From 3551367fe412fabf12e01ff4fba821dcd8d723fb Mon Sep 17 00:00:00 2001
From: Glenn Maynard <gmaynard@users.sourceforge.net>
Date: Wed, 27 Dec 2006 09:19:02 +0000
Subject: [PATCH] These attempt to flush buffers and go back to reading
 directly if ratios are set back to 1.  They don't work; the speed shift
 buffer won't line up perfectly for all channels, and the resampler would need
 to be lined up with the window and lerped.  Make these only read directly if
 the buffers are empty, so these filters are cheap if their ratios are never
 used.  Fixes clicks when moving the ratio around 1.0.

---
 .../src/RageSoundReader_Resample_Good.cpp     | 47 +------------------
 stepmania/src/RageSoundReader_SpeedChange.cpp |  2 +-
 2 files changed, 2 insertions(+), 47 deletions(-)

diff --git a/stepmania/src/RageSoundReader_Resample_Good.cpp b/stepmania/src/RageSoundReader_Resample_Good.cpp
index 843ab9cf70..67cbebe687 100644
--- a/stepmania/src/RageSoundReader_Resample_Good.cpp
+++ b/stepmania/src/RageSoundReader_Resample_Good.cpp
@@ -204,7 +204,6 @@ struct PolyphaseFilter
 	void Generate( const float *pFIR );
 	int RunPolyphaseFilter( State &State, const float *pIn, int iSamplesIn, int iDownFactor,
 			float *pOut, int iSamplesOut ) const;
-	int ReadBuffer( State &State, float *pOut, int iSamplesOut ) const;
 	int GetLatency() const { return L/2; }
 
 	int NumInputsForOutputSamples( const State &State, int iOut, int iDownFactor ) const;
@@ -345,24 +344,6 @@ int PolyphaseFilter::RunPolyphaseFilter(
 	return pOut - pOutOrig;
 }
 
-int PolyphaseFilter::ReadBuffer( State &State, float *pOut, int iSamplesOut ) const
-{
-	float *pOutOrig = pOut;
-	
-	while( State.m_iFilled && iSamplesOut-- )
-	{
-		*pOut = State.m_fBuf[State.m_iBufNext];
-		++pOut;
-		--State.m_iFilled;
-
-		float fRot = State.m_fBuf[0];
-		memmove( State.m_fBuf, State.m_fBuf+1, ((L*2)-1) * sizeof(float) );
-		State.m_fBuf[L*2-1] = fRot;
-	}
-
-	return pOut - pOutOrig;
-}
-
 /*
  * Return the number of input samples needed to produce the given number of output
  * samples.  This is dependent on the number of bytes in the buffer and the current
@@ -513,11 +494,6 @@ public:
 		return m_pPolyphase->RunPolyphaseFilter( *m_pState, pIn, iSamplesIn, m_iDownFactor, pOut, iSamplesOut );
 	}
 
-	int FlushBuffer( float *pOut, int iSamplesOut ) const
-	{
-		return m_pPolyphase->ReadBuffer( *m_pState, pOut, iSamplesOut );
-	}
-
 	void Reset()
 	{
 		delete m_pState;
@@ -684,29 +660,8 @@ int RageSoundReader_Resample_Good::Read( char *pBuf_, int iFrames )
 	int iDownFactor, iUpFactor;
 	GetFactors( iDownFactor, iUpFactor );
 
-	if( iDownFactor == iUpFactor && m_fRate == 1.0f )
-	{
-		/* Before reading directly, flush the data from the polyphase filters. */
-		if( m_apResamplers[0]->GetFilled() )
-		{
-			float *pFloatOut = (float *) alloca( iFrames * sizeof(float) );
-			for( int iChannel = 0; iChannel < iChannels; ++iChannel )
-			{
-				int iGotFrames = m_apResamplers[iChannel]->FlushBuffer( pFloatOut, iFrames );
-				ASSERT( iGotFrames <= iFrames );
-
-				for( int i = 0; i < iGotFrames; ++i )
-					pBuf[i*iChannels+iChannel] = int16_t(lrintf(clamp(pFloatOut[i], -32768, 32767)));
-				if( iChannel == 0 )
-					iFramesRead += iGotFrames;
-			}
-			
-			return iFramesRead;
-		}
-
-		// XXX: errors
+	if( m_apResamplers[0]->GetFilled() == 0 && iDownFactor == iUpFactor && m_fRate == 1.0f )
 		return m_pSource->Read( pBuf_, iFrames );
-	}
 
 	{
 		int iFramesNeeded = m_apResamplers[0]->NumInputsForOutputSamples(iFrames);
diff --git a/stepmania/src/RageSoundReader_SpeedChange.cpp b/stepmania/src/RageSoundReader_SpeedChange.cpp
index 79d3a2a552..6d0c8d5591 100644
--- a/stepmania/src/RageSoundReader_SpeedChange.cpp
+++ b/stepmania/src/RageSoundReader_SpeedChange.cpp
@@ -242,7 +242,7 @@ int RageSoundReader_SpeedChange::Read( char *buf, int iFrames )
 		// m_iDataBufferAvailFrames-m_iCorrelatedPos < GetWindowSizeFrames when flushing
 		int iCursorAvail = GetCursorAvail();
 
-		if( iCursorAvail == 0 && m_fTrailingSpeedRatio == m_fSpeedRatio && m_fSpeedRatio == 1.0f )
+		if( m_iDataBufferAvailFrames == 0 && m_fTrailingSpeedRatio == m_fSpeedRatio && m_fSpeedRatio == 1.0f )
 		{
 			/* Fast path: the buffer is empty, and we're not scaling the audio.  Read directly
 			 * into the output buffer, to eliminate memory and copying overhead. */