gbadev.org forum archive

Taking a look at the positioned sound code from the SDL/Id source:
I have no idea what is going on, it looks like a table of modifiers to either sound position or volume level.

Code:

*
==========================
=
= SetSoundLoc - Given the location of an object (in terms of global
= coordinates, held in globalsoundx and globalsoundy), munges the values
= for an approximate distance from the left and right ear, and puts
= those values into leftchannel and rightchannel.
=
= JAB
=
==========================
*/

#define ATABLEMAX 15
static const byte righttable[ATABLEMAX][ATABLEMAX * 2] = {
{ 8, 8, 8, 8, 8, 8, 8, 7, 7, 7, 7, 7, 7, 6, 0, 0, 0, 0, 0, 1, 3, 5, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 7, 7, 7, 7, 7, 6, 4, 0, 0, 0, 0, 0, 2, 4, 6, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 7, 7, 7, 7, 6, 6, 4, 1, 0, 0, 0, 1, 2, 4, 6, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 7, 7, 7, 7, 6, 5, 4, 2, 1, 0, 1, 2, 3, 5, 7, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 7, 7, 7, 6, 5, 4, 3, 2, 2, 3, 3, 5, 6, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 7, 7, 7, 6, 6, 5, 4, 4, 4, 4, 5, 6, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 7, 7, 7, 6, 6, 5, 5, 5, 6, 6, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 7, 7, 7, 6, 6, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8}
};
static const byte lefttable[ATABLEMAX][ATABLEMAX * 2] = {
{ 8, 8, 8, 8, 8, 8, 8, 8, 5, 3, 1, 0, 0, 0, 0, 0, 6, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 6, 4, 2, 0, 0, 0, 0, 0, 4, 6, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 6, 4, 2, 1, 0, 0, 0, 1, 4, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 7, 5, 3, 2, 1, 0, 1, 2, 4, 5, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 6, 5, 3, 3, 2, 2, 3, 4, 5, 6, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 7, 6, 5, 4, 4, 4, 4, 5, 6, 6, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 7, 6, 6, 5, 5, 5, 6, 6, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 7, 7, 6, 6, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8}
};

static void SetSoundLoc(fixed gx, fixed gy)
{
fixed xt, yt;
int x, y;

// translate point to view centered coordinates
//
gx -= viewx;
gy -= viewy;

//
// calculate newx
//
xt = FixedByFrac(gx,viewcos);
yt = FixedByFrac(gy,viewsin);
x = (xt - yt) >> TILESHIFT;

//
// calculate newy
//
xt = FixedByFrac(gx,viewsin);
yt = FixedByFrac(gy,viewcos);
y = (yt + xt) >> TILESHIFT;

if (y >= ATABLEMAX)
   y = ATABLEMAX - 1;
else if (y <= -ATABLEMAX)
   y = -ATABLEMAX;
if (x < 0)
   x = -x;
if (x >= ATABLEMAX)
   x = ATABLEMAX - 1;

leftchannel = lefttable[x][y + ATABLEMAX];
rightchannel = righttable[x][y + ATABLEMAX];
}

Life issues aside I'm looking at Wolf3d more as I can, but I cannot imagine what operation is supposed to be applied from the values in the table.

From the looks of it, it calculates the distance between an object and another and applies the according sound level for effects. I suppose the point of the table was speed rather than calculating the vector length.

EDIT:
On further inspection, it appears to be an attenuation table - that is, the amount to SUBTRACT from the volume [ie, the further an object is, the more attenuation].

Cool, looking at the original sources seem to confirm this as well as suggesting positioned sound was only done on the SBPro.
Interesting stuff since I had no idea it supported the SBPro at all.

I guess the best way to modify this would be to make new tables except fill it with volume levels and play the same sound on 2 channels?

the ds sound channels support panning.

It does, but I think volume adjustments are the way to go here.
I just quickly hacked it in and the results so far are mixed:

Good: Doors in the distance sound quieter
Bad: Non existent or unnoticeable left/right positioning

I only have channels 11-15 to work with since 0-10 will be used by Pate's AdLib emulator.
Even worse: I use 2 channels for this effect.

[Edit]
Got it working well with 2 channels, but that sucks since there can only be 2 sounds at once.
Maybe one channel can be used by combining the panning and expected volume levels somehow?

[Edit again]
It seems to work but I'm not sure the magic numbers used to get the panning value really do anything.

Code:

void VolumePanningHack( int LeftVolume, int RightVolume, int* Volume, int* Panning ) {
/*
* Easiest case first, if Left == Right then center the sound.
*/
if ( LeftVolume == RightVolume ) {
*Volume = LeftVolume;
*Panning = 64;
}
/*
* Left is louder than right, pan more to the left.
*/
else if ( LeftVolume > RightVolume ) {
*Volume = ( LeftVolume - ( LeftVolume - RightVolume ) );
*Panning = 63 - ( LeftVolume - RightVolume );
}
/*
* Right is louder than left, pan to the right.
*/
else {
*Volume = ( RightVolume - ( RightVolume - LeftVolume ) );
*Panning = 64 + ( RightVolume - LeftVolume );
}

if ( *Volume < 0 ) *Volume = 0;
if ( *Volume > 127 ) *Volume = 127;

if ( *Panning < 0 ) *Panning = 0;
if ( *Panning > 127 ) *Panning = 127;
}

Quick sound code, DON'T JUDGE ME! /cry

Code:

int FindFreeSoundChannel( void ) {
int i;

for ( i = 11; i <= 15; i++ ) {
if ( ! ( SCHANNEL_CR( i ) & SCHANNEL_ENABLE ) )
return i;
}

return -1;
}

void WolfSoundSVC( int ByteCount, void* UserData ) {
u32 Data[ 4 ];
int ChanL;
int ChanR;

fifoGetDatamsg( FIFO_USER_02, sizeof( Data ), ( u8* ) Data );
ChanL = FindFreeSoundChannel( );
ChanR = FindFreeSoundChannel( );

if ( ChanL >= 11 && ChanL <= 15 && ChanR >= 11 && ChanL <= 15 ) {
SCHANNEL_SOURCE( ChanL ) = Data[ 0 ];
SCHANNEL_LENGTH( ChanL ) = Data[ 1 ] >> 2;
SCHANNEL_TIMER( ChanL ) = SOUND_FREQ( 7000 );

SCHANNEL_SOURCE( ChanR ) = Data[ 0 ];
SCHANNEL_LENGTH( ChanR ) = Data[ 1 ] >> 2;
SCHANNEL_TIMER( ChanR ) = SOUND_FREQ( 7000 );

SCHANNEL_CR( ChanL ) = SCHANNEL_ENABLE | SOUND_VOL( Data[ 2 ] ) | SOUND_PAN( 64 ) | SOUND_FORMAT_8BIT | SOUND_ONE_SHOT;
SCHANNEL_CR( ChanR ) = SCHANNEL_ENABLE | SOUND_VOL( Data[ 3 ] ) | SOUND_PAN( 64 ) | SOUND_FORMAT_8BIT | SOUND_ONE_SHOT;
}
}

Code:

///////////////////////////////////////////////////////////////////////////
//
// SD_PlaySound() - plays the specified sound on the appropriate hardware
//
///////////////////////////////////////////////////////////////////////////
boolean SD_PlaySound( soundnames sound ) {
//SoundCommon* sc = ( SoundCommon* ) audiosegs[ STARTADLIBSOUNDS + sound ];
int SoundPage;
int SoundLength;
void* SoundData;
int x, y;

if ( DigiMap[ sound ] != -1 ) {
x = SoundIsPositioned == true ? LeftVolAdjust : 128;
y = SoundIsPositioned == true ? RightVolAdjust : 128;

SoundPage = DigiList[ 0 + ( DigiMap[ sound ] * 2 ) ];
SoundLength = DigiList[ 1 + ( DigiMap[ sound ] * 2 ) ];

PM_SetPageSize( SoundPage, SoundLength );
SoundData = ( void* ) PM_GetSoundPage( SoundPage );

EmitSound( SoundData, SoundLength, x, y );
return true;
}

return false;
}

/*
==========================
=
= SetSoundLoc - Given the location of an object (in terms of global
= coordinates, held in globalsoundx and globalsoundy), munges the values
= for an approximate distance from the left and right ear, and puts
= those values into leftchannel and rightchannel.
=
= JAB
=
==========================
*/
#define ATABLEMAX 15

static const byte RightVolTable[ ATABLEMAX ][ ATABLEMAX * 2 ] = {
{ 8, 8, 8, 8, 8, 8, 8, 16, 16, 16, 16, 16, 16, 32, 128, 128, 128, 128, 128, 112, 80, 48, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 16, 16, 16, 16, 16, 32, 64, 128, 128, 128, 128, 128, 96, 64, 32, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 16, 16, 16, 16, 32, 32, 64, 112, 128, 128, 128, 112, 96, 64, 32, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 16, 16, 16, 16, 32, 48, 64, 96, 112, 128, 112, 96, 80, 48, 16, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 16, 16, 16, 32, 48, 64, 80, 96, 96, 80, 80, 48, 32, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 16, 16, 16, 32, 32, 48, 64, 64, 64, 64, 48, 32, 16, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 16, 16, 16, 32, 32, 48, 48, 48, 32, 32, 16, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 16, 16, 16, 32, 32, 16, 16, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8}
};

static const byte LeftVolTable[ ATABLEMAX ][ ATABLEMAX * 2 ] = {
{ 8, 8, 8, 8, 8, 8, 8, 8, 48, 80, 112, 128, 128, 128, 128, 128, 32, 128, 128, 128, 128, 128, 128, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 32, 64, 96, 128, 128, 128, 128, 128, 64, 32, 128, 128, 128, 128, 128, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 32, 64, 96, 112, 128, 128, 128, 112, 64, 32, 32, 128, 128, 128, 128, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 128, 48, 80, 96, 112, 128, 112, 96, 64, 48, 32, 128, 128, 128, 128, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 32, 48, 80, 80, 96, 96, 80, 64, 48, 32, 128, 128, 128, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 128, 32, 48, 64, 64, 64, 64, 48, 32, 32, 128, 128, 128, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 128, 32, 32, 48, 48, 48, 32, 32, 128, 128, 128, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 128, 128, 32, 32, 128, 128, 128, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8},
{ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8}
};

static void SetSoundLoc(fixed gx, fixed gy)
{
fixed xt, yt;
int x, y;

// translate point to view centered coordinates
//
gx -= viewx;
gy -= viewy;

//
// calculate newx
//
xt = FixedByFrac(gx,viewcos);
yt = FixedByFrac(gy,viewsin);
x = (xt - yt) >> TILESHIFT;

//
// calculate newy
//
xt = FixedByFrac(gx,viewsin);
yt = FixedByFrac(gy,viewcos);
y = (yt + xt) >> TILESHIFT;

if (y >= ATABLEMAX)
   y = ATABLEMAX - 1;
else if (y <= -ATABLEMAX)
   y = -ATABLEMAX;
if (x < 0)
   x = -x;
if (x >= ATABLEMAX)
   x = ATABLEMAX - 1;

LeftVolAdjust = LeftVolTable[ x ][ y + ATABLEMAX ];
RightVolAdjust = RightVolTable[ x ][ y + ATABLEMAX ];
}

void PlaySoundLocGlobal( word s, int id, fixed gx, fixed gy ) {
SoundIsPositioned = true;

SetSoundLoc( gx, gy );
SD_PlaySound( s );

SoundIsPositioned = false;
}

void UpdateSoundLoc(fixed x, fixed y, int angle) {
/*
* Cannot implement this, sounds are fire and forget.
*/
}

void EmitSound( void* SoundBase, int Length, int LeftVol, int RightVol ) {
u32 Data[ 4 ];

if ( SoundBase == NULL )
return;

if ( LeftVol < 0 ) LeftVol = 0;
if ( RightVol < 0 ) RightVol = 0;

if ( LeftVol > 127 ) LeftVol = 127;
if ( RightVol > 127 ) RightVol = 127;

Data[ 0 ] = ( u32 ) SoundBase;
Data[ 1 ] = ( u32 ) Length;
Data[ 2 ] = ( u32 ) LeftVol;
Data[ 3 ] = ( u32 ) RightVol;

fifoSendDatamsg( FIFO_USER_02, sizeof( Data ), ( u8* ) Data );
}

Let me know if there are fatal flaws here, still getting back into things.

to get the final volume you should add both values and subtract from 16, IMHO. So you'll get a volume 0-16 to give to the channel (0-127).
For panning, subtract the left from the right and, this way it'll be -8...+8. multiply by 16 and add 63 :) Dirty method but should work :D

gbadev.org forum archive

DS development > Out of practice - can you help me decypher this?

#175967 - Lazy1 - Sat Mar 12, 2011 5:04 am

#175968 - Ruben - Sat Mar 12, 2011 12:08 pm

#175973 - Lazy1 - Sun Mar 13, 2011 9:18 pm

#175975 - elhobbs - Mon Mar 14, 2011 12:56 am

#175976 - Lazy1 - Mon Mar 14, 2011 1:48 am

#175981 - sverx - Mon Mar 14, 2011 12:56 pm