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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"
44 class AudioNodeOutput;
46 class AudioParam FINAL : public RefCountedWillBeGarbageCollectedFinalized<AudioParam>, public ScriptWrappable, public AudioSummingJunction {
48 static const double DefaultSmoothingConstant;
49 static const double SnapThreshold;
51 static PassRefPtrWillBeRawPtr<AudioParam> create(AudioContext* context, const String& name, double defaultValue, double minValue, double maxValue, unsigned units = 0)
53 return adoptRefWillBeNoop(new AudioParam(context, name, defaultValue, minValue, maxValue, units));
56 // AudioSummingJunction
57 virtual bool canUpdateState() OVERRIDE { return true; }
58 virtual void didUpdate() OVERRIDE { }
64 // Final value for k-rate parameters, otherwise use calculateSampleAccurateValues() for a-rate.
65 // Must be called in the audio thread.
68 String name() const { return m_name; }
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; }
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();
81 // Smoothly exponentially approaches to (de-zippers) the desired value.
82 // Returns true if smoothed value has already snapped exactly to value.
85 void resetSmoothedValue() { m_smoothedValue = m_value; }
87 // Parameter automation.
88 void setValueAtTime(float value, double time) { m_timeline.setValueAtTime(value, time); }
89 void linearRampToValueAtTime(float value, double time) { m_timeline.linearRampToValueAtTime(value, time); }
90 void exponentialRampToValueAtTime(float value, double time, ExceptionState& es) { m_timeline.exponentialRampToValueAtTime(value, time, es); }
91 void setTargetAtTime(float target, double time, double timeConstant) { m_timeline.setTargetAtTime(target, time, timeConstant); }
92 void setValueCurveAtTime(Float32Array* curve, double time, double duration) { m_timeline.setValueCurveAtTime(curve, time, duration); }
93 void cancelScheduledValues(double startTime) { m_timeline.cancelScheduledValues(startTime); }
95 bool hasSampleAccurateValues() { return m_timeline.hasValues() || numberOfRenderingConnections(); }
97 // Calculates numberOfValues parameter values starting at the context's current time.
98 // Must be called in the context's render thread.
99 void calculateSampleAccurateValues(float* values, unsigned numberOfValues);
101 // Connect an audio-rate signal to control this parameter.
102 void connect(AudioNodeOutput*);
103 void disconnect(AudioNodeOutput*);
105 void trace(Visitor*) { }
108 AudioParam(AudioContext* context, const String& name, double defaultValue, double minValue, double maxValue, unsigned units = 0)
109 : AudioSummingJunction(context)
111 , m_value(defaultValue)
112 , m_defaultValue(defaultValue)
113 , m_minValue(minValue)
114 , m_maxValue(maxValue)
116 , m_smoothedValue(defaultValue)
118 ScriptWrappable::init(this);
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);
128 double m_defaultValue;
133 // Smoothing (de-zippering)
134 double m_smoothedValue;
136 AudioParamTimeline m_timeline;
139 } // namespace WebCore
141 #endif // AudioParam_h