/// <snip>
public WaveGenerator(Int64 amplitude, double freq)
{
header = new WaveHeader();
format = new WaveFormatChunk();
data = new WaveDataChunk();
// Fill the data array with sample data
if (freq < 262)
{
freq = 262;
}
if (freq > 1975)
{
freq = 1975;
}
// Number of samples = sample rate * channels * bytes per sample
uint numSamples = format.dwSamplesPerSec * format.wChannels;
// Initialize the 16-bit array
data.shortArray = new short[numSamples];
// The "angle" used in the function, adjusted for the number of channels and sample rate.
// This value is like the period of the wave.
double t = (Math.PI * 2 * freq) / (format.dwSamplesPerSec * format.wChannels);
for (uint i = 0; i < numSamples - 1; i++)
{
// Fill with a simple sine wave at max amplitude
for (int channel = 0; channel < format.wChannels; channel++)
{
data.shortArray[i + channel] = Convert.ToInt16(amplitude * Math.Sin(t * i) + amplitude * Math.Sin(t * i * 1.05946 * 1.05946));
}
}
// Calculate data chunk size in bytes
data.dwChunkSize = (uint)(data.shortArray.Length * (format.wBitsPerSample / 8));
}
public WaveGenerator(WaveExampleType type)
{
// Init chunks
header = new WaveHeader();
format = type == WaveExampleType.MonoWave ? new WaveFormatChunk(false) : new WaveFormatChunk();
data = new WaveDataChunk();
// Fill the data array with sample data
switch (type)
{
case WaveExampleType.ExampleSineWave:
{
// Number of samples = sample rate * channels * bytes per sample
uint numSamples = format.dwSamplesPerSec * format.wChannels;
// Initialize the 16-bit array
data.shortArray = new short[numSamples];
int amplitude = 32760; // Max amplitude for 16-bit audio
double freq = 440.0f; // Concert A: 440Hz
// The "angle" used in the function, adjusted for the number of channels and sample rate.
// This value is like the period of the wave.
double t = (Math.PI * 2 * freq) / (format.dwSamplesPerSec * format.wChannels);
for (uint i = 0; i < numSamples; i+=2)
{
// Fill in the stereo channels
short outp = Convert.ToInt16(amplitude * Math.Sin(t * i));
data.shortArray[i] = outp;
data.shortArray[i + 1] = outp;
}
// Calculate data chunk size in bytes
data.dwChunkSize = (uint)(data.shortArray.Length * (format.wBitsPerSample / 8));
break;
}
case WaveExampleType.TetrisWave:
{
double[] tetrisNoteSequence =
{
WaveNoteFreq.E, WaveNoteFreq.B, WaveNoteFreq.C, WaveNoteFreq.D,
WaveNoteFreq.C, WaveNoteFreq.B, WaveNoteFreq.A, WaveNoteFreq.A,
WaveNoteFreq.C, WaveNoteFreq.E, WaveNoteFreq.D, WaveNoteFreq.C, WaveNoteFreq.B,
WaveNoteFreq.C, WaveNoteFreq.D, WaveNoteFreq.E, WaveNoteFreq.C, WaveNoteFreq.A
};
double[] tetrisNoteLength =
{
WaveNoteLength.Quarter, WaveNoteLength.Eighth, WaveNoteLength.Eighth, WaveNoteLength.Quarter,
WaveNoteLength.Eighth, WaveNoteLength.Eighth, WaveNoteLength.Quarter, WaveNoteLength.Eighth,
WaveNoteLength.Eighth, WaveNoteLength.Quarter, WaveNoteLength.Eighth, WaveNoteLength.Eighth, WaveNoteLength.ThreeQuarters,
WaveNoteLength.Eighth, WaveNoteLength.Quarter, WaveNoteLength.Quarter, WaveNoteLength.Quarter, WaveNoteLength.Half
};
double secondsLong = 0;
foreach (double noteLen in tetrisNoteLength)
{
secondsLong += noteLen;
}
// Number of samples = sample rate * channels * bytes per sample
uint numSamples = (uint)(format.dwSamplesPerSec * format.wChannels * secondsLong);
// Initialize the 16-bit array
data.shortArray = new short[numSamples];
// Max amplitude for 16-bit audio
int amplitude = 32760;
// Keep track of samples recorded
uint samplesRecorded = 0;
// Loop through each note
for (int i = 0; i < tetrisNoteSequence.Length; i++)
{
// The "angle" used in the function, adjusted for the number of channels and sample rate.
// This value is like the period of the wave.
double t = (Math.PI * 2 * tetrisNoteSequence[i]) / (format.dwSamplesPerSec * format.wChannels);
// The length in samples of the note
uint noteLengthSamples = (uint)(format.dwSamplesPerSec * format.wChannels * tetrisNoteLength[i]);
uint endTheNoteHere = samplesRecorded + noteLengthSamples;
for (uint j = samplesRecorded; j < endTheNoteHere - 1; j++)
{
// Convert to int16
short conv = Convert.ToInt16(amplitude * Math.Sin(t * j));
// Fill with a simple sine wave at max amplitude
for (int channel = 0; channel < format.wChannels; channel++)
{
data.shortArray[j + channel] = conv;
}
}
samplesRecorded += noteLengthSamples;
}
// Calculate data chunk size in bytes
data.dwChunkSize = (uint)(data.shortArray.Length * (format.wBitsPerSample / 8));
break;
}
case WaveExampleType.MessingWave:
{
// Number of samples = sample rate * channels * bytes per sample * seconds
uint numSamples = format.dwSamplesPerSec * format.wChannels * 40;
// Initialize the 16-bit array
data.shortArray = new short[numSamples];
int amplitude = 32760; // Max amplitude for 16-bit audio
double freq = 20.0f; // Concert A: 440Hz
double hz = 0.0009;
// Stereo volume interleave
double stereoInterleaveFreq = 0.5f;
// Channel amplitudes
double c = (Math.PI * 2 * stereoInterleaveFreq) / (format.dwSamplesPerSec * format.wChannels);
for (uint i = 0; i < numSamples - 1; i++)
{
// The "angle" used in the function, adjusted for the number of channels and sample rate.
// This value is like the period of the wave.
double t = (Math.PI * 2 * freq) / (format.dwSamplesPerSec * format.wChannels);
double s = Math.Sin(t * i);
double d = Math.Sin(c * i);
double channelAmp = amplitude * d;
// Fill with a simple sine wave at max amplitude
var sound = Convert.ToInt16(channelAmp * s);
data.shortArray[i] = sound; // Channel 1
data.shortArray[i + 1] = sound; // Channel 2
freq += hz;
}
// Calculate data chunk size in bytes
data.dwChunkSize = (uint)(data.shortArray.Length * (format.wBitsPerSample / 8));
break;
}
case WaveExampleType.MonoWave:
{
// Number of samples = sample rate * channels * bytes per sample
uint numSamples = format.dwSamplesPerSec * format.wChannels;
// Initialize the 16-bit array
data.shortArray = new short[numSamples];
int amplitude = 32760; // Max amplitude for 16-bit audio
double freq = 40.0f; // Concert A: 440Hz
// The "angle" used in the function, adjusted for the number of channels and sample rate.
// This value is like the period of the wave.
double t = (Math.PI * 2 * freq) / (format.dwSamplesPerSec * format.wChannels);
for (uint i = 0; i < numSamples - 1; i++)
{
// Fill with a simple sine wave at max amplitude
for (int channel = 0; channel < format.wChannels; channel++)
{
data.shortArray[i + channel] = Convert.ToInt16(amplitude * Math.Sin(t * i));
}
}
// Calculate data chunk size in bytes
data.dwChunkSize = (uint)(data.shortArray.Length * (format.wBitsPerSample / 8));
break;
}
}
}
