Spécificités Windows

GFX_*/Windows

DIGI_*/Windows

MIDI_*/Windows

Windows programs normally start with a WinMain() function, rather than the ANSI C main() routine. Allegro does some magic to make a regular main() work like you expect, but you have to help it out a bit by writing END_OF_MAIN() right after your main() function. If you don't want to do that, you can of course just write a WinMain() in the usual Windows way. If you want to generate a console application, you have to disable this special processing of the main() function by defining the preprocessor symbol USE_CONSOLE before you include allegro.h.

DirectX requires bitmaps to be locked before you can draw onto them. This will be done automatically, but you can usually get much better performance by doing it yourself: see the acquire_bitmap() function for details.

Due to a major oversight in the design of DirectX, there is no way to preserve the contents of video memory when the user switches away from your program. You need to be prepared for the fact that your screen contents, and the contents of any video memory bitmaps, may be destroyed at any point. You can use the set_display_switch_callback() function to find out when this happens.

There are some conflicts between allegro.h and windows.h, so you will have problems if you include both of these from the same source file. If you need to access the Windows headers, #include <winalleg.h> after allegro.h. This will include windows.h for you, doing some magic to make it work correctly.

Drivers: GFX_*/Windows
The Windows library supports the following card parameters for the set_gfx_mode() function:

• GFX_TEXT
  Return to text mode.

• GFX_AUTODETECT
  Let Allegro pick an appropriate graphics driver.

• GFX_SAFE
  Special driver for when you want to reliably set a graphics mode and don't really care what resolution. See the set_gfx_mode() documentation for details.

• GFX_DIRECTX
  Alias for GFX_DIRECTX_ACCEL.

• GFX_DIRECTX_ACCEL
  The regular DirectX driver, running in fullscreen mode with hardware acceleration enabled.

• GFX_DIRECTX_SOFT
  DirectX driver that only uses software drawing, rather than any hardware accelerated features.

• GFX_DIRECTX_SAFE
  Simplified DirectX driver that doesn't support any hardware acceleration, video or system bitmaps, etc.

• GFX_DIRECTX_WIN
  Windowed DirectX driver.

• GFX_DIRECTX_OVL
  DirectX overlay driver. This uses special hardware features to run your program in a windowed mode: it doesn't work on all hardware, but performance is excellent on cards that are capable of it.

• GFX_GDI
  Windowed mode GDI driver. This is extremely inefficient, but works on all hardware, so it can be useful for situations where you want to run in a window, and don't care about performance.

      DIGI_AUTODETECT      - let Allegro pick a digital sound driver
      DIGI_NONE            - no digital sound
      DIGI_DIRECTX(n)      - use DirectSound device #n (zero-based)

      MIDI_AUTODETECT      - let Allegro pick a MIDI sound driver
      MIDI_NONE            - no MIDI sound
      MIDI_WIN32(n)        - use win32 device #n (zero-based)
      MIDI_DIGMID          - sample-based software wavetable player

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