scummvm/engines/agi/sound_coco3.cpp
2024-10-28 21:02:51 -07:00

146 lines
4.6 KiB
C++

/* 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 3 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, see <http://www.gnu.org/licenses/>.
*
*/
#include "audio/mixer.h"
#include "agi/agi.h"
#include "agi/sound_coco3.h"
namespace Agi {
// SoundGenCoCo3 plays Tandy Color Computer sounds.
//
// CoCo3 AGI sounds are a series of monotonic notes. They sound similar to
// PC speaker versions, but they use a different resource format. As with
// the Apple II, sound playback is a blocking operation.
//
// The sound resource is a stream of four-byte notes. The frequency is a table
// index. The volume is a boolean. The duration changed between interpreters;
// originally the units were 1/10 of a second, then 1/60.
//
// Common::PCSpeaker is used for sound generation. It produces significantly
// louder volumes than the other AGI sound generators, so I've lowered the
// mixer volume for consistency.
//
// Thanks to Guillaume Major for documenting the sound format in their
// conversion program, cc3snd.c.
static const uint16 cocoFrequencies[] = {
130, 138, 146, 155, 164, 174, 184, 195, 207, 220, 233, 246,
261, 277, 293, 311, 329, 349, 369, 391, 415, 440, 466, 493,
523, 554, 587, 622, 659, 698, 739, 783, 830, 880, 932, 987,
1046, 1108, 1174, 1244, 1318, 1396, 1479, 1567, 1661, 1760, 1864, 1975,
2093, 2217, 2349, 2489, 2637, 2793, 2959, 3135, 3322, 3520, 3729, 3951
};
#define COCO3_MIXER_VOLUME 20
SoundGenCoCo3::SoundGenCoCo3(AgiBase *vm, Audio::Mixer *pMixer) :
_isPlaying(false),
SoundGen(vm, pMixer) {
_mixer->playStream(Audio::Mixer::kMusicSoundType, _soundHandle, this, -1, COCO3_MIXER_VOLUME, 0, DisposeAfterUse::NO, true);
}
SoundGenCoCo3::~SoundGenCoCo3() {
_mixer->stopHandle(*_soundHandle);
}
void SoundGenCoCo3::play(int resnum) {
Common::StackLock lock(_mutex);
if (_vm->_game.sounds[resnum] == nullptr ||
_vm->_game.sounds[resnum]->type() != AGI_SOUND_COCO3) {
error("CoCo3 sound %d not loaded", resnum);
}
_speaker.stop();
// KQ3 (Int. 2.023) stored the duration in 1/10 of a second.
// LSL1 (Int, 2.072) stored the duration in 1/60 of a second.
// Fan ports have been made using both interpreters, but our
// detection table doesn't capture this. For now, treat KQ3
// as the early interpreter and all others as the later one.
// TODO: create detection heuristic
bool isEarlySound = (_vm->getGameID() == GID_KQ3);
// parse and enqueue all notes
AgiSound *sound = _vm->_game.sounds[resnum];
byte *data = sound->getData();
uint32 dataLength = sound->getLength();
for (uint32 i = 0; i + 4 < dataLength; i += 4) {
// the third byte is apparently unused, and always zero
byte freqIndex = data[i];
byte volume = data[i + 1];
byte duration = data[i + 3];
if (freqIndex == 0xff) {
break;
}
// get duration in ticks (1/60 of a second)
uint32 ticks = duration;
if (isEarlySound) {
ticks *= 6;
}
// convert ticks to microseconds for PCSpeaker
uint32 duration_usec = ticks * (1000000.0f / 60.0f);
// play if volume is non-zero (it's always 0x3f or zero)
if (volume != 0 && freqIndex < ARRAYSIZE(cocoFrequencies)) {
int freq = cocoFrequencies[freqIndex];
_speaker.playQueue(Audio::PCSpeaker::kWaveFormSquare, freq, duration_usec);
} else {
_speaker.playQueue(Audio::PCSpeaker::kWaveFormSilence, 0, duration_usec);
}
}
_isPlaying = true;
}
void SoundGenCoCo3::stop() {
Common::StackLock lock(_mutex);
_speaker.stop();
_isPlaying = false;
}
int SoundGenCoCo3::readBuffer(int16 *buffer, const int numSamples) {
Common::StackLock lock(_mutex);
// if not playing then there are no samples
if (!_isPlaying) {
return 0;
}
// fill the buffer with PCSpeaker samples
int result = _speaker.readBuffer(buffer, numSamples);
// if PCSpeaker is no longer playing then sound is finished
if (!_speaker.isPlaying()) {
_isPlaying = false;
_vm->_sound->soundIsFinished();
}
return result;
}
} // End of namespace Agi