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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2014 Franklin Wei, Benjamin Brown
* Copyright (C) 2004 Gregory Montoir
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
***************************************************************************/
#include "mixer.h"
#include "serializer.h"
#include "sys.h"
static int8_t ICODE_ATTR addclamp(int a, int b) {
int add = a + b;
if (add < -128) {
add = -128;
}
else if (add > 127) {
add = 127;
}
return (int8_t)add;
}
void mixer_create(struct Mixer* mx, struct System *stub)
{
mx->sys = stub;
}
static void mixer_mixCallback(void *param, uint8_t *buf, int len);
void mixer_init(struct Mixer* mx) {
rb->memset(mx->_channels, 0, sizeof(mx->_channels));
if(!mx->sys)
{
error("in mixer sys is NULL");
}
mx->_mutex = sys_createMutex(mx->sys);
sys_startAudio(mx->sys, mixer_mixCallback, mx);
}
void mixer_free(struct Mixer* mx) {
mixer_stopAll(mx);
sys_stopAudio(mx->sys);
sys_destroyMutex(mx->sys, mx->_mutex);
}
void mixer_playChannel(struct Mixer* mx, uint8_t channel, const struct MixerChunk *mc, uint16_t freq, uint8_t volume) {
debug(DBG_SND, "mixer_playChannel(%d, %d, %d)", channel, freq, volume);
assert(channel < AUDIO_NUM_CHANNELS);
/* FW: the mutex code was converted 1:1 from C++ to C, leading to the ugly calls */
/* to constructors/destructors as seen here */
struct MutexStack_t ms;
MutexStack(&ms, mx->sys, mx->_mutex);
struct MixerChannel *ch = &mx->_channels[channel];
ch->active = true;
ch->volume = volume;
ch->chunk = *mc;
ch->chunkPos = 0;
ch->chunkInc = (freq << 8) / sys_getOutputSampleRate(mx->sys);
MutexStack_destroy(&ms);
}
void mixer_stopChannel(struct Mixer* mx, uint8_t channel) {
debug(DBG_SND, "mixer_stopChannel(%d)", channel);
assert(channel < AUDIO_NUM_CHANNELS);
struct MutexStack_t ms;
MutexStack(&ms, mx->sys, mx->_mutex);
mx->_channels[channel].active = false;
MutexStack_destroy(&ms);
}
void mixer_setChannelVolume(struct Mixer* mx, uint8_t channel, uint8_t volume) {
debug(DBG_SND, "mixer_setChannelVolume(%d, %d)", channel, volume);
assert(channel < AUDIO_NUM_CHANNELS);
struct MutexStack_t ms;
MutexStack(&ms, mx->sys, mx->_mutex);
mx->_channels[channel].volume = volume;
MutexStack_destroy(&ms);
}
void mixer_stopAll(struct Mixer* mx) {
debug(DBG_SND, "mixer_stopAll()");
struct MutexStack_t ms;
MutexStack(&ms, mx->sys, mx->_mutex);
for (uint8_t i = 0; i < AUDIO_NUM_CHANNELS; ++i) {
mx->_channels[i].active = false;
}
MutexStack_destroy(&ms);
}
/* Mx is SDL callback. Called in order to populate the buf with len bytes. */
/* The mixer iterates through all active channels and combine all sounds. */
/* Since there is no way to know when SDL will ask for a buffer fill, we need */
/* to synchronize with a mutex so the channels remain stable during the execution */
/* of this method. */
static void ICODE_ATTR mixer_mix(struct Mixer* mx, int8_t *buf, int len) {
int8_t *pBuf;
struct MutexStack_t ms;
MutexStack(&ms, mx->sys, mx->_mutex);
/* Clear the buffer since nothing guarantees we are receiving clean memory. */
rb->memset(buf, 0, len);
for (uint8_t i = 0; i < AUDIO_NUM_CHANNELS; ++i) {
struct MixerChannel *ch = &mx->_channels[i];
if (!ch->active)
continue;
pBuf = buf;
for (int j = 0; j < len; ++j, ++pBuf) {
uint16_t p1, p2;
uint16_t ilc = (ch->chunkPos & 0xFF);
p1 = ch->chunkPos >> 8;
ch->chunkPos += ch->chunkInc;
if (ch->chunk.loopLen != 0) {
if (p1 == ch->chunk.loopPos + ch->chunk.loopLen - 1) {
debug(DBG_SND, "Looping sample on channel %d", i);
ch->chunkPos = p2 = ch->chunk.loopPos;
} else {
p2 = p1 + 1;
}
} else {
if (p1 == ch->chunk.len - 1) {
debug(DBG_SND, "Stopping sample on channel %d", i);
ch->active = false;
break;
} else {
p2 = p1 + 1;
}
}
/* interpolate */
int8_t b1 = *(int8_t *)(ch->chunk.data + p1);
int8_t b2 = *(int8_t *)(ch->chunk.data + p2);
int8_t b = (int8_t)((b1 * (0xFF - ilc) + b2 * ilc) >> 8);
/* set volume and clamp */
*pBuf = addclamp(*pBuf, (int)b * ch->volume / 0x40); /* 0x40=64 */
}
}
MutexStack_destroy(&ms);
}
static void ICODE_ATTR mixer_mixCallback(void *param, uint8_t *buf, int len) {
debug(DBG_SND, "mixer_mixCallback");
mixer_mix((struct Mixer*)param, (int8_t *)buf, len);
}
void mixer_saveOrLoad(struct Mixer* mx, struct Serializer *ser) {
sys_lockMutex(mx->sys, mx->_mutex);
for (int i = 0; i < AUDIO_NUM_CHANNELS; ++i) {
struct MixerChannel *ch = &mx->_channels[i];
struct Entry entries[] = {
SE_INT(&ch->active, SES_BOOL, VER(2)),
SE_INT(&ch->volume, SES_INT8, VER(2)),
SE_INT(&ch->chunkPos, SES_INT32, VER(2)),
SE_INT(&ch->chunkInc, SES_INT32, VER(2)),
SE_PTR(&ch->chunk.data, VER(2)),
SE_INT(&ch->chunk.len, SES_INT16, VER(2)),
SE_INT(&ch->chunk.loopPos, SES_INT16, VER(2)),
SE_INT(&ch->chunk.loopLen, SES_INT16, VER(2)),
SE_END()
};
ser_saveOrLoadEntries(ser, entries);
}
sys_unlockMutex(mx->sys, mx->_mutex);
};
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