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 AudioParam_h
30#define AudioParam_h
31
32#include "bindings/v8/ScriptWrappable.h"
33#include "modules/webaudio/AudioContext.h"
34#include "modules/webaudio/AudioParamTimeline.h"
35#include "modules/webaudio/AudioSummingJunction.h"
36#include <sys/types.h>
37#include "wtf/Float32Array.h"
38#include "wtf/PassRefPtr.h"
39#include "wtf/RefCounted.h"
40#include "wtf/text/WTFString.h"
41
42namespace WebCore {
43
44class AudioNodeOutput;
45
46class AudioParam : public RefCounted<AudioParam>, public ScriptWrappable, public AudioSummingJunction {
47public:
48    static const double DefaultSmoothingConstant;
49    static const double SnapThreshold;
50
51    static PassRefPtr<AudioParam> create(AudioContext* context, const String& name, double defaultValue, double minValue, double maxValue, unsigned units = 0)
52    {
53        return adoptRef(new AudioParam(context, name, defaultValue, minValue, maxValue, units));
54    }
55
56    // AudioSummingJunction
57    virtual bool canUpdateState() OVERRIDE { return true; }
58    virtual void didUpdate() OVERRIDE { }
59
60    // Intrinsic value.
61    float value();
62    void setValue(float);
63
64    // Final value for k-rate parameters, otherwise use calculateSampleAccurateValues() for a-rate.
65    // Must be called in the audio thread.
66    float finalValue();
67
68    String name() const { return m_name; }
69
70    float minValue() const { return static_cast<float>(m_minValue); }
71    float maxValue() const { return static_cast<float>(m_maxValue); }
72    float defaultValue() const { return static_cast<float>(m_defaultValue); }
73    unsigned units() const { return m_units; }
74
75    // Value smoothing:
76
77    // When a new value is set with setValue(), in our internal use of the parameter we don't immediately jump to it.
78    // Instead we smoothly approach this value to avoid glitching.
79    float smoothedValue();
80
81    // Smoothly exponentially approaches to (de-zippers) the desired value.
82    // Returns true if smoothed value has already snapped exactly to value.
83    bool smooth();
84
85    void resetSmoothedValue() { m_smoothedValue = m_value; }
86    void setSmoothingConstant(double k) { m_smoothingConstant = k; }
87
88    // Parameter automation.
89    void setValueAtTime(float value, double time) { m_timeline.setValueAtTime(value, time); }
90    void linearRampToValueAtTime(float value, double time) { m_timeline.linearRampToValueAtTime(value, time); }
91    void exponentialRampToValueAtTime(float value, double time) { m_timeline.exponentialRampToValueAtTime(value, time); }
92    void setTargetAtTime(float target, double time, double timeConstant) { m_timeline.setTargetAtTime(target, time, timeConstant); }
93    void setValueCurveAtTime(Float32Array* curve, double time, double duration) { m_timeline.setValueCurveAtTime(curve, time, duration); }
94    void cancelScheduledValues(double startTime) { m_timeline.cancelScheduledValues(startTime); }
95
96    bool hasSampleAccurateValues() { return m_timeline.hasValues() || numberOfRenderingConnections(); }
97
98    // Calculates numberOfValues parameter values starting at the context's current time.
99    // Must be called in the context's render thread.
100    void calculateSampleAccurateValues(float* values, unsigned numberOfValues);
101
102    // Connect an audio-rate signal to control this parameter.
103    void connect(AudioNodeOutput*);
104    void disconnect(AudioNodeOutput*);
105
106protected:
107    AudioParam(AudioContext* context, const String& name, double defaultValue, double minValue, double maxValue, unsigned units = 0)
108        : AudioSummingJunction(context)
109        , m_name(name)
110        , m_value(defaultValue)
111        , m_defaultValue(defaultValue)
112        , m_minValue(minValue)
113        , m_maxValue(maxValue)
114        , m_units(units)
115        , m_smoothedValue(defaultValue)
116        , m_smoothingConstant(DefaultSmoothingConstant)
117    {
118        ScriptWrappable::init(this);
119    }
120
121private:
122    // sampleAccurate corresponds to a-rate (audio rate) vs. k-rate in the Web Audio specification.
123    void calculateFinalValues(float* values, unsigned numberOfValues, bool sampleAccurate);
124    void calculateTimelineValues(float* values, unsigned numberOfValues);
125
126    String m_name;
127    double m_value;
128    double m_defaultValue;
129    double m_minValue;
130    double m_maxValue;
131    unsigned m_units;
132
133    // Smoothing (de-zippering)
134    double m_smoothedValue;
135    double m_smoothingConstant;
136
137    AudioParamTimeline m_timeline;
138};
139
140} // namespace WebCore
141
142#endif // AudioParam_h
143