     Allegro's docs
   - Allegro's drivers don't work on your system and chosen platform

   In order to narrow down the cause, consider the following:

   - Do you get any other sound from your program?
   - Do other Allegro+DUMB programs generate sound?
   - Do other Allegro programs generate sound?
   - Do other non-Allegro programs generate sound?
   - Does your program fail only on a specific platform (e.g. DOS but not
     Windows)?

   This problem is highly system-specific; please try hard to solve it by
   yourself before contacting me. However, if you think this problem could
   affect other people, please let me know what the problem is and how you
   fixed it, if you did. Be as specific as possible.


*****************************************************************************
* The music stutters! What can I do?                                        *
*****************************************************************************

   If you have an older computer, it may not be able to cope with the load.
   Try reducing quality options; look up dumb_resampling_quality and
   dumb_it_max_to_mix in docs/dumb.txt, and consider changing the frequency
   you pass to al_start_duh().

   Stuttering may not be caused by excessive load. To find out, try
   increasing the buffer size passed to al_start_duh(). Beware of making it
   too big though; older systems will freeze periodically if it's too big,
   because they render larger chunks less frequently. The timing of callbacks
   will also be less accurate, if you are using those.

   If you're using the 'dumbplay' example, you can control these parameters
   by editing dumb.ini.


*****************************************************************************
* Why does DUMB use so much processor time compared with other players?     *
*****************************************************************************

   This should be less so in this release than in previous releases; the
   resampling and filtering algorithms have been optimised.

   By default, DUMB uses the most expensive resampling quality option. I've
   found on an AthlonXP 1800+ and on a Pentium 233 that it typically uses
   about twice as much processor time as the least expensive option.

   Try setting dumb_resampling_quality to DUMB_RQ_ALIASING or DUMB_RQ_LINEAR.
   See dumb.txt for more information. If you're using the example programs,
   you can control this variable by editing dumb.ini.

   DUMB uses 32-bit ints for mixing. Some players use 16-bit ints, and are
   therefore marginally faster (not much!) and lower quality. So you can't
   expect DUMB to beat these players. Furthermore, DUMB is currently written
   entirely in C. GCC does an impressive job on the C code, but that's not to
   say some custom-written assembly language couldn't beat it ...


*****************************************************************************
* Why does DUMB generate so much background noise?                          *
*****************************************************************************

   You're probably using the DOS build on a system with bad Sound Blaster
   compatibility (most Windows XP systems fall in this category). This would
   mean DUMB could only access an 8-bit driver. The Windows build will almost
   certainly give better results. Your DOS binary will still give good
   results on systems with better compatibility (like my Windows 98 system).


*****************************************************************************
* I e-mailed you and you replied with "RTFM"! What does that mean?          *
*****************************************************************************

   Read The Manual. If it's a specific problem, I'll probably be kind and
   tell you where to look in the manual. However, if I get the impression you
   haven't even looked for a solution in the manual, expect no mercy ...


Ben Davis
entheh@users.sf.net
IRC EFnet #dumb
See readme.txt for details on using IRC.