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      1 /*
      2  * Copyright (C) 2010 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  *
      8  * 1.  Redistributions of source code must retain the above copyright
      9  *     notice, this list of conditions and the following disclaimer.
     10  * 2.  Redistributions in binary form must reproduce the above copyright
     11  *     notice, this list of conditions and the following disclaimer in the
     12  *     documentation and/or other materials provided with the distribution.
     13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
     14  *     its contributors may be used to endorse or promote products derived
     15  *     from this software without specific prior written permission.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
     18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
     21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #include "config.h"
     30 
     31 #if ENABLE(WEB_AUDIO)
     32 
     33 #include "Cone.h"
     34 #include <wtf/MathExtras.h>
     35 
     36 namespace WebCore {
     37 
     38 ConeEffect::ConeEffect()
     39     : m_innerAngle(360.0)
     40     , m_outerAngle(360.0)
     41     , m_outerGain(0.0)
     42 {
     43 }
     44 
     45 double ConeEffect::gain(FloatPoint3D sourcePosition, FloatPoint3D sourceOrientation, FloatPoint3D listenerPosition)
     46 {
     47     if (sourceOrientation.isZero() || ((m_innerAngle == 360.0) && (m_outerAngle == 360.0)))
     48         return 1.0; // no cone specified - unity gain
     49 
     50     // Normalized source-listener vector
     51     FloatPoint3D sourceToListener = listenerPosition - sourcePosition;
     52     sourceToListener.normalize();
     53 
     54     FloatPoint3D normalizedSourceOrientation = sourceOrientation;
     55     normalizedSourceOrientation.normalize();
     56 
     57     // Angle between the source orientation vector and the source-listener vector
     58     double dotProduct = sourceToListener.dot(normalizedSourceOrientation);
     59     double angle = 180.0 * acos(dotProduct) / piDouble;
     60     double absAngle = fabs(angle);
     61 
     62     // Divide by 2.0 here since API is entire angle (not half-angle)
     63     double absInnerAngle = fabs(m_innerAngle) / 2.0;
     64     double absOuterAngle = fabs(m_outerAngle) / 2.0;
     65     double gain = 1.0;
     66 
     67     if (absAngle <= absInnerAngle)
     68         // No attenuation
     69         gain = 1.0;
     70     else if (absAngle >= absOuterAngle)
     71         // Max attenuation
     72         gain = m_outerGain;
     73     else {
     74         // Between inner and outer cones
     75         // inner -> outer, x goes from 0 -> 1
     76         double x = (absAngle - absInnerAngle) / (absOuterAngle - absInnerAngle);
     77         gain = (1.0 - x) + m_outerGain * x;
     78     }
     79 
     80     return gain;
     81 }
     82 
     83 } // namespace WebCore
     84 
     85 #endif // ENABLE(WEB_AUDIO)
     86