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
32namespace WebCore {
33
34// Distance models are defined according to the OpenAL specification
35
36class DistanceEffect {
37public:
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
66protected:
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