Validate POC A and POC B foundations

src/alarm_player.gd

@@ -0,0 +1,71 @@
+class_name AlarmPlayer
+extends AudioStreamPlayer
+
+var _last_severity := 0
+var _repeat_timer := 0.0
+
+
+func update_alerts(delta: float, alerts: Array[int]) -> void:
+	var severity := 0
+	for alert in alerts:
+		severity = maxi(severity, alert)
+
+	_repeat_timer = maxf(0.0, _repeat_timer - delta)
+	if severity > _last_severity:
+		_play_alarm(severity)
+		_repeat_timer = _repeat_delay(severity)
+	elif severity >= SurvivalModel.AlertLevel.RETURN and _repeat_timer <= 0.0:
+		_play_alarm(severity)
+		_repeat_timer = _repeat_delay(severity)
+
+	_last_severity = severity
+
+
+func reset() -> void:
+	_last_severity = 0
+	_repeat_timer = 0.0
+	stop()
+
+
+func _repeat_delay(severity: int) -> float:
+	match severity:
+		SurvivalModel.AlertLevel.EMPTY:
+			return 0.75
+		SurvivalModel.AlertLevel.CRITICAL:
+			return 1.25
+		SurvivalModel.AlertLevel.RETURN:
+			return 2.5
+		SurvivalModel.AlertLevel.CAUTION:
+			return 5.0
+		_:
+			return 999.0
+
+
+func _play_alarm(severity: int) -> void:
+	if severity <= SurvivalModel.AlertLevel.NORMAL:
+		return
+
+	var generator := AudioStreamGenerator.new()
+	generator.mix_rate = 22050.0
+	generator.buffer_length = 0.45
+	stream = generator
+	play()
+
+	var playback := get_stream_playback() as AudioStreamGeneratorPlayback
+	if playback == null:
+		return
+
+	var frequency := 520.0 + float(severity) * 110.0
+	var duration := 0.35
+	var frame_count := int(generator.mix_rate * duration)
+	var pulse_count := 1 if severity == SurvivalModel.AlertLevel.CAUTION else 2
+	if severity >= SurvivalModel.AlertLevel.CRITICAL:
+		pulse_count = 3
+
+	for frame_index in frame_count:
+		var time := float(frame_index) / generator.mix_rate
+		var phase_in_pulse := fmod(time * float(pulse_count), duration) / duration
+		var gate := 1.0 if phase_in_pulse < 0.62 else 0.0
+		var envelope := minf(time * 30.0, 1.0) * minf((duration - time) * 30.0, 1.0)
+		var sample := sin(TAU * frequency * time) * 0.16 * gate * envelope
+		playback.push_frame(Vector2(sample, sample))