void Sprite::setScale(frac_t scale) {
assert(scale != 0);
_scale = scale;
// Is there a better way to do that? :/
_scaleInverse = doubleToFrac(1.0 / fracToDouble(scale));
}
uint32 SoundGen2GS::mixSound() {
int i, b;
memset(_sndBuffer, 0, BUFFER_SIZE << 1);
if (!_playing || _playingSound == -1)
return BUFFER_SIZE;
// Handle Apple IIGS sound mixing here
// TODO: Implement playing both waves in an oscillator
// TODO: Implement swap-mode in an oscillator
for (uint midiChan = 0; midiChan < _midiChannels.size(); midiChan++) {
for (uint gsChan = 0; gsChan < _midiChannels[midiChan]._gsChannels.size(); gsChan++) {
IIgsChannelInfo &channel = _midiChannels[midiChan]._gsChannels[gsChan];
if (channel.playing()) { // Only mix in actively playing channels
// Frequency multiplier was 1076.0 based on tests made with MESS 0.117.
// Tests made with KEGS32 averaged the multiplier to around 1045.
// So this is a guess but maybe it's 1046.5... i.e. C6's frequency?
double hertz = C6_FREQ * pow(SEMITONE, fracToDouble(channel.note));
channel.posAdd = doubleToFrac(hertz / getRate());
channel.vol = doubleToFrac(fracToDouble(channel.envVol) * fracToDouble(channel.chanVol) / 127.0);
double tempVol = fracToDouble(channel.vol)/127.0;
for (i = 0; i < IIGS_BUFFER_SIZE; i++) {
b = channel.relocatedSample[fracToInt(channel.pos)];
// TODO: Find out what volume/amplification setting is loud enough
// but still doesn't clip when playing many channels on it.
_sndBuffer[i] += (int16) (b * tempVol * 256/4);
channel.pos += channel.posAdd;
if (channel.pos >= intToFrac(channel.size)) {
if (channel.loop) {
// Don't divide by zero on zero length samples
channel.pos %= intToFrac(channel.size + (channel.size == 0));
// Probably we should loop the envelope too
channel.envSeg = 0;
channel.envVol = channel.startEnvVol;
} else {
channel.pos = channel.chanVol = 0;
channel.end = true;
break;
}
}
}
if (channel.envSeg < ENVELOPE_SEGMENT_COUNT) {
const IIgsEnvelopeSegment &seg = channel.ins->env.seg[channel.envSeg];
// I currently assume enveloping works with the same speed as the MIDI
// (i.e. with 1/60ths of a second ticks).
// TODO: Check if enveloping really works with the same speed as MIDI
frac_t envVolDelta = doubleToFrac(seg.inc/256.0);
if (intToFrac(seg.bp) >= channel.envVol) {
channel.envVol += envVolDelta;
if (channel.envVol >= intToFrac(seg.bp)) {
channel.envVol = intToFrac(seg.bp);
channel.envSeg += 1;
}
} else {
channel.envVol -= envVolDelta;
if (channel.envVol <= intToFrac(seg.bp)) {
channel.envVol = intToFrac(seg.bp);
channel.envSeg += 1;
}
}
}
}
}
}
removeStoppedSounds();
return IIGS_BUFFER_SIZE;
}