<button onclick="startMusic()">🎵 음악 시작</button>

<script>

const audioCtx = new (window.AudioContext || window.webkitAudioContext)();

let isPlaying = false;

function playNote(freq, startTime, duration = 0.2, type = 'sine', volume = 0.3) {

const osc = audioCtx.createOscillator();

const gain = audioCtx.createGain();

osc.type = type;

osc.frequency.value = freq;

gain.gain.setValueAtTime(volume, startTime);

gain.gain.exponentialRampToValueAtTime(0.001, startTime + duration);

osc.connect(gain);

gain.connect(audioCtx.destination);

osc.start(startTime);

osc.stop(startTime + duration);

}

function scheduleRhythm(startTime, tempo, measures = 8) {

const beatTime = 60 / tempo;

const totalBeats = measures * 4;

for (let i = 0; i < totalBeats; i++) {

const t = startTime + i * beatTime;

if (i % 4 === 0) playNote(100, t, 0.1, 'square', 0.4); // Kick

if (i % 4 === 2) playNote(180, t, 0.1, 'triangle', 0.2); // Snare

const bassNotes = [130.81, 196.00, 220.00, 174.61]; // C-G-A-F

const bassFreq = bassNotes[Math.floor(i / 8) % 4];

if (i % 2 === 0) playNote(bassFreq, t, 0.2, 'sawtooth', 0.3);

}

return totalBeats * beatTime;

}

function scheduleMelodyPhase(startTime, tempo) {

const beat = 60 / tempo;

// Phase 1: 기 - 단순하고 안정적인 멜로디 (C E G 반복)

[[523.25, 0], [659.25, 1], [783.99, 2], [659.25, 3]].forEach(([f, i]) =>

playNote(f, startTime + i * beat, 0.3, 'triangle', 0.2)

);

// Phase 2: 승 - 음 올라가고 속도 빨라짐

[[659.25, 4], [698.46, 4.5], [783.99, 5], [880.00, 5.5], [987.77, 6], [880.00, 6.5]].forEach(([f, i]) =>

playNote(f, startTime + i * beat, 0.2, 'triangle', 0.25)

);

// Phase 3: 전 - 강렬하게! 16분음표 느낌

[880.00, 987.77, 1046.50, 1174.66].forEach((f, idx) =>

playNote(f, startTime + (7 + idx * 0.25) * beat, 0.15, 'triangle', 0.25)

);

// Phase 4: 결 - 처음 멜로디의 변형, 낮아지며 안정감

[[783.99, 8], [659.25, 9], [587.33, 10], [523.25, 11]].forEach(([f, i]) =>

playNote(f, startTime + i * beat, 0.25, 'triangle', 0.2)

);

}

function startMusic() {

if (isPlaying) return;

isPlaying = true;

const tempo1 = 120;

const tempo2 = 160;

const now = audioCtx.currentTime;

const dur1 = scheduleRhythm(now, tempo1, 8);

scheduleMelodyPhase(now, tempo1); // 🎵 기승전결 멜로디

function loopFastPart(start) {

const dur2 = scheduleRhythm(start, tempo2, 8);

scheduleMelodyPhase(start, tempo2);

setTimeout(() => loopFastPart(start + dur2), dur2 * 1000);

}

setTimeout(() => loopFastPart(now + dur1), dur1 * 1000);

}

</script>