Sound? « Virtual Boy Development Board « Forum

#11

Re: Sound?

Posted on: 2011/1/2 21:48

VUE(xpert)

Joined 2008/12/28

Slovenia

456 Posts

Thanks!

I'm having some difficulty though. My libgccvb's audio.h is a bit different:



typedef struct SOUNDREG

{

    u8 ctl;

    u8 spacer1[3];

    u8 vol;

    u8 spacer2[3];

    u8 fql;

    u8 spacer3[3];

    u8 fqh;

    u8 spacer4[3];

    u8 env;

    u8 spacer5[3];

    u8 unk;

    u8 spacer6[3];

    u8 ram;

    u8 spacer7[3];

    u8 spacer8[36];

} SOUNDREG;

Which register is which? I'm assuming 'EV0' is 'env' and 'INT' is 'ctl'. What I'm trying to do is this:



int main ()

{

  unsigned int Freq;



  SND_REGS[WAVE1].ram = 0;

  SND_REGS[WAVE1].vol = 0x66;

  SND_REGS[WAVE1].ctl = 0x80;



  while(1)

  {

    for(Freq = 0; Freq <= 1000; Freq++)

    {

      SND_REGS[WAVE1].fql = (Freq << 4) & 0xFF;

      SND_REGS[WAVE1].fqh = (Freq >> 4) + 1;

    }

  }

}

#12

Re: Sound?

Posted on: 2011/1/3 6:48

PVB Elite

Joined 2003/7/25

USA

1244 Posts

Check the libgccvb.h included in Super Bounce... they're defined like:



u8 SxINT;

u8 spacer1[3];

u8 SxLRV;

u8 spacer2[3];

u8 SxFQL;

u8 spacer3[3];

u8 SxFQH;

u8 spacer4[3];

u8 SxEV0;

u8 spacer5[3];

u8 SxEV1;

u8 spacer6[3];

//Ch. 1-5 only 

u8 SxRAM;

u8 spacer7[3];

//Ch. 5 only

u8 S5SWP;

u8 spacer8[35];

DogP

#13

Re: Sound?

Posted on: 2011/1/3 18:42

VUE(xpert)

Joined 2008/12/28

Slovenia

456 Posts

Nothing changes.

#14

Re: Sound?

Posted on: 2011/1/3 21:15

VUE(xpert)

Joined 2003/9/3

Sweden

393 Posts

I think you do need to fill the waveform RAM to get sound?
At least in Mednafen...

Anyways, maybe it's time to share a little

Here is a basic function from my midi player that plays a single note:



void PlayNote(u8 chan, u16 freq, u8 vol) {

    //Set up the frequency the channel will play

    SND_REGS[chan].SxFQH = freq >> 8;

    SND_REGS[chan].SxFQL = freq & 0xFF;



    //Set the volume for the channel (0-15, same for left/right)

    SND_REGS[chan].SxLRV = (vol << 4) | vol;



    //Envelope for the channel (makes the tone fade out)

    SND_REGS[chan].SxEV0 = 0xF7;

    SND_REGS[chan].SxEV1 = 0x01;



    //Start the channel without interval

    SND_REGS[chan].SxINT = 0x9F;

}

Usage:



#include "audio.h"

#include "notes.h"

#include "voices.h"



//Copy the piano "instrument" to soundbank 1

copymem((void*)WAVEDATA1, (void*)PIANO, 128);



//Tell channel 0 to use soundbank 1

SND_REGS[0].SxRAM = 0;



//Play a "Middle-C" note on channel 0 with volume 8

PlayNote(0, C_4, 8);

The file "voices.h" includes a couple of different "instruments" that I made, to be loaded into the soundbanks.

The file "notes.h" defines all standard notes, fine-tuned manually to fit the VB's frequencies.

This should help you to get some tunes flowing

Just call PlayNote() with different note values (E_4, D_4, G_4 etc.) within your main loop (or better, on a timer interrupt)

Attach file:

audio.h Size: 2.72 KB; Hits: 79

notes.h Size: 3.50 KB; Hits: 80

voices.h Size: 1.25 KB; Hits: 64

Edited by DanB on 2011/1/3 21:25

#15

Re: Sound?

Posted on: 2011/1/3 21:57

VUE(xpert)

Joined 2008/12/28

Slovenia

456 Posts

Wow, that's great! Actually the only thing DogP wasn't clear on are the envelope registers and the waveform register. Now that I see how your PlayNote function works, it all seems really simple. Thank you once again!

#16

Re: Sound?

Posted on: 2011/1/3 22:00

Newbie

Joined 2011/1/3

3 Posts

Unfortunately, your PlayNote() doesn't show tempo, and if it did, wouldn't it take a long time to get a complex song on there?

#17

Re: Sound?

Posted on: 2011/1/3 22:11

VUE(xpert)

Joined 2008/12/28

Slovenia

456 Posts

It wouldn't be too difficult to write some code to read a music track from an array and play it at the right speed. Getting it to play in the background, however, is another thing.

#18

Re: Sound?

Posted on: 2011/1/3 22:16

VUE(xpert)

Joined 2003/9/3

Sweden

393 Posts

Well, it's up to you to decide the tempo by controlling how often you call PlayNote()...

To play a simple song, you can do something like:



u16 song[] = {C_4, D_4, E4, FS4, A_5};

u32 songTick = 0;

u8 currNote = 0;

while(1){

  //Playing the song in the background is easy,

  //just control its tempo by only calling playnote every

  //57:th (or whatever) pass through the game loop

  if (songTick == 57) {

    PlayNote(0, song[currNote], 8);

    currNote++;

    if (currNote > 4)

      currNote = 0;

    songTick = 0;

  }

  

  //Do other game-stuff



  songTick++;

}