https://github.com/agehama/synthesizertutorial
ソフトウェアシンセサイザーの作成チュートリアル
https://github.com/agehama/synthesizertutorial
audio-programming cpp digital-signal-processing opensiv3d synthesizer
Last synced: 2 months ago
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ソフトウェアシンセサイザーの作成チュートリアル
- Host: GitHub
- URL: https://github.com/agehama/synthesizertutorial
- Owner: agehama
- License: unlicense
- Created: 2022-12-18T10:20:50.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2023-02-07T09:12:28.000Z (over 2 years ago)
- Last Synced: 2025-04-04T14:46:05.933Z (2 months ago)
- Topics: audio-programming, cpp, digital-signal-processing, opensiv3d, synthesizer
- Language: C++
- Homepage:
- Size: 1.06 MB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# SynthesizerTutorial
ソフトウェアシンセサイザーを作成するチュートリアルです
記事：
１．https://qiita.com/agehama_/items/7da430491400e9a2b6a7
２．https://qiita.com/agehama_/items/863933459ca44ca5dbe0
３．https://qiita.com/agehama_/items/29175c24eae588c3e9f7
## ビルド環境
- Visual Studio 2022
- OpenSiv3D v0.6.6
## その１：サイン波でMIDIを再生する
### １.１ サイン波を再生する
```diff
@@ -0,0 +1,45 @@
+# include // OpenSiv3D v0.6.6
+
+const auto SliderHeight = 36;
+const auto SliderWidth = 400;
+const auto LabelWidth = 200;
+
+Wave RenderWave(uint32 seconds, double amplitude, double frequency)
+{
+ const auto lengthOfSamples = seconds * Wave::DefaultSampleRate;
+
+ Wave wave(lengthOfSamples);
+
+ for (uint32 i = 0; i < lengthOfSamples; ++i)
+ {
+ const double sec = 1.0f * i / Wave::DefaultSampleRate;
+ const double w = sin(Math::TwoPiF * frequency * sec) * amplitude;
+ wave[i].left = wave[i].right = static_cast(w);
+ }
+
+ return wave;
+}
+
+void Main()
+{
+ double amplitude = 0.2;
+ double frequency = 440.0;
+
+ uint32 seconds = 3;
+
+ Audio audio(RenderWave(seconds, amplitude, frequency));
+ audio.play();
+
+ while (System::Update())
+ {
+ Vec2 pos(20, 20 - SliderHeight);
+ SimpleGUI::Slider(U"amplitude : {:.2f}"_fmt(amplitude), amplitude, 0.0, 1.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
+ SimpleGUI::Slider(U"frequency : {:.0f}"_fmt(frequency), frequency, 100.0, 1000.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
+
+ if (SimpleGUI::Button(U"波形を再生成", Vec2{ pos.x, pos.y += SliderHeight }))
+ {
+ audio = Audio(RenderWave(seconds, amplitude, frequency));
+ audio.play();
+ }
+ }
+}
```
### １.２ ADSR エンベロープを実装する
```diff
@@ -4,17 +4,134 @@ const auto SliderHeight = 36;
const auto SliderWidth = 400;
const auto LabelWidth = 200;
-Wave RenderWave(uint32 seconds, double amplitude, double frequency)
+struct ADSRConfig
+{
+ double attackTime = 0.01;
+ double decayTime = 0.01;
+ double sustainLevel = 0.6;
+ double releaseTime = 0.4;
+
+ void updateGUI(Vec2& pos)
+ {
+ SimpleGUI::Slider(U"attack : {:.2f}"_fmt(attackTime), attackTime, 0.0, 0.5, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
+ SimpleGUI::Slider(U"decay : {:.2f}"_fmt(decayTime), decayTime, 0.0, 1.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
+ SimpleGUI::Slider(U"sustain : {:.2f}"_fmt(sustainLevel), sustainLevel, 0.0, 1.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
+ SimpleGUI::Slider(U"release : {:.2f}"_fmt(releaseTime), releaseTime, 0.0, 1.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
+ }
+};
+
+class EnvGenerator
+{
+public:
+
+ enum class State
+ {
+ Attack, Decay, Sustain, Release
+ };
+
+ void noteOff()
+ {
+ if (m_state != State::Release)
+ {
+ m_elapsed = 0;
+ m_state = State::Release;
+ }
+ }
+
+ void reset(State state)
+ {
+ m_elapsed = 0;
+ m_state = state;
+ }
+
+ void update(const ADSRConfig& adsr, double dt)
+ {
+ switch (m_state)
+ {
+ case State::Attack: // 0.0 から 1.0 まで attackTime かけて増幅する
+ if (m_elapsed < adsr.attackTime)
+ {
+ m_currentLevel = m_elapsed / adsr.attackTime;
+ break;
+ }
+ m_elapsed -= adsr.attackTime;
+ m_state = State::Decay;
+ [[fallthrough]]; // Decay処理にそのまま続く
+
+ case State::Decay: // 1.0 から sustainLevel まで decayTime かけて減衰する
+ if (m_elapsed < adsr.decayTime)
+ {
+ m_currentLevel = Math::Lerp(1.0, adsr.sustainLevel, m_elapsed / adsr.decayTime);
+ break;
+ }
+ m_elapsed -= adsr.decayTime;
+ m_state = State::Sustain;
+ [[fallthrough]]; // Sustain処理にそのまま続く
+
+
+ case State::Sustain: // ノートオンの間 sustainLevel を維持する
+ m_currentLevel = adsr.sustainLevel;
+ break;
+
+ case State::Release: // sustainLevel から 0.0 まで releaseTime かけて減衰する
+ m_currentLevel = m_elapsed < adsr.releaseTime
+ ? Math::Lerp(adsr.sustainLevel, 0.0, m_elapsed / adsr.releaseTime)
+ : 0.0;
+ break;
+
+ default: break;
+ }
+
+ m_elapsed += dt;
+ }
+
+ bool isReleased(const ADSRConfig& adsr) const
+ {
+ return m_state == State::Release && adsr.releaseTime <= m_elapsed;
+ }
+
+ double currentLevel() const
+ {
+ return m_currentLevel;
+ }
+
+ State state() const
+ {
+ return m_state;
+ }
+
+private:
+
+ State m_state = State::Attack;
+ double m_elapsed = 0; // ステート変更からの経過秒数
+ double m_currentLevel = 0; // 現在のレベル [0, 1]
+};
+
+Wave RenderWave(uint32 seconds, double amplitude, double frequency, const ADSRConfig& adsr)
{
const auto lengthOfSamples = seconds * Wave::DefaultSampleRate;
Wave wave(lengthOfSamples);
+ // 0サンプル目でノートオン
+ EnvGenerator envelope;
+
+ // 半分経過したところでノートオフ
+ const auto noteOffSample = lengthOfSamples / 2;
+
+ const float deltaT = 1.0f / Wave::DefaultSampleRate;
+ float time = 0;
for (uint32 i = 0; i < lengthOfSamples; ++i)
{
- const double sec = 1.0f * i / Wave::DefaultSampleRate;
- const double w = sin(Math::TwoPiF * frequency * sec) * amplitude;
+ if (i == noteOffSample)
+ {
+ envelope.noteOff();
+ }
+ const auto w = sin(Math::TwoPiF * frequency * time)
+ * amplitude * envelope.currentLevel();
wave[i].left = wave[i].right = static_cast(w);
+ time += deltaT;
+ envelope.update(adsr, deltaT);
}
return wave;
@@ -27,7 +144,13 @@ void Main()
uint32 seconds = 3;
- Audio audio(RenderWave(seconds, amplitude, frequency));
+ ADSRConfig adsr;
+ adsr.attackTime = 0.1;
+ adsr.decayTime = 0.1;
+ adsr.sustainLevel = 0.8;
+ adsr.releaseTime = 0.5;
+
+ Audio audio(RenderWave(seconds, amplitude, frequency, adsr));
audio.play();
while (System::Update())
@@ -36,9 +159,11 @@ void Main()
SimpleGUI::Slider(U"amplitude : {:.2f}"_fmt(amplitude), amplitude, 0.0, 1.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
SimpleGUI::Slider(U"frequency : {:.0f}"_fmt(frequency), frequency, 100.0, 1000.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
+ adsr.updateGUI(pos);
+
if (SimpleGUI::Button(U"波形を再生成", Vec2{ pos.x, pos.y += SliderHeight }))
{
- audio = Audio(RenderWave(seconds, amplitude, frequency));
+ audio = Audio(RenderWave(seconds, amplitude, frequency, adsr));
audio.play();
}
}
```
### １.３ 音階に対応させる
```diff
@@ -107,7 +107,12 @@ private:
double m_currentLevel = 0; // 現在のレベル [0, 1]
};
-Wave RenderWave(uint32 seconds, double amplitude, double frequency, const ADSRConfig& adsr)
+float NoteNumberToFrequency(int8_t d)
+{
+ return 440.0f * pow(2.0f, (d - 69) / 12.0f);
+}
+
+Wave RenderWave(uint32 seconds, double amplitude, const Array& noteNumbers, const ADSRConfig& adsr)
{
const auto lengthOfSamples = seconds * Wave::DefaultSampleRate;
@@ -121,14 +126,23 @@ Wave RenderWave(uint32 seconds, double amplitude, double frequency, const ADSRCo
const float deltaT = 1.0f / Wave::DefaultSampleRate;
float time = 0;
+
for (uint32 i = 0; i < lengthOfSamples; ++i)
{
if (i == noteOffSample)
{
envelope.noteOff();
}
- const auto w = sin(Math::TwoPiF * frequency * time)
- * amplitude * envelope.currentLevel();
+
+ // 和音の各波形を加算合成する
+ double w = 0;
+ for (auto note : noteNumbers)
+ {
+ const auto freq = NoteNumberToFrequency(note);
+ w += sin(Math::TwoPiF * freq * time)
+ * amplitude * envelope.currentLevel();
+ }
+
wave[i].left = wave[i].right = static_cast(w);
time += deltaT;
envelope.update(adsr, deltaT);
@@ -140,7 +154,6 @@ Wave RenderWave(uint32 seconds, double amplitude, double frequency, const ADSRCo
void Main()
{
double amplitude = 0.2;
- double frequency = 440.0;
uint32 seconds = 3;
@@ -150,20 +163,26 @@ void Main()
adsr.sustainLevel = 0.8;
adsr.releaseTime = 0.5;
- Audio audio(RenderWave(seconds, amplitude, frequency, adsr));
+ const Array noteNumbers =
+ {
+ 60, // C_4
+ 64, // E_4
+ 67, // G_4
+ };
+
+ Audio audio(RenderWave(seconds, amplitude, noteNumbers, adsr));
audio.play();
while (System::Update())
{
Vec2 pos(20, 20 - SliderHeight);
SimpleGUI::Slider(U"amplitude : {:.2f}"_fmt(amplitude), amplitude, 0.0, 1.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
- SimpleGUI::Slider(U"frequency : {:.0f}"_fmt(frequency), frequency, 100.0, 1000.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
adsr.updateGUI(pos);
if (SimpleGUI::Button(U"波形を再生成", Vec2{ pos.x, pos.y += SliderHeight }))
{
- audio = Audio(RenderWave(seconds, amplitude, frequency, adsr));
+ audio = Audio(RenderWave(seconds, amplitude, noteNumbers, adsr));
audio.play();
}
}
```
### １.４ シンセサイザーを定義する
```diff
@@ -112,40 +112,114 @@ float NoteNumberToFrequency(int8_t d)
return 440.0f * pow(2.0f, (d - 69) / 12.0f);
}
-Wave RenderWave(uint32 seconds, double amplitude, const Array& noteNumbers, const ADSRConfig& adsr)
+struct NoteState
+{
+ EnvGenerator m_envelope;
+};
+
+class Synthesizer
+{
+public:
+
+ // 1サンプル波形を生成して返す
+ WaveSample renderSample()
+ {
+ const auto deltaT = 1.0 / Wave::DefaultSampleRate;
+
+ // エンベロープの更新
+ for (auto& [noteNumber, noteState] : m_noteState)
+ {
+ noteState.m_envelope.update(m_adsr, deltaT);
+ }
+
+ // リリースが終了したノートを削除する
+ std::erase_if(m_noteState, [&](const auto& noteState) { return noteState.second.m_envelope.isReleased(m_adsr); });
+
+ // 入力中の波形を加算して書き込む
+ WaveSample sample(0, 0);
+ for (auto& [noteNumber, noteState] : m_noteState)
+ {
+ const auto envLevel = noteState.m_envelope.currentLevel();
+ const auto frequency = NoteNumberToFrequency(noteNumber);
+
+ const auto w = static_cast(sin(Math::TwoPiF * frequency * m_time) * envLevel);
+ sample.left += w;
+ sample.right += w;
+ }
+
+ m_time += deltaT;
+
+ return sample * static_cast(m_amplitude);
+ }
+
+ void noteOn(int8_t noteNumber)
+ {
+ m_noteState.emplace(noteNumber, NoteState());
+ }
+
+ void noteOff(int8_t noteNumber)
+ {
+ auto [beginIt, endIt] = m_noteState.equal_range(noteNumber);
+
+ for (auto it = beginIt; it != endIt; ++it)
+ {
+ auto& envelope = it->second.m_envelope;
+
+ // noteOnになっている最初の要素をnoteOffにする
+ if (envelope.state() != EnvGenerator::State::Release)
+ {
+ envelope.noteOff();
+ break;
+ }
+ }
+ }
+
+ void updateGUI(Vec2& pos)
+ {
+ SimpleGUI::Slider(U"amplitude : {:.2f}"_fmt(m_amplitude), m_amplitude, 0.0, 1.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
+
+ m_adsr.updateGUI(pos);
+ }
+
+ void clear()
+ {
+ m_noteState.clear();
+ }
+
+private:
+
+ std::multimap m_noteState;
+
+ ADSRConfig m_adsr;
+
+ double m_amplitude = 0.2;
+
+ double m_time = 0;
+};
+
+Wave RenderWave(uint32 seconds, Synthesizer& synth)
{
const auto lengthOfSamples = seconds * Wave::DefaultSampleRate;
Wave wave(lengthOfSamples);
- // 0サンプル目でノートオン
- EnvGenerator envelope;
-
// 半分経過したところでノートオフ
const auto noteOffSample = lengthOfSamples / 2;
- const float deltaT = 1.0f / Wave::DefaultSampleRate;
- float time = 0;
+ synth.noteOn(60); // C_4
+ synth.noteOn(64); // E_4
+ synth.noteOn(67); // G_4
for (uint32 i = 0; i < lengthOfSamples; ++i)
{
if (i == noteOffSample)
{
- envelope.noteOff();
- }
-
- // 和音の各波形を加算合成する
- double w = 0;
- for (auto note : noteNumbers)
- {
- const auto freq = NoteNumberToFrequency(note);
- w += sin(Math::TwoPiF * freq * time)
- * amplitude * envelope.currentLevel();
+ synth.noteOff(60);
+ synth.noteOff(64);
+ synth.noteOff(67);
}
- wave[i].left = wave[i].right = static_cast(w);
- time += deltaT;
- envelope.update(adsr, deltaT);
+ wave[i] = synth.renderSample();
}
return wave;
@@ -153,36 +227,24 @@ Wave RenderWave(uint32 seconds, double amplitude, const Array& noteNumbe
void Main()
{
- double amplitude = 0.2;
-
uint32 seconds = 3;
- ADSRConfig adsr;
- adsr.attackTime = 0.1;
- adsr.decayTime = 0.1;
- adsr.sustainLevel = 0.8;
- adsr.releaseTime = 0.5;
+ Synthesizer synth;
- const Array noteNumbers =
- {
- 60, // C_4
- 64, // E_4
- 67, // G_4
- };
-
- Audio audio(RenderWave(seconds, amplitude, noteNumbers, adsr));
+ Audio audio(RenderWave(seconds, synth));
audio.play();
while (System::Update())
{
Vec2 pos(20, 20 - SliderHeight);
- SimpleGUI::Slider(U"amplitude : {:.2f}"_fmt(amplitude), amplitude, 0.0, 1.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
- adsr.updateGUI(pos);
+ synth.updateGUI(pos);
if (SimpleGUI::Button(U"波形を再生成", Vec2{ pos.x, pos.y += SliderHeight }))
{
- audio = Audio(RenderWave(seconds, amplitude, noteNumbers, adsr));
+ synth.clear();
+
+ audio = Audio(RenderWave(seconds, synth));
audio.play();
}
}
```
### １.５ 譜面を再生する
```diff
@@ -1,5 +1,7 @@
# include // OpenSiv3D v0.6.6
+#include "SoundTools.hpp"
+
const auto SliderHeight = 36;
const auto SliderWidth = 400;
const auto LabelWidth = 200;
@@ -114,6 +116,7 @@ float NoteNumberToFrequency(int8_t d)
struct NoteState
{
+ float m_velocity = 1.f;
EnvGenerator m_envelope;
};
@@ -139,7 +142,7 @@ public:
WaveSample sample(0, 0);
for (auto& [noteNumber, noteState] : m_noteState)
{
- const auto envLevel = noteState.m_envelope.currentLevel();
+ const auto envLevel = noteState.m_envelope.currentLevel() * noteState.m_velocity;
const auto frequency = NoteNumberToFrequency(noteNumber);
const auto w = static_cast(sin(Math::TwoPiF * frequency * m_time) * envLevel);
@@ -152,9 +155,11 @@ public:
return sample * static_cast(m_amplitude);
}
- void noteOn(int8_t noteNumber)
+ void noteOn(int8_t noteNumber, int8_t velocity)
{
- m_noteState.emplace(noteNumber, NoteState());
+ NoteState noteState;
+ noteState.m_velocity = velocity / 127.0f;
+ m_noteState.emplace(noteNumber, noteState);
}
void noteOff(int8_t noteNumber)
@@ -192,33 +197,52 @@ private:
ADSRConfig m_adsr;
- double m_amplitude = 0.2;
+ double m_amplitude = 0.1;
double m_time = 0;
};
-Wave RenderWave(uint32 seconds, Synthesizer& synth)
+Wave RenderWave(Synthesizer& synth, const MidiData& midiData)
{
- const auto lengthOfSamples = seconds * Wave::DefaultSampleRate;
+ const auto lengthOfSamples = static_cast(ceil(midiData.lengthOfTime() * Wave::DefaultSampleRate));
Wave wave(lengthOfSamples);
- // 半分経過したところでノートオフ
- const auto noteOffSample = lengthOfSamples / 2;
+ for (int64 i = 0; i < lengthOfSamples; ++i)
+ {
+ const auto currentTime = 1.0 * i / wave.sampleRate();
+ const auto nextTime = 1.0 * (i + 1) / wave.sampleRate();
- synth.noteOn(60); // C_4
- synth.noteOn(64); // E_4
- synth.noteOn(67); // G_4
+ const auto currentTick = midiData.secondsToTicks(currentTime);
+ const auto nextTick = midiData.secondsToTicks(nextTime);
- for (uint32 i = 0; i < lengthOfSamples; ++i)
- {
- if (i == noteOffSample)
+ // tick が進んだら MIDI イベントの処理を更新する
+ if (currentTick != nextTick)
{
- synth.noteOff(60);
- synth.noteOff(64);
- synth.noteOff(67);
+ for (const auto& track : midiData.tracks())
+ {
+ if (track.isPercussionTrack())
+ {
+ continue;
+ }
+
+ // 発生したノートオフイベントをシンセに登録
+ const auto noteOffEvents = track.getMIDIEvent(currentTick, nextTick);
+ for (auto& [tick, noteOff] : noteOffEvents)
+ {
+ synth.noteOff(noteOff.note_number);
+ }
+
+ // 発生したノートオンイベントをシンセに登録
+ const auto noteOnEvents = track.getMIDIEvent(currentTick, nextTick);
+ for (auto& [tick, noteOn] : noteOnEvents)
+ {
+ synth.noteOn(noteOn.note_number, noteOn.velocity);
+ }
+ }
}
+ // シンセを1サンプル更新して波形を書き込む
wave[i] = synth.renderSample();
}
@@ -227,11 +251,18 @@ Wave RenderWave(uint32 seconds, Synthesizer& synth)
void Main()
{
- uint32 seconds = 3;
+ auto midiDataOpt = LoadMidi(U"short_loop.mid");
+ if (!midiDataOpt)
+ {
+ // ファイルが見つからない or 読み込みエラー
+ return;
+ }
+
+ const MidiData& midiData = midiDataOpt.value();
Synthesizer synth;
- Audio audio(RenderWave(seconds, synth));
+ Audio audio(RenderWave(synth, midiData));
audio.play();
while (System::Update())
@@ -242,9 +273,10 @@ void Main()
if (SimpleGUI::Button(U"波形を再生成", Vec2{ pos.x, pos.y += SliderHeight }))
{
+ audio.stop();
synth.clear();
- audio = Audio(RenderWave(seconds, synth));
+ audio = Audio(RenderWave(synth, midiData));
audio.play();
}
}
```
## その２：基本波形とリアルタイム再生
### ２.１ 基本波形を追加する
```diff
@@ -2,6 +2,76 @@
#include "SoundTools.hpp"
+double WaveSaw(double t, int n)
+{
+ double sum = 0;
+ for (int k = 1; k <= n; ++k)
+ {
+ const double a = (k % 2 == 0 ? 1.0 : -1.0) / k;
+ sum += a * sin(k * t);
+ }
+
+ return -2.0 * sum / Math::Pi;
+}
+
+double WaveSquare(double t, int n)
+{
+ double sum = 0;
+ for (int k = 1; k <= n; ++k)
+ {
+ const double a = 2.0 * k - 1.0;
+ sum += sin(a * t) / a;
+ }
+
+ return 4.0 * sum / Math::Pi;
+}
+
+double WavePulse(double t, int n, double d)
+{
+ double sum = 0;
+ for (int k = 1; k <= n; ++k)
+ {
+ const double a = sin(k * d * Math::Pi) / k;
+ sum += a * cos(k * (t - d * Math::Pi));
+ }
+
+ return 2.0 * d - 1.0 + 4.0 * sum / Math::Pi;
+}
+
+double WaveNoise()
+{
+ return Random(-1.0, 1.0);
+}
+
+enum class WaveForm
+{
+ Saw, Sin, Square, Noise,
+};
+
+static constexpr uint32 SamplingFreq = Wave::DefaultSampleRate;
+static constexpr uint32 MaxFreq = SamplingFreq / 2;
+
+class Oscillator
+{
+public:
+
+ double get(double t, double freq, WaveForm waveForm) const
+ {
+ switch (waveForm)
+ {
+ case WaveForm::Saw:
+ return WaveSaw(freq * t * 2_pi, static_cast(MaxFreq / freq));
+ case WaveForm::Sin:
+ return sin(freq * t * 2_pi);
+ case WaveForm::Square:
+ return WaveSquare(freq * t * 2_pi, static_cast((MaxFreq + freq) / (freq * 2.0)));
+ case WaveForm::Noise:
+ return WaveNoise();
+ default: return 0;
+ }
+ }
+};
+
const auto SliderHeight = 36;
const auto SliderWidth = 400;
const auto LabelWidth = 200;
@@ -22,6 +92,15 @@ struct ADSRConfig
}
};
+bool SliderInt(const String& label, int& value, double min, double max, const Vec2& pos, double labelWidth = 80.0, double sliderWidth = 120.0, bool enabled = true)
+{
+ static std::unordered_map val;
+ val[&value] = value;
+ const bool result = SimpleGUI::Slider(label, val[&value], min, max, pos, labelWidth, sliderWidth, enabled);
+ value = static_cast(Math::Round(val[&value]));
+ return result;
+}
+
class EnvGenerator
{
public:
@@ -145,7 +224,8 @@ public:
const auto envLevel = noteState.m_envelope.currentLevel() * noteState.m_velocity;
const auto frequency = NoteNumberToFrequency(noteNumber);
- const auto w = static_cast(sin(Math::TwoPiF * frequency * m_time) * envLevel);
+ const auto osc = m_oscillator.get(m_time, frequency, static_cast(m_oscIndex));
+ const auto w = static_cast(osc * envLevel);
sample.left += w;
sample.right += w;
}
@@ -182,6 +262,7 @@ public:
void updateGUI(Vec2& pos)
{
SimpleGUI::Slider(U"amplitude : {:.2f}"_fmt(m_amplitude), m_amplitude, 0.0, 1.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
+ SliderInt(U"oscillator : {}"_fmt(m_oscIndex), m_oscIndex, 0, 3, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
m_adsr.updateGUI(pos);
}
@@ -198,6 +279,8 @@ private:
ADSRConfig m_adsr;
double m_amplitude = 0.1;
+ Oscillator m_oscillator;
+ int m_oscIndex = 0;
double m_time = 0;
};
@@ -251,6 +334,7 @@ Wave RenderWave(Synthesizer& synth, const MidiData& midiData)
void Main()
{
+ // 注意：波形生成に数秒かかります。example/midi/test.mid を渡すと長すぎて返って来ないので注意
auto midiDataOpt = LoadMidi(U"short_loop.mid");
if (!midiDataOpt)
{
```
### ２.２ オシレータをウェーブテーブル化する
```diff
@@ -51,25 +51,62 @@ enum class WaveForm
static constexpr uint32 SamplingFreq = Wave::DefaultSampleRate;
static constexpr uint32 MaxFreq = SamplingFreq / 2;
-class Oscillator
+class OscillatorWavetable
{
public:
- double get(double t, double freq, WaveForm waveForm) const
+ OscillatorWavetable() = default;
+
+ OscillatorWavetable(size_t resolution, double frequency, WaveForm waveType) :
+ m_wave(resolution)
{
- switch (waveForm)
+ const int mSaw = static_cast(MaxFreq / frequency);
+ const int mSquare = static_cast((MaxFreq + frequency) / (frequency * 2.0));
+
+ for (size_t i = 0; i < resolution; ++i)
{
- case WaveForm::Saw:
- return WaveSaw(freq * t * 2_pi, static_cast(MaxFreq / freq));
- case WaveForm::Sin:
- return sin(freq * t * 2_pi);
- case WaveForm::Square:
- return WaveSquare(freq * t * 2_pi, static_cast((MaxFreq + freq) / (freq * 2.0)));
- case WaveForm::Noise:
- return WaveNoise();
- default: return 0;
+ const double angle = 2_pi * i / resolution;
+
+ switch (waveType)
+ {
+ case WaveForm::Saw:
+ m_wave[i] = static_cast(WaveSaw(angle, mSaw));
+ break;
+ case WaveForm::Sin:
+ m_wave[i] = static_cast(sin(angle));
+ break;
+ case WaveForm::Square:
+ m_wave[i] = static_cast(WaveSquare(angle, mSquare));
+ break;
+ case WaveForm::Noise:
+ m_wave[i] = static_cast(WaveNoise());
+ break;
+ default: break;
+ }
}
}
+
+ double get(double x) const
+ {
+ const size_t resolution = m_wave.size();
+ const double indexFloat = fmod(x * resolution / 2_pi, resolution);
+ const int indexInt = static_cast(indexFloat);
+ const double rate = indexFloat - indexInt;
+ return Math::Lerp(m_wave[indexInt], m_wave[(indexInt + 1) % resolution], rate);
+ }
+
+private:
+
+ Array m_wave;
+};
+
+// とりあえず440Hzで生成
+static Array OscWaveTables =
+{
+ OscillatorWavetable(2048, 440, WaveForm::Saw),
+ OscillatorWavetable(2048, 440, WaveForm::Sin),
+ OscillatorWavetable(2048, 440, WaveForm::Square),
+ OscillatorWavetable(SamplingFreq, 440, WaveForm::Noise),
};
const auto SliderHeight = 36;
@@ -206,7 +243,7 @@ public:
// 1サンプル波形を生成して返す
WaveSample renderSample()
{
- const auto deltaT = 1.0 / Wave::DefaultSampleRate;
+ const auto deltaT = 1.0 / SamplingFreq;
// エンベロープの更新
for (auto& [noteNumber, noteState] : m_noteState)
@@ -224,7 +261,7 @@ public:
const auto envLevel = noteState.m_envelope.currentLevel() * noteState.m_velocity;
const auto frequency = NoteNumberToFrequency(noteNumber);
- const auto osc = m_oscillator.get(m_time, frequency, static_cast(m_oscIndex));
+ const auto osc = OscWaveTables[m_oscIndex].get(m_time * frequency * 2_pi);
const auto w = static_cast(osc * envLevel);
sample.left += w;
sample.right += w;
@@ -279,7 +316,6 @@ private:
ADSRConfig m_adsr;
double m_amplitude = 0.1;
- Oscillator m_oscillator;
int m_oscIndex = 0;
double m_time = 0;
@@ -334,7 +370,6 @@ Wave RenderWave(Synthesizer& synth, const MidiData& midiData)
void Main()
{
- // 注意：波形生成に数秒かかります。example/midi/test.mid を渡すと長すぎて返って来ないので注意
auto midiDataOpt = LoadMidi(U"short_loop.mid");
if (!midiDataOpt)
{
```
### ２.３ 帯域制限付きウェーブテーブルを実装する
```diff
@@ -49,6 +49,7 @@ enum class WaveForm
};
static constexpr uint32 SamplingFreq = Wave::DefaultSampleRate;
+static constexpr uint32 MinFreq = 20;
static constexpr uint32 MaxFreq = SamplingFreq / 2;
class OscillatorWavetable
@@ -100,13 +101,59 @@ private:
Array m_wave;
};
-// とりあえず440Hzで生成
-static Array OscWaveTables =
+class BandLimitedWaveTables
{
- OscillatorWavetable(2048, 440, WaveForm::Saw),
- OscillatorWavetable(2048, 440, WaveForm::Sin),
- OscillatorWavetable(2048, 440, WaveForm::Square),
- OscillatorWavetable(SamplingFreq, 440, WaveForm::Noise),
+public:
+
+ BandLimitedWaveTables() = default;
+
+ BandLimitedWaveTables(size_t tableCount, size_t waveResolution, WaveForm waveType)
+ {
+ m_waveTables.reserve(tableCount);
+ m_tableFreqs.reserve(tableCount);
+
+ for (size_t i = 0; i < tableCount; ++i)
+ {
+ const double rate = 1.0 * i / tableCount;
+ const double freq = pow(2, Math::Lerp(m_minFreqLog, m_maxFreqLog, rate));
+
+ m_waveTables.emplace_back(waveResolution, freq, waveType);
+ m_tableFreqs.push_back(static_cast(freq));
+ }
+ }
+
+ double get(double x, double freq) const
+ {
+ const auto nextIt = std::upper_bound(m_tableFreqs.begin(), m_tableFreqs.end(), freq);
+ const auto nextIndex = std::distance(m_tableFreqs.begin(), nextIt);
+ if (nextIndex == 0)
+ {
+ return m_waveTables.front().get(x);
+ }
+ if (static_cast(nextIndex) == m_tableFreqs.size())
+ {
+ return m_waveTables.back().get(x);
+ }
+
+ const auto prevIndex = nextIndex - 1;
+ const auto rate = Math::InvLerp(m_tableFreqs[prevIndex], m_tableFreqs[nextIndex], freq);
+ return Math::Lerp(m_waveTables[prevIndex].get(x), m_waveTables[nextIndex].get(x), rate);
+ }
+
+private:
+
+ double m_minFreqLog = log2(MinFreq);
+ double m_maxFreqLog = log2(MaxFreq);
+ Array m_waveTables;
+ Array m_tableFreqs;
+};
+
+static Array OscWaveTables =
+{
+ BandLimitedWaveTables(80, 2048, WaveForm::Saw),
+ BandLimitedWaveTables(1, 2048, WaveForm::Sin),
+ BandLimitedWaveTables(80, 2048, WaveForm::Square),
+ BandLimitedWaveTables(1, SamplingFreq, WaveForm::Noise),
};
const auto SliderHeight = 36;
@@ -261,7 +308,7 @@ public:
const auto envLevel = noteState.m_envelope.currentLevel() * noteState.m_velocity;
const auto frequency = NoteNumberToFrequency(noteNumber);
- const auto osc = OscWaveTables[m_oscIndex].get(m_time * frequency * 2_pi);
+ const auto osc = OscWaveTables[m_oscIndex].get(m_time * frequency * 2_pi, frequency);
const auto w = static_cast(osc * envLevel);
sample.left += w;
sample.right += w;
@@ -309,6 +356,11 @@ public:
m_noteState.clear();
}
+ ADSRConfig& adsr()
+ {
+ return m_adsr;
+ }
+
private:
std::multimap m_noteState;
@@ -370,7 +422,8 @@ Wave RenderWave(Synthesizer& synth, const MidiData& midiData)
void Main()
{
- auto midiDataOpt = LoadMidi(U"short_loop.mid");
+ Window::Resize(1280, 720);
+ auto midiDataOpt = LoadMidi(U"C1_B8.mid");
if (!midiDataOpt)
{
// ファイルが見つからない or 読み込みエラー
@@ -380,17 +433,20 @@ void Main()
const MidiData& midiData = midiDataOpt.value();
Synthesizer synth;
+ auto& adsr = synth.adsr();
+ adsr.attackTime = 0.02;
+ adsr.releaseTime = 0.02;
Audio audio(RenderWave(synth, midiData));
audio.play();
+ AudioVisualizer visualizer(Scene::Rect().stretched(-50), AudioVisualizer::Spectrogram, AudioVisualizer::LogScale);
+ visualizer.setFreqRange(100, 20000); // [100, 20000] Hz
+ visualizer.setSplRange(-120, -60); // [-120, -60] dB
+
while (System::Update())
{
- Vec2 pos(20, 20 - SliderHeight);
-
- synth.updateGUI(pos);
-
- if (SimpleGUI::Button(U"波形を再生成", Vec2{ pos.x, pos.y += SliderHeight }))
+ if (KeySpace.down())
{
audio.stop();
synth.clear();
@@ -398,5 +454,9 @@ void Main()
audio = Audio(RenderWave(synth, midiData));
audio.play();
}
+
+ visualizer.setInputWave(audio);
+ visualizer.updateFFT();
+ visualizer.draw();
}
}
```
### ２.４ 波形生成をリアルタイムに行う
```diff
@@ -373,90 +373,94 @@ private:
double m_time = 0;
};
-Wave RenderWave(Synthesizer& synth, const MidiData& midiData)
+class AudioRenderer : public IAudioStream
{
- const auto lengthOfSamples = static_cast(ceil(midiData.lengthOfTime() * Wave::DefaultSampleRate));
+public:
- Wave wave(lengthOfSamples);
+ void setMidiData(const MidiData& midiData)
+ {
+ m_midiData = midiData;
+ }
- for (int64 i = 0; i < lengthOfSamples; ++i)
+ void updateGUI(Vec2& pos)
{
- const auto currentTime = 1.0 * i / wave.sampleRate();
- const auto nextTime = 1.0 * (i + 1) / wave.sampleRate();
+ m_synth.updateGUI(pos);
+ }
- const auto currentTick = midiData.secondsToTicks(currentTime);
- const auto nextTick = midiData.secondsToTicks(nextTime);
+private:
- // tick が進んだら MIDI イベントの処理を更新する
- if (currentTick != nextTick)
+ void getAudio(float* left, float* right, const size_t samplesToWrite) override
+ {
+ for (size_t i = 0; i < samplesToWrite; ++i)
{
- for (const auto& track : midiData.tracks())
- {
- if (track.isPercussionTrack())
- {
- continue;
- }
+ const double currentTime = 1.0 * m_readMIDIPos / SamplingFreq;
+ const double nextTime = 1.0 * (m_readMIDIPos + 1) / SamplingFreq;
- // 発生したノートオフイベントをシンセに登録
- const auto noteOffEvents = track.getMIDIEvent(currentTick, nextTick);
- for (auto& [tick, noteOff] : noteOffEvents)
- {
- synth.noteOff(noteOff.note_number);
- }
+ const auto currentTick = m_midiData.secondsToTicks(currentTime);
+ const auto nextTick = m_midiData.secondsToTicks(nextTime);
- // 発生したノートオンイベントをシンセに登録
- const auto noteOnEvents = track.getMIDIEvent(currentTick, nextTick);
- for (auto& [tick, noteOn] : noteOnEvents)
+ // tick が進んだら MIDI イベントの処理を更新する
+ if (currentTick != nextTick)
+ {
+ for (const auto& track : m_midiData.tracks())
{
- synth.noteOn(noteOn.note_number, noteOn.velocity);
+ if (track.isPercussionTrack())
+ {
+ continue;
+ }
+
+ // 発生したノートオフイベントをシンセに登録
+ const auto noteOffEvents = track.getMIDIEvent(currentTick, nextTick);
+ for (auto& [tick, noteOff] : noteOffEvents)
+ {
+ m_synth.noteOff(noteOff.note_number);
+ }
+
+ // 発生したノートオンイベントをシンセに登録
+ const auto noteOnEvents = track.getMIDIEvent(currentTick, nextTick);
+ for (auto& [tick, noteOn] : noteOnEvents)
+ {
+ m_synth.noteOn(noteOn.note_number, noteOn.velocity);
+ }
}
}
- }
- // シンセを1サンプル更新して波形を書き込む
- wave[i] = synth.renderSample();
+ const auto waveSample = m_synth.renderSample();
+
+ *left++ = waveSample.left;
+ *right++ = waveSample.right;
+
+ ++m_readMIDIPos;
+ }
}
- return wave;
-}
+ bool hasEnded() override { return false; }
+ void rewind() override {}
+
+ Synthesizer m_synth;
+ MidiData m_midiData;
+ size_t m_readMIDIPos = 0;
+};
void Main()
{
- Window::Resize(1280, 720);
- auto midiDataOpt = LoadMidi(U"C1_B8.mid");
+ auto midiDataOpt = LoadMidi(U"example/midi/test.mid");
if (!midiDataOpt)
{
// ファイルが見つからない or 読み込みエラー
return;
}
- const MidiData& midiData = midiDataOpt.value();
-
- Synthesizer synth;
- auto& adsr = synth.adsr();
- adsr.attackTime = 0.02;
- adsr.releaseTime = 0.02;
+ std::shared_ptr audioStream = std::make_shared();
+ audioStream->setMidiData(midiDataOpt.value());
- Audio audio(RenderWave(synth, midiData));
+ Audio audio(audioStream);
audio.play();
- AudioVisualizer visualizer(Scene::Rect().stretched(-50), AudioVisualizer::Spectrogram, AudioVisualizer::LogScale);
- visualizer.setFreqRange(100, 20000); // [100, 20000] Hz
- visualizer.setSplRange(-120, -60); // [-120, -60] dB
-
while (System::Update())
{
- if (KeySpace.down())
- {
- audio.stop();
- synth.clear();
-
- audio = Audio(RenderWave(synth, midiData));
- audio.play();
- }
+ Vec2 pos(20, 20 - SliderHeight);
- visualizer.setInputWave(audio);
- visualizer.updateFFT();
- visualizer.draw();
+ audioStream->updateGUI(pos);
}
}
```
### ２.５ パフォーマンスをもう少し最適化する
```diff
@@ -59,7 +59,8 @@ public:
OscillatorWavetable() = default;
OscillatorWavetable(size_t resolution, double frequency, WaveForm waveType) :
- m_wave(resolution)
+ m_wave(resolution),
+ m_xToIndex(resolution / 2_pi)
{
const int mSaw = static_cast(MaxFreq / frequency);
const int mSquare = static_cast((MaxFreq + frequency) / (frequency * 2.0));
@@ -89,16 +90,26 @@ public:
double get(double x) const
{
- const size_t resolution = m_wave.size();
- const double indexFloat = fmod(x * resolution / 2_pi, resolution);
- const int indexInt = static_cast(indexFloat);
- const double rate = indexFloat - indexInt;
- return Math::Lerp(m_wave[indexInt], m_wave[(indexInt + 1) % resolution], rate);
+ auto indexFloat = x * m_xToIndex;
+ auto prevIndex = static_cast(indexFloat);
+ if (m_wave.size() == prevIndex)
+ {
+ prevIndex -= m_wave.size();
+ indexFloat -= m_wave.size();
+ }
+ auto nextIndex = prevIndex + 1;
+ if (m_wave.size() == nextIndex)
+ {
+ nextIndex = 0;
+ }
+ const auto x01 = indexFloat - prevIndex;
+ return Math::Lerp(m_wave[prevIndex], m_wave[nextIndex], x01);
}
private:
Array m_wave;
+ double m_xToIndex = 0;
};
class BandLimitedWaveTables
@@ -120,12 +131,22 @@ public:
m_waveTables.emplace_back(waveResolution, freq, waveType);
m_tableFreqs.push_back(static_cast(freq));
}
+
+ {
+ m_indices.resize(2048);
+ m_freqToIndex = m_indices.size() / (1.0 * MaxFreq);
+ for (int i = 0; i < m_indices.size(); ++i)
+ {
+ const float freq = static_cast(i / m_freqToIndex);
+ const auto nextIt = std::upper_bound(m_tableFreqs.begin(), m_tableFreqs.end(), freq);
+ m_indices[i] = static_cast(nextIt - m_tableFreqs.begin());
+ }
+ }
}
double get(double x, double freq) const
{
- const auto nextIt = std::upper_bound(m_tableFreqs.begin(), m_tableFreqs.end(), freq);
- const auto nextIndex = std::distance(m_tableFreqs.begin(), nextIt);
+ const auto nextIndex = m_indices[static_cast(freq * m_freqToIndex)];
if (nextIndex == 0)
{
return m_waveTables.front().get(x);
@@ -146,6 +167,9 @@ private:
double m_maxFreqLog = log2(MaxFreq);
Array m_waveTables;
Array m_tableFreqs;
+
+ Array m_indices;
+ double m_freqToIndex = 0;
};
static Array OscWaveTables =
@@ -279,6 +303,7 @@ float NoteNumberToFrequency(int8_t d)
struct NoteState
{
+ double m_phase = 0;
float m_velocity = 1.f;
EnvGenerator m_envelope;
};
@@ -308,14 +333,18 @@ public:
const auto envLevel = noteState.m_envelope.currentLevel() * noteState.m_velocity;
const auto frequency = NoteNumberToFrequency(noteNumber);
- const auto osc = OscWaveTables[m_oscIndex].get(m_time * frequency * 2_pi, frequency);
+ const auto osc = OscWaveTables[m_oscIndex].get(noteState.m_phase, frequency);
+ noteState.m_phase += deltaT * frequency * 2_pi;
+ if (Math::TwoPi < noteState.m_phase)
+ {
+ noteState.m_phase -= Math::TwoPi;
+ }
+
const auto w = static_cast(osc * envLevel);
sample.left += w;
sample.right += w;
}
- m_time += deltaT;
-
return sample * static_cast(m_amplitude);
}
@@ -369,69 +398,89 @@ private:
double m_amplitude = 0.1;
int m_oscIndex = 0;
-
- double m_time = 0;
};
class AudioRenderer : public IAudioStream
{
public:
+ AudioRenderer()
+ {
+ // 100ms分のバッファを確保する
+ const size_t bufferSize = SamplingFreq / 10;
+ m_buffer.resize(bufferSize);
+ }
+
void setMidiData(const MidiData& midiData)
{
m_midiData = midiData;
}
- void updateGUI(Vec2& pos)
+ void bufferSample()
{
- m_synth.updateGUI(pos);
- }
+ const double currentTime = 1.0 * m_readMIDIPos / SamplingFreq;
+ const double nextTime = 1.0 * (m_readMIDIPos + 1) / SamplingFreq;
-private:
+ const auto currentTick = m_midiData.secondsToTicks(currentTime);
+ const auto nextTick = m_midiData.secondsToTicks(nextTime);
- void getAudio(float* left, float* right, const size_t samplesToWrite) override
- {
- for (size_t i = 0; i < samplesToWrite; ++i)
+ // tick が進んだら MIDI イベントの処理を更新する
+ if (currentTick != nextTick)
{
- const double currentTime = 1.0 * m_readMIDIPos / SamplingFreq;
- const double nextTime = 1.0 * (m_readMIDIPos + 1) / SamplingFreq;
+ for (const auto& track : m_midiData.tracks())
+ {
+ if (track.isPercussionTrack())
+ {
+ continue;
+ }
- const auto currentTick = m_midiData.secondsToTicks(currentTime);
- const auto nextTick = m_midiData.secondsToTicks(nextTime);
+ // 発生したノートオフイベントをシンセに登録
+ const auto noteOffEvents = track.getMIDIEvent(currentTick, nextTick);
+ for (auto& [tick, noteOff] : noteOffEvents)
+ {
+ m_synth.noteOff(noteOff.note_number);
+ }
- // tick が進んだら MIDI イベントの処理を更新する
- if (currentTick != nextTick)
- {
- for (const auto& track : m_midiData.tracks())
+ // 発生したノートオンイベントをシンセに登録
+ const auto noteOnEvents = track.getMIDIEvent(currentTick, nextTick);
+ for (auto& [tick, noteOn] : noteOnEvents)
{
- if (track.isPercussionTrack())
- {
- continue;
- }
-
- // 発生したノートオフイベントをシンセに登録
- const auto noteOffEvents = track.getMIDIEvent(currentTick, nextTick);
- for (auto& [tick, noteOff] : noteOffEvents)
- {
- m_synth.noteOff(noteOff.note_number);
- }
-
- // 発生したノートオンイベントをシンセに登録
- const auto noteOnEvents = track.getMIDIEvent(currentTick, nextTick);
- for (auto& [tick, noteOn] : noteOnEvents)
- {
- m_synth.noteOn(noteOn.note_number, noteOn.velocity);
- }
+ m_synth.noteOn(noteOn.note_number, noteOn.velocity);
}
}
+ }
+
+ const size_t writeIndex = m_bufferWritePos % m_buffer.size();
+
+ m_buffer[writeIndex] = m_synth.renderSample();
+
+ ++m_bufferWritePos;
+ ++m_readMIDIPos;
+ }
- const auto waveSample = m_synth.renderSample();
+ bool bufferCompleted() const
+ {
+ return m_bufferReadPos + m_buffer.size() - 1 < m_bufferWritePos;
+ }
- *left++ = waveSample.left;
- *right++ = waveSample.right;
+ void updateGUI(Vec2& pos)
+ {
+ m_synth.updateGUI(pos);
+ }
+
+private:
+
+ void getAudio(float* left, float* right, const size_t samplesToWrite) override
+ {
+ for (size_t i = 0; i < samplesToWrite; ++i)
+ {
+ const auto& readSample = m_buffer[(m_bufferReadPos + i) % m_buffer.size()];
- ++m_readMIDIPos;
+ *left++ = readSample.left;
+ *right++ = readSample.right;
}
+
+ m_bufferReadPos += samplesToWrite;
}
bool hasEnded() override { return false; }
@@ -439,7 +488,10 @@ private:
Synthesizer m_synth;
MidiData m_midiData;
+ Array m_buffer;
size_t m_readMIDIPos = 0;
+ size_t m_bufferReadPos = 0;
+ size_t m_bufferWritePos = 0;
};
void Main()
@@ -454,6 +506,23 @@ void Main()
std::shared_ptr audioStream = std::make_shared();
audioStream->setMidiData(midiDataOpt.value());
+ bool isRunning = true;
+
+ auto renderUpdate = [&]()
+ {
+ while (isRunning)
+ {
+ while (!audioStream->bufferCompleted())
+ {
+ audioStream->bufferSample();
+ }
+
+ std::this_thread::sleep_for(std::chrono::milliseconds(1));
+ }
+ };
+
+ std::thread audioRenderThread(renderUpdate);
+
Audio audio(audioStream);
audio.play();
@@ -463,4 +532,7 @@ void Main()
audioStream->updateGUI(pos);
}
+
+ isRunning = false;
+ audioRenderThread.join();
}
```
## その３：波形を合成して音を作る
### ３.０ 可視化機能を実装する
```diff
@@ -390,6 +390,24 @@ public:
return m_adsr;
}
+ int oscIndex() const
+ {
+ return m_oscIndex;
+ }
+ void setOscIndex(int oscIndex)
+ {
+ m_oscIndex = oscIndex;
+ }
+
+ double amplitude() const
+ {
+ return m_amplitude;
+ }
+ void setAmplitude(double amplitude)
+ {
+ m_amplitude = amplitude;
+ }
+
private:
std::multimap m_noteState;
@@ -468,6 +486,26 @@ public:
m_synth.updateGUI(pos);
}
+ const Array& buffer() const
+ {
+ return m_buffer;
+ }
+
+ size_t bufferReadPos() const
+ {
+ return m_bufferReadPos;
+ }
+
+ size_t playingMIDIPos() const
+ {
+ return m_readMIDIPos - (m_bufferWritePos - m_bufferReadPos);
+ }
+
+ Synthesizer& synth()
+ {
+ return m_synth;
+ }
+
private:
void getAudio(float* left, float* right, const size_t samplesToWrite) override
@@ -496,6 +534,8 @@ private:
void Main()
{
+ Window::Resize(1600, 900);
+
auto midiDataOpt = LoadMidi(U"example/midi/test.mid");
if (!midiDataOpt)
{
@@ -503,9 +543,24 @@ void Main()
return;
}
+ AudioVisualizer visualizer;
+ visualizer.setSplRange(-60, -30);
+ visualizer.setWindowType(AudioVisualizer::Hamming);
+ visualizer.setDrawScore(NoteNumber::C_2, NoteNumber::B_7);
+ visualizer.setDrawArea(Scene::Rect());
+
std::shared_ptr audioStream = std::make_shared();
audioStream->setMidiData(midiDataOpt.value());
+ auto& synth = audioStream->synth();
+ synth.setOscIndex(static_cast(WaveForm::Sin));
+
+ auto& adsr = synth.adsr();
+ adsr.attackTime = 0.01;
+ adsr.decayTime = 0.0;
+ adsr.sustainLevel = 1.0;
+ adsr.releaseTime = 0.01;
+
bool isRunning = true;
auto renderUpdate = [&]()
@@ -526,11 +581,43 @@ void Main()
Audio audio(audioStream);
audio.play();
+ bool showGUI = true;
while (System::Update())
{
Vec2 pos(20, 20 - SliderHeight);
- audioStream->updateGUI(pos);
+ // visualizerの更新
+ {
+ auto& visualizeBuffer = visualizer.inputWave();
+ visualizeBuffer.fill(0);
+
+ const auto& streamBuffer = audioStream->buffer();
+ const auto readStartPos = audioStream->bufferReadPos();
+
+ const auto fftInputSize = Min(visualizeBuffer.size(), streamBuffer.size());
+
+ for (size_t i = 0; i < fftInputSize; ++i)
+ {
+ const auto inputIndex = (readStartPos + i) % streamBuffer.size();
+ const auto& sample = streamBuffer[inputIndex];
+ visualizeBuffer[i] = (sample.left + sample.right) * 0.5f;
+ }
+
+ visualizer.updateFFT(fftInputSize);
+
+ const auto currentTime = 1.0 * audioStream->playingMIDIPos() / SamplingFreq;
+ visualizer.drawScore(midiDataOpt.value(), currentTime);
+ }
+
+ if (KeyG.down())
+ {
+ showGUI = !showGUI;
+ }
+
+ if (showGUI)
+ {
+ audioStream->updateGUI(pos);
+ }
}
isRunning = false;
```
### ３.１ パンとピッチシフト
```diff
@@ -326,12 +326,14 @@ public:
// リリースが終了したノートを削除する
std::erase_if(m_noteState, [&](const auto& noteState) { return noteState.second.m_envelope.isReleased(m_adsr); });
+ const auto pitch = pow(2.0, m_pitchShift / 12.0);
+
// 入力中の波形を加算して書き込む
WaveSample sample(0, 0);
for (auto& [noteNumber, noteState] : m_noteState)
{
const auto envLevel = noteState.m_envelope.currentLevel() * noteState.m_velocity;
- const auto frequency = NoteNumberToFrequency(noteNumber);
+ const auto frequency = NoteNumberToFrequency(noteNumber) * pitch;
const auto osc = OscWaveTables[m_oscIndex].get(noteState.m_phase, frequency);
noteState.m_phase += deltaT * frequency * 2_pi;
@@ -345,6 +347,9 @@ public:
sample.right += w;
}
+ sample.left *= static_cast(cos(Math::HalfPi * m_pan));
+ sample.right *= static_cast(sin(Math::HalfPi * m_pan));
+
return sample * static_cast(m_amplitude);
}
@@ -375,8 +380,15 @@ public:
void updateGUI(Vec2& pos)
{
SimpleGUI::Slider(U"amplitude : {:.2f}"_fmt(m_amplitude), m_amplitude, 0.0, 1.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
+ SimpleGUI::Slider(U"pan : {:.2f}"_fmt(m_pan), m_pan, 0.0, 1.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
SliderInt(U"oscillator : {}"_fmt(m_oscIndex), m_oscIndex, 0, 3, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
+ if (SimpleGUI::Slider(U"pitchShift : {:.2f}"_fmt(m_pitchShift), m_pitchShift, -24.0, 24.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth)
+ && KeyControl.pressed())
+ {
+ m_pitchShift = Math::Round(m_pitchShift);
+ }
+
m_adsr.updateGUI(pos);
}
@@ -408,6 +420,24 @@ public:
m_amplitude = amplitude;
}
+ double pan() const
+ {
+ return m_pan;
+ }
+ void setPan(double pan)
+ {
+ m_pan = pan;
+ }
+
+ double pitchShift() const
+ {
+ return m_pitchShift;
+ }
+ void setPitchShift(double pitchShift)
+ {
+ m_pitchShift = pitchShift;
+ }
+
private:
std::multimap m_noteState;
@@ -415,6 +445,8 @@ private:
ADSRConfig m_adsr;
double m_amplitude = 0.1;
+ double m_pan = 0.5;
+ double m_pitchShift = 0.0;
int m_oscIndex = 0;
};
```
### ３.２ ユニゾン
```diff
@@ -301,9 +301,22 @@ float NoteNumberToFrequency(int8_t d)
return 440.0f * pow(2.0f, (d - 69) / 12.0f);
}
+static constexpr uint32 MaxUnisonSize = 16;
+static const double Semitone = pow(2.0, 1.0 / 12.0) - 1.0;
+
struct NoteState
{
- double m_phase = 0;
+ NoteState()
+ {
+ for (auto& initialPhase : m_phase)
+ {
+ // 初期位相をランダムに設定する
+ initialPhase = Random(0.0, 2_pi);
+ }
+ }
+
+ // ユニゾン波形ごとに進む周波数が異なるので、別々に位相を管理する
+ std::array m_phase = {};
float m_velocity = 1.f;
EnvGenerator m_envelope;
};
@@ -312,6 +325,12 @@ class Synthesizer
{
public:
+ Synthesizer()
+ {
+ m_detunePitch.fill(1);
+ m_unisonPan.fill(Float2::One().normalize());
+ }
+
// 1サンプル波形を生成して返す
WaveSample renderSample()
{
@@ -330,27 +349,34 @@ public:
// 入力中の波形を加算して書き込む
WaveSample sample(0, 0);
+
for (auto& [noteNumber, noteState] : m_noteState)
{
const auto envLevel = noteState.m_envelope.currentLevel() * noteState.m_velocity;
const auto frequency = NoteNumberToFrequency(noteNumber) * pitch;
- const auto osc = OscWaveTables[m_oscIndex].get(noteState.m_phase, frequency);
- noteState.m_phase += deltaT * frequency * 2_pi;
- if (Math::TwoPi < noteState.m_phase)
+ for (int d = 0; d < m_unisonCount; ++d)
{
- noteState.m_phase -= Math::TwoPi;
- }
+ const auto detuneFrequency = frequency * m_detunePitch[d];
+ auto& phase = noteState.m_phase[d];
- const auto w = static_cast(osc * envLevel);
- sample.left += w;
- sample.right += w;
+ const auto osc = OscWaveTables[m_oscIndex].get(phase, detuneFrequency);
+ phase += deltaT * detuneFrequency * Math::TwoPiF;
+ if (Math::TwoPi < phase)
+ {
+ phase -= Math::TwoPi;
+ }
+
+ const auto w = static_cast(osc * envLevel);
+ sample.left += w * m_unisonPan[d].x;
+ sample.right += w * m_unisonPan[d].y;
+ }
}
sample.left *= static_cast(cos(Math::HalfPi * m_pan));
sample.right *= static_cast(sin(Math::HalfPi * m_pan));
- return sample * static_cast(m_amplitude);
+ return sample * static_cast(m_amplitude / sqrt(m_unisonCount));
}
void noteOn(int8_t noteNumber, int8_t velocity)
@@ -389,6 +415,16 @@ public:
m_pitchShift = Math::Round(m_pitchShift);
}
+ bool unisonUpdated = false;
+ unisonUpdated = SliderInt(U"unisonCount : {}"_fmt(m_unisonCount), m_unisonCount, 1, 16, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth) || unisonUpdated;
+ unisonUpdated = SimpleGUI::Slider(U"detune : {:.2f}"_fmt(m_detune), m_detune, 0.0, 1.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth) || unisonUpdated;
+ unisonUpdated = SimpleGUI::Slider(U"spread : {:.2f}"_fmt(m_spread), m_spread, 0.0, 1.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth) || unisonUpdated;
+
+ if (unisonUpdated)
+ {
+ updateUnisonParam();
+ }
+
m_adsr.updateGUI(pos);
}
@@ -438,8 +474,63 @@ public:
m_pitchShift = pitchShift;
}
+ int unisonCount() const
+ {
+ return m_unisonCount;
+ }
+ void setUnisonCount(int unisonCount)
+ {
+ m_unisonCount = unisonCount;
+ updateUnisonParam();
+ }
+
+ double detune() const
+ {
+ return m_detune;
+ }
+ void setDetune(double detune)
+ {
+ m_detune = detune;
+ updateUnisonParam();
+ }
+
+ double spread() const
+ {
+ return m_spread;
+ }
+ void setSpread(double spread)
+ {
+ m_spread = spread;
+ updateUnisonParam();
+ }
+
private:
+ void updateUnisonParam()
+ {
+ // ユニゾンなし
+ if (m_unisonCount == 1)
+ {
+ m_detunePitch.fill(1);
+ m_unisonPan.fill(Float2::One().normalize());
+ return;
+ }
+
+ // ユニゾンあり
+ for (int d = 0; d < m_unisonCount; ++d)
+ {
+ // 各波形の位置を[-1, 1]で計算する
+ const auto detunePos = Math::Lerp(-1.0, 1.0, 1.0 * d / (m_unisonCount - 1));
+
+ // 現在の周波数から最大で Semitone * m_detune だけピッチシフトする
+ m_detunePitch[d] = static_cast(1.0 + Semitone * m_detune * detunePos);
+
+ // Math::QuarterPi が中央
+ const auto unisonAngle = Math::QuarterPi * (1.0 + detunePos * m_spread);
+ m_unisonPan[d] = Float2(cos(unisonAngle), sin(unisonAngle));
+ }
+ }
+
std::multimap m_noteState;
ADSRConfig m_adsr;
@@ -448,6 +539,13 @@ private:
double m_pan = 0.5;
double m_pitchShift = 0.0;
int m_oscIndex = 0;
+
+ int m_unisonCount = 1;
+ double m_detune = 0;
+ double m_spread = 1.0;
+
+ std::array m_detunePitch;
+ std::array m_unisonPan;
};
class AudioRenderer : public IAudioStream
@@ -568,7 +666,7 @@ void Main()
{
Window::Resize(1600, 900);
- auto midiDataOpt = LoadMidi(U"example/midi/test.mid");
+ auto midiDataOpt = LoadMidi(U"C5_B8.mid");
if (!midiDataOpt)
{
// ファイルが見つからない or 読み込みエラー
@@ -578,14 +676,17 @@ void Main()
AudioVisualizer visualizer;
visualizer.setSplRange(-60, -30);
visualizer.setWindowType(AudioVisualizer::Hamming);
- visualizer.setDrawScore(NoteNumber::C_2, NoteNumber::B_7);
- visualizer.setDrawArea(Scene::Rect());
+ visualizer.setFreqRange(300, 10000);
+ visualizer.setDrawArea(Scene::Rect().stretched(-50));
std::shared_ptr audioStream = std::make_shared();
audioStream->setMidiData(midiDataOpt.value());
auto& synth = audioStream->synth();
- synth.setOscIndex(static_cast(WaveForm::Sin));
+ synth.setOscIndex(static_cast(WaveForm::Saw));
+ synth.setUnisonCount(4);
+ synth.setDetune(0.5);
+ synth.setSpread(0.0);
auto& adsr = synth.adsr();
adsr.attackTime = 0.01;
@@ -637,8 +738,7 @@ void Main()
visualizer.updateFFT(fftInputSize);
- const auto currentTime = 1.0 * audioStream->playingMIDIPos() / SamplingFreq;
- visualizer.drawScore(midiDataOpt.value(), currentTime);
+ visualizer.draw();
}
if (KeyG.down())
```
### ３.３ モノフォニックとポリフォニック
```diff
@@ -189,6 +189,7 @@ struct ADSRConfig
double attackTime = 0.01;
double decayTime = 0.01;
double sustainLevel = 0.6;
+ double sustainResetTime = 0.05;
double releaseTime = 0.4;
void updateGUI(Vec2& pos)
@@ -222,6 +223,7 @@ public:
{
if (m_state != State::Release)
{
+ m_prevStateLevel = m_currentLevel;
m_elapsed = 0;
m_state = State::Release;
}
@@ -229,6 +231,7 @@ public:
void reset(State state)
{
+ m_prevStateLevel = m_currentLevel;
m_elapsed = 0;
m_state = state;
}
@@ -240,9 +243,10 @@ public:
case State::Attack: // 0.0 から 1.0 まで attackTime かけて増幅する
if (m_elapsed < adsr.attackTime)
{
- m_currentLevel = m_elapsed / adsr.attackTime;
+ m_currentLevel = Math::Lerp(m_prevStateLevel, 1.0, m_elapsed / adsr.attackTime);
break;
}
+ m_prevStateLevel = m_currentLevel;
m_elapsed -= adsr.attackTime;
m_state = State::Decay;
[[fallthrough]]; // Decay処理にそのまま続く
@@ -250,21 +254,28 @@ public:
case State::Decay: // 1.0 から sustainLevel まで decayTime かけて減衰する
if (m_elapsed < adsr.decayTime)
{
- m_currentLevel = Math::Lerp(1.0, adsr.sustainLevel, m_elapsed / adsr.decayTime);
+ m_currentLevel = Math::Lerp(m_prevStateLevel, adsr.sustainLevel, m_elapsed / adsr.decayTime);
break;
}
+ m_prevStateLevel = m_currentLevel;
m_elapsed -= adsr.decayTime;
m_state = State::Sustain;
[[fallthrough]]; // Sustain処理にそのまま続く
-
case State::Sustain: // ノートオンの間 sustainLevel を維持する
- m_currentLevel = adsr.sustainLevel;
+ if (m_elapsed < adsr.sustainResetTime)
+ {
+ m_currentLevel = Math::Lerp(m_prevStateLevel, adsr.sustainLevel, m_elapsed / adsr.sustainResetTime);
+ }
+ else
+ {
+ m_currentLevel = adsr.sustainLevel;
+ }
break;
case State::Release: // sustainLevel から 0.0 まで releaseTime かけて減衰する
m_currentLevel = m_elapsed < adsr.releaseTime
- ? Math::Lerp(adsr.sustainLevel, 0.0, m_elapsed / adsr.releaseTime)
+ ? Math::Lerp(m_prevStateLevel, 0.0, m_elapsed / adsr.releaseTime)
: 0.0;
break;
@@ -294,6 +305,7 @@ private:
State m_state = State::Attack;
double m_elapsed = 0; // ステート変更からの経過秒数
double m_currentLevel = 0; // 現在のレベル [0, 1]
+ double m_prevStateLevel = 0; // ステート変更前のレベル [0, 1]
};
float NoteNumberToFrequency(int8_t d)
@@ -381,9 +393,24 @@ public:
void noteOn(int8_t noteNumber, int8_t velocity)
{
- NoteState noteState;
- noteState.m_velocity = velocity / 127.0f;
- m_noteState.emplace(noteNumber, noteState);
+ if (!m_mono || m_noteState.empty())
+ {
+ NoteState noteState;
+ noteState.m_velocity = velocity / 127.0f;
+ m_noteState.emplace(noteNumber, noteState);
+ }
+ else
+ {
+ auto [key, oldState] = *m_noteState.begin();
+
+ // ノート番号が同じとは限らないので一回消して作り直す
+ m_noteState.clear();
+
+ NoteState noteState = oldState;
+ noteState.m_velocity = velocity / 127.0f;
+ noteState.m_envelope.reset(m_legato ? EnvGenerator::State::Sustain : EnvGenerator::State::Attack);
+ m_noteState.emplace(noteNumber, noteState);
+ }
}
void noteOff(int8_t noteNumber)
@@ -426,6 +453,20 @@ public:
}
m_adsr.updateGUI(pos);
+
+ const int marginWidth = 32;
+
+ {
+ pos.y += SliderHeight;
+ RectF(pos, LabelWidth + SliderWidth, SliderHeight * (m_mono ? 2 : 1)).draw();
+ SimpleGUI::CheckBox(m_mono, U"mono", pos);
+ if (m_mono)
+ {
+ pos.x += marginWidth;
+ SimpleGUI::CheckBox(m_legato, U"legato", Vec2(pos.x, pos.y += SliderHeight));
+ pos.x -= marginWidth;
+ }
+ }
}
void clear()
@@ -504,6 +545,24 @@ public:
updateUnisonParam();
}
+ bool mono() const
+ {
+ return m_mono;
+ }
+ void setMono(bool mono)
+ {
+ m_mono = mono;
+ }
+
+ bool legato() const
+ {
+ return m_legato;
+ }
+ void setLegato(bool legato)
+ {
+ m_legato = legato;
+ }
+
private:
void updateUnisonParam()
@@ -544,6 +603,9 @@ private:
double m_detune = 0;
double m_spread = 1.0;
+ bool m_mono = false;
+ bool m_legato = false;
+
std::array m_detunePitch;
std::array m_unisonPan;
};
@@ -666,7 +728,7 @@ void Main()
{
Window::Resize(1600, 900);
- auto midiDataOpt = LoadMidi(U"C5_B8.mid");
+ auto midiDataOpt = LoadMidi(U"glide_test.mid");
if (!midiDataOpt)
{
// ファイルが見つからない or 読み込みエラー
@@ -676,22 +738,23 @@ void Main()
AudioVisualizer visualizer;
visualizer.setSplRange(-60, -30);
visualizer.setWindowType(AudioVisualizer::Hamming);
- visualizer.setFreqRange(300, 10000);
- visualizer.setDrawArea(Scene::Rect().stretched(-50));
+ visualizer.setShowPastNotes(false);
+ visualizer.setDrawScore(NoteNumber::C_2, NoteNumber::B_7);
+ visualizer.setDrawArea(Scene::Rect());
std::shared_ptr audioStream = std::make_shared();
audioStream->setMidiData(midiDataOpt.value());
auto& synth = audioStream->synth();
- synth.setOscIndex(static_cast(WaveForm::Saw));
- synth.setUnisonCount(4);
- synth.setDetune(0.5);
- synth.setSpread(0.0);
+ synth.setOscIndex(static_cast(WaveForm::Sin));
+ synth.setMono(true);
+ synth.setLegato(false);
+ synth.setAmplitude(0.4);
auto& adsr = synth.adsr();
adsr.attackTime = 0.01;
- adsr.decayTime = 0.0;
- adsr.sustainLevel = 1.0;
+ adsr.decayTime = 0.1;
+ adsr.sustainLevel = 0.2;
adsr.releaseTime = 0.01;
bool isRunning = true;
@@ -738,7 +801,8 @@ void Main()
visualizer.updateFFT(fftInputSize);
- visualizer.draw();
+ const auto currentTime = 1.0 * audioStream->playingMIDIPos() / SamplingFreq;
+ visualizer.drawScore(midiDataOpt.value(), currentTime);
}
if (KeyG.down())
```
### ３.４ グライド（ポルタメント）
```diff
@@ -364,8 +364,22 @@ public:
for (auto& [noteNumber, noteState] : m_noteState)
{
+ const auto targetFreq = NoteNumberToFrequency(noteNumber);
+
+ if (m_mono && m_glide)
+ {
+ const double targetScale = targetFreq / m_startGlideFreq;
+ const double rate = Saturate(m_glideElapsed / m_glideTime);
+ m_currentFreq = m_startGlideFreq * pow(targetScale, rate);
+ m_glideElapsed += deltaT;
+ }
+ else
+ {
+ m_currentFreq = targetFreq;
+ }
+
const auto envLevel = noteState.m_envelope.currentLevel() * noteState.m_velocity;
- const auto frequency = NoteNumberToFrequency(noteNumber) * pitch;
+ const auto frequency = m_currentFreq * pitch;
for (int d = 0; d < m_unisonCount; ++d)
{
@@ -411,6 +425,12 @@ public:
noteState.m_envelope.reset(m_legato ? EnvGenerator::State::Sustain : EnvGenerator::State::Attack);
m_noteState.emplace(noteNumber, noteState);
}
+
+ if (m_mono && m_glide)
+ {
+ m_startGlideFreq = m_currentFreq;
+ m_glideElapsed = 0;
+ }
}
void noteOff(int8_t noteNumber)
@@ -458,12 +478,15 @@ public:
{
pos.y += SliderHeight;
- RectF(pos, LabelWidth + SliderWidth, SliderHeight * (m_mono ? 2 : 1)).draw();
+ RectF(pos, LabelWidth + SliderWidth, SliderHeight * (m_mono ? 3 : 1)).draw();
SimpleGUI::CheckBox(m_mono, U"mono", pos);
if (m_mono)
{
+ const auto legatoWidth = SimpleGUI::CheckBoxRegion(U"legato", {}).w;
pos.x += marginWidth;
SimpleGUI::CheckBox(m_legato, U"legato", Vec2(pos.x, pos.y += SliderHeight));
+ SimpleGUI::CheckBox(m_glide, U"glide", Vec2(pos.x + legatoWidth, pos.y));
+ SimpleGUI::Slider(U"glideTime : {:.2f}"_fmt(m_glideTime), m_glideTime, 0.001, 0.5, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth - marginWidth, SliderWidth);
pos.x -= marginWidth;
}
}
@@ -563,6 +586,24 @@ public:
m_legato = legato;
}
+ bool glide() const
+ {
+ return m_glide;
+ }
+ void setGlide(bool glide)
+ {
+ m_glide = glide;
+ }
+
+ double glideTime() const
+ {
+ return m_glideTime;
+ }
+ void setGlideTime(double glideTime)
+ {
+ m_glideTime = glideTime;
+ }
+
private:
void updateUnisonParam()
@@ -605,9 +646,15 @@ private:
bool m_mono = false;
bool m_legato = false;
+ bool m_glide = false;
+ double m_glideTime = 0.001;
std::array m_detunePitch;
std::array m_unisonPan;
+
+ double m_currentFreq = 440; //現在の周波数を常に保存しておく
+ double m_startGlideFreq = 440; // グライド開始時の周波数
+ double m_glideElapsed = 0.0; // グライド開始から経過した秒数
};
class AudioRenderer : public IAudioStream
@@ -626,6 +673,12 @@ public:
m_midiData = midiData;
}
+ void restart()
+ {
+ m_synth.clear();
+ m_readMIDIPos = 0;
+ }
+
void bufferSample()
{
const double currentTime = 1.0 * m_readMIDIPos / SamplingFreq;
@@ -736,10 +789,10 @@ void Main()
}
AudioVisualizer visualizer;
- visualizer.setSplRange(-60, -30);
+ visualizer.setThresholdFromPeak(-20);
+ visualizer.setLerpStrength(0.5);
visualizer.setWindowType(AudioVisualizer::Hamming);
- visualizer.setShowPastNotes(false);
- visualizer.setDrawScore(NoteNumber::C_2, NoteNumber::B_7);
+ visualizer.setDrawScore(NoteNumber::C_3, NoteNumber::B_6);
visualizer.setDrawArea(Scene::Rect());
std::shared_ptr audioStream = std::make_shared();
@@ -748,8 +801,10 @@ void Main()
auto& synth = audioStream->synth();
synth.setOscIndex(static_cast(WaveForm::Sin));
synth.setMono(true);
- synth.setLegato(false);
- synth.setAmplitude(0.4);
+ synth.setLegato(true);
+ synth.setGlide(true);
+ synth.setGlideTime(0.1);
+ synth.setAmplitude(0.2);
auto& adsr = synth.adsr();
adsr.attackTime = 0.01;
@@ -758,11 +813,18 @@ void Main()
adsr.releaseTime = 0.01;
bool isRunning = true;
+ bool requestRestart = false;
auto renderUpdate = [&]()
{
while (isRunning)
{
+ if (requestRestart)
+ {
+ audioStream->restart();
+ requestRestart = false;
+ }
+
while (!audioStream->bufferCompleted())
{
audioStream->bufferSample();
@@ -814,6 +876,11 @@ void Main()
{
audioStream->updateGUI(pos);
}
+
+ if (KeySpace.down())
+ {
+ requestRestart = true;
+ }
}
isRunning = false;
```
### ３.５ LFO による変調
```diff
@@ -308,6 +308,134 @@ private:
double m_prevStateLevel = 0; // ステート変更前のレベル [0, 1]
};
+class LFO
+{
+public:
+
+ // 位相をリセットする
+ void reset()
+ {
+ m_phase = 0;
+ }
+
+ void update(double dt)
+ {
+ if (m_lfoFunction)
+ {
+ // 音符の長さで周期を設定する場合は、ここでBPMを受け取って時間に変換する
+ const double cycleTime = m_seconds;
+ const double deltaPhase = Math::TwoPi * dt / cycleTime;
+
+ m_currentLevel = m_lfoFunction(m_phase);
+ m_phase += deltaPhase;
+
+ if (Math::TwoPi < m_phase)
+ {
+ if (m_loop)
+ {
+ m_phase -= Math::TwoPi;
+ }
+ else
+ {
+ m_phase = Math::TwoPi;
+ }
+ }
+ }
+ }
+
+ // 現在の入力値: [0, 2pi]
+ double phase() const
+ {
+ return m_phase;
+ }
+
+ // 現在の出力値: [-1.0, 1.0]
+ double currentLevel() const
+ {
+ return m_currentLevel;
+ }
+
+ // 周期を設定する
+ void setSeconds(double seconds)
+ {
+ m_seconds = seconds;
+ }
+
+ // カーブを設定する
+ void setFunction(std::function func)
+ {
+ m_lfoFunction = func;
+ }
+
+ bool isLoop() const
+ {
+ return m_loop;
+ }
+
+ // ループを有効にする
+ void setLoop(bool isLoop)
+ {
+ m_loop = isLoop;
+ }
+
+private:
+
+ double m_seconds = 1;
+ bool m_loop = true;
+ std::function m_lfoFunction;
+
+ double m_phase = 0;
+ double m_currentLevel = 0;
+};
+
+class ModParameter
+{
+public:
+
+ ModParameter(double value) : value(value) {}
+
+ // 値が書き換わったら true を返す
+ bool fetch(const Array& lfoTable)
+ {
+ if (m_modIndex)
+ {
+ const double x = lfoTable[m_modIndex.value()].currentLevel();
+ const double newValue = Math::Lerp(m_low, m_high, x * 0.5 + 0.5);
+ if (value != newValue)
+ {
+ value = newValue;
+ return true;
+ }
+ }
+
+ return false;
+ }
+
+ void setRange(double lowValue, double highValue)
+ {
+ m_low = lowValue;
+ m_high = highValue;
+ }
+
+ void setModIndex(int index)
+ {
+ m_modIndex = index;
+ }
+
+ void unsetModIndex()
+ {
+ m_modIndex = none;
+ }
+
+ double value = 0;
+
+private:
+
+ double m_low = 0;
+ double m_high = 1;
+ Optional m_modIndex;
+};
+
float NoteNumberToFrequency(int8_t d)
{
return 440.0f * pow(2.0f, (d - 69) / 12.0f);
@@ -354,10 +482,20 @@ public:
noteState.m_envelope.update(m_adsr, deltaT);
}
+ // 再生中のノートがあれば LFO を更新する
+ if (!m_noteState.empty())
+ {
+ for (auto& lfoState : m_lfoStates)
+ {
+ lfoState.update(deltaT);
+ }
+ }
+
// リリースが終了したノートを削除する
std::erase_if(m_noteState, [&](const auto& noteState) { return noteState.second.m_envelope.isReleased(m_adsr); });
- const auto pitch = pow(2.0, m_pitchShift / 12.0);
+ m_pitchShift.fetch(m_lfoStates);
+ const auto pitch = pow(2.0, m_pitchShift.value / 12.0);
// 入力中の波形を加算して書き込む
WaveSample sample(0, 0);
@@ -399,10 +537,12 @@ public:
}
}
- sample.left *= static_cast(cos(Math::HalfPi * m_pan));
- sample.right *= static_cast(sin(Math::HalfPi * m_pan));
+ m_pan.fetch(m_lfoStates);
+ sample.left *= static_cast(cos(Math::HalfPi * m_pan.value));
+ sample.right *= static_cast(sin(Math::HalfPi * m_pan.value));
- return sample * static_cast(m_amplitude / sqrt(m_unisonCount));
+ m_amplitude.fetch(m_lfoStates);
+ return sample * static_cast(m_amplitude.value / sqrt(m_unisonCount));
}
void noteOn(int8_t noteNumber, int8_t velocity)
@@ -431,6 +571,15 @@ public:
m_startGlideFreq = m_currentFreq;
m_glideElapsed = 0;
}
+
+ if (!m_mono)
+ {
+ // LFO の再生状態をリセットする
+ for (auto& lfoState : m_lfoStates)
+ {
+ lfoState.reset();
+ }
+ }
}
void noteOff(int8_t noteNumber)
@@ -452,14 +601,14 @@ public:
void updateGUI(Vec2& pos)
{
- SimpleGUI::Slider(U"amplitude : {:.2f}"_fmt(m_amplitude), m_amplitude, 0.0, 1.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
- SimpleGUI::Slider(U"pan : {:.2f}"_fmt(m_pan), m_pan, 0.0, 1.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
+ SimpleGUI::Slider(U"amplitude : {:.2f}"_fmt(m_amplitude.value), m_amplitude.value, 0.0, 1.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
+ SimpleGUI::Slider(U"pan : {:.2f}"_fmt(m_pan.value), m_pan.value, 0.0, 1.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
SliderInt(U"oscillator : {}"_fmt(m_oscIndex), m_oscIndex, 0, 3, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth);
- if (SimpleGUI::Slider(U"pitchShift : {:.2f}"_fmt(m_pitchShift), m_pitchShift, -24.0, 24.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth)
+ if (SimpleGUI::Slider(U"pitchShift : {:.2f}"_fmt(m_pitchShift.value), m_pitchShift.value, -24.0, 24.0, Vec2{ pos.x, pos.y += SliderHeight }, LabelWidth, SliderWidth)
&& KeyControl.pressed())
{
- m_pitchShift = Math::Round(m_pitchShift);
+ m_pitchShift.value = Math::Round(m_pitchShift.value);
}
bool unisonUpdated = false;
@@ -502,6 +651,11 @@ public:
return m_adsr;
}
+ Array& lfoStates()
+ {
+ return m_lfoStates;
+ }
+
int oscIndex() const
{
return m_oscIndex;
@@ -511,31 +665,31 @@ public:
m_oscIndex = oscIndex;
}
- double amplitude() const
+ const ModParameter& amplitude() const
{
return m_amplitude;
}
- void setAmplitude(double amplitude)
+ ModParameter& amplitude()
{
- m_amplitude = amplitude;
+ return m_amplitude;
}
- double pan() const
+ const ModParameter& pan() const
{
return m_pan;
}
- void setPan(double pan)
+ ModParameter& pan()
{
- m_pan = pan;
+ return m_pan;
}
- double pitchShift() const
+ const ModParameter& pitchShift() const
{
return m_pitchShift;
}
- void setPitchShift(double pitchShift)
+ ModParameter& pitchShift()
{
- m_pitchShift = pitchShift;
+ return m_pitchShift;
}
int unisonCount() const
@@ -635,9 +789,11 @@ private:
ADSRConfig m_adsr;
- double m_amplitude = 0.1;
- double m_pan = 0.5;
- double m_pitchShift = 0.0;
+ Array m_lfoStates;
+
+ ModParameter m_amplitude = 0.1;
+ ModParameter m_pan = 0.5;
+ ModParameter m_pitchShift = 0.0;
int m_oscIndex = 0;
int m_unisonCount = 1;
@@ -804,7 +960,7 @@ void Main()
synth.setLegato(true);
synth.setGlide(true);
synth.setGlideTime(0.1);
- synth.setAmplitude(0.2);
+ synth.amplitude().value = 0.2;
auto& adsr = synth.adsr();
adsr.attackTime = 0.01;
@@ -812,6 +968,16 @@ void Main()
adsr.sustainLevel = 0.2;
adsr.releaseTime = 0.01;
+ auto& lfoStates = synth.lfoStates();
+ lfoStates.resize(1);
+ lfoStates[0].setFunction(Sin);
+ lfoStates[0].setSeconds(0.1);
+ lfoStates[0].setLoop(true);
+
+ auto& pitchShift = synth.pitchShift();
+ pitchShift.setModIndex(0);
+ pitchShift.setRange(-0.5, 0.5);
+
bool isRunning = true;
bool requestRestart = false;
```