/// <summary>
/// 在指定的声道生成指定持续时间的具有指定波形参数的波形声音，并输出到指定的波形声音流。
/// </summary>
/// <param name="waveWriter">要输出波形的流。</param>
/// <param name="parameters">波形声音的参数。</param>
/// <param name="channelEnables">指定输出声音的声道。</param>
/// <param name="durationSeconds">波形声音的持续时间。</param>
/// <exception cref="ArgumentNullException"><paramref name="waveWriter"/>
/// 或 <paramref name="channelEnables"/> 为 <see langword="null"/>，
/// 或 <paramref name="parameters"/> 为默认值。</exception>
/// <exception cref="ArgumentOutOfRangeException">
/// <paramref name="durationSeconds"/> 为负数，或枚举值不为定义的值。</exception>
/// <exception cref="ArgumentException">
/// <paramref name="channelEnables"/> 的数量与声道数量不匹配。</exception>
public static void GenerateWave(WaveStreamWriter waveWriter,
WaveformParameters parameters, bool[] channelEnables, double durationSeconds)
{
if (waveWriter is null)
{
throw new ArgumentNullException(nameof(waveWriter));
}
if (channelEnables is null)
{
throw new ArgumentNullException(nameof(channelEnables));
}
if (parameters == default)
{
throw new ArgumentNullException(nameof(parameters));
}
if (durationSeconds < 0.0)
{
throw new ArgumentOutOfRangeException(nameof(durationSeconds));
}
if (channelEnables.Length != (int)waveWriter.Channels)
{
throw new ArgumentException(
new ArgumentException().Message, nameof(channelEnables));
}
var peek = parameters.Amplitude;
switch (waveWriter.BitDepth)
{
case WaveBitDepth.Bit8: peek *= sbyte.MaxValue; break;
case WaveBitDepth.Bit16: peek *= short.MaxValue; break;
case WaveBitDepth.Bit24: peek *= Int24.MaxValue; break;
case WaveBitDepth.Bit32:
switch (waveWriter.Format)
{
case WaveFormat.PCM: peek *= int.MaxValue; break;
case WaveFormat.IEEEFloat: peek *= 1.0; break;
default: throw new ArgumentOutOfRangeException();
}
break;
default: throw new ArgumentOutOfRangeException();
}
var count = (int)(durationSeconds * (int)waveWriter.SampleRate);
var waveFunc = default(WaveformFunction);
switch (parameters.Waveform)
{
case Waveform.Sine: waveFunc = WaveformFunctions.Sine; break;
case Waveform.Square: waveFunc = WaveformFunctions.Square; break;
case Waveform.Triangle: waveFunc = WaveformFunctions.Triangle; break;
case Waveform.Sawtooth: waveFunc = WaveformFunctions.Sawtooth; break;
default: throw new ArgumentOutOfRangeException();
}
for (int i = 0; i < count; i++)
{
var channels = (int)waveWriter.Channels;
var amplitude = parameters.Amplitude * peek;
var frequency = parameters.Frequency;
var time = (double)i / (int)waveWriter.SampleRate;
var value = waveFunc(amplitude, frequency, time);
var sample = default(WaveSample);
switch (waveWriter.BitDepth)
{
case WaveBitDepth.Bit8:
sample = WaveSample.Int8(channels.InitializeArray(
channel => (byte)((channelEnables[channel] ? value : 0.0) - sbyte.MinValue)));
break;
case WaveBitDepth.Bit16:
sample = WaveSample.Int16(channels.InitializeArray(
channel => (short)(channelEnables[channel] ? value : 0.0)));
break;
case WaveBitDepth.Bit24:
sample = WaveSample.Int24(channels.InitializeArray(
channel => (Int24)(channelEnables[channel] ? value : 0.0)));
break;
case WaveBitDepth.Bit32:
switch (waveWriter.Format)
{
case WaveFormat.PCM:
sample = WaveSample.Int32(channels.InitializeArray(
channel => (int)(channelEnables[channel] ? value : 0.0)));
break;
case WaveFormat.IEEEFloat:
sample = WaveSample.Float32(channels.InitializeArray(
channel => (float)(channelEnables[channel] ? value : 0.0)));
break;
default:
throw new ArgumentOutOfRangeException();
}
break;
default:
throw new ArgumentOutOfRangeException();
}
waveWriter.WriteSample(sample);
}
waveWriter.UpdateChunkSize();
}
/// <summary>
/// 生成指定持续时间的具有指定波形参数的波形声音，并输出到指定的波形声音流。
/// </summary>
/// <param name="waveWriter">要输出波形的流。</param>
/// <param name="parameters">波形声音的参数。</param>
/// <param name="durationSeconds">波形声音的持续时间。</param>
/// <exception cref="ArgumentNullException">
/// <paramref name="waveWriter"/> 为 <see langword="null"/>，
/// 或 <paramref name="parameters"/> 为默认值。</exception>
/// <exception cref="ArgumentOutOfRangeException">
/// <paramref name="durationSeconds"/> 为负数，或枚举值不为定义的值。</exception>
public static void GenerateWave(WaveStreamWriter waveWriter,
WaveformParameters parameters, double durationSeconds)
{
WaveformGenerator.GenerateWave(waveWriter, parameters,
((int)waveWriter.Channels).InitializeArray(_ => true), durationSeconds);
}