/// <summary>
/// Promotes the current channel to a stream.
/// This is necessary if the pitch is shifted, because BASS_FX only works on streams.
/// </summary>
/// <param name="volume">The stream's initial volume.</param>
/// <param name="pitch">The stream's initial pitch.</param>
/// <param name="pan">The stream's initial pan.</param>
/// <param name="loop">A value indicating whether to loop the stream.</param>
private Boolean PromoteToStream(Single volume, Single pitch, Single pan, Boolean loop)
{
if (BASSUtil.IsValidHandle(stream))
{
return(false);
}
// If the channel is currently playing, pause it.
var playing = (State == PlaybackState.Playing);
if (playing)
{
if (!BASSNative.ChannelPause(channel))
{
throw new BASSException();
}
}
// Get the current position of the playing channel so that we can advance the stream to match.
var streampos = (uint)BASSNative.ChannelGetPosition(channel, 0);
if (!BASSUtil.IsValidValue(streampos))
{
throw new BASSException();
}
// Create a process for streaming data from our sample into the new stream.
sampleDataPosition = (int)streampos;
sampleDataLength = (int)sampleInfo.length;
sampleDataStreamProc = new StreamProc((handle, buffer, length, user) =>
{
if (sampleDataPosition >= sampleDataLength)
{
sampleDataPosition = 0;
}
var byteCount = Math.Min(length, (uint)sampleDataLength - streampos);
unsafe
{
byte *pBufferSrc = (byte *)(sampleData + sampleDataPosition).ToPointer();
byte *pBufferDst = (byte *)(buffer).ToPointer();
for (int i = 0; i < byteCount; i++)
{
*pBufferDst++ = *pBufferSrc++;
}
}
sampleDataPosition += (int)byteCount;
return(streampos >= sampleDataLength ?
byteCount | BASSNative.BASS_STREAMPROC_END :
byteCount);
});
// Create a decoding stream based on our sample channel.
stream = BASSNative.StreamCreate(sampleInfo.freq, sampleInfo.chans, sampleInfo.flags | BASSNative.BASS_STREAM_DECODE, sampleDataStreamProc, IntPtr.Zero);
if (!BASSUtil.IsValidHandle(stream))
{
throw new BASSException();
}
// Create an FX stream to shift the sound effect's pitch.
stream = BASSFXNative.TempoCreate(stream, BASSNative.BASS_FX_FREESOURCE);
if (!BASSUtil.IsValidHandle(stream))
{
throw new BASSException();
}
// Set the new stream's attributes.
BASSUtil.SetVolume(stream, volume);
BASSUtil.SetPitch(stream, pitch);
BASSUtil.SetPan(stream, pan);
BASSUtil.SetIsLooping(stream, loop);
// Stop the old channel and switch to the stream.
if (!BASSNative.ChannelStop(channel))
{
throw new BASSException();
}
channel = stream;
// If we were previously playing, play the stream.
if (playing)
{
if (!BASSNative.ChannelPlay(channel, false))
{
throw new BASSException();
}
}
promoted = true;
return(true);
}
