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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* 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 program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
#include "common/system.h"
#include "sci/tools.h"
#include "sci/sfx/mixer.h"
#include "sound/audiostream.h"
#include "sound/mixer.h"
namespace Sci {
class PCMFeedAudioStream : public Audio::AudioStream {
protected:
enum FeedMode {
FEED_MODE_ALIVE,
FEED_MODE_IDLE,
FEED_MODE_DEAD,
FEED_MODE_RESTART
};
/* Whether feed is alive or dead. */
FeedMode _mode;
/* Blank gap in frames. */
int _gap;
/* Feed. */
sfx_pcm_feed_t *_feed;
/* Timestamp of next frame requested by stream driver. */
Audio::Timestamp _time;
public:
PCMFeedAudioStream(sfx_pcm_feed_t *feed)
: _feed(feed),
_time(g_system->getMillis(), feed->conf.rate) {
_feed->frame_size = (_feed->conf.stereo ? 2 : 1) * ((_feed->conf.format & SFX_PCM_FORMAT_16) ? 2 : 1);
_mode = FEED_MODE_ALIVE;
_gap = 0;
}
~PCMFeedAudioStream() {
_feed->destroy(_feed);
}
virtual int readBuffer(int16 *buffer, const int numSamples);
virtual bool isStereo() const { return _feed->conf.stereo; }
virtual int getRate() const { return _feed->conf.rate; }
virtual bool endOfData() const { return _mode == FEED_MODE_DEAD; }
protected:
void queryTimestamp();
};
void PCMFeedAudioStream::queryTimestamp() {
if (_feed->get_timestamp) {
Audio::Timestamp stamp;
int val = _feed->get_timestamp(_feed, stamp);
switch (val) {
case PCM_FEED_TIMESTAMP:
_gap = stamp.frameDiff(_time);
if (_gap >= 0)
_mode = FEED_MODE_ALIVE;
else {
// FIXME: I don't quite understand what FEED_MODE_RESTART is for.
// The original DC mixer seemed to just stop and restart the stream.
// But why? To catch up with lagging sound?
//
// Walter says the following:
// "The FEED_MODE_RESTART might be there to re-sync after a debugger
// session where time passes for the mixer but not for the engine.
// I may have added this as a workaround for not being able to come
// up with a convenient way to implement mixer->pause() and mixer->resume()
// on DC."
// That makes some sense.
_mode = FEED_MODE_RESTART;
_time = Audio::Timestamp(g_system->getMillis(), _feed->conf.rate);
_gap = stamp.frameDiff(_time);
if (_gap < 0)
_gap = 0;
}
break;
case PCM_FEED_IDLE:
_mode = FEED_MODE_IDLE;
break;
case PCM_FEED_EMPTY:
_mode = FEED_MODE_DEAD;
_gap = 0;
}
} else {
_mode = FEED_MODE_DEAD;
_gap = 0;
}
}
static void U8_to_S16(byte *buf, int samples) {
for (int i = samples - 1; i >= 0; i--) {
buf[i * 2 + 1] = buf[i] - 0x80;
buf[i * 2] = 0;
}
}
int PCMFeedAudioStream::readBuffer(int16 *buffer, const int numSamples) {
// FIXME: If ScummVM's mixer supported timestamps, then it would pass them
// as a parameter to this function. But currently, it doesn't. Therefore, we
// create a fake timestamp based on the current time. For comparison, a real
// timestamp could be adjusted for pauses in sound processing. And it would
// be synced for all audio streams.
Audio::Timestamp timestamp(g_system->getMillis(), _feed->conf.rate);
int channels, frames_req;
int frames_recv = 0;
_time = timestamp;
channels = _feed->conf.stereo == SFX_PCM_MONO ? 1 : 2;
frames_req = numSamples / channels;
while (frames_req != frames_recv) {
int frames_left = frames_req - frames_recv;
byte *buf_pos = ((byte *)buffer) + frames_recv * channels * 2;
if (_mode == FEED_MODE_IDLE)
queryTimestamp();
if (_mode == FEED_MODE_IDLE || _mode == FEED_MODE_DEAD) {
memset(buf_pos, 0, frames_left * channels * 2);
_time = _time.addFrames(frames_left);
break;
}
if (_gap) {
int frames = _gap;
if (frames > frames_left)
frames = frames_left;
memset(buf_pos, 0, frames * channels * 2);
_gap -= frames;
frames_recv += frames;
_time = _time.addFrames(frames);
} else {
int frames = _feed->poll(_feed, buf_pos, frames_left);
if (_feed->conf.format == SFX_PCM_FORMAT_U8)
U8_to_S16(buf_pos, frames * channels);
frames_recv += frames;
_time = _time.addFrames(frames);
if (frames < frames_left)
queryTimestamp();
}
}
return numSamples;
}
void mixer_subscribe(sfx_pcm_feed_t *feed) {
if ((feed->conf.format != SFX_PCM_FORMAT_S16_NATIVE) && (feed->conf.format != SFX_PCM_FORMAT_U8)) {
error("[soft-mixer] Unsupported feed format %d", feed->conf.format);
}
PCMFeedAudioStream *newStream = new PCMFeedAudioStream(feed);
// FIXME: Is this sound type appropriate? The mixer seems to handle music, too.
g_system->getMixer()->playInputStream(Audio::Mixer::kSFXSoundType, 0, newStream);
debug(2, "[soft-mixer] Subscribed %s-%x (%d Hz, %d/%x)",
feed->debug_name, feed->debug_nr, feed->conf.rate, feed->conf.stereo, feed->conf.format);
}
} // End of namespace Sci
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