third_party/WebKit/Source/platform/audio/Cone.cpp

   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;
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  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 "platform/audio/Cone.h"
  34 #include "wtf/MathExtras.h"
  35
  36 namespace blink {
  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     // Source-listener vector
  51     FloatPoint3D sourceToListener = listenerPosition - sourcePosition;
  52
  53     // Angle between the source orientation vector and the source-listener vector
  54     double angle = rad2deg(sourceToListener.angleBetween(sourceOrientation));
  55     double absAngle = fabs(angle);
  56
  57     // Divide by 2.0 here since API is entire angle (not half-angle)
  58     double absInnerAngle = fabs(m_innerAngle) / 2.0;
  59     double absOuterAngle = fabs(m_outerAngle) / 2.0;
  60     double gain = 1.0;
  61
  62     if (absAngle <= absInnerAngle)
  63         // No attenuation
  64         gain = 1.0;
  65     else if (absAngle >= absOuterAngle)
  66         // Max attenuation
  67         gain = m_outerGain;
  68     else {
  69         // Between inner and outer cones
  70         // inner -> outer, x goes from 0 -> 1
  71         double x = (absAngle - absInnerAngle) / (absOuterAngle - absInnerAngle);
  72         gain = (1.0 - x) + m_outerGain * x;
  73     }
  74
  75     return gain;
  76 }
  77
  78 } // namespace blink
  79
  80 #endif // ENABLE(WEB_AUDIO)