Audio code refactoring.

build/android/app/CMakeLists.txt

@@ -66,7 +66,6 @@ add_library(kaliber SHARED
     ../../../src/engine/animator.cc
     ../../../src/engine/audio/audio_base.cc
     ../../../src/engine/audio/audio_oboe.cc
-    ../../../src/engine/audio/audio_resource.cc
     ../../../src/engine/drawable.cc
     ../../../src/engine/engine.cc
     ../../../src/engine/font.cc

build/linux/Makefile

@@ -91,7 +91,6 @@ GLTEST_SRC := \
   $(SRC_ROOT)/engine/animator.cc \
   $(SRC_ROOT)/engine/audio/audio_alsa.cc \
   $(SRC_ROOT)/engine/audio/audio_base.cc \
-  $(SRC_ROOT)/engine/audio/audio_resource.cc \
   $(SRC_ROOT)/engine/drawable.cc \
   $(SRC_ROOT)/engine/engine.cc \
   $(SRC_ROOT)/engine/font.cc \

src/base/mem.h

@@ -46,6 +46,11 @@ inline void AlignedFree(void* mem) {
   free(mem);
 }
 
+template <int kAlignment>
+inline bool IsAligned(void* ptr) {
+  return (reinterpret_cast<uintptr_t>(ptr) & (kAlignment - 1)) == 0U;
+}
+
 }  // namespace base
 
 #endif  // MEM_H

src/engine/BUILD.gn

@@ -8,8 +8,6 @@ source_set("engine") {
         "audio/audio_base.cc",
         "audio/audio_base.h",
         "audio/audio_forward.h",
-        "audio/audio_resource.cc",
-        "audio/audio_resource.h",
         "audio/audio_sample.h",
         "audio/audio.h",
         "drawable.cc",

src/engine/audio/audio_alsa.cc

@@ -5,7 +5,6 @@
 #include <memory>
 
 #include "../../base/log.h"
-#include "audio_resource.h"
 
 using namespace base;
 

src/engine/audio/audio_alsa.h

@@ -10,8 +10,6 @@ typedef struct _snd_pcm snd_pcm_t;
 
 namespace eng {
 
-class AudioResource;
-
 class AudioAlsa : public AudioBase {
  public:
   AudioAlsa();

src/engine/audio/audio_base.cc

@@ -16,50 +16,161 @@ AudioBase::AudioBase()
 
 AudioBase::~AudioBase() = default;
 
-void AudioBase::Play(std::shared_ptr<AudioSample> sample) {
+size_t AudioBase::CreateResource() {
-  if (audio_enabled_) {
+  size_t resource_id = ++last_resource_id_;
-    std::lock_guard<std::mutex> scoped_lock(lock_);
+  resources_[resource_id] = std::make_shared<Resource>();
-    samples_[0].push_back(sample);
+  return resource_id;
-  } else if ((sample->flags.load(std::memory_order_relaxed) &
+}
-              AudioSample::kStopped) == 0) {
+
-    sample->active = false;
+void AudioBase::DestroyResource(size_t resource_id) {
+  auto it = resources_.find(resource_id);
+  if (it == resources_.end())
+    return;
+
+  it->second->flags.fetch_or(kStopped, std::memory_order_relaxed);
+  resources_.erase(it);
+}
+
+void AudioBase::Play(size_t resource_id,
+                     std::shared_ptr<Sound> sound,
+                     float amplitude,
+                     bool reset_pos) {
+  if (!audio_enabled_)
+    return;
+
+  auto it = resources_.find(resource_id);
+  if (it == resources_.end())
+    return;
+
+  if (it->second->active) {
+    if (reset_pos)
+      it->second->flags.fetch_or(kStopped, std::memory_order_relaxed);
+
+    if (it->second->flags.load(std::memory_order_relaxed) & kStopped) {
+      Closure ocb = std::move(it->second->end_cb);
+      SetEndCallback(
+          resource_id,
+          [&, resource_id, sound, amplitude, reset_pos, ocb]() -> void {
+            Play(resource_id, sound, amplitude, reset_pos);
+            SetEndCallback(resource_id, std::move(ocb));
+          });
+    }
+
+    return;
   }
+
+  if (reset_pos) {
+    it->second->src_index = 0;
+    it->second->accumulator = 0;
+    sound->ResetStream();
+  }
+
+  it->second->active = true;
+  it->second->flags.fetch_and(~kStopped, std::memory_order_relaxed);
+  it->second->sound = sound;
+  if (amplitude >= 0)
+    it->second->amplitude = amplitude;
+
+  std::lock_guard<std::mutex> scoped_lock(lock_);
+  play_list_[0].push_back(it->second);
+}
+
+void AudioBase::Stop(size_t resource_id) {
+  auto it = resources_.find(resource_id);
+  if (it == resources_.end())
+    return;
+
+  if (it->second->active)
+    it->second->flags.fetch_or(kStopped, std::memory_order_relaxed);
+}
+
+void AudioBase::SetLoop(size_t resource_id, bool loop) {
+  auto it = resources_.find(resource_id);
+  if (it == resources_.end())
+    return;
+
+  if (loop)
+    it->second->flags.fetch_or(kLoop, std::memory_order_relaxed);
+  else
+    it->second->flags.fetch_and(~kLoop, std::memory_order_relaxed);
+}
+
+void AudioBase::SetSimulateStereo(size_t resource_id, bool simulate) {
+  auto it = resources_.find(resource_id);
+  if (it == resources_.end())
+    return;
+
+  if (simulate)
+    it->second->flags.fetch_or(kSimulateStereo, std::memory_order_relaxed);
+  else
+    it->second->flags.fetch_and(~kSimulateStereo, std::memory_order_relaxed);
+}
+
+void AudioBase::SetResampleStep(size_t resource_id, size_t step) {
+  auto it = resources_.find(resource_id);
+  if (it == resources_.end())
+    return;
+
+  it->second->step.store(step + 100, std::memory_order_relaxed);
+}
+
+void AudioBase::SetMaxAmplitude(size_t resource_id, float max_amplitude) {
+  auto it = resources_.find(resource_id);
+  if (it == resources_.end())
+    return;
+
+  it->second->max_amplitude.store(max_amplitude, std::memory_order_relaxed);
+}
+
+void AudioBase::SetAmplitudeInc(size_t resource_id, float amplitude_inc) {
+  auto it = resources_.find(resource_id);
+  if (it == resources_.end())
+    return;
+
+  it->second->amplitude_inc.store(amplitude_inc, std::memory_order_relaxed);
+}
+
+void AudioBase::SetEndCallback(size_t resource_id, base::Closure cb) {
+  auto it = resources_.find(resource_id);
+  if (it == resources_.end())
+    return;
+
+  it->second->end_cb = std::move(cb);
 }
 
 void AudioBase::RenderAudio(float* output_buffer, size_t num_frames) {
   {
     std::unique_lock<std::mutex> scoped_lock(lock_, std::try_to_lock);
     if (scoped_lock)
-      samples_[1].splice(samples_[1].end(), samples_[0]);
+      play_list_[1].splice(play_list_[1].end(), play_list_[0]);
   }
 
   memset(output_buffer, 0, sizeof(float) * num_frames * kChannelCount);
 
-  for (auto it = samples_[1].begin(); it != samples_[1].end();) {
+  for (auto it = play_list_[1].begin(); it != play_list_[1].end();) {
-    AudioSample* sample = it->get();
+    auto sound = it->get()->sound.get();
+    unsigned flags = it->get()->flags.load(std::memory_order_relaxed);
+    bool marked_for_removal = false;
 
-    auto sound = sample->sound.get();
+    if (flags & kStopped) {
-    unsigned flags = sample->flags.load(std::memory_order_relaxed);
+      marked_for_removal = true;
-
+    } else {
-    if (flags & AudioSample::kStopped) {
-      sample->marked_for_removal = true;
-    } else if (!sample->marked_for_removal) {
       const float* src[2] = {sound->GetBuffer(0), sound->GetBuffer(1)};
       if (!src[1])
         src[1] = src[0];  // mono.
 
       size_t num_samples = sound->GetNumSamples();
-      size_t src_index = sample->src_index;
+      size_t src_index = it->get()->src_index;
-      size_t step = sample->step.load(std::memory_order_relaxed);
+      size_t step = it->get()->step.load(std::memory_order_relaxed);
-      size_t accumulator = sample->accumulator;
+      size_t accumulator = it->get()->accumulator;
-      float amplitude = sample->amplitude;
+      float amplitude = it->get()->amplitude;
       float amplitude_inc =
-          sample->amplitude_inc.load(std::memory_order_relaxed);
+          it->get()->amplitude_inc.load(std::memory_order_relaxed);
       float max_amplitude =
-          sample->max_amplitude.load(std::memory_order_relaxed);
+          it->get()->max_amplitude.load(std::memory_order_relaxed);
 
       size_t channel_offset =
-          (flags & AudioSample::kSimulateStereo) && !sound->is_streaming_sound()
+          (flags & kSimulateStereo) && !sound->is_streaming_sound()
               ? sound->sample_rate() / 10
               : 0;
 
@@ -74,7 +185,7 @@ void AudioBase::RenderAudio(float* output_buffer, size_t num_frames) {
           size_t ind = channel_offset + src_index;
           if (ind < num_samples)
             output_buffer[i++] += src[1][ind] * amplitude;
-          else if (flags & AudioSample::kLoop)
+          else if (flags & kLoop)
             output_buffer[i++] += src[1][ind % num_samples] * amplitude;
           else
             i++;
@@ -82,39 +193,40 @@ void AudioBase::RenderAudio(float* output_buffer, size_t num_frames) {
           // Apply amplitude modification.
           amplitude += amplitude_inc;
           if (amplitude <= 0) {
-            sample->marked_for_removal = true;
+            marked_for_removal = true;
             break;
           } else if (amplitude > max_amplitude) {
             amplitude = max_amplitude;
           }
 
-          // Basic resampling for variations.
+          // Advance source index. Apply basic resampling for variations.
           accumulator += step;
           src_index += accumulator / 100;
           accumulator %= 100;
         }
 
-        // Advance source index.
+        // Remove, loop or stream if the source data is consumed
         if (src_index >= num_samples) {
           if (!sound->is_streaming_sound()) {
             src_index %= num_samples;
 
-            if (!(flags & AudioSample::kLoop)) {
+            if (!(flags & kLoop)) {
-              sample->marked_for_removal = true;
+              marked_for_removal = true;
               break;
             }
-          } else if (!sample->streaming_in_progress.load(
+          } else if (!it->get()->streaming_in_progress.load(
                          std::memory_order_acquire)) {
             if (num_samples)
               src_index %= num_samples;
 
+            // Looping streaming sounds never return eof.
             if (sound->eof()) {
-              sample->marked_for_removal = true;
+              marked_for_removal = true;
               break;
             }
 
-            sample->streaming_in_progress.store(true,
+            it->get()->streaming_in_progress.store(true,
-                                                std::memory_order_relaxed);
+                                                   std::memory_order_relaxed);
 
             // Swap buffers and start streaming in background.
             sound->SwapBuffers();
@@ -124,9 +236,8 @@ void AudioBase::RenderAudio(float* output_buffer, size_t num_frames) {
               src[1] = src[0];  // mono.
             num_samples = sound->GetNumSamples();
 
-            Worker::Get().PostTask(HERE,
+            Worker::Get().PostTask(HERE, std::bind(&AudioBase::DoStream, this,
-                                   std::bind(&AudioBase::DoStream, this, *it,
+                                                   *it, flags & kLoop));
-                                             flags & AudioSample::kLoop));
           } else if (num_samples) {
             DLOG << "Buffer underrun!";
             src_index %= num_samples;
@@ -134,37 +245,44 @@ void AudioBase::RenderAudio(float* output_buffer, size_t num_frames) {
         }
       }
 
-      sample->src_index = src_index;
+      it->get()->src_index = src_index;
-      sample->accumulator = accumulator;
+      it->get()->accumulator = accumulator;
-      sample->amplitude = amplitude;
+      it->get()->amplitude = amplitude;
     }
 
-    if (sample->marked_for_removal &&
+    if (marked_for_removal) {
-        (!sound->is_streaming_sound() ||
+      end_list_.push_back(*it);
-         !sample->streaming_in_progress.load(std::memory_order_relaxed))) {
+      it = play_list_[1].erase(it);
-      sample->marked_for_removal = false;
+    } else {
+      ++it;
+    }
+  }
+
+  for (auto it = end_list_.begin(); it != end_list_.end();) {
+    if ((!it->get()->sound->is_streaming_sound() ||
+         !it->get()->streaming_in_progress.load(std::memory_order_relaxed))) {
       main_thread_task_runner_->PostTask(
           HERE, std::bind(&AudioBase::EndCallback, this, *it));
-      it = samples_[1].erase(it);
+      it = end_list_.erase(it);
     } else {
       ++it;
     }
   }
 }
 
-void AudioBase::DoStream(std::shared_ptr<AudioSample> sample, bool loop) {
+void AudioBase::DoStream(std::shared_ptr<Resource> resource, bool loop) {
-  sample->sound->Stream(loop);
+  resource->sound->Stream(loop);
 
   // Memory barrier to ensure all memory writes become visible to the audio
   // thread.
-  sample->streaming_in_progress.store(false, std::memory_order_release);
+  resource->streaming_in_progress.store(false, std::memory_order_release);
 }
 
-void AudioBase::EndCallback(std::shared_ptr<AudioSample> sample) {
+void AudioBase::EndCallback(std::shared_ptr<Resource> resource) {
-  sample->active = false;
+  resource->active = false;
 
-  if (sample->end_cb)
+  if (resource->end_cb)
-    sample->end_cb();
+    resource->end_cb();
 }
 
 }  // namespace eng

src/engine/audio/audio_base.h

@@ -4,9 +4,9 @@
 #include <list>
 #include <memory>
 #include <mutex>
+#include <unordered_map>
 
 #include "../../base/closure.h"
-#include "audio_sample.h"
 
 namespace base {
 class TaskRunner;
@@ -16,9 +16,26 @@ namespace eng {
 
 class Sound;
 
+// Class representing the end-point for rendered audio. A platform specific
+// implementation is expected to periodically call RenderAudio() in a background
+// thread.
 class AudioBase {
  public:
-  void Play(std::shared_ptr<AudioSample> sample);
+  size_t CreateResource();
+  void DestroyResource(size_t resource_id);
+
+  void Play(size_t resource_id,
+            std::shared_ptr<Sound> sound,
+            float amplitude,
+            bool reset_pos);
+  void Stop(size_t resource_id);
+
+  void SetLoop(size_t resource_id, bool loop);
+  void SetSimulateStereo(size_t resource_id, bool simulate);
+  void SetResampleStep(size_t resource_id, size_t step);
+  void SetMaxAmplitude(size_t resource_id, float max_amplitude);
+  void SetAmplitudeInc(size_t resource_id, float amplitude_inc);
+  void SetEndCallback(size_t resource_id, base::Closure cb);
 
   void SetEnableAudio(bool enable) { audio_enabled_ = enable; }
 
@@ -31,16 +48,44 @@ class AudioBase {
   void RenderAudio(float* output_buffer, size_t num_frames);
 
  private:
-  std::list<std::shared_ptr<AudioSample>> samples_[2];
+  enum SampleFlags { kLoop = 1, kStopped = 2, kSimulateStereo = 4 };
+
+  struct Resource {
+    // Accessed by main thread only.
+    bool active = false;
+    base::Closure end_cb;
+
+    // Initialized by main thread, used by audio thread.
+    std::shared_ptr<Sound> sound;
+    size_t src_index = 0;
+    size_t accumulator = 0;
+    float amplitude = 1.0f;
+
+    // Write accessed by main thread, read-only accessed by audio thread.
+    std::atomic<unsigned> flags{0};
+    std::atomic<size_t> step{100};
+    std::atomic<float> amplitude_inc{0};
+    std::atomic<float> max_amplitude{1.0f};
+
+    // Accessed by audio thread and decoder thread.
+    std::atomic<bool> streaming_in_progress{false};
+  };
+
+  std::unordered_map<size_t, std::shared_ptr<Resource>> resources_;
+  size_t last_resource_id_ = 0;
+
+  std::list<std::shared_ptr<Resource>> play_list_[2];
   std::mutex lock_;
 
+  std::list<std::shared_ptr<Resource>> end_list_;
+
   base::TaskRunner* main_thread_task_runner_;
 
   bool audio_enabled_ = true;
 
-  void DoStream(std::shared_ptr<AudioSample> sample, bool loop);
+  void DoStream(std::shared_ptr<Resource> sample, bool loop);
 
-  void EndCallback(std::shared_ptr<AudioSample> sample);
+  void EndCallback(std::shared_ptr<Resource> sample);
 
   AudioBase(const AudioBase&) = delete;
   AudioBase& operator=(const AudioBase&) = delete;

src/engine/audio/audio_oboe.cc

@@ -2,7 +2,6 @@
 
 #include "../../base/log.h"
 #include "../../third_party/oboe/include/oboe/Oboe.h"
-#include "audio_resource.h"
 
 using namespace base;
 

src/engine/audio/audio_oboe.h

@@ -9,8 +9,6 @@
 
 namespace eng {
 
-class AudioResource;
-
 class AudioOboe : public AudioBase {
  public:
   AudioOboe();

src/engine/audio/audio_resource.cc

@@ -1,92 +0,0 @@
-#include "audio_resource.h"
-
-#include "../../base/log.h"
-#include "../sound.h"
-#include "audio.h"
-#include "audio_sample.h"
-
-using namespace base;
-
-namespace eng {
-
-AudioResource::AudioResource(Audio* audio)
-    : sample_(std::make_shared<AudioSample>()), audio_(audio) {}
-
-AudioResource::~AudioResource() {
-  sample_->flags.fetch_or(AudioSample::kStopped, std::memory_order_relaxed);
-}
-
-void AudioResource::Play(std::shared_ptr<Sound> sound,
-                         float amplitude,
-                         bool reset_pos) {
-  AudioSample* sample = sample_.get();
-
-  if (sample->active) {
-    if (reset_pos)
-      sample_->flags.fetch_or(AudioSample::kStopped, std::memory_order_relaxed);
-
-    if (reset_pos ||
-        sample->flags.load(std::memory_order_relaxed) & AudioSample::kStopped) {
-      Closure ocb = sample_->end_cb;
-      SetEndCallback([&, sound, amplitude, reset_pos, ocb]() -> void {
-        Play(sound, amplitude, reset_pos);
-        SetEndCallback(ocb);
-      });
-    }
-
-    return;
-  }
-
-  if (reset_pos) {
-    sample->src_index = 0;
-    sample->accumulator = 0;
-    sound->ResetStream();
-  }
-
-  sample->active = true;
-  sample_->flags.fetch_and(~AudioSample::kStopped, std::memory_order_relaxed);
-  sample->sound = sound;
-  if (amplitude >= 0)
-    sample->amplitude = amplitude;
-
-  audio_->Play(sample_);
-}
-
-void AudioResource::Stop() {
-  if (sample_->active)
-    sample_->flags.fetch_or(AudioSample::kStopped, std::memory_order_relaxed);
-}
-
-void AudioResource::SetLoop(bool loop) {
-  if (loop)
-    sample_->flags.fetch_or(AudioSample::kLoop, std::memory_order_relaxed);
-  else
-    sample_->flags.fetch_and(~AudioSample::kLoop, std::memory_order_relaxed);
-}
-
-void AudioResource::SetSimulateStereo(bool simulate) {
-  if (simulate)
-    sample_->flags.fetch_or(AudioSample::kSimulateStereo,
-                            std::memory_order_relaxed);
-  else
-    sample_->flags.fetch_and(~AudioSample::kSimulateStereo,
-                             std::memory_order_relaxed);
-}
-
-void AudioResource::SetResampleStep(size_t step) {
-  sample_->step.store(step + 100, std::memory_order_relaxed);
-}
-
-void AudioResource::SetMaxAmplitude(float max_amplitude) {
-  sample_->max_amplitude.store(max_amplitude, std::memory_order_relaxed);
-}
-
-void AudioResource::SetAmplitudeInc(float amplitude_inc) {
-  sample_->amplitude_inc.store(amplitude_inc, std::memory_order_relaxed);
-}
-
-void AudioResource::SetEndCallback(base::Closure cb) {
-  sample_->end_cb = cb;
-}
-
-}  // namespace eng

src/engine/audio/audio_resource.h

@@ -1,41 +0,0 @@
-#ifndef AUDIO_RESOURCE_H
-#define AUDIO_RESOURCE_H
-
-#include <memory>
-
-#include "../../base/closure.h"
-#include "audio_forward.h"
-
-namespace eng {
-
-struct AudioSample;
-class Sound;
-
-class AudioResource {
- public:
-  AudioResource(Audio* audio);
-  ~AudioResource();
-
-  void Play(std::shared_ptr<Sound> sound, float amplitude, bool reset_pos);
-
-  void Stop();
-
-  void SetLoop(bool loop);
-  void SetSimulateStereo(bool simulate);
-  void SetResampleStep(size_t step);
-  void SetMaxAmplitude(float max_amplitude);
-  void SetAmplitudeInc(float amplitude_inc);
-  void SetEndCallback(base::Closure cb);
-
- private:
-  std::shared_ptr<AudioSample> sample_;
-
-  Audio* audio_ = nullptr;
-
-  AudioResource(const AudioResource&) = delete;
-  AudioResource& operator=(const AudioResource&) = delete;
-};
-
-}  // namespace eng
-
-#endif  // AUDIO_RESOURCE_H

src/engine/audio/audio_sample.h

@@ -1,41 +0,0 @@
-#ifndef AUDIO_SAMPLE_H
-#define AUDIO_SAMPLE_H
-
-#include <atomic>
-#include <memory>
-
-#include "../../base/closure.h"
-
-namespace eng {
-
-class Sound;
-
-struct AudioSample {
-  enum SampleFlags { kLoop = 1, kStopped = 2, kSimulateStereo = 4 };
-
-  // Accessed by main thread only.
-  bool active = false;
-  base::Closure end_cb;
-
-  // Accessed by audio thread only.
-  bool marked_for_removal = false;
-
-  // Initialized by main thread, used by audio thread.
-  std::shared_ptr<Sound> sound;
-  size_t src_index = 0;
-  size_t accumulator = 0;
-  float amplitude = 1.0f;
-
-  // Write accessed by main thread, read-only accessed by audio thread.
-  std::atomic<unsigned> flags{0};
-  std::atomic<size_t> step{100};
-  std::atomic<float> amplitude_inc{0};
-  std::atomic<float> max_amplitude{1.0f};
-
-  // Accessed by audio thread and decoder thread.
-  std::atomic<bool> streaming_in_progress{false};
-};
-
-}  // namespace eng
-
-#endif  // AUDIO_SAMPLE_H

src/engine/engine.cc

@@ -4,7 +4,6 @@
 #include "../third_party/texture_compressor/texture_compressor.h"
 #include "animator.h"
 #include "audio/audio.h"
-#include "audio/audio_resource.h"
 #include "drawable.h"
 #include "font.h"
 #include "game.h"
@@ -274,10 +273,6 @@ std::shared_ptr<Texture> Engine::GetTexture(const std::string& asset_name) {
   return texture;
 }
 
-std::unique_ptr<AudioResource> Engine::CreateAudioResource() {
-  return std::make_unique<AudioResource>(audio_);
-}
-
 void Engine::AddInputEvent(std::unique_ptr<InputEvent> event) {
   if (replaying_)
     return;

src/engine/engine.h

@@ -19,7 +19,6 @@ class TextureCompressor;
 namespace eng {
 
 class Animator;
-class AudioResource;
 class Font;
 class Game;
 class Drawable;
@@ -83,8 +82,6 @@ class Engine {
 
   std::shared_ptr<Texture> GetTexture(const std::string& asset_name);
 
-  std::unique_ptr<AudioResource> CreateAudioResource();
-
   void AddInputEvent(std::unique_ptr<InputEvent> event);
   std::unique_ptr<InputEvent> GetNextInputEvent();
 
@@ -108,6 +105,8 @@ class Engine {
 
   void SetEnableVibration(bool enable) { vibration_enabled_ = enable; }
 
+  Audio* GetAudio() { return audio_; }
+
   // Access to the render resources.
   Geometry* GetQuad() { return quad_.get(); }
   Shader* GetPassThroughShader() { return pass_through_shader_.get(); }

src/engine/sound_player.cc

@@ -2,7 +2,7 @@
 
 #include "../base/interpolation.h"
 #include "../base/log.h"
-#include "audio/audio_resource.h"
+#include "audio/audio.h"
 #include "engine.h"
 #include "sound.h"
 
@@ -10,9 +10,12 @@ using namespace base;
 
 namespace eng {
 
-SoundPlayer::SoundPlayer() : resource_(Engine::Get().CreateAudioResource()) {}
+SoundPlayer::SoundPlayer()
+    : resource_id_(Engine::Get().GetAudio()->CreateResource()) {}
 
-SoundPlayer::~SoundPlayer() = default;
+SoundPlayer::~SoundPlayer() {
+  Engine::Get().GetAudio()->DestroyResource(resource_id_);
+}
 
 void SoundPlayer::SetSound(std::shared_ptr<Sound> sound) {
   CHECK(!sound->is_streaming_sound()) << "Streaming sound cannot be shared.";
@@ -29,14 +32,15 @@ void SoundPlayer::Play(bool loop, float fade_in_duration) {
     return;
 
   int step = variate_ ? Engine::Get().GetRandomGenerator().Roll(3) - 2 : 0;
-  resource_->SetResampleStep(step * 12);
+  Engine::Get().GetAudio()->SetResampleStep(resource_id_, step * 12);
-  resource_->SetLoop(loop);
+  Engine::Get().GetAudio()->SetLoop(resource_id_, loop);
   if (fade_in_duration > 0)
-    resource_->SetAmplitudeInc(1.0f /
+    Engine::Get().GetAudio()->SetAmplitudeInc(
-                               (sound_->sample_rate() * fade_in_duration));
+        resource_id_, 1.0f / (sound_->sample_rate() * fade_in_duration));
   else
-    resource_->SetAmplitudeInc(0);
+    Engine::Get().GetAudio()->SetAmplitudeInc(resource_id_, 0);
-  resource_->Play(sound_, fade_in_duration > 0 ? 0 : max_amplitude_, true);
+  Engine::Get().GetAudio()->Play(
+      resource_id_, sound_, fade_in_duration > 0 ? 0 : max_amplitude_, true);
 }
 
 void SoundPlayer::Resume(float fade_in_duration) {
@@ -44,9 +48,10 @@ void SoundPlayer::Resume(float fade_in_duration) {
     return;
 
   if (fade_in_duration > 0)
-    resource_->SetAmplitudeInc(1.0f /
+    Engine::Get().GetAudio()->SetAmplitudeInc(
-                               (sound_->sample_rate() * fade_in_duration));
+        resource_id_, 1.0f / (sound_->sample_rate() * fade_in_duration));
-  resource_->Play(sound_, fade_in_duration > 0 ? 0 : -1, false);
+  Engine::Get().GetAudio()->Play(resource_id_, sound_,
+                                 fade_in_duration > 0 ? 0 : -1, false);
 }
 
 void SoundPlayer::Stop(float fade_out_duration) {
@@ -54,10 +59,10 @@ void SoundPlayer::Stop(float fade_out_duration) {
     return;
 
   if (fade_out_duration > 0)
-    resource_->SetAmplitudeInc(-1.0f /
+    Engine::Get().GetAudio()->SetAmplitudeInc(
-                               (sound_->sample_rate() * fade_out_duration));
+        resource_id_, -1.0f / (sound_->sample_rate() * fade_out_duration));
   else
-    resource_->Stop();
+    Engine::Get().GetAudio()->Stop(resource_id_);
 }
 
 void SoundPlayer::SetVariate(bool variate) {
@@ -65,16 +70,16 @@ void SoundPlayer::SetVariate(bool variate) {
 }
 
 void SoundPlayer::SetSimulateStereo(bool simulate) {
-  resource_->SetSimulateStereo(simulate);
+  Engine::Get().GetAudio()->SetSimulateStereo(resource_id_, simulate);
 }
 
 void SoundPlayer::SetMaxAplitude(float max_amplitude) {
   max_amplitude_ = max_amplitude;
-  resource_->SetMaxAmplitude(max_amplitude);
+  Engine::Get().GetAudio()->SetMaxAmplitude(resource_id_, max_amplitude);
 }
 
 void SoundPlayer::SetEndCallback(base::Closure cb) {
-  resource_->SetEndCallback(cb);
+  Engine::Get().GetAudio()->SetEndCallback(resource_id_, cb);
 }
 
 }  // namespace eng

src/engine/sound_player.h

@@ -7,7 +7,6 @@
 
 namespace eng {
 
-class AudioResource;
 class Sound;
 
 class SoundPlayer {
@@ -37,7 +36,7 @@ class SoundPlayer {
   void SetEndCallback(base::Closure cb);
 
  private:
-  std::unique_ptr<AudioResource> resource_;
+  size_t resource_id_ = 0;
   std::shared_ptr<Sound> sound_;
 
   float max_amplitude_ = 1.0f;