/// <summary>
/// Initialize the sound buffer with a <see cref="SoundDecoder"/>.
/// </summary>
/// <param name="decoder"><see cref="SoundDecoder"/> containing audio information and sample to fill the current buffer.</param>
private void Initialize(SoundDecoder decoder)
{
// Retrieve the decoder
Decoder = decoder;
// Retrieve sound parameters
SampleCount = decoder.SampleCount;
ChannelCount = decoder.ChannelCount;
SampleRate = decoder.SampleRate;
// Compute duration
Duration = TimeSpan.FromSeconds((float)SampleCount / SampleRate / ChannelCount);
// Fill entire buffer immediately if its a sample mode
if (Mode == BufferMode.Sample)
{
// Create the buffer handle
Handle = ALChecker.Check(() => AL.GenBuffer());
// Decode the samples
var samples = new short[SampleCount];
if (decoder.Decode(samples, SampleCount) == SampleCount)
{
// Update the internal buffer with the new samples
LoadBuffer(samples, ChannelCount, SampleRate);
}
else
{
throw new Exception("Failed to initialize Sample Buffer");
}
}
}
protected override bool GetStreamData(out short[] samples)
{
// Now, lock with sound object instead since the decoder / underlying stream can be shared among other SoundStream instances
// This will guarantee that none but this SoundStream that has access to the decoder / underlying stream
lock (Buffer)
{
// Initialize the number of sample should be read into buffer
int sampleCount = ChannelCount * SampleRate;
// Rebuild the given samples
samples = new short[sampleCount];
// Now, the decoder and / or the underlying stream instance can be shared among existing instances of SoundStream
// In this case, decoder offset might have been changed / moved somewhere else by another instance due to decoding process that advance the offset.
// So we need to track the offset, restore it before decoding the sample and keep tracking it after decoding process finish
decoder.Seek(offset);
// Decode the audio sample
long read = decoder.Decode(samples, sampleCount);
// Track the offset in case it modified by another instance of sound stream
offset = decoder.SampleOffset;
// Trim samples to the number of sample actually read
// otherwise, the sound may have extended duration which will make an empty gap for looping sound.
samples = read != samples.Length ? samples.Take((int)read).ToArray() : samples;
// Tell whether any data left to stream
return(read == sampleCount);
}
}