Real thunder (Gitea #4): six CC0 recordings, close cracks and distant rolls, in place of the synthesised rumble; a storm's flash is followed by a roll seconds later or a crack sooner, quieter indoors, and a strike on a tree cracks from the tree

assets/audio/CREDITS.md

@@ -39,6 +39,21 @@ Breviceps (https://freesound.org/people/Breviceps/sounds/465697/, License:
 Creative Commons 0; the preview is in `tools/audio/sources/`), cut at 0.12 s
 and 2.65 s (leaving out the short sound between them), then levelled. Thank you.
 
+## Thunder (CC0)
+`sfx/thunder/` is cut from six Freesound recordings, all License: Creative
+Commons 0 (the previews are in `tools/audio/sources/thunder_*`), each round
+its loudest strike, faded out and levelled by
+`tools/audio/make_audio.py thunder`. Close cracks: "Thunder 08" by Emulius
+(https://freesound.org/people/Emulius/sounds/744723/), "thunder11" by
+saha213131 (https://freesound.org/people/saha213131/sounds/696550/) and
+"Thunder strike" by AyaDrevis
+(https://freesound.org/people/AyaDrevis/sounds/652690/). Distant rolls:
+"Short_Thunder_Mid" by SholeColtis
+(https://freesound.org/people/SholeColtis/sounds/683421/), "thunder7" by
+nednednerb (https://freesound.org/people/nednednerb/sounds/38250/) and
+"Thunder Clap OWB KY 441x16.wav" by Dave Welsh
+(https://freesound.org/people/Dave%20Welsh/sounds/194364/). Thank you.
+
 ## Old Tam's voice
 `voice/` is spoken by **Kokoro** (Kokoro-82M by hexgrad, Apache-2.0,
 https://huggingface.co/hexgrad/Kokoro-82M) with its British "George" voice,

scripts/core/sfx.gd

@@ -19,6 +19,7 @@ extends Node
 const K := "res://assets/audio/sfx/kenney/"
 const S := "res://assets/audio/sfx/synth/"
 const C := "res://assets/audio/sfx/creatures/"
+const T := "res://assets/audio/sfx/thunder/"
 const EARSHOT := 45.0            ## a server sends a sound to players this close
 
 ## id -> files (or a [prefix, count] pair), volume (dB), pitch range, reach (m),
@@ -28,6 +29,10 @@ const SOUNDS := {
 	"tree_fall": {"set": [K + "wood_heavy_%d.ogg", 5], "db": 0.0, "pitch": [0.6, 0.7], "reach": 60.0, "with": "creak"},
 	"creak": {"set": [K + "creak_%d.ogg", 3], "db": -2.0, "pitch": [0.8, 0.95], "reach": 50.0},
 	"mine": {"set": [K + "mine_%d.ogg", 5], "db": -1.0, "pitch": [0.9, 1.1]},
+	# Thunder (0.6.2, CC0 recordings: assets/audio/CREDITS.md). The weather
+	# plays the storm's own (weather_fx.gd); a strike on a tree cracks from it.
+	"thunder_near": {"set": [T + "thunder_near_%d.ogg", 3], "db": 0.0, "pitch": [0.92, 1.05], "reach": 400.0},
+	"thunder_far": {"set": [T + "thunder_far_%d.ogg", 3], "db": -5.0, "pitch": [0.9, 1.05], "reach": 400.0},
 	"rock_break": {"set": [K + "mine_%d.ogg", 5], "db": 1.0, "pitch": [0.6, 0.7], "reach": 50.0},
 	"rustle": {"set": [K + "cloth_%d.ogg", 4], "db": -4.0, "pitch": [0.7, 0.9]},
 	"pickup": {"set": [K + "leather_%d.ogg", 3], "db": -6.0, "pitch": [0.95, 1.15], "reach": 15.0},
@@ -196,6 +201,17 @@ func me(id: String) -> void:
 	_log(id, null)
 	_play2(id)
 
+## A random one of sound `id`'s files, and its volume: for a player of your
+## own (the weather's thunder). Not logged: call log_heard() when it plays.
+func stream_for(id: String) -> AudioStream:
+	return _pick(id) if SOUNDS.has(id) else null
+
+func db_for(id: String) -> float:
+	return float(SOUNDS.get(id, {}).get("db", 0.0))
+
+func log_heard(id: String) -> void:
+	_log(id, null)
+
 ## Menus and the HUD.
 func ui(id: String) -> void:
 	_log(id, null)

scripts/world/hazards.gd

@@ -92,6 +92,7 @@ func pick_tree() -> Node3D:
 func strike(n: Node3D) -> void:
 	strikes += 1
 	show_strike(n)
+	Sfx.at("thunder_near", n.global_position + Vector3(0, 6, 0))   # (a crack from the tree itself)
 	if world.server_mode:
 		WorldNet.struck(n)
 	for p in world.players():

scripts/world/weather_fx.gd

@@ -7,8 +7,11 @@ extends Node3D
 ## - Ground wetness, settled snow and wind strength are global shader uniforms
 ##   (weather_wet, weather_snow, weather_wind) read by the terrain, grass,
 ##   foliage and rock shaders.
-## - Sound is synthesised: filtered noise for rain and wind, a decaying
+## - Rain and wind are synthesised (filtered noise). Thunder is recorded
-##   low rumble for thunder. No audio assets, nothing to license.
+##   (CC0, 0.6.2: assets/audio/sfx/thunder, Sfx "thunder_far"/"thunder_near"):
+##   after each flash in a storm, usually a distant roll a few seconds later,
+##   sometimes a nearer crack sooner. Quieter under a roof. (A strike on a
+##   tree near you cracks from the tree itself: hazards.gd.)
 ##
 ## Client-side only: in M2 the server runs weather.gd and never this.
 
@@ -31,10 +34,11 @@ var _rng := RandomNumberGenerator.new()
 var _rain_lp := 0.0
 var _rain_hp := 0.0
 var _brown := 0.0
-var _brown2 := 0.0
 var _gust_t := 0.0
-var _thunder_env := 0.0
 var _thunder_delay := -1.0
+var _thunder_id := ""
+var _thunder: AudioStreamPlayer
+const NEAR_CHANCE := 0.3          ## of a storm's flashes, the share that are close
 var _seen_strikes := 0
 var _rain_amp := 0.0
 var _wind_amp := 0.0
@@ -83,6 +87,10 @@ func setup(w: Node, p: Node3D) -> void:
 		add_child(_audio)
 		_audio.play()
 		_playback = _audio.get_stream_playback()
+		_thunder = AudioStreamPlayer.new()
+		_thunder.name = "Thunder"
+		_thunder.bus = "SFX" if AudioServer.get_bus_index("SFX") >= 0 else "Master"
+		add_child(_thunder)
 
 func _make_particles(amount: int, life: float, pm: ParticleProcessMaterial, mesh: Mesh) -> GPUParticles3D:
 	var p := GPUParticles3D.new()
@@ -173,13 +181,32 @@ func _process(delta: float) -> void:
 	_wind_amp = weather.wind * weather.wind * 0.22 * (0.35 if sheltered else 1.0)
 	if weather.lightning_count != _seen_strikes:
 		_seen_strikes = weather.lightning_count
-		_thunder_delay = _rng.randf_range(0.5, 2.5)
+		lightning()
 	if _thunder_delay >= 0.0:
 		_thunder_delay -= delta
 		if _thunder_delay < 0.0:
-			_thunder_env = 1.0
+			_thunder_now()
 	_fill_audio()
 
+## A flash in the sky: its thunder follows, after the time the sound takes
+## to come (a near one sooner, a distant one later).
+func lightning() -> void:
+	var near := _rng.randf() < NEAR_CHANCE
+	_thunder_id = "thunder_near" if near else "thunder_far"
+	_thunder_delay = _rng.randf_range(0.3, 0.9) if near else _rng.randf_range(1.5, 4.0)
+
+func _thunder_now() -> void:
+	Sfx.log_heard(_thunder_id)
+	if _thunder == null:
+		return
+	var st: AudioStream = Sfx.stream_for(_thunder_id)
+	if st == null:
+		return
+	_thunder.stream = st
+	_thunder.volume_db = Sfx.db_for(_thunder_id) - 8.0 * _muffle
+	_thunder.pitch_scale = _rng.randf_range(0.9, 1.05)
+	_thunder.play()
+
 func _set_amount(p: GPUParticles3D, a: float) -> void:
 	p.amount_ratio = a
 	p.emitting = a > 0.0
@@ -194,7 +221,6 @@ func _fill_audio() -> void:
 	var rain_cut := lerpf(0.55, 0.12, _muffle)
 	var buf := PackedVector2Array()
 	buf.resize(n)
-	var thunder_decay := exp(-1.0 / (MIX_RATE * 0.9))
 	for i in range(n):
 		var white := _rng.randf() * 2.0 - 1.0
 		# Rain: band-limited hiss (low-pass, minus a slower low-pass).
@@ -206,12 +232,6 @@ func _fill_audio() -> void:
 		_gust_t += 1.0 / MIX_RATE
 		var gust := 0.6 + 0.4 * sin(_gust_t * 0.7) * sin(_gust_t * 0.23 + 1.0)
 		var wind_s := _brown * _wind_amp * gust * 2.0
-		# Thunder: a heavier brown rumble with a long decay.
+		var s := clampf(rain + wind_s, -1.0, 1.0)
-		var thunder := 0.0
-		if _thunder_env > 0.001:
-			_brown2 = clampf(_brown2 * 0.9995 + white * 0.02, -1.0, 1.0)
-			thunder = _brown2 * _thunder_env * 2.2
-			_thunder_env *= thunder_decay
-		var s := clampf(rain + wind_s + thunder, -1.0, 1.0)
 		buf[i] = Vector2(s, s)
 	_playback.push_buffer(buf)

tests/test_hazards.gd

@@ -269,6 +269,31 @@ func _lightning() -> void:
 	var tree: Node3D = hz._burning.keys()[0]
 	check(tree.global_position.distance_to(at) < hz.STRIKE_RANGE, "near you (%.0f m away)" % tree.global_position.distance_to(at))
 	check(_toast_has("Lightning struck"), "you see it (%s)" % [_toasts])
+	# Gitea #4: thunder is recorded now; the strike cracks from the tree.
+	var SX: Node = root.get_node("Sfx")
+	var cracks: Array = SX.heard.filter(func(h): return h[0] == "thunder_near" and h[1] is Vector3 and (h[1] as Vector3).distance_to(tree.global_position) < 8.0)
+	check(cracks.size() == 1, "and hear it: a thunder crack from the tree")
+	check(SX.files("thunder_near").size() == 3 and SX.files("thunder_far").size() == 3 and
+		SX.files("thunder_near").all(func(f): return ResourceLoader.exists(f)) and SX.files("thunder_far").all(func(f): return ResourceLoader.exists(f)),
+		"(three recorded cracks and three distant rolls)")
+	var fx: Node3D = load("res://scripts/world/weather_fx.gd").new()
+	world.add_child(fx)
+	fx.setup(wx, player)
+	var kinds := {}
+	var delays := {"thunder_near": [], "thunder_far": []}
+	for _i in range(60):
+		fx.lightning()
+		kinds[fx._thunder_id] = int(kinds.get(fx._thunder_id, 0)) + 1
+		delays[fx._thunder_id].append(fx._thunder_delay)
+	check(kinds.has("thunder_near") and kinds.has("thunder_far") and int(kinds.thunder_far) > int(kinds.thunder_near),
+		"a storm's flashes: mostly distant rolls, sometimes a crack close by (%s)" % [kinds])
+	check(delays.thunder_near.all(func(d): return d < 1.0) and delays.thunder_far.all(func(d): return d >= 1.5),
+		"a close one follows its flash quickly, a distant one seconds later")
+	var h0: int = SX.heard.size()
+	fx._thunder_delay = 0.01
+	fx._process(0.05)
+	check(SX.heard.size() > h0 and SX.heard.slice(h0).any(func(h): return String(h[0]).begins_with("thunder_")), "and then you hear it")
+	fx.queue_free()
 	check(world.heat_at(tree.global_position + Vector3(2.5, 0, 0)) > 0.3, "it burns: you can warm yourself by it")
 	check(not tree.depleted, "still standing while it burns")
 	for _i in range(41):

tools/audio/make_audio.py

@@ -699,6 +699,44 @@ def _decode(src, sr, af=None):
     return [x * 0.06 / rms for x in left], [x * 0.06 / rms for x in right]
 
 
+def make_thunder():
+    """Thunder (0.6.2, Gitea #4): CC0 recordings (tools/audio/sources/
+    thunder_near_* and thunder_far_*, credited in assets/audio/CREDITS.md),
+    each cut round its loudest strike, faded out and evened out in level, into
+    assets/audio/sfx/thunder/thunder_near_N.ogg (a crack close by) and
+    thunder_far_N.ogg (a roll in the distance). Replaces the synthesised rumble."""
+    d = os.path.join(OUT, "sfx", "thunder")
+    os.makedirs(d, exist_ok=True)
+    print("thunder ->", os.path.relpath(d, ROOT))
+    sr = 44100
+    for kind, lead, most in (("near", 0.15, 7.0), ("far", 0.6, 10.0)):
+        for n, src in enumerate(sources("thunder_" + kind)):
+            raw = subprocess.run(["ffmpeg", "-v", "error", "-i", src, "-ac", "1", "-ar", str(sr), "-f", "s16le", "-"],
+                                 capture_output=True, check=True).stdout
+            x = [struct.unpack_from("<h", raw, i * 2)[0] / 32768.0 for i in range(len(raw) // 2)]
+            win = sr // 20
+            env = [math.sqrt(sum(v * v for v in x[i:i + win]) / win) + 1e-9 for i in range(0, len(x) - win, win)]
+            ip = max(range(len(env)), key=lambda i: env[i])
+            top = env[ip]
+            # Back from the loudest moment to where this strike starts (20 dB down).
+            j = ip
+            while j > 0 and env[j] > top * 0.1:
+                j -= 1
+            start = max(0, int((j * 0.05 - lead) * sr))
+            # On until it's died away (40 dB down), or `most` seconds.
+            k = ip
+            while k < len(env) - 1 and env[k] > top * 0.01 and (k - j) * 0.05 < most:
+                k += 1
+            end = min(len(x), int(k * 0.05 * sr) + win)
+            seg = x[start:end]
+            fade_in, fade_out = int(0.02 * sr), min(int(1.5 * sr), len(seg) // 3)
+            for i in range(fade_in):
+                seg[i] *= i / fade_in
+            for i in range(fade_out):
+                seg[-1 - i] *= i / fade_out
+            _encode(os.path.join(d, "thunder_%s_%d.ogg" % (kind, n)), [seg], sr, 5)
+
+
 def make_recorded(name, srcs=None):
     """A field-recorded ambience loop (assets/audio/ambience/<name>.ogg) from
     CC0 recordings (tools/audio/sources/<name>_*, or the files given): each
@@ -808,6 +846,9 @@ if __name__ == "__main__":
     if what in RECORDED:   # one recorded loop: birds | crickets
         make_recorded(what)
         sys.exit(0)
+    if what == "thunder":  # the recorded thunder (not part of "all": it's from sources/)
+        make_thunder()
+        sys.exit(0)
     if what in ("all", "sfx"):
         make_sfx()
     if what in ("all", "sfx", "voices"):