125 lines
3.1 KiB
C++
125 lines
3.1 KiB
C++
/* REminiscence - Flashback interpreter
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* Copyright (C) 2005-2007 Gregory Montoir
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include "mixer.h"
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#include "systemstub.h"
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Mixer::Mixer(SystemStub *stub)
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: _stub(stub) {
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}
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void Mixer::init() {
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memset(_channels, 0, sizeof(_channels));
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_premixHook = 0;
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_mutex = _stub->createMutex();
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_stub->startAudio(Mixer::mixCallback, this);
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}
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void Mixer::free() {
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stopAll();
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_stub->stopAudio();
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_stub->destroyMutex(_mutex);
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}
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void Mixer::setPremixHook(PremixHook premixHook, void *userData) {
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debug(DBG_SND, "Mixer::setPremixHook()");
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MutexStack(_stub, _mutex);
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_premixHook = premixHook;
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_premixHookData = userData;
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}
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void Mixer::play(const MixerChunk *mc, uint16 freq, uint8 volume) {
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debug(DBG_SND, "Mixer::play(%d, %d)", freq, volume);
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MutexStack(_stub, _mutex);
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MixerChannel *ch = 0;
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for (int i = 0; i < NUM_CHANNELS; ++i) {
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MixerChannel *cur = &_channels[i];
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if (cur->active) {
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if (cur->chunk.data == mc->data) {
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cur->chunkPos = 0;
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return;
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}
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} else {
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ch = cur;
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break;
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}
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}
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if (ch) {
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ch->active = true;
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ch->volume = volume;
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ch->chunk = *mc;
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ch->chunkPos = 0;
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ch->chunkInc = (freq << FRAC_BITS) / _stub->getOutputSampleRate();
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}
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}
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uint32 Mixer::getSampleRate() const {
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return _stub->getOutputSampleRate();
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}
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void Mixer::stopAll() {
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debug(DBG_SND, "Mixer::stopAll()");
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MutexStack(_stub, _mutex);
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for (uint8 i = 0; i < NUM_CHANNELS; ++i) {
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_channels[i].active = false;
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}
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}
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inline void addclamp(int16& a, int b) {
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int add = a + b;
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if (add < -32767) {
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add = -32767;
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} else if (add > 32767) {
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add = 32767;
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}
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a = add;
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}
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void Mixer::mix(int8 *buf1, int len) {
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int16 *buf = (int16 *)buf1;
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MutexStack(_stub, _mutex);
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memset(buf, 0, len);
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len /= 2;
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if (_premixHook) {
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if (!_premixHook(_premixHookData, buf, len)) {
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_premixHook = 0;
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_premixHookData = 0;
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}
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}
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for (uint8 i = 0; i < NUM_CHANNELS; ++i) {
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MixerChannel *ch = &_channels[i];
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if (ch->active) {
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for (int pos = 0; pos < len; ++pos) {
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if ((ch->chunkPos >> FRAC_BITS) >= (ch->chunk.len - 1)) {
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ch->active = false;
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break;
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}
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int out = resampleLinear(&ch->chunk, ch->chunkPos, ch->chunkInc, FRAC_BITS);
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addclamp(buf[pos], out * Mixer::MIX_AMPLIFICATIION * ch->volume / Mixer::MAX_VOLUME );
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ch->chunkPos += ch->chunkInc;
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}
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}
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}
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}
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void Mixer::mixCallback(void *param, uint8 *buf, int len) {
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((Mixer *)param)->mix((int8 *)buf, len);
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}
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