Thsound

What is this?

Some audio functions for the NDS. Features among other things include .wav file loading.

Functions common to both CPU

thSndInit
This needs to be called at startup on both CPU before any other audio functions.

void thSndInit(void);

Sample loading and management functions

thSampleLoadWav
Load a sample from .wav file. Supported formats are 8bit mono, 16bit mono, and IMA-ADPCM. Stereo sample support MAY be added later.

• name - name of file to load

Returns pointer to newly created sample.

thSample_t *thSampleLoadWav(const char *name);

thSampleCreate
Create a sample from raw audio data.

• start - pointer to start of sample in memory
• len - length of sample (in samples)
• loopstart - Loop point of sample. in number of samples from start.
• rate - sample rate in hertz (44100, 11025, etc etc)
• opts - options. Should include one each of: SNDPCM8, SNDPCM16, SNDADPCM. Additionally may OR on SNDLOOP (or even specify a default volume, pan, but wont get into this yet.. :P)

Returns Pointer to newly created sample.

thSample_t *thSampleCreate(void *start, int len, void *loopstart, int rate, u8 opts);

thSampleDestroy
Unloads a sample from memory. If it was loaded from .wav file will automagically unload that as well.. :p

void thSampleDestroy(thSample_t *thSample);

General Sound Functions

thPlayDefaults
Sets default sample playback options.

void thPlayDefaults(int rate, char level, char pan, u32 flags);

thSndPlaySample
Starts playing a previously loaded sample.

• chan - channel to use for playback
• sample - previously loaded sample
• vol - playback volume (0 to 127)
• pan - playback pan (0 to 127, 0 = left, 127 = right, 64 = center)

void thSndPlaySample(char chan, thSample_t *sample, char vol, char pan);

thSndPlayRaw
Plays a sound in raw format from memory on the specified channel.

• chan - channel to use for playback (0 to 15)
• start - pointer to start of audio data in memory
• len - length of sample (in samples)
• vol - playback volume (0 to 127)
• pan - playback pan (0 to 127, 0 = left, 127 = right, 64 = center)
• loopstart - position to start looping sound (in samples)
• opts - options (such as SNDPCM16, SNDPCM8, etc... see options sections)

void thSndPlayRaw(char chan, void *start, int len, int rate, char vol, char pan, u32 loopstart, u32 opts);

thSndRegDirect
Direct manipulation of the arm7's audio registers from the arm9

• chan - channel to manipulate (0 to 15)
• start - start register
• len - length register
• rate - rate register
• loopstart - loopstart register
• opt - channel's CR register

void thSndRegDirect(char chan, u32 start, int len, int rate, u32 loopstart, u32 opts);

thSndDefPlaySample
Playback a sample use default volume and pan settings

• chan - channel to manipulate (0 to 15)
• sample - pointer to previously loaded audio sample

void thSndDefPlaySample(char chan, thSample_t *sample);

thSndDefPlayRaw
Playback a sample using default volume, pan, and rate settings

• chan - channel to manipulate (0 to 15)
• start - pointer to start of audio data
• len - length of audio data (in samples)

void thSndDefPlayRaw(char chan, void *start, int len);

thSndPlayNoise
Plays noise on the specified channel.

• chan - channel to play noise (14 or 15 only! :)
• rate - rate of playback (use 11025 if in doubt ?_?)
• vol - playback volume (0 to 127)
• pan - playback pan (0 to 127, 0 = left, 127 = right, 64 = center)

void thSndPlayNoise(char chan, u16 rate, char vol, char pan);

thSndPlayNote
Plays a note on the specified channel via the PSG. Note is a square wave with adjustable duty cycle.

• chan - channel to play note (8 to 13 only!)
• note - note to play 0 = c, 1 = c#, 2 = d, 3 = d#, 4 = e, 5 = f, etc etc up to 64 or so (range depends on tuning)
• duty - duty cycle of PSG (0 to 7, use 4 if in doubt ?_?)
• vol - playback volume (0 to 127)
• pan - playback pan (0 to 127, 0 = left, 127 = right, 64 = center)

void thSndPlayNote(char chan, char note, char duty, char vol, char pan);

thSndStop
Immediately stops playing sample, note, noise, or raw data the specified channel.

• chan - channel to stop

void thSndStop(char chan);

Changing Active Parameters

These functions change various attributes after sound has already began playing.

thSndSetVol
Change channel's volume.

• chan - channel to change (0-15)
• vol - playback volume (0 to 127)

void thSndSetVol(char chan, char vol);

thSndSetPan
Change channel's Pan..

• chan - channel to change (0-15)
• pan - playback pan (0 to 127, 0 = left, 127 = right, 64 = center)

void thSndSetPan(char chan, char pan);

thSndSetRate
Change channel's sample rate. Usefull for special effects! :p

• chan - channel to change (0-15)
• rate - new channel frequency (in hertz)

void thSndSetRate(char chan, u32 rate);

Change PSG's duty cycle. thSndSetDuty

• chan - channel to play note (8 to 13 only!)
• duty - duty cycle of PSG (0 to 7, use 4 if in doubt ?_?)

void thSndSetDuty(char chan, char duty);

thSndFade
Initiate a fadeout on specified channel. Useful for fading out repeating wavforms, mp3s, or even can be used with PSG note generation for rudamentary synth effects. Once volume reaches 0 audio playback is stopped on specified channel

• chan - channel to change (0-15)
• faderate - how fast to fade out... higher the number, faster the playback.. need to write formula here eh? 256 would = approx 2 seconds if volume = 127. @_@???

could make this a bit simpler, make faderate a time in ms and do math on arm7...hmmm

void thSndFade(char chan, u16 faderate);