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