public bool Process()
{
if (noteGain < SoundFontMath.NonAudible)
{
return(false);
}
var channelInfo = synthesizer.Channels[channel];
ReleaseIfNecessary(channelInfo);
if (!volEnv.Process())
{
return(false);
}
modEnv.Process();
vibLfo.Process();
modLfo.Process();
var vibPitchChange = (0.01F * channelInfo.Modulation + vibLfoToPitch) * vibLfo.Value;
var modPitchChange = modLfoToPitch * modLfo.Value + modEnvToPitch * modEnv.Value;
var channelPitchChange = channelInfo.Tune + channelInfo.PitchBend;
var pitch = key + vibPitchChange + modPitchChange + channelPitchChange;
if (!oscillator.Process(block, pitch))
{
return(false);
}
if (dynamicCutoff)
{
var cents = modLfoToCutoff * modLfo.Value + modEnvToCutoff * modEnv.Value;
var factor = SoundFontMath.CentsToMultiplyingFactor(cents);
var newCutoff = factor * cutoff;
// The cutoff change is limited within x0.5 and x2 to reduce pop noise.
var lowerLimit = 0.5F * smoothedCutoff;
var upperLimit = 2F * smoothedCutoff;
if (newCutoff < lowerLimit)
{
smoothedCutoff = lowerLimit;
}
else if (newCutoff > upperLimit)
{
smoothedCutoff = upperLimit;
}
else
{
smoothedCutoff = newCutoff;
}
filter.SetLowPassFilter(smoothedCutoff, resonance);
}
filter.Process(block);
previousMixGainLeft = currentMixGainLeft;
previousMixGainRight = currentMixGainRight;
previousReverbSend = currentReverbSend;
previousChorusSend = currentChorusSend;
// According to the GM spec, the following value should be squared.
var ve = channelInfo.Volume * channelInfo.Expression;
var channelGain = ve * ve;
var mixGain = noteGain * channelGain * volEnv.Value;
if (dynamicVolume)
{
var decibels = modLfoToVolume * modLfo.Value;
mixGain *= SoundFontMath.DecibelsToLinear(decibels);
}
var angle = (MathF.PI / 200F) * (channelInfo.Pan + instrumentPan + 50F);
if (angle <= 0F)
{
currentMixGainLeft = mixGain;
currentMixGainRight = 0F;
}
else if (angle >= SoundFontMath.HalfPi)
{
currentMixGainLeft = 0F;
currentMixGainRight = mixGain;
}
else
{
currentMixGainLeft = mixGain * MathF.Cos(angle);
currentMixGainRight = mixGain * MathF.Sin(angle);
}
currentReverbSend = SoundFontMath.Clamp(channelInfo.ReverbSend + instrumentReverb, 0F, 1F);
currentChorusSend = SoundFontMath.Clamp(channelInfo.ChorusSend + instrumentChorus, 0F, 1F);
if (voiceLength == 0)
{
previousMixGainLeft = currentMixGainLeft;
previousMixGainRight = currentMixGainRight;
previousReverbSend = currentReverbSend;
previousChorusSend = currentChorusSend;
}
voiceLength += synthesizer.BlockSize;
return(true);
}
