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Testing with ADSR envelopes, additive voice signal generator
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129 changes: 129 additions & 0 deletions
129
ComputerSystems/Commodore64/Sid/NAudioImpl/SidAdsrSampleProvider.cs
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,129 @@ | ||
| using NAudio.Wave; | ||
| using System; | ||
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| namespace Commodore64.Sid.NAudioImpl | ||
| { | ||
| public class SidAdsrSampleProvider : ISampleProvider | ||
| { | ||
| private readonly ISampleProvider source; | ||
| private int position; | ||
| private readonly int sampleRate; | ||
| private bool gate; | ||
| private float lastLevel; | ||
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| private int attackSamples, decaySamples, releaseSamples; | ||
| private float sustainLevel; | ||
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| public float AttackSeconds | ||
| { | ||
| get => attackSamples / (float)sampleRate; | ||
| set => attackSamples = (int)(sampleRate * value); | ||
| } | ||
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| public float DecaySeconds | ||
| { | ||
| get => decaySamples / (float)sampleRate; | ||
| set => decaySamples = (int)(sampleRate * value); | ||
| } | ||
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| public float SustainLevel | ||
| { | ||
| get => sustainLevel; | ||
| set => sustainLevel = value; | ||
| } | ||
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| public float ReleaseSeconds | ||
| { | ||
| get => releaseSamples / (float)sampleRate; | ||
| set => releaseSamples = (int)(sampleRate * value); | ||
| } | ||
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| public SidAdsrSampleProvider(ISampleProvider source) | ||
| { | ||
| this.source = source; | ||
| sampleRate = source.WaveFormat.SampleRate; | ||
| } | ||
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| public void Gate(bool isOpen) | ||
| { | ||
| gate = isOpen; | ||
| if (!gate) // If gate is closed, it's the start of the Release phase | ||
| { | ||
| position = 0; | ||
| } | ||
| } | ||
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| public WaveFormat WaveFormat => source.WaveFormat; | ||
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| public int Read(float[] buffer, int offset, int count) | ||
| { | ||
| int sourceSamplesRead = source.Read(buffer, offset, count); | ||
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| for (int n = 0; n < sourceSamplesRead; n++) | ||
| { | ||
| float envMultiplier = GetEnvelopeMultiplier(position++); | ||
| buffer[offset + n] *= envMultiplier; | ||
| } | ||
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| return sourceSamplesRead; | ||
| } | ||
|
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| private float GetEnvelopeMultiplier(int position) | ||
| { | ||
| if (gate) // Attack and Decay | ||
| { | ||
| if (position < attackSamples) | ||
| { | ||
| return lastLevel = (float)position / attackSamples; // Linear Attack | ||
| } | ||
|
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| int decayPosition = position - attackSamples; | ||
| if (decayPosition < decaySamples) | ||
| { | ||
| float decayRate = (sustainLevel - lastLevel) / decaySamples; // Calculate the rate of decay | ||
| return lastLevel += decayRate; // Linear Decay | ||
| } | ||
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| return lastLevel = sustainLevel; // Sustain | ||
| } | ||
| else // Release | ||
| { | ||
| if (position < releaseSamples) | ||
| { | ||
| float releaseRate = lastLevel / releaseSamples; // Calculate the rate of release | ||
| return lastLevel -= releaseRate; // Linear Release | ||
| } | ||
| return 0f; | ||
| } | ||
| } | ||
|
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| private float GetEnvelopeMultiplierExponential(int position) | ||
| { | ||
| if (gate) // Attack and Decay | ||
| { | ||
| if (position < attackSamples) | ||
| { | ||
| return lastLevel = (float)Math.Pow(position / (double)attackSamples, 0.3f); // Exponential Attack | ||
| } | ||
|
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| int decayPosition = position - attackSamples; | ||
| if (decayPosition < decaySamples) | ||
| { | ||
| return lastLevel *= (float)Math.Pow(sustainLevel / lastLevel, 1.0f / decaySamples); // Exponential Decay | ||
| } | ||
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| return lastLevel = sustainLevel; // Sustain | ||
| } | ||
| else // Release | ||
| { | ||
| if (position < releaseSamples) | ||
| { | ||
| float releaseFactor = 1.0f - (position / (float)releaseSamples); | ||
| return lastLevel *= (float)Math.Pow(releaseFactor, 0.03f); // Exponential Release | ||
| } | ||
| return 0f; | ||
| } | ||
| } | ||
| } | ||
| } |
109 changes: 109 additions & 0 deletions
109
ComputerSystems/Commodore64/Sid/NAudioImpl/SidAdsrSampleProvider2.cs
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,109 @@ | ||
| using NAudio.Wave; | ||
| using System; | ||
|
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| namespace Commodore64.Sid.NAudioImpl | ||
| { | ||
| public class SidAdsrSampleProvider2 : ISampleProvider | ||
| { | ||
| private readonly ISampleProvider source; | ||
|
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| private readonly SidEnvelopeGenerator adsr; | ||
|
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| private float attackSeconds; | ||
| private float decaySeconds; | ||
| private float sustainLevel; | ||
| private float releaseSeconds; | ||
|
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|
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| public float AttackSeconds | ||
| { | ||
| get | ||
| { | ||
| return attackSeconds; | ||
| } | ||
| set | ||
| { | ||
| attackSeconds = value; | ||
| adsr.AttackRate = attackSeconds * WaveFormat.SampleRate; | ||
| } | ||
| } | ||
|
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| public float DecaySeconds | ||
| { | ||
| get | ||
| { | ||
| return decaySeconds; | ||
| } | ||
| set | ||
| { | ||
| decaySeconds = value; | ||
| adsr.DecayRate = decaySeconds * WaveFormat.SampleRate; | ||
| } | ||
| } | ||
|
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| public float SustainLevel | ||
| { | ||
| get | ||
| { | ||
| return sustainLevel; | ||
| } | ||
| set | ||
| { | ||
| sustainLevel = value; | ||
| adsr.SustainLevel = sustainLevel; | ||
| } | ||
| } | ||
|
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| public float ReleaseSeconds | ||
| { | ||
| get | ||
| { | ||
| return releaseSeconds; | ||
| } | ||
| set | ||
| { | ||
| releaseSeconds = value; | ||
| adsr.ReleaseRate = releaseSeconds * WaveFormat.SampleRate; | ||
| } | ||
| } | ||
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| public WaveFormat WaveFormat => source.WaveFormat; | ||
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| public SidAdsrSampleProvider2(ISampleProvider source) | ||
| { | ||
| if (source.WaveFormat.Channels > 1) | ||
| { | ||
| throw new ArgumentException("Currently only supports mono inputs"); | ||
| } | ||
|
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| this.source = source; | ||
| adsr = new SidEnvelopeGenerator(); | ||
| AttackSeconds = 0.01f; | ||
| adsr.SustainLevel = 1f; | ||
| adsr.DecayRate = 0f * WaveFormat.SampleRate; | ||
| ReleaseSeconds = 0.3f; | ||
| adsr.Gate(gate: true); | ||
| } | ||
|
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| public int Read(float[] buffer, int offset, int count) | ||
| { | ||
| if (adsr.State == SidEnvelopeGenerator.EnvelopeState.Idle) | ||
| { | ||
| return 0; | ||
| } | ||
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| int num = source.Read(buffer, offset, count); | ||
| for (int i = 0; i < num; i++) | ||
| { | ||
| buffer[offset++] *= adsr.Process(); | ||
| } | ||
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| return num; | ||
| } | ||
|
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| public void Gate(bool gate) | ||
| { | ||
| adsr.Gate(gate); | ||
| } | ||
| } | ||
| } |
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