internal int FillChannel(int channel, Tone tone)
{
if (!this.State.Flags[Flags.SoundOn])
{
return(-1);
}
SoundChannel soundChannel = this.soundChannels[channel];
if (soundChannel.Avail == 0)
{
return(-1);
}
byte[] soundData = soundChannel.Data;
while (soundChannel.Duration == 0 && soundChannel.Duration != 0xffff)
{
int offset = soundChannel.DataIndex;
if (offset >= (soundData.Length - 2))
{
soundChannel.Duration = 0xffff;
break;
}
soundChannel.Duration = (soundData[offset + 1] * 0x100) + soundData[offset];
if (soundChannel.Duration != 0 && soundChannel.Duration != 0xffff)
{
// Only tone channels dissolve
if (channel != 3 && this.Preferences.SoundDissolve != 0)
{
soundChannel.DissolveCount = 0;
}
// Volume
soundChannel.Attenuation = soundData[offset + 4] & 0x0f;
// Frequency
if (channel < 3)
{
soundChannel.FreqCount = (ushort)(soundData[offset + 2] & 0x3f);
soundChannel.FreqCount <<= 4;
soundChannel.FreqCount |= (byte)(soundData[offset + 3] & 0x0f);
soundChannel.GenType = PcmSoundDriver.GenerateTone;
}
else
{
byte noiseType = (byte)(soundData[offset + 3] & 0x04);
soundChannel.GenType = noiseType != 0 ? PcmSoundDriver.GenerateWhite : PcmSoundDriver.GeneratePeriod;
int noiseFreq = (byte)(soundData[offset + 3] & 0x03);
switch (noiseFreq)
{
case 0:
soundChannel.FreqCount = 32;
break;
case 1:
soundChannel.FreqCount = 64;
break;
case 2:
soundChannel.FreqCount = 128;
break;
case 3:
soundChannel.FreqCount = this.soundChannels[2].FreqCount * 2;
break;
}
}
}
soundChannel.DataIndex += 5;
}
if (soundChannel.Duration != 0xffff)
{
tone.FrequencyCount = soundChannel.FreqCount;
tone.Attenuation = this.CalculateVolume(soundChannel);
tone.Type = soundChannel.GenType;
soundChannel.Duration--;
}
else
{
soundChannel.Avail = 0;
soundChannel.Attenuation = 0x0f; // silent
soundChannel.AttenuationCopy = 0x0f;
return(-1);
}
return(0);
}
private int TonePcmCallback(ToneChannel ch, short[] buffer, int count)
{
int result = -1;
int index = 0;
while (count > 0)
{
if (ch.NoteCount <= 0)
{
// Get new tone data
Tone tone = new Tone();
tone.FrequencyCount = 0;
tone.Attenuation = 0x0f;
tone.Type = GenerateTone;
if (ch.Avail != 0 && this.interpreter.SoundManager.FillChannel(ch.AgiChannel, tone) == 0)
{
ch.Attenuation = tone.Attenuation;
ch.FreqCount = tone.FrequencyCount;
ch.GenType = tone.Type;
// setup counters 'n stuff
// 44100 samples per sec.. tone changes 60 times per sec
ch.NoteCount = 44100 / 60;
result = 0;
}
else
{
ch.GenType = GenerateSilence;
ch.NoteCount = count;
ch.Avail = 0;
}
}
// Write nothing
if (ch.FreqCount == 0 || ch.Attenuation == 0x0f)
{
ch.GenType = GenerateSilence;
}
// Find which is smaller, the buffer or the note count
int fillSize = ch.NoteCount < count ? ch.NoteCount : count;
switch (ch.GenType)
{
case GenerateTone:
fillSize = PcmSoundDriver.SquareFill(ch, buffer, index, fillSize);
break;
case GeneratePeriod:
case GenerateWhite:
fillSize = PcmSoundDriver.NoiseFill(ch, buffer, index, fillSize);
break;
case GenerateSilence:
default:
fillSize = PcmSoundDriver.SilenceFill(buffer, index, fillSize);
break;
}
ch.NoteCount -= fillSize;
count -= fillSize;
index += fillSize;
}
return(result);
}
