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Sound Engine Evaluation for Computer Games Case Study: fmod Jyun-Ming Chen.

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Presentation on theme: "Sound Engine Evaluation for Computer Games Case Study: fmod Jyun-Ming Chen."— Presentation transcript:

1 Sound Engine Evaluation for Computer Games Case Study: fmod Jyun-Ming Chen

2 Fall Typical Game Loop Roles of music/sound BGM (background music) Sound effect

3 Fall Microsoft SDK BGM (Midi) mciSendCommand ( … ) Sound (Wave) sndPlaySound See msdn for detailsmsdn Ex: midi_wav.zip on webhd2/game-ex Need more sophisticated tools!

4 Fall Check List BGM File formats supported: mid, mp3, mod, … Looping Early termination Volume control Sound effects File formats supported Trigger mechanism Reverb and other DSP FX (e.g., room effects) Pre-load to avoid delay in first play General Mixing capability (how many sounds can be mixed at one time) Spatial sound Position: 3D vs. panning Velocity: Doppler supported? Occlusion?! Sync capability sound to action Action to sound Others CPU overhead

5 Fall Case Study: fmod Cross platform audio library (Win32, Linux, mac, WinCE, PS2, Xbox, … ) Free unless for commercial use

6 Fall Documentation FSOUND: for sound effect FMUSIC: for bgm

7 Fall FSOUND API

8 Fall Initialization Required for both FMUSIC & FSOUND

9 Fall FSOUND_Sample Load, Free SetMode: LOOP normal | bidi | off Get/SetLoopPoints GetLength Get/SetMinMaxDistance (min is the distance where the sound starts to attenuate) increase the min_distance of a sound to make it 'louder' in a 3d world, and decrease it to make it 'quieter' in a 3d world.

10 Fall FSOUND_Stream If the PCM data (wav) or compressed file (ogg, mp3, … ) is too big to be read in as a sample, we can use stream functions to read it (decompress it on- the-fly) Certain functionalities are restricted

11 Fall Channel Functions FSOUND_PlaySound, PlaySoundEx FSOUND_FREE: Choose a free channel to play in Returns the channel selected Extended version can play paused (allow attributes to be changed, then play) FSOUND_SetFrequency (channel, 11025); FSOUND_SetVolume(channel, 255); FSOUND_SetPan(channel, 255); FSOUND_SetPaused(channel, FALSE); FSOUND_StopSound

12 Fall FMUSIC (mid, mod; mp3) LoadSong PlaySong: can play more than one music (yes, but why?) SetPaused SetLooping: default TRUE SetPanSeparation, SetMasterSpeed, SetMasterVolume StopSong, StopAllSongs FreeSong SetReverb (midi only)

13 OpenGL Tests Webhd2/game- ex/fmod_opengl_tests

14 Fall Basics

15 Fall Bgmusic FMUSIC PLAYS S3M AND MID; NOT MP3 (sequenced file, not PCM-type) OK for mod files

16 Fall Stream Works for mp3, ogg, wav Only wav can store cue point (for sync)

17 Fall dsound FSOUND_Update(): This updates the 3d sound engine, and should be called whether sound source or listener changes position

18 Fall Listener Attributes Float *pos Float *Vel (per second) NULL to ignore Fx, fy, fz (forward orientation unit vector) Tx, ty, tz (top-up orientation unit vector) x y z Global Axes in Fmod Left-handed

19 Fall Doppler FSOUND_3D_SetDopplerFactor (4.0);

20 Commonly Used APIs Fall Init and Close Load and Free sample

21 Sound API Fall


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