Modify sound system to use single AudioStream

src/interface.cpp

@@ -149,7 +149,8 @@ void Interface::initialize() {
   int monitor_height = GetMonitorHeight(monitor);
   spdlog::trace("Monitor resolution: {}x{}", monitor_width, monitor_height);
 
-  sounds.push_back(std::make_unique<WaveGeneratorSource>());
+  sounds.initialize();
+  sounds.add_source(std::make_unique<WaveGeneratorSource>());
 
   if (settings.lock_fps) {
     SetTargetFPS(kDefaultFPS);
@@ -227,9 +228,7 @@ bool Interface::update() {
   keyboard.update();
 
   bool is_playing = regs->st > 0;
-  for (auto &sound : sounds) {
-    sound->update(is_playing || force_play_all_sounds);
-  }
+  sounds.update(is_playing || force_play_all_sounds);
 
   screen.update();
 
@@ -531,33 +530,14 @@ bool Interface::update() {
       }
 
       ImGui::Checkbox("Force Play All Sounds", &force_play_all_sounds);
-
       ImGui::NewLine();
 
-      int sid_to_remove = -1;
-      for (int sid = 0; sid < sounds.size(); sid += 1) {
-        ImGui::PushID(sid);
-        ImGui::BeginChild("##Sound", ImVec2(0, 0), ImGuiChildFlags_Border | ImGuiChildFlags_AutoResizeY);
-        ImGui::Text("Sound #%d", (sid + 1));
-
-        sounds[sid]->render();
-
-        if (ImGui::Button("Remove")) {
-          sid_to_remove = sid;
-        }
-
-        ImGui::EndChild();
-        ImGui::PopID();
-      }
-
-      if (sid_to_remove != -1) {
-        sounds.erase(sounds.begin() + sid_to_remove);
-      }
+      sounds.render();
     }
 
     ImGui::NewLine();
     if (ImGui::Button("Add sound")) {
-      sounds.push_back(std::make_unique<WaveGeneratorSource>());
+      sounds.add_source(std::make_unique<WaveGeneratorSource>());
     }
 
     ImGui::End();
@@ -702,7 +682,7 @@ void Interface::cleanup() {
   settings.window_height = GetScreenHeight();
 
   spdlog::info("Cleaning up interface");
-  sounds.clear();
+  sounds.cleanup();
   rlImGuiShutdown();
   CloseAudioDevice();
   CloseWindow();

src/interface.h

@@ -76,7 +76,7 @@ class Interface {
   AssemblyViewer assembly;
   Keyboard keyboard;
   Config<interface_settings> config;
+  SoundManager sounds;
   std::vector<uint8_t> rom;
   std::shared_ptr<registers> regs;
-  std::vector<std::unique_ptr<SoundSource>> sounds;
 };

src/sound.cpp

@@ -1,32 +1,38 @@
 #include "sound.h"
 
+#include <array>
 #include <cmath>
 #include <cstring>
 #include <spdlog/spdlog.h>
 #include <raylib.h>
 #include <imgui.h>
 #include <random>
 
-SoundSource::SoundSource() {
-  spdlog::trace("Initializing SoundSource");
-  SetAudioStreamBufferSizeDefault(kMaxSamplesPerUpdate);
-  stream = LoadAudioStream(kAudioSampleRate, kAudioSampleSize, kAudioNumChannels);
-  PlayAudioStream(stream);
+static inline float noise(double x) {
+  static std::random_device rd;
+  static std::mt19937 gen(rd());
+  static std::uniform_real_distribution<> dist(-1.0f, 1.0f);
+  return dist(gen);
 }
 
-SoundSource::~SoundSource() {
-  spdlog::trace("Destructing SoundSource");
-  StopAudioStream(stream);
-  UnloadAudioStream(stream);
+static inline float sine_wave(double x) {
+  return std::sin(2 * PI * x);
 }
 
-void SoundSource::update(bool play_sound) {
-  if (!IsAudioStreamProcessed(stream)) {
-    return;
+static inline float square_wave(double x) {
+  float s = sine_wave(x);
+  if (std::abs(s) <= 0.001f) {
+    return 0.f;
   }
+  return std::abs(s) / s;
+}
 
-  gen_sound_data(play_sound, buffer.data(), buffer.size());
-  UpdateAudioStream(stream, buffer.data(), buffer.size());
+static inline float triangle_wave(double x) {
+  return std::abs(fmod(x, 1.0f) - 0.5f) * 4 - 1;
+}
+
+static inline float sawtooth_wave(double x) {
+  return std::abs(fmod(x, 1.0f)) * 2 - 1;
 }
 
 void WaveGeneratorSource::render() {
@@ -50,17 +56,26 @@ void WaveGeneratorSource::render() {
     }
     ImGui::EndCombo();
   }
-  ImGui::PlotLines("Sound", samples.data(), samples.size(), 0, nullptr, -1.5f, 1.5f, ImVec2(0, 80.0f));
-  ImGui::SliderFloat("Volume", &volume, 0.0f, 100.0f);
-  ImGui::SliderFloat("Frequency", &frequency, 20.0f, 15000.0f);
-  if (ImGui::Button("20Hz")) {
-    frequency = 20.0f;
+  ImGui::PlotLines("Sound", samples.data(), samples.size(), 0, nullptr, -1.2f, 1.2f, ImVec2(0, 50.0f));
+  ImGui::SliderFloat("Volume", &volume, 0.0f, 100.0f, "%.0f");
+  ImGui::SliderFloat("Offset", &offset, 0.0f, 1.0f, "%0.2f");
+  if (ImGui::Button("+0.0")) {
+    offset = 0.0f;
   }
   ImGui::SameLine();
-  if (ImGui::Button("50Hz")) {
-    frequency = 50.0f;
+  if (ImGui::Button("+0.25")) {
+    offset = 0.25f;
   }
   ImGui::SameLine();
+  if (ImGui::Button("+0.5")) {
+    offset = 0.50f;
+  }
+  ImGui::SameLine();
+  if (ImGui::Button("+0.75")) {
+    offset = 0.75f;
+  }
+
+  ImGui::SliderFloat("Frequency", &frequency, 20.0f, 15000.0f, "%.0f");
   if (ImGui::Button("100Hz")) {
     frequency = 100.0f;
   }
@@ -83,42 +98,12 @@ void WaveGeneratorSource::render() {
   ImGui::Checkbox("Force Play", &force_play);
 }
 
-static inline float noise(float idx) {
-  static std::random_device rd;
-  static std::mt19937 gen(rd());
-  static std::uniform_real_distribution<> dist(-1.0f, 1.0f);
-  return dist(gen);
-}
-
-static inline float sine_wave(float idx) {
-  return std::sin(2 * PI * idx);
-}
-
-static inline float square_wave(float idx) {
-  float s = sine_wave(idx);
-  if (std::abs(s) <= 0.001f) {
-    return 0.f;
-  }
-  return std::abs(s) / s;
-}
-
-static inline float triangle_wave(float idx) {
-  return std::abs(fmod(idx, 1.0f) - 0.5f) * 4 - 1;
-}
-
-static inline float sawtooth_wave(float idx) {
-  return std::abs(fmod(idx, 1.0f)) * 2 - 1;
-}
-
-void WaveGeneratorSource::gen_sound_data(bool play_sound, short buffer[], size_t buffer_size) {
+void WaveGeneratorSource::update(bool play_sound, double time) {
   if (!play_sound && !force_play) {
-    memset(buffer, 0, sizeof(short) * buffer_size);
     memset(&samples, 0, sizeof(float) * samples.size());
     return;
   }
 
-  float incr = frequency / static_cast<float>(kAudioSampleRate);
-
   auto wave_func = ([this]() {
     switch (wave_type) {
       case 0: return sine_wave;
@@ -129,16 +114,84 @@ void WaveGeneratorSource::gen_sound_data(bool play_sound, short buffer[], size_t
     }
   })();
 
-  for (int i = 0; i < buffer_size; i++) {
-    float sample = wave_func(wave_idx) * (volume / 100.0f);
-    buffer[i] = static_cast<short>(((1 << 15) - 1) * sample);
+  double incr = 1.0 / kAudioSampleRate;
+
+  for (int i = 0; i < samples.size(); i++) {
+    samples[i] = wave_func((time * frequency) + offset) * (volume / 100.0f);
+    time += incr;
+  }
+}
+
+void SoundManager::initialize() {
+  spdlog::trace("Initializing SoundSource");
+
+  memset(buffer.data(), 0, buffer.size() * sizeof(short));
+  memset(samples.data(), 0, samples.size() * sizeof(float));
+
+  SetAudioStreamBufferSizeDefault(kMaxSamplesPerUpdate);
+  stream = LoadAudioStream(kAudioSampleRate, kAudioSampleSize, kAudioNumChannels);
+  PlayAudioStream(stream);
+}
+
+void SoundManager::cleanup() {
+  spdlog::trace("Destructing SoundSource");
+  sources.clear();
+  StopAudioStream(stream);
+  UnloadAudioStream(stream);
+}
+
+void SoundManager::render() {
+  ImGui::PlotLines("Sound", samples.data(), samples.size(), 0, nullptr, -1.5f, 1.5f, ImVec2(0, 80.0f));
+
+  int sid_to_remove = -1;
+  for (int sid = 0; sid < sources.size(); sid += 1) {
+    ImGui::PushID(sid);
+    ImGui::BeginChild("##Sound", ImVec2(0, 0), ImGuiChildFlags_Border | ImGuiChildFlags_AutoResizeY);
+    ImGui::Text("Sound #%d", (sid + 1));
 
-    if (i < samples.size()) {
-      samples[i] = sample;
+    sources[sid]->render();
+
+    if (ImGui::Button("Remove")) {
+      sid_to_remove = sid;
     }
 
-    wave_idx += incr;
-    if (wave_idx > 1.0f)
-      wave_idx -= 1.0f;
+    ImGui::EndChild();
+    ImGui::PopID();
+  }
+
+  if (sid_to_remove != -1) {
+    remove_source_at(sid_to_remove);
   }
 }
+
+void SoundManager::update(bool play_sound) {
+  if (!IsAudioStreamProcessed(stream)) {
+    return;
+  }
+
+  memset(samples.data(), 0, samples.size() * sizeof(float));
+
+  for (auto &source : sources) {
+    source->update(play_sound, time);
+    const float* source_samples = source->get_samples();
+    for (int i = 0; i < buffer.size(); i += 1) {
+      samples[i] += source_samples[i];
+    }
+  }
+
+  for (int i = 0; i < buffer.size(); i += 1) {
+    buffer[i] = static_cast<short>(((1 << 15) - 1) * samples[i]);
+  }
+
+  time = fmod(time + (1.0 / kAudioSampleRate) * buffer.size(), 1.0);
+
+  UpdateAudioStream(stream, buffer.data(), buffer.size());
+}
+
+void SoundManager::add_source(std::unique_ptr<SoundSource> source) {
+  sources.push_back(std::move(source));
+}
+
+void SoundManager::remove_source_at(size_t index) {
+  sources.erase(sources.begin() + index);
+}

src/sound.h

@@ -1,40 +1,59 @@
 #pragma once
 
+#include <memory>
 #include <raylib.h>
 #include <array>
+#include <vector>
 
-constexpr int kMaxSamplesPerUpdate = 4096;
+constexpr int kMaxSamplesPerUpdate = 1024;
 constexpr int kAudioSampleRate = 44100;
 constexpr int kAudioSampleSize = 16;
 constexpr int kAudioNumChannels = 1;
 
 class SoundSource {
 public:
-  SoundSource();
-  virtual ~SoundSource();
+  virtual ~SoundSource() = default;
 
   virtual void render() = 0;
-  virtual void gen_sound_data(bool play_sound, short buffer[], size_t buffer_size) = 0;
+  virtual void update(bool play_sound, double time) = 0;
 
-  void update(bool play_sound);
+  auto get_samples() const {
+    return samples.data();
+  }
 
-private:
-  AudioStream stream;
-  std::array<short, kMaxSamplesPerUpdate> buffer;
+protected:
+  std::array<float, kMaxSamplesPerUpdate> samples;
 };
 
-class WaveGeneratorSource : public SoundSource {
+class WaveGeneratorSource final : public SoundSource {
 public:
   virtual ~WaveGeneratorSource() = default;
 
   virtual void render() override;
-  virtual void gen_sound_data(bool play_sound, short buffer[], size_t buffer_size) override;
+  virtual void update(bool play_sound, double time) override;
 
 private:
-  std::array<float, 1000> samples;
   bool force_play = false;
   float frequency = 440.0f;
-  float volume = 100.0f;
-  float wave_idx = 0.0f;
+  float offset = 0.0f;
+  float volume = 50.0f;
   int wave_type = 0;
 };
+
+class SoundManager final {
+public:
+  void initialize();
+  void render();
+  void update(bool play_sound);
+  void cleanup();
+
+  void add_source(std::unique_ptr<SoundSource> source);
+  void remove_source_at(size_t index);
+
+private:
+  double time = 0;
+  AudioStream stream;
+  std::array<float, kMaxSamplesPerUpdate> samples;
+  std::array<short, kMaxSamplesPerUpdate> buffer;
+  std::vector<std::unique_ptr<SoundSource>> sources;
+};