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/* libClunk - cross-platform 3D audio API built on top SDL library
* Copyright (C) 2007-2008 Netive Media Group
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "distance_model.h"
#define _USE_MATH_DEFINES
#include <math.h>
float clunk::DistanceModel::gain(float distance) const {
float gain = 0;
distance /= distance_divisor;
switch(type) {
case Inverse:
if (clamped) {
if (distance < reference_distance)
distance = reference_distance;
if (distance > max_distance)
distance = max_distance;
}
gain = reference_distance / (reference_distance + rolloff_factor * (distance - reference_distance));
break;
case Linear:
if (clamped && distance < reference_distance) {
distance = reference_distance;
}
if (distance > max_distance)
distance = max_distance;
gain = 1 - rolloff_factor * (distance - reference_distance) / (max_distance - reference_distance);
break;
case Exponent:
if (clamped) {
if (distance < reference_distance)
distance = reference_distance;
if (distance > max_distance)
distance = max_distance;
}
gain = powf(distance / reference_distance, - rolloff_factor);
break;
}
if (gain < 0)
gain = 0;
else if (gain > 1)
gain = 1;
return gain;
}
float clunk::DistanceModel::doppler_pitch(const v3<float> &sl, const v3<float> &s_vel, const v3<float> &l_vel) const {
if (doppler_factor <= 0)
return 1.0f;
float len = sl.length();
if (len <= 0)
return 1.0f;
float max_speed = speed_of_sound / doppler_factor;
float vls = sl.dot_product(l_vel) / len;
if (vls > max_speed)
vls = max_speed;
float vss = sl.dot_product(s_vel) / len;
if (vss > max_speed)
vss = max_speed;
return (speed_of_sound - doppler_factor * vls) / (speed_of_sound - doppler_factor * vss);
}
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