int RageSoundReader_Chain::ReadBlock( int16_t *pBuffer, int iFrames )
{
/* How many samples should we read before we need to start up a sound? */
int iFramesToRead = INT_MAX;
if( m_iNextSound < m_Sounds.size() )
{
int iStartFrame = m_iCurrentFrame;
int iOffsetFrame = m_Sounds[m_iNextSound].GetOffsetFrame(m_iActualSampleRate);
ASSERT_M( iOffsetFrame >= iStartFrame, ssprintf("%i %i", iOffsetFrame, iStartFrame) );
iFramesToRead = iOffsetFrame - iStartFrame;
}
iFramesToRead = min( iFramesToRead, iFrames );
if( iFramesToRead > 0 && m_apActiveSounds.size() == 1 &&
m_apActiveSounds.front().fPan == 0 &&
m_apActiveSounds.front().pSound->GetNumChannels() == m_iChannels &&
m_apActiveSounds.front().pSound->GetSampleRate() == m_iActualSampleRate )
{
/* We have only one source, and it matches our target. Don't mix; read
* directly from the source into the destination. This is to optimize
* the common case of having one BGM track and no autoplay sounds. */
int iBytes = m_apActiveSounds.front().pSound->Read( (char *) pBuffer, iFramesToRead * sizeof(int16_t) * m_iChannels );
if( iBytes == 0 )
ReleaseSound( 0 );
return iBytes / (sizeof(int16_t) * m_iChannels);
}
if( iFramesToRead > 0 && !m_apActiveSounds.empty() )
{
RageSoundMixBuffer mix;
/* Read iFramesToRead from each sound. */
int16_t Buffer[2048];
iFramesToRead = min( iFramesToRead, 1024 );
int iMaxFramesRead = 0;
for( unsigned i = 0; i < m_apActiveSounds.size(); )
{
ActiveSound &s = m_apActiveSounds[i];
SoundReader *pSound = s.pSound;
int iSamples = min( iFramesToRead * pSound->GetNumChannels(), ARRAYLEN(Buffer) );
int iBytesRead = pSound->Read( (char *) Buffer, iSamples*sizeof(int16_t) );
if( iBytesRead == -1 || iBytesRead == 0 )
{
/* The sound is at EOF. Release it. */
ReleaseSound( i );
continue;
}
int iSamplesRead = iBytesRead / sizeof(int16_t);
int iFramesRead = iSamplesRead / pSound->GetNumChannels();
iMaxFramesRead = max( iMaxFramesRead, iFramesRead );
if( m_iChannels == 2 && pSound->GetNumChannels() == 1 )
{
RageSoundUtil::ConvertMonoToStereoInPlace( Buffer, iSamplesRead );
iSamplesRead *= 2;
}
if( fabsf(s.fPan) > 0.0001f )
RageSoundUtil::Pan( Buffer, iFramesRead, s.fPan );
mix.write( Buffer, iSamplesRead );
++i;
}
/* Read mixed frames into the output buffer. */
mix.read( (int16_t *) pBuffer );
return iMaxFramesRead;
}
/* If we have more sounds ahead of us, pretend we read the entire block, since
* there's silence in between. Otherwise, we're at EOF. */
if( iFramesToRead > 0 )
{
memset( pBuffer, 0, iFramesToRead * m_iChannels * sizeof(int16_t) );
return iFramesToRead;
}
return 0;
}
