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  * 1.  Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2.  Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND
14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16  * ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE
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24  */
25 
26 #ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_EQUAL_POWER_PANNER_H_
27 #define THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_EQUAL_POWER_PANNER_H_
28 
29 #include "third_party/blink/renderer/platform/audio/panner.h"
30 
31 namespace blink {
32 
33 // Common type of stereo panner as found in normal audio mixing equipment.
34 
35 class PLATFORM_EXPORT EqualPowerPanner final : public Panner {
36  public:
37   EqualPowerPanner(float sample_rate);
38 
39   void Pan(double azimuth,
40            double elevation,
41            const AudioBus* input_bus,
42            AudioBus* output_buf,
43            uint32_t frames_to_process,
44            AudioBus::ChannelInterpretation) override;
45   void PanWithSampleAccurateValues(double* azimuth,
46                                    double* elevation,
47                                    const AudioBus* input_bus,
48                                    AudioBus* output_bus,
49                                    uint32_t frames_to_process,
50                                    AudioBus::ChannelInterpretation) override;
51 
Reset()52   void Reset() override {}
53 
TailTime()54   double TailTime() const override { return 0; }
LatencyTime()55   double LatencyTime() const override { return 0; }
RequiresTailProcessing()56   bool RequiresTailProcessing() const override { return false; }
57 
58  private:
59   void CalculateDesiredGain(double& desired_gain_l,
60                             double& desired_gain_r,
61                             double azimuth,
62                             int number_of_channels);
63 };
64 
65 }  // namespace blink
66 
67 #endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_EQUAL_POWER_PANNER_H_
68