AUD_FaderReader.cpp

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/*
 * $Id: AUD_FaderReader.cpp 35141 2011-02-25 10:21:56Z jesterking $
 *
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * Copyright 2009-2011 Jörg Hermann Müller
 *
 * This file is part of AudaSpace.
 *
 * Audaspace 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.
 *
 * AudaSpace 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 Audaspace; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include "AUD_FaderReader.h"

#include <cstring>

AUD_FaderReader::AUD_FaderReader(AUD_IReader* reader, AUD_FadeType type,
                                                                 float start,float length) :
                AUD_EffectReader(reader),
                m_type(type),
                m_start(start),
                m_length(length),
                m_empty(true)
{
}

void AUD_FaderReader::read(int & length, sample_t* & buffer)
{
        int position = m_reader->getPosition();
        AUD_Specs specs = m_reader->getSpecs();
        int samplesize = AUD_SAMPLE_SIZE(specs);

        m_reader->read(length, buffer);

        if((position + length) / (float)specs.rate <= m_start)
        {
                if(m_type != AUD_FADE_OUT)
                {
                        if(m_buffer.getSize() < length * samplesize)
                        {
                                m_buffer.resize(length * samplesize);
                                m_empty = false;
                        }

                        buffer = m_buffer.getBuffer();

                        if(!m_empty)
                        {
                                memset(buffer, 0, length * samplesize);
                                m_empty = true;
                        }
                }
        }
        else if(position / (float)specs.rate >= m_start+m_length)
        {
                if(m_type == AUD_FADE_OUT)
                {
                        if(m_buffer.getSize() < length * samplesize)
                        {
                                m_buffer.resize(length * samplesize);
                                m_empty = false;
                        }

                        buffer = m_buffer.getBuffer();

                        if(!m_empty)
                        {
                                memset(buffer, 0, length * samplesize);
                                m_empty = true;
                        }
                }
        }
        else
        {
                if(m_buffer.getSize() < length * samplesize)
                        m_buffer.resize(length * samplesize);

                sample_t* buf = m_buffer.getBuffer();
                float volume = 1.0f;

                for(int i = 0; i < length * specs.channels; i++)
                {
                        if(i % specs.channels == 0)
                        {
                                volume = (((position+i)/(float)specs.rate)-m_start) / m_length;
                                if(volume > 1.0f)
                                        volume = 1.0f;
                                else if(volume < 0.0f)
                                        volume = 0.0f;

                                if(m_type == AUD_FADE_OUT)
                                        volume = 1.0f - volume;
                        }

                        buf[i] = buffer[i] * volume;
                }

                buffer = buf;
                m_empty = false;
        }
}