1 files changed, 100 insertions, 0 deletions
diff --git a/src/game/AudioEngine.ts b/src/game/AudioEngine.ts
new file mode 100644
index 0000000..1a6f907
--- /dev/null
+++ b/src/game/AudioEngine.ts
@@ -0,0 +1,100 @@
+type AudioContextCtor = typeof AudioContext;
+
+export class AudioEngine {
+  private context?: AudioContext;
+  private master?: GainNode;
+  private drone?: OscillatorNode;
+  private shimmer?: OscillatorNode;
+  private active = false;
+
+  activate(): void {
+    if (this.active) {
+      void this.context?.resume();
+      return;
+    }
+
+    const ctor = window.AudioContext ?? (window as Window & { webkitAudioContext?: AudioContextCtor }).webkitAudioContext;
+    if (!ctor) {
+      return;
+    }
+
+    this.context = new ctor();
+    this.master = this.context.createGain();
+    this.master.gain.value = 0.07;
+    this.master.connect(this.context.destination);
+
+    this.drone = this.context.createOscillator();
+    this.drone.type = 'sawtooth';
+    this.drone.frequency.value = 82;
+    const droneGain = this.context.createGain();
+    droneGain.gain.value = 0.18;
+    this.drone.connect(droneGain);
+    droneGain.connect(this.master);
+    this.drone.start();
+
+    this.shimmer = this.context.createOscillator();
+    this.shimmer.type = 'triangle';
+    this.shimmer.frequency.value = 164;
+    const shimmerGain = this.context.createGain();
+    shimmerGain.gain.value = 0.08;
+    this.shimmer.connect(shimmerGain);
+    shimmerGain.connect(this.master);
+    this.shimmer.start();
+
+    this.active = true;
+  }
+
+  setMood(fidelity: number, cycle: number, layerIndex: number): void {
+    if (!this.context || !this.master || !this.drone || !this.shimmer) {
+      return;
+    }
+
+    const now = this.context.currentTime;
+    const base = 82 + cycle * 8 + layerIndex * 3;
+    this.drone.frequency.linearRampToValueAtTime(base + fidelity * 18, now + 0.18);
+    this.shimmer.frequency.linearRampToValueAtTime(base * 2 + (1 - fidelity) * 70, now + 0.22);
+    this.master.gain.linearRampToValueAtTime(0.045 + fidelity * 0.04, now + 0.25);
+  }
+
+  pulseJump(boost = false): void {
+    if (!this.context || !this.master) {
+      return;
+    }
+
+    const osc = this.context.createOscillator();
+    const gain = this.context.createGain();
+    osc.type = boost ? 'square' : 'sine';
+    osc.frequency.value = boost ? 420 : 260;
+    gain.gain.value = 0.0001;
+    osc.connect(gain);
+    gain.connect(this.master);
+
+    const now = this.context.currentTime;
+    gain.gain.exponentialRampToValueAtTime(0.06, now + 0.01);
+    gain.gain.exponentialRampToValueAtTime(0.0001, now + 0.24);
+    osc.frequency.exponentialRampToValueAtTime(boost ? 170 : 120, now + 0.24);
+    osc.start(now);
+    osc.stop(now + 0.26);
+  }
+
+  pulseSnap(): void {
+    if (!this.context || !this.master) {
+      return;
+    }
+
+    const osc = this.context.createOscillator();
+    const gain = this.context.createGain();
+    osc.type = 'triangle';
+    osc.frequency.value = 680;
+    gain.gain.value = 0.0001;
+    osc.connect(gain);
+    gain.connect(this.master);
+
+    const now = this.context.currentTime;
+    gain.gain.exponentialRampToValueAtTime(0.08, now + 0.01);
+    gain.gain.exponentialRampToValueAtTime(0.0001, now + 0.45);
+    osc.frequency.exponentialRampToValueAtTime(240, now + 0.45);
+    osc.start(now);
+    osc.stop(now + 0.5);
+  }
+}