Files
lmms/plugins/Delay/StereoDelay.cpp
Dave French b432707b9b Remove glitching from the Flanger and Delay plugins (#3524)
The previous delay code was incorrectly not utalising the whole buffer, causing glitches when
incressing the delay time, due to outputting incorrect data, This was apparent when using the
lfo in the Delay and Flanger plugins.

This has been rectified. The read index is now offset from the write index. and the complete buffer is used in a circular fashon.

Flanger - resolved issue where the lfo could create negative delay lengths
2017-05-17 12:18:47 +02:00

97 lines
2.1 KiB
C++

/*
* stereodelay.cpp - defination of StereoDelay class.
*
* Copyright (c) 2014 David French <dave/dot/french3/at/googlemail/dot/com>
*
* This file is part of LMMS - https://lmms.io
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program (see COPYING); if not, write to the
* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301 USA.
*
*/
#include "StereoDelay.h"
#include <cstdlib>
#include "lmms_basics.h"
#include "interpolation.h"
#include "lmms_math.h"
StereoDelay::StereoDelay( int maxTime, int sampleRate )
{
m_buffer = 0;
m_maxTime = maxTime;
m_maxLength = maxTime * sampleRate;
m_length = m_maxLength;
m_writeIndex = 0;
m_feedback = 0.0f;
setSampleRate( sampleRate );
}
StereoDelay::~StereoDelay()
{
if( m_buffer )
{
delete[] m_buffer;
}
}
void StereoDelay::tick( sampleFrame frame )
{
m_writeIndex = ( m_writeIndex + 1 ) % ( int )m_maxLength;
int readIndex = m_writeIndex - m_length;
if (readIndex < 0 ) { readIndex += m_maxLength; }
float lOut = m_buffer[ readIndex ][ 0 ];
float rOut = m_buffer[ readIndex ] [1 ];
m_buffer[ m_writeIndex ][ 0 ] = frame[ 0 ] + ( lOut * m_feedback );
m_buffer[ m_writeIndex ][ 1 ] = frame[ 1 ] + ( rOut * m_feedback );
frame[ 0 ] = lOut;
frame[ 1 ] = rOut;
}
void StereoDelay::setSampleRate( int sampleRate )
{
if( m_buffer )
{
delete[] m_buffer;
}
int bufferSize = ( int )( sampleRate * m_maxTime );
m_buffer = new sampleFrame[bufferSize];
for( int i = 0 ; i < bufferSize ; i++)
{
m_buffer[i][0] = 0.0;
m_buffer[i][1] = 0.0;
}
}