ref: 31a6f6c83db8e845bc5bf2f0927685a6c2bdfdb2
dir: /sys/src/games/doom/i_sound.c/
/* i_sound.c */
#include "i_system.h"
#include "i_sound.h"
#include "w_wad.h" // W_GetNumForName()
#include "z_zone.h"
/* The number of internal mixing channels,
** the samples calculated for each mixing step,
** the size of the 16bit, 2 hardware channel (stereo)
** mixing buffer, and the samplerate of the raw data.
*/
/* Needed for calling the actual sound output. */
#define SAMPLECOUNT (512<<2)
#define NUM_CHANNELS 8
/* The actual lengths of all sound effects. */
int lengths[NUMSFX];
/* The actual output device. */
static int audio_fd;
/* The global mixing buffer.
** Basically, samples from all active internal channels
** are modified and added, and stored in the buffer
** that is submitted to the audio device.
*/
signed short mixbuffer[SAMPLECOUNT*2];
/* The channel step amount... */
uint channelstep[NUM_CHANNELS];
/* ... and a 0.16 bit remainder of last step. */
uint channelstepremainder[NUM_CHANNELS];
/* The channel data pointers, start and end. */
uchar* channels[NUM_CHANNELS];
uchar* channelsend[NUM_CHANNELS];
/* Time/gametic that the channel started playing,
** used to determine oldest, which automatically
** has lowest priority.
** In case number of active sounds exceeds
** available channels.
*/
int channelstart[NUM_CHANNELS];
/* The sound in channel handles,
** determined on registration,
** might be used to unregister/stop/modify,
** currently unused.
*/
int channelhandles[NUM_CHANNELS];
/* SFX id of the playing sound effect.
** Used to catch duplicates (like chainsaw).
*/
int channelids[NUM_CHANNELS];
/* Pitch to stepping lookup, unused. */
int steptable[256];
/* Volume lookups. */
int vol_lookup[128*256];
/* Hardware left and right channel volume lookup. */
int* channelleftvol_lookup[NUM_CHANNELS];
int* channelrightvol_lookup[NUM_CHANNELS];
static void* getsfx(char *sfxname, int *len)
{
uchar *sfx;
uchar *paddedsfx;
int i;
int size;
int paddedsize;
char name[20];
int sfxlump;
/* Get the sound data from the WAD, allocate lump
** in zone memory. */
sprintf(name, "ds%s", sfxname);
/* Now, there is a severe problem with the
** sound handling, in it is not (yet/anymore)
** gamemode aware. That means, sounds from
** DOOM II will be requested even with DOOM
** shareware.
** The sound list is wired into sounds.c,
** which sets the external variable.
** I do not do runtime patches to that
** variable. Instead, we will use a
** default sound for replacement.
*/
if ( W_CheckNumForName(name) == -1 )
sfxlump = W_GetNumForName("dspistol");
else
sfxlump = W_GetNumForName(name);
size = W_LumpLength( sfxlump );
sfx = (uchar *)W_CacheLumpNum(sfxlump, PU_STATIC);
/* Pads the sound effect out to the mixing buffer size.
** The original realloc would interfere with zone memory.
*/
paddedsize = ((size-8 + (SAMPLECOUNT-1)) / SAMPLECOUNT) * SAMPLECOUNT;
/* Allocate from zone memory. */
paddedsfx = (uchar *)Z_Malloc(paddedsize+8, PU_STATIC, 0);
/* Now copy and pad. */
memcpy(paddedsfx, sfx, size);
for (i=size ; i<paddedsize+8 ; i++)
paddedsfx[i] = 128;
/* Remove the cached lump. */
Z_Free(sfx);
/* Preserve padded length. */
*len = paddedsize;
/* Return allocated padded data. */
return (void *)(paddedsfx + 8);
}
void I_InitSound(void)
{
int i;
audio_fd = open("/dev/audio", OWRITE);
if(audio_fd < 0)
printf("WARN Failed to open /dev/audio, sound disabled\n");
/* Initialize external data (all sounds) at start, keep static. */
for (i=1 ; i<NUMSFX ; i++)
{
if (!S_sfx[i].link)
{
/* Load data from WAD file. */
S_sfx[i].data = getsfx( S_sfx[i].name, &lengths[i] );
}
}
/* Alias? Example is the chaingun sound linked to pistol. */
for (i=1 ; i<NUMSFX ; i++)
{
if (S_sfx[i].link)
{
/* Previously loaded already? */
S_sfx[i].data = S_sfx[i].link->data;
lengths[i] = lengths[S_sfx[i].link - S_sfx];
}
}
/* Now initialize mixbuffer with zero. */
memset(mixbuffer, 0, sizeof mixbuffer);
}
/* This function loops all active (internal) sound
** channels, retrieves a given number of samples
** from the raw sound data, modifies it according
** to the current (internal) channel parameters,
** mixes the per-channel samples into the global
** mixbuffer, clamping it to the allowed range,
** and sets up everything for transferring the
** contents of the mixbuffer to the (two)
** hardware channels (left and right, that is).
**
** This function currently supports only 16bit.
*/
void I_UpdateSound(void)
{
/* Mix current sound data.
** Data, from raw sound, for right and left.
*/
register uint sample;
register int dl;
register int dr;
/* Pointers in global mixbuffer, left, right, end. */
signed short *leftout;
signed short *rightout;
signed short *leftend;
/* Step in mixbuffer, left and right, thus two. */
int step;
/* Mixing channel index. */
int chan;
/* Left and right channel
** are in global mixbuffer, alternating. */
leftout = mixbuffer;
rightout = mixbuffer+1;
step = 2;
/* Determine end, for left channel only
** (right channel is implicit). */
leftend = mixbuffer + SAMPLECOUNT*step;
/* Mix sounds into the mixing buffer.
** Loop over step*SAMPLECOUNT
** that is 512 values for two channels.
*/
while (leftout != leftend)
{
/* Reset left/right value. */
dl = 0;
dr = 0;
/* Love thy L2 cache - made this a loop.
** Now more channels could be set at compile time
** as well. Thus loop those channels.
*/
for(chan=0; chan < NUM_CHANNELS; chan++)
{
/* Check channel, if active. */
if(channels[ chan ])
{
/* Get the raw data from the channel. */
sample = *channels[ chan ];
/* Add left and right part
** for this channel (sound)
** to the current data.
** Adjust volume accordingly.
*/
dl += channelleftvol_lookup[ chan ][sample];
dr += channelrightvol_lookup[ chan ][sample];
/* Increment index ??? */
channelstepremainder[ chan ] += channelstep[ chan ];
/* MSB is next sample??? */
channels[ chan ] += channelstepremainder[ chan ] >> 16;
/* Limit to LSB??? */
channelstepremainder[ chan ] &= 65536-1;
/* Check whether we are done. */
if (channels[ chan ] >= channelsend[ chan ])
channels[ chan ] = 0;
}
}
/* Clamp to range. */
if (dl > 0x7fff)
dl = 0x7fff;
else if (dl < -0x8000)
dl = -0x8000;
if (dr > 0x7fff)
dr = 0x7fff;
else if (dr < -0x8000)
dr = -0x8000;
*leftout = dl;
*rightout = dr;
/* Increment current pointers in mixbuffer. */
leftout += step;
rightout += step;
*leftout = dl;
*rightout = dr;
leftout += step;
rightout += step;
*leftout = dl;
*rightout = dr;
leftout += step;
rightout += step;
*leftout = dl;
*rightout = dr;
leftout += step;
rightout += step;
}
}
void I_SubmitSound(void)
{
if(audio_fd >= 0)
write(audio_fd, mixbuffer, sizeof mixbuffer);
}
void I_ShutdownSound(void)
{
if(audio_fd >= 0) {
close(audio_fd);
audio_fd = -1;
}
}
void I_SetChannels(void)
{
/* Init internal lookups (raw data, mixing buffer, channels).
** This function sets up internal lookups used during
** the mixing process.
*/
int i;
int j;
int *steptablemid = steptable + 128;
/* This table provides step widths for pitch parameters.
** I fail to see that this is currently used. */
for (i=-128 ; i<128 ; i++)
steptablemid[i] = (int)(pow(2.0, (i/64.0))*65536.0);
/* Generates volume lookup tables
** which also turn the unsigned samples
** into signed samples.
*/
for (i=0 ; i<128 ; i++)
for (j=0 ; j<256 ; j++)
vol_lookup[i*256+j] = (i*(j-128)*256)/127;
}
int I_GetSfxLumpNum(sfxinfo_t *sfxinfo)
{
char namebuf[9];
sprintf(namebuf, "ds%s", sfxinfo->name);
return W_GetNumForName(namebuf);
}
/* This function adds a sound to the
** list of currently active sounds,
** which is maintained as a given number
** (eight, usually) of internal channels.
** eturns a handle.
*/
static int
addsfx(int id, int vol, int step, int sep)
{
static unsigned short handlenums = 0;
int i;
int rc;
int oldest = gametic;
int oldestnum = 0;
int slot;
int rightvol;
int leftvol;
/* Chainsaw troubles.
** Play these sound effects only one at a time. */
if ( id == sfx_sawup ||
id == sfx_sawidl ||
id == sfx_sawful ||
id == sfx_sawhit ||
id == sfx_stnmov ||
id == sfx_pistol )
{
/* Loop all channels, check. */
for (i=0 ; i < NUM_CHANNELS ; i++)
{
/* Active and using the same SFX? */
if( (channels[i]) && (channelids[i] == id) )
{
/* Reset. */
channels[i] = 0;
/* We are sure that iff,
** there will only be one. */
break;
}
}
}
/* Loop all channels to find oldest SFX. */
for (i=0 ; (i<NUM_CHANNELS) && (channels[i]) ; i++)
{
if(channelstart[i] < oldest)
{
oldestnum = i;
oldest = channelstart[i];
}
}
/* Tales from the cryptic.
** If we found a channel, fine.
** If not, we simply overwrite the first one, 0.
** Probably only happens at startup.
*/
if (i == NUM_CHANNELS)
slot = oldestnum;
else
slot = i;
/* Okay, in the less recent channel,
** we will handle the new SFX.
** Set pointer to raw data.
*/
channels[slot] = (uchar*) S_sfx[id].data;
/* Set pointer to end of raw data. */
channelsend[slot] = channels[slot] + lengths[id];
/* Reset current handle number, limited to 0..100. */
if (!handlenums)
handlenums = 100;
/* Assign current handle number.
** Preserved so sounds could be stopped (unused).
*/
channelhandles[slot] = rc = handlenums++;
/* Set stepping???
** Kinda getting the impression this is never used.
*/
channelstep[slot] = step;
/* ??? */
channelstepremainder[slot] = 0;
/* Should be gametic, I presume. */
channelstart[slot] = gametic;
/* Separation, that is, orientation/stereo.
** range is : 1 - 256
*/
sep += 1;
/* Per left/right channel.
** x^2 seperation,
** adjust volume properly.
*/
leftvol = vol - ((vol*sep*sep) >> 16); // /(256*256);
sep = sep - 257;
rightvol = vol - ((vol*sep*sep) >> 16);
/* Sanity check, clamp volume. */
if (rightvol < 0 || rightvol > 127)
I_Error("rightvol out of bounds");
if (leftvol < 0 || leftvol > 127)
I_Error("leftvol out of bounds");
/* Get the proper lookup table piece
** for this volume level???
*/
channelleftvol_lookup[slot] = &vol_lookup[leftvol*256];
channelrightvol_lookup[slot] = &vol_lookup[rightvol*256];
/* Preserve sound SFX id,
** e.g. for avoiding duplicates of chainsaw.
*/
channelids[slot] = id;
/* You tell me. */
return rc;
}
int I_StartSound(int id, int vol, int sep, int pitch, int priority)
{
USED(priority);
id = addsfx(id, vol, steptable[pitch], sep);
return id;
}
void I_StopSound(int handle)
{
USED(handle);
// printf("PORTME i_sound.c I_StopSound\n");
}
int I_SoundIsPlaying(int handle)
{
/* Ouch. */
return gametic < handle;
}
void I_UpdateSoundParams(int handle, int vol, int sep, int pitch)
{
/* I fail to see that this is used.
** Would be using the handle to identify
** on which channel the sound might be active,
** and resetting the channel parameters.
*/
USED(handle, vol, sep, pitch);
}
void I_InitMusic(void)
{
// printf("PORTME i_sound.c I_InitMusic\n");
}
void I_ShutdownMusic(void)
{
// printf("PORTME i_sound.c I_ShutdownMusic\n");
}
void I_SetMusicVolume(int volume)
{
USED(volume);
// printf("PORTME i_sound.c I_SetMusicVolume\n");
}
void I_PauseSong(int handle)
{
USED(handle);
// printf("PORTME i_sound.c I_PauseSong\n");
}
void I_ResumeSong(int handle)
{
USED(handle);
// printf("PORTME i_sound.c I_ResumeSong\n");
}
int I_RegisterSong(void *data)
{
USED(data);
// printf("PORTME i_sound.c I_RegisterSong\n");
return 0;
}
void I_PlaySong(int handle, int looping)
{
USED(handle, looping);
// printf("PORTME i_sound.c I_PlaySong\n");
}
void I_StopSong(int handle)
{
USED(handle);
// printf("PORTME i_sound.c I_StopSong\n");
}
void I_UnRegisterSong(int handle)
{
USED(handle);
// printf("PORTME i_sound.c I_UnregisterSong\n");
}