Polish title screen presentation

src/game/audio/SoundDirector.ts

@@ -0,0 +1,120 @@
+class SoundDirector {
+  private context?: AudioContext;
+  private master?: GainNode;
+  private musicGain?: GainNode;
+  private started = false;
+  private sequenceTimer?: number;
+
+  start() {
+    if (this.started) {
+      return;
+    }
+
+    const AudioContextCtor = window.AudioContext ?? window.webkitAudioContext;
+    if (!AudioContextCtor) {
+      return;
+    }
+
+    this.context = new AudioContextCtor();
+    this.master = this.context.createGain();
+    this.master.gain.value = 0.34;
+    this.master.connect(this.context.destination);
+
+    this.musicGain = this.context.createGain();
+    this.musicGain.gain.value = 0.0;
+    this.musicGain.connect(this.master);
+    this.started = true;
+
+    this.createAmbientBed();
+    this.schedulePlucks();
+    this.musicGain.gain.linearRampToValueAtTime(0.72, this.context.currentTime + 2.4);
+  }
+
+  resume() {
+    void this.context?.resume();
+  }
+
+  playHover() {
+    this.playTone(660, 0.035, 0.04, 'sine');
+  }
+
+  playSelect() {
+    this.playTone(330, 0.08, 0.12, 'triangle');
+    window.setTimeout(() => this.playTone(495, 0.1, 0.08, 'triangle'), 65);
+  }
+
+  private createAmbientBed() {
+    if (!this.context || !this.musicGain) {
+      return;
+    }
+
+    const base = this.context.createOscillator();
+    const fifth = this.context.createOscillator();
+    const filter = this.context.createBiquadFilter();
+    const bedGain = this.context.createGain();
+
+    base.type = 'sine';
+    fifth.type = 'sine';
+    base.frequency.value = 110;
+    fifth.frequency.value = 165;
+    filter.type = 'lowpass';
+    filter.frequency.value = 520;
+    bedGain.gain.value = 0.08;
+
+    base.connect(filter);
+    fifth.connect(filter);
+    filter.connect(bedGain);
+    bedGain.connect(this.musicGain);
+    base.start();
+    fifth.start();
+  }
+
+  private schedulePlucks() {
+    if (!this.context) {
+      return;
+    }
+
+    const notes = [220, 247, 294, 330, 392, 330, 294, 247];
+    let index = 0;
+    this.sequenceTimer = window.setInterval(() => {
+      this.playTone(notes[index % notes.length], 0.18, 0.09, 'triangle', true);
+      index += 1;
+    }, 1800);
+  }
+
+  private playTone(
+    frequency: number,
+    duration: number,
+    gainValue: number,
+    type: OscillatorType,
+    routeToMusic = false
+  ) {
+    if (!this.context) {
+      return;
+    }
+
+    const oscillator = this.context.createOscillator();
+    const gain = this.context.createGain();
+    const now = this.context.currentTime;
+    const destination = routeToMusic && this.musicGain ? this.musicGain : this.master;
+
+    oscillator.type = type;
+    oscillator.frequency.value = frequency;
+    gain.gain.setValueAtTime(0, now);
+    gain.gain.linearRampToValueAtTime(gainValue, now + 0.012);
+    gain.gain.exponentialRampToValueAtTime(0.0001, now + duration);
+
+    oscillator.connect(gain);
+    gain.connect(destination ?? this.context.destination);
+    oscillator.start(now);
+    oscillator.stop(now + duration + 0.04);
+  }
+}
+
+declare global {
+  interface Window {
+    webkitAudioContext?: typeof AudioContext;
+  }
+}
+
+export const soundDirector = new SoundDirector();