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/*
$Id: fadefilter_generic.cpp,v 1.1 2001/03/06 15:09:26 mbn Exp $
------------------------------------------------------------------------
ClanLib, the platform independent game SDK.
This library is distributed under the GNU LIBRARY GENERAL PUBLIC LICENSE
version 2. See COPYING for details.
For a total list of contributers see CREDITS.
------------------------------------------------------------------------
*/
#ifdef WIN32
#pragma warning (disable:4786)
#endif
#include "fadefilter_generic.h"
CL_FadeFilter::CL_FadeFilter(int initial_volume)
{
impl = new CL_FadeFilter_Generic;
impl->cur_volume = initial_volume/100.0f;
impl->new_volume = initial_volume/100.0f;
impl->speed = 0;
}
CL_FadeFilter::~CL_FadeFilter()
{
delete impl;
}
void CL_FadeFilter::fade_to_volume(int new_volume, int duration)
{
impl->new_volume = new_volume/100.0f;
float delta_volume = impl->new_volume - impl->cur_volume;
impl->speed = delta_volume / 22.05f / duration;
}
void CL_FadeFilter::filter(int *data, int size)
{
float &cur_volume = impl->cur_volume;
float &new_volume = impl->new_volume;
float &speed = impl->speed;
for (int i=0; i<size*2; i++)
{
data[i] = (int) (data[i] * cur_volume);
if ((i&1) == 1) // change volume for every second sample (because data is in stereo).
{
cur_volume += speed;
if (
(speed > 0 && cur_volume > new_volume) ||
(speed < 0 && cur_volume < new_volume))
{
cur_volume = new_volume;
speed = 0;
}
}
}
}
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