Last updated on Feb. 26, 2006.

First of all, you have to put the OS/2-specific Watcom makefiles into the

source code tree by unzipping the file Watcom-OS2.zip here.  This will

result in a Watcom.mif and a setvars.cmd file in this folder, and several

Makefile.wat files in the src\ folder and in some of its subfolders.

6. Proportional windows

-----------------------

For some SDL applications it can be handy to have proportional windows, so

the windows will keep their aspect ratio when resized.

This can be achieved in two ways:

- Before starting the given SDL application, set the

  SDL_USE_PROPORTIONAL_WINDOW environment variable to something, e.g.:

  SET SDL_USE_PROPORTIONAL_WINDOW=1

  dosbox.exe

- If you have a HOME environment variable set, then SDL will look for a file

  in there called ".sdl.proportionals". If that file contains the name of the

  currently running SDL executable, then that process will have proportional

  windows automatically.

  Please note that this file is created automatically with default values

  at the first run.

7. Audio in SDL applications

----------------------------

Audio effects are one of the most important features in games. Creating audio

effects in sync with the game and without hickups and pauses in the audio are

very important things.

However there are multithreaded SDL applications that have tight loops as their

main logic loop. This kills performance in OS/2, and takes too much CPU from

other threads in the same process, for example from the thread to create the 

sound effects.

For this reason, the OS/2 port of SDL can be instructed to run the audio thread

in high priority, which makes sure that there will be enough time for the 

processing of the audio data.

At default, SDL/2 runs the audio thread at ForegroundServer+0 priority. Well 

written and well behaving SDL applications should work well in this mode.

For other applications, you can tell SDL/2 to run the audio thread at 

TimeCritical priority by setting an env.variable before starting the SDL app:

    SET SDL_USE_TIMECRITICAL_AUDIO=1

Please note that this is a bit risky, because if the SDL application runs a

tight infinite loop in this thread, this will make the whole system 

unresponsive, so use it with care, and only for applications that need it!

8. Next steps...

9. Contacts

10. Changelog of the OS/2 port

------------------------------

Version 1.2 - 2006-02-26  - Doodle

 - Updated the official SDL version with the OS/2 specific changes.

 - Added support for real unicode keycode conversion.

Version 1.2.7 - 2006-01-20  - Doodle

 - Added support for selectively using timecritical priority for

   audio threads by SDL_USE_TIMECRITICAL_AUDIO environment variable.

   (e.g.: 

    SET SDL_USE_TIMECRITICAL_AUDIO=1

    dosbox.exe

   )

Version 1.2.7 - 2005-12-22  - Doodle

 - Added support for proportional SDL windows.

   There are two ways to have proportional (aspect-keeping) windows for

   a given SDL application: Either set the SDL_USE_PROPORTIONAL_WINDOW

   environment variable to something before starting the application

   (e.g.: 

    SET SDL_USE_PROPORTIONAL_WINDOW=1

    dosbox.exe

   )

   or, if you have the HOME environment variable set, then SDL.DLL will

   create a file in that directory called .sdl.proportionals, and you can

   put there the name of executable files that will be automatically made

   proportional.

Version 1.2.7 - 2005-10-14  - Doodle

 - Enabled Exception handler code in FSLib to be able to restore original

   desktop video mode in case the application crashes.

 - Added the missing FSLib_Uninitialize() call into SDL.

   (The lack of it did not cause problems, but it's cleaner this way.)

 - Fixed a mouse problem in Fullscreen mode where any mouse click

   re-centered the mouse.

Version 1.2.7 - 2005-10-09  - Doodle

 - Implemented window icon support

Version 1.2.7 - 2005-10-03  - Doodle

 - Reworked semaphore support again

 - Tuned thread priorities

Version 1.2.7 - 2005-10-02  - Doodle

 - Added support for custom mouse pointers

 - Fixed WM_CLOSE processing: give a chance to SDL app to ask user...

 - Added support for MMX-accelerated audio mixers

 - Other small fixes

Version 1.2.7 - 2005-09-12  - Doodle

 - Small fixes for DosBox incorporated into public release

 - Fixed semaphore support (SDL_syssem.c)

 - Fixed FSLib to have good clipping in scaled window mode,

   and to prevent occasional desktop freezes.

Version 1.2.7 - 2004-09-08a - Caetano

	- Improved joystick support (general verifications about hardware).

	- Added support up to 8 buttons in 2 axes joysticks and 6 buttons in 3 axes joysticks.

	- Added support to environment variable SDL_OS2_JOYSTICK to specify a joystick.

	- Improved Joystick test to handle every type of joystick and display only relevant information.

	- Merged with Doodle 2004-09-08

	- Little tid up in README.OS2

	- Added explanation about SDL_OS2_JOYSTICK environment variable on README.OS2

Version 1.2.7 - 2004-09-07 - Caetano

	- Merged with changes in headers for GCC compiling.

	- Added Joystick support using basic IBM GAME$ support, allowing it to work with all joystick drivers since OS/2 2.1.

	- Improved joystick detection (hacked!). OS/2 do not allow real joystick detection, so... 

	- Modified makefile in test to compile "testjoystick". Anyway, it's useless, since it seems to cause a lot of trouble in OS/2 (because os video routines, not Joystick support).

	- Created separated Joystick test program to test only joystick functions.

	- Improved joystick auto-centering.

	- Improved the coordinate correction routine to use two scale factors for each axis.

Version 1.2.7 - 2004-07-05 - Caetano

	- Corrected the time returned by status in CDROM support (it was incorrect)

	- Added the testcdrom.c and corrected the linking directive (it was causing an error)

Version 1.2.7 - 2004-07-02a - Caetano

	- Corrected a little problem in a comment at SDL-1.2.7\test\torturethread.c, line 18 (missing */, nested comment)

	- Added CDROM support to tree (SDL-1.2.7\src\cdrom\os2\SDL_syscdrom.c)

	- Modified makefile (SDL-1.2.7\src\makefiles.wat and SDL-1.2.7\watcom.mif) to build with CDROM support

	- Added the "extra" SDL_types.h forgotten in 2004-07-02 version.

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