最近对ALLEGRO感兴趣，所以来写写，希望大家能来共同学习一下，共同进步

allegro是一个c/c++的游戏库，免费，开源，最初作者是shawn hargreaves，他支持DOS，UNIX（Linux, FreeBSD, Irix, Solaris, Darwin), Windows, QNX, BeOS 还有 MacOS X.提供了大量的图形，声音，输入（键盘，鼠标，操纵杆）定时器等函数，同时也有数学，3D，文件管理函数

Cross-platform support

• Unix (Linux, FreeBSD, Irix, Solaris, Darwin)
• Windows (MSVC, MinGW, Cygwin, Borland)
• BeOS
• QNX
• MacOS X
• Dos (DJGPP, Watcom)

Graphic functions

• Vector drawing:
  • pixels, lines, rectangles, circles, ellipses, arcs, Bezier splines
  • shape fill, with or without pattern
  • polygons: flat, Gouraud, textured (3D) and translucent
• Sprites:
  • masked, compressed and compiled sprites
  • blitting, rotation, stretching, reduction, alpha blending, Gouraud shading
  • native support for BMP, LBM, PCX and TGA files (others supported with library extensions)
• Color palettes:
  • color palette manipulation (reading, writing, conversion)
  • conversion of color formats RGB <-> HSV
• Text:
  • support for different encodings and conversion, default is UTF-8
  • bitmap fonts (masking, colouring, alignment)
• Misc:
  • draw directly on the screen or on any-size memory bitmaps
  • hardware scrolling and triple buffering (where available), mode-X split screen
  • animation functions for FLI/FLC format

Graphic drivers

• Unix:
  • X Window, DGA, fbcon
  • SVGAlib
  • VBE/AF
  • mode-X
  • VGA
• Windows:
  • DirectX (windowed or full-screen)
  • GDI
• MacOS X:
  • Quartz (windowed or full-screen)
• BeOS:
  • BWindowScreen
  • BDirectWindow
• Dos:
  • VGA 13h mode
  • mode-X (23 VGA resolution plus unchained 640x400 extended mode)
  • SVGA modes in 8, 15, 16, 24 and 32 bits per pixel
  • linear VBE 2.0 framebuffer access
  • hardware acceleration through VBE/AF API if supported
  • additional graphic drivers through FreeBE/AF project
• OpenGL:
  • The AllegroGL addon allows to use OpenGL graphics with Allegro.

Sound functions

• Midi:
  • native MIDI music format support (with 64 simultaneous effects)
  • dynamic control/response to music note on, note off, main volume, pan, pitch bend, and program change
  • uses General MIDI patches
  • you can read in wavetable patches for MIDI files (SF2 and GUS patches)
• Wave:
  • native support of WAV and VOC file formats (playing looped forward, backwards or bidirectional)
  • streaming audio
  • modify volume, pan, pitch, etc during play

Sound drivers

• Unix:
  • OSS
  • ALSA (0.5/0.9/1.0)
  • ESD
  • aRts
  • JACK
  • SGI AL
• Windows:
  • DirectSound
  • WaveOut
  • MIDI system drivers
• MacOS X:
  • Core Audio
  • Sound Manager
  • Core Audio MIDI
  • QuickTime MIDI
• Dos:
  • Adlib, SB, SB Pro, SB16, AWE32
  • MPU-401
  • ESS AudioDrive
  • Ensoniq Soundscape
  • Windows Sound System

Math functions

• fixed point arithmetic and trigonometric routines
• precalculated trigonometric tables
• vector/matrix/quaternions 3d manipulation (translation, rotation, scaling, projection)

Misc

• mouse, keyboard and joystick management
• high resolution interrupt timers (resolution of 10, 5 or less ms depending on platform)
• vertical retrace simulation
• manipulate configuration files
• manipulate compressed files in LZSS format
• manipulate multi-object resource-like compressed datafiles
• tool for creating datafiles (grabber)
• simple GUI for dialogs and file selector