third_party/WebKit/Source/platform/audio/Distance.h

   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 #ifndef Distance_h
  30 #define Distance_h
  31
  32 #include "platform/PlatformExport.h"
  33
  34 namespace blink {
  35
  36 // Distance models are defined according to the OpenAL specification:
  37 // http://connect.creativelabs.com/openal/Documentation/OpenAL%201.1%20Specification.htm.
  38
  39 class PLATFORM_EXPORT DistanceEffect {
  40 public:
  41     enum ModelType {
  42         ModelLinear = 0,
  43         ModelInverse = 1,
  44         ModelExponential = 2
  45     };
  46
  47     DistanceEffect();
  48
  49     // Returns scalar gain for the given distance the current distance model is used
  50     double gain(double distance);
  51
  52     ModelType model() { return m_model; }
  53
  54     void setModel(ModelType model, bool clamped)
  55     {
  56         m_model = model;
  57         m_isClamped = clamped;
  58     }
  59
  60     // Distance params
  61     void setRefDistance(double refDistance) { m_refDistance = refDistance; }
  62     void setMaxDistance(double maxDistance) { m_maxDistance = maxDistance; }
  63     void setRolloffFactor(double rolloffFactor) { m_rolloffFactor = rolloffFactor; }
  64
  65     double refDistance() const { return m_refDistance; }
  66     double maxDistance() const { return m_maxDistance; }
  67     double rolloffFactor() const { return m_rolloffFactor; }
  68
  69 protected:
  70     double linearGain(double distance);
  71     double inverseGain(double distance);
  72     double exponentialGain(double distance);
  73
  74     ModelType m_model;
  75     bool m_isClamped;
  76     double m_refDistance;
  77     double m_maxDistance;
  78     double m_rolloffFactor;
  79 };
  80
  81 } // namespace blink
  82
  83 #endif // Distance_h