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