ref: 38a17aa05616a0f792b054ba8ed23a9645b76721
dir: /snd_mix.c/
// snd_mix.c -- portable code to mix sounds for snd_dma.c
#include <u.h>
#include <libc.h>
#include <stdio.h>
#include "dat.h"
#include "fns.h"
#define PAINTBUFFER_SIZE 2048
portable_samplepair_t paintbuffer[PAINTBUFFER_SIZE];
int snd_scaletable[32][256];
int *snd_p, snd_linear_count, snd_vol;
short *snd_out;
void S_WriteLinearBlastStereo16 (void)
{
int i;
int val;
for (i=0 ; i<snd_linear_count ; i+=2)
{
val = snd_p[i]>>8;
if (val > 0x7fff)
snd_out[i] = 0x7fff;
else if (val < (short)0x8000)
snd_out[i] = (short)0x8000;
else
snd_out[i] = val;
val = snd_p[i+1]>>8;
if (val > 0x7fff)
snd_out[i+1] = 0x7fff;
else if (val < (short)0x8000)
snd_out[i+1] = (short)0x8000;
else
snd_out[i+1] = val;
}
}
void S_TransferStereo16 (unsigned long *pbuf, int endtime)
{
int lpos;
int lpaintedtime;
snd_p = (int *) paintbuffer;
lpaintedtime = paintedtime;
while (lpaintedtime < endtime)
{
// handle recirculating buffer issues
lpos = lpaintedtime & ((dma.samples>>1)-1);
snd_out = (short *) pbuf + (lpos<<1);
snd_linear_count = (dma.samples>>1) - lpos;
if (lpaintedtime + snd_linear_count > endtime)
snd_linear_count = endtime - lpaintedtime;
snd_linear_count <<= 1;
// write a linear blast of samples
S_WriteLinearBlastStereo16 ();
snd_p += snd_linear_count;
lpaintedtime += (snd_linear_count>>1);
}
}
/*
===================
S_TransferPaintBuffer
===================
*/
void S_TransferPaintBuffer(int endtime)
{
int out_idx;
int count;
int out_mask;
int *p;
int step;
int val;
unsigned long *pbuf;
pbuf = (unsigned long *)dma.buffer;
if (dma.samplebits == 16 && dma.channels == 2)
{ // optimized case
S_TransferStereo16 (pbuf, endtime);
}
else
{ // general case
p = (int *) paintbuffer;
count = (endtime - paintedtime) * dma.channels;
out_mask = dma.samples - 1;
out_idx = paintedtime * dma.channels & out_mask;
step = 3 - dma.channels;
if (dma.samplebits == 16)
{
short *out = (short *) pbuf;
while (count--)
{
val = *p >> 8;
p+= step;
if (val > 0x7fff)
val = 0x7fff;
else if (val < (short)0x8000)
val = (short)0x8000;
out[out_idx] = val;
out_idx = (out_idx + 1) & out_mask;
}
}
else if (dma.samplebits == 8)
{
unsigned char *out = (unsigned char *) pbuf;
while (count--)
{
val = *p >> 8;
p+= step;
if (val > 0x7fff)
val = 0x7fff;
else if (val < (short)0x8000)
val = (short)0x8000;
out[out_idx] = (val>>8) + 128;
out_idx = (out_idx + 1) & out_mask;
}
}
}
}
/*
===============================================================================
CHANNEL MIXING
===============================================================================
*/
void S_PaintChannelFrom8 (channel_t *ch, sfxcache_t *sc, int endtime, int offset);
void S_PaintChannelFrom16 (channel_t *ch, sfxcache_t *sc, int endtime, int offset);
void S_PaintChannels(int endtime)
{
int i;
int end;
channel_t *ch;
sfxcache_t *sc;
int ltime, count;
playsound_t *ps;
snd_vol = s_volume->value*256;
//Com_Printf ("%i to %i\n", paintedtime, endtime);
while (paintedtime < endtime)
{
// if paintbuffer is smaller than DMA buffer
end = endtime;
if (endtime - paintedtime > PAINTBUFFER_SIZE)
end = paintedtime + PAINTBUFFER_SIZE;
// start any playsounds
while (1)
{
ps = s_pendingplays.next;
if (ps == &s_pendingplays)
break; // no more pending sounds
if (ps->begin <= paintedtime)
{
S_IssuePlaysound (ps);
continue;
}
if (ps->begin < end)
end = ps->begin; // stop here
break;
}
// clear the paint buffer
if (s_rawend < paintedtime)
{
// Com_Printf ("clear\n");
memset(paintbuffer, 0, (end - paintedtime) * sizeof(portable_samplepair_t));
}
else
{ // copy from the streaming sound source
int s;
int stop;
stop = (end < s_rawend) ? end : s_rawend;
for (i=paintedtime ; i<stop ; i++)
{
s = i&(MAX_RAW_SAMPLES-1);
paintbuffer[i-paintedtime] = s_rawsamples[s];
}
// if (i != end)
// Com_Printf ("partial stream\n");
// else
// Com_Printf ("full stream\n");
for ( ; i<end ; i++)
{
paintbuffer[i-paintedtime].left =
paintbuffer[i-paintedtime].right = 0;
}
}
// paint in the channels.
ch = channels;
for (i=0; i<MAX_CHANNELS ; i++, ch++)
{
ltime = paintedtime;
while (ltime < end)
{
if (!ch->sfx || (!ch->leftvol && !ch->rightvol) )
break;
// max painting is to the end of the buffer
count = end - ltime;
// might be stopped by running out of data
if (ch->end - ltime < count)
count = ch->end - ltime;
sc = S_LoadSound (ch->sfx);
if (!sc)
break;
if (count > 0 && ch->sfx)
{
if (sc->width == 1)// FIXME; 8 bit asm is wrong now
S_PaintChannelFrom8(ch, sc, count, ltime - paintedtime);
else
S_PaintChannelFrom16(ch, sc, count, ltime - paintedtime);
ltime += count;
}
// if at end of loop, restart
if (ltime >= ch->end)
{
if (ch->autosound)
{ // autolooping sounds always go back to start
ch->pos = 0;
ch->end = ltime + sc->length;
}
else if (sc->loopstart >= 0)
{
ch->pos = sc->loopstart;
ch->end = ltime + sc->length - ch->pos;
}
else
{ // channel just stopped
ch->sfx = NULL;
}
}
}
}
// transfer out according to DMA format
S_TransferPaintBuffer(end);
paintedtime = end;
}
}
void S_InitScaletable (void)
{
int i, j;
int scale;
s_volume->modified = false;
for (i=0 ; i<32 ; i++)
{
scale = i * 8 * 256 * s_volume->value;
for (j=0 ; j<256 ; j++)
snd_scaletable[i][j] = ((signed char)j) * scale;
}
}
void S_PaintChannelFrom8 (channel_t *ch, sfxcache_t *sc, int count, int offset)
{
int data;
int *lscale, *rscale;
unsigned char *sfx;
int i;
portable_samplepair_t *samp;
if (ch->leftvol > 255)
ch->leftvol = 255;
if (ch->rightvol > 255)
ch->rightvol = 255;
lscale = snd_scaletable[ ch->leftvol >> 11];
rscale = snd_scaletable[ ch->rightvol >> 11];
sfx = (uchar *)sc->data + ch->pos;
samp = &paintbuffer[offset];
for (i=0 ; i<count ; i++, samp++)
{
data = sfx[i];
samp->left += lscale[data];
samp->right += rscale[data];
}
ch->pos += count;
}
void S_PaintChannelFrom16 (channel_t *ch, sfxcache_t *sc, int count, int offset)
{
int data;
int left, right;
int leftvol, rightvol;
signed short *sfx;
int i;
portable_samplepair_t *samp;
leftvol = ch->leftvol*snd_vol;
rightvol = ch->rightvol*snd_vol;
sfx = (signed short *)sc->data + ch->pos;
samp = &paintbuffer[offset];
for (i=0 ; i<count ; i++, samp++)
{
data = sfx[i];
left = (data * leftvol)>>8;
right = (data * rightvol)>>8;
samp->left += left;
samp->right += right;
}
ch->pos += count;
}