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
34namespace 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
39class PLATFORM_EXPORT DistanceEffect {
40public:
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
69protected:
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
84