dolphin/Source/Core/AudioCommon/Mixer.h

// Copyright 2009 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#pragma once

#include <array>
#include <atomic>

#include "AudioCommon/AudioStretcher.h"
#include "AudioCommon/WaveFile.h"
#include "Common/CommonTypes.h"

class Mixer final
{
public:
  explicit Mixer(unsigned int BackendSampleRate);
  ~Mixer();

  // Called from audio threads
  unsigned int Mix(short* samples, unsigned int numSamples);
  unsigned int MixSurround(float* samples, unsigned int num_samples);

  // Called from main thread
  void PushSamples(const short* samples, unsigned int num_samples);
  void PushStreamingSamples(const short* samples, unsigned int num_samples);
  void PushWiimoteSpeakerSamples(const short* samples, unsigned int num_samples,
                                 unsigned int sample_rate);
  unsigned int GetSampleRate() const { return m_sampleRate; }
  void SetDMAInputSampleRate(unsigned int rate);
  void SetStreamInputSampleRate(unsigned int rate);
  void SetStreamingVolume(unsigned int lvolume, unsigned int rvolume);
  void SetWiimoteSpeakerVolume(unsigned int lvolume, unsigned int rvolume);

  void StartLogDTKAudio(const std::string& filename);
  void StopLogDTKAudio();

  void StartLogDSPAudio(const std::string& filename);
  void StopLogDSPAudio();

  float GetCurrentSpeed() const { return m_speed.load(); }
  void UpdateSpeed(float val) { m_speed.store(val); }
private:
  static constexpr u32 MAX_SAMPLES = 1024 * 4;  // 128 ms
  static constexpr u32 INDEX_MASK = MAX_SAMPLES * 2 - 1;
  static constexpr int MAX_FREQ_SHIFT = 200;  // Per 32000 Hz
  static constexpr float CONTROL_FACTOR = 0.2f;
  static constexpr u32 CONTROL_AVG = 32;  // In freq_shift per FIFO size offset

  class MixerFifo final
  {
  public:
    MixerFifo(Mixer* mixer, unsigned sample_rate) : m_mixer(mixer), m_input_sample_rate(sample_rate)
    {
    }
    void PushSamples(const short* samples, unsigned int num_samples);
    unsigned int Mix(short* samples, unsigned int numSamples, bool consider_framelimit = true);
    void SetInputSampleRate(unsigned int rate);
    unsigned int GetInputSampleRate() const;
    void SetVolume(unsigned int lvolume, unsigned int rvolume);
    unsigned int AvailableSamples() const;

  private:
    Mixer* m_mixer;
    unsigned m_input_sample_rate;
    std::array<short, MAX_SAMPLES * 2> m_buffer{};
    std::atomic<u32> m_indexW{0};
    std::atomic<u32> m_indexR{0};
    // Volume ranges from 0-256
    std::atomic<s32> m_LVolume{256};
    std::atomic<s32> m_RVolume{256};
    float m_numLeftI = 0.0f;
    u32 m_frac = 0;
  };

  MixerFifo m_dma_mixer{this, 32000};
  MixerFifo m_streaming_mixer{this, 48000};
  MixerFifo m_wiimote_speaker_mixer{this, 3000};
  unsigned int m_sampleRate;

  bool m_is_stretching = false;
  AudioCommon::AudioStretcher m_stretcher;
  std::array<short, MAX_SAMPLES * 2> m_scratch_buffer;
  std::array<float, MAX_SAMPLES * 2> m_float_conversion_buffer;

  WaveFileWriter m_wave_writer_dtk;
  WaveFileWriter m_wave_writer_dsp;

  bool m_log_dtk_audio = false;
  bool m_log_dsp_audio = false;

  // Current rate of emulation (1.0 = 100% speed)
  std::atomic<float> m_speed{0.0f};
};