feat(sites): strata on the Banc du Vigilant drop-off and multi-scale seabed relief

Strata now take a world rectangle, so the 4 m ledges cover the whole break
and talus south of z = 118 m without touching la Saignée or the landmarks.
Roughness gains octave and fractal-type parameters; a SlopeRoughness
modifier roughens rock faces only. Both sites are re-baked with hummocks
from 250 m down to 5 m. The secondary item, the first debris piece and one
safe-route waypoint move a few metres to keep their contracts.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

content/sites/zone1_vigilant.tres

@@ -9,7 +9,7 @@
 script = ExtResource("1_n3xpu")
 placement_id = &"prospection_vessel"
 kind = 0
-position_m = Vector3(-14.154642, -37.198338, 98.39586)
+position_m = Vector3(-14.154642, -36.88306, 98.39586)
 yaw_radians = -1.380808047881126
 footprint_m = Vector3(28, 8, 9)
 
@@ -17,7 +17,7 @@ footprint_m = Vector3(28, 8, 9)
 script = ExtResource("1_n3xpu")
 placement_id = &"decoy_yacht"
 kind = 1
-position_m = Vector3(-30, -25.199738, -150)
+position_m = Vector3(-30, -24.996498, -150)
 yaw_radians = 1.1
 footprint_m = Vector3(12, 3, 4)
 
@@ -25,7 +25,7 @@ footprint_m = Vector3(12, 3, 4)
 script = ExtResource("1_n3xpu")
 placement_id = &"decoy_coaster"
 kind = 1
-position_m = Vector3(140, -35.265244, 40)
+position_m = Vector3(140, -35.34944, 40)
 yaw_radians = -0.6
 footprint_m = Vector3(26, 6, 8)
 
@@ -33,14 +33,14 @@ footprint_m = Vector3(26, 6, 8)
 script = ExtResource("1_n3xpu")
 placement_id = &"secondary_item"
 kind = 2
-position_m = Vector3(-6, -61.61916, 157)
+position_m = Vector3(-6, -63.26594, 160)
 footprint_m = Vector3(1, 1, 1)
 
 [sub_resource type="Resource" id="Resource_aervf"]
 script = ExtResource("1_n3xpu")
 placement_id = &"debris_1"
 kind = 3
-position_m = Vector3(-12, -45.756382, 134)
+position_m = Vector3(-12, -45.80824, 136)
 yaw_radians = 0.4
 footprint_m = Vector3(3, 2, 2)
 
@@ -48,7 +48,7 @@ footprint_m = Vector3(3, 2, 2)
 script = ExtResource("1_n3xpu")
 placement_id = &"debris_2"
 kind = 3
-position_m = Vector3(-10, -48.518223, 139)
+position_m = Vector3(-10, -47.295185, 139)
 yaw_radians = 1.2
 footprint_m = Vector3(6, 2.5, 2.5)
 
@@ -56,14 +56,14 @@ footprint_m = Vector3(6, 2.5, 2.5)
 script = ExtResource("1_n3xpu")
 placement_id = &"debris_3"
 kind = 3
-position_m = Vector3(-9, -53.75445, 146)
+position_m = Vector3(-9, -52.854576, 146)
 footprint_m = Vector3(2, 1.5, 2)
 
 [sub_resource type="Resource" id="Resource_hd5cl"]
 script = ExtResource("1_n3xpu")
 placement_id = &"debris_4"
 kind = 3
-position_m = Vector3(-7, -58.142864, 152)
+position_m = Vector3(-7, -58.174175, 152)
 yaw_radians = 2.0
 footprint_m = Vector3(4, 1.5, 1.5)
 
@@ -91,7 +91,7 @@ position_m = Vector3(0, -25, -230)
 [sub_resource type="Resource" id="Resource_u8dqp"]
 script = ExtResource("1_n3xpu")
 placement_id = &"saignee_entrance"
-position_m = Vector3(-56.978443, -35.474903, -124.287895)
+position_m = Vector3(-56.978443, -35.54769, -124.287895)
 
 [sub_resource type="Resource" id="Resource_3uttw"]
 script = ExtResource("1_n3xpu")
@@ -101,7 +101,7 @@ position_m = Vector3(40, -40, 125)
 [sub_resource type="Resource" id="Resource_xvesq"]
 script = ExtResource("2_36hd6")
 route_id = &"safe_ridge"
-waypoints_m = PackedVector3Array(0, -14, -210, 70, -16, -200, 76, -16, -100, 78, -16, 0, 76, -18, 80, 40, -24, 105, 0, -26, 100, -14, -30, 98)
+waypoints_m = PackedVector3Array(0, -14, -210, 70, -16, -200, 76, -16, -100, 78, -16, 0, 76, -18, 80, 40, -24, 105, 0, -24, 100, -14, -30, 98)
 maximum_depth_m = 32.0
 
 [sub_resource type="Resource" id="Resource_lcu7s"]

docs/adr/0012-authored-heightfield-dive-sites.md

@@ -74,8 +74,11 @@ pente, des matériaux imposés par primitive et des `MaterialPatch`.
   (butte ou fosse à sommet plat, contour bruité, matériau roche imposé),
   `BoulderField` (blocs semi-ellipsoïdaux tirés par graine, combinés par
   maximum, roche imposée).
-- Modificateur : `Strata` quantifie les pentes raides en gradins horizontaux ;
-  les fonds et sommets plats ne bougent pas.
+- Modificateurs : `Strata` quantifie les pentes raides en gradins horizontaux
+  dans un rectangle monde, les fonds et sommets plats ne bougent pas ;
+  `SlopeRoughness` ajoute un bruit à crêtes pondéré par la pente (roche
+  éraillée, sable lisse). `Roughness` accepte un nombre d'octaves et un type
+  fractal pour donner du relief de fond à plusieurs échelles.
 
 Tout aléa passe par une graine explicite (`FastNoiseLite`,
 `RandomNumberGenerator`) ; `tests/unit/run_site_baker_tests.gd` vérifie que

docs/briefs/captures/zone1_vigilant_plateau.png.import

@@ -0,0 +1,40 @@
+[remap]
+
+importer="texture"
+type="CompressedTexture2D"
+uid="uid://d3qajwshxpplq"
+path="res://.godot/imported/zone1_vigilant_plateau.png-6e6da03a831034d096e040e9808fd1b8.ctex"
+metadata={
+"vram_texture": false
+}
+
+[deps]
+
+source_file="res://docs/briefs/captures/zone1_vigilant_plateau.png"
+dest_files=["res://.godot/imported/zone1_vigilant_plateau.png-6e6da03a831034d096e040e9808fd1b8.ctex"]
+
+[params]
+
+compress/mode=0
+compress/high_quality=false
+compress/lossy_quality=0.7
+compress/uastc_level=0
+compress/rdo_quality_loss=0.0
+compress/hdr_compression=1
+compress/normal_map=0
+compress/channel_pack=0
+mipmaps/generate=false
+mipmaps/limit=-1
+roughness/mode=0
+roughness/src_normal=""
+process/channel_remap/red=0
+process/channel_remap/green=1
+process/channel_remap/blue=2
+process/channel_remap/alpha=3
+process/fix_alpha_border=true
+process/premult_alpha=false
+process/normal_map_invert_y=false
+process/hdr_as_srgb=false
+process/hdr_clamp_exposure=false
+process/size_limit=0
+detect_3d/compress_to=1

docs/briefs/captures/zone1_vigilant_tombant.png.import

@@ -0,0 +1,40 @@
+[remap]
+
+importer="texture"
+type="CompressedTexture2D"
+uid="uid://cm2nm65ktggp"
+path="res://.godot/imported/zone1_vigilant_tombant.png-71b9b2e227c187a355cfe8ea0a7a15f7.ctex"
+metadata={
+"vram_texture": false
+}
+
+[deps]
+
+source_file="res://docs/briefs/captures/zone1_vigilant_tombant.png"
+dest_files=["res://.godot/imported/zone1_vigilant_tombant.png-71b9b2e227c187a355cfe8ea0a7a15f7.ctex"]
+
+[params]
+
+compress/mode=0
+compress/high_quality=false
+compress/lossy_quality=0.7
+compress/uastc_level=0
+compress/rdo_quality_loss=0.0
+compress/hdr_compression=1
+compress/normal_map=0
+compress/channel_pack=0
+mipmaps/generate=false
+mipmaps/limit=-1
+roughness/mode=0
+roughness/src_normal=""
+process/channel_remap/red=0
+process/channel_remap/green=1
+process/channel_remap/blue=2
+process/channel_remap/alpha=3
+process/fix_alpha_border=true
+process/premult_alpha=false
+process/normal_map_invert_y=false
+process/hdr_as_srgb=false
+process/hdr_clamp_exposure=false
+process/size_limit=0
+detect_3d/compress_to=1

docs/briefs/terrain-site-zone1-gameplay.md

@@ -2,6 +2,14 @@
 
 **Statut : validé par Olivier le 2026-10-06** (plan de masse, objet secondaire à 62 m, pipeline par script de cuisson, nom « Banc du Vigilant » conservé). Sert de spécification de référence pour l'implémentation.
 
+**Recuisson du 2026-10-06 (demande d'Olivier)** : la rupture et le tombant
+sont stratifiés en gradins de 4 m (`Strata`, bande z ≥ 118 m, hors Saignée et
+amers) ; le plateau reçoit un relief de fond à trois échelles (250–15 m ± 2,2 m,
+80–10 m ± 1,2 m, 20–5 m ± 0,6 m) et la roche un bruit de pente (`SlopeRoughness`).
+L'objet secondaire est reculé de 3 m (63 m), le premier débris de 2 m, et le
+point de la route sûre au-dessus de la lèvre de la Saignée remonté à 24 m pour
+garder 3 m de dégagement. Voir `docs/briefs/terrain-varied-landforms.md` §4.3 bis.
+
 Rédigée le 2026-10-06 à partir de `docs/GAME_DESIGN_PLAN.md`,
 `docs/VERTICAL_SLICE_TECHNICAL_PLAN.md`, `docs/POC_B_TECHNICAL_BASELINE.md`,
 des ADR 0004, 0006, 0008, 0010 et du code sous `game/world/`. Rien n'a été

docs/briefs/terrain-varied-landforms.md

@@ -91,12 +91,23 @@ ou `smoothstep`) et **mono-segment**. Il manque :
 
 | Modificateur | Paramètres | Effet |
 |---|---|---|
-| `Strata` | `layer_height_m`, `sharpness` (0–1), `minimum_slope_degrees`, `full_slope_degrees`, `centre`, `radius_m` (0 = partout) | quantifie l'élévation en gradins de `layer_height_m` là où la pente dépasse `minimum_slope_degrees` (plein effet à `full_slope_degrees`) ; `sharpness` 0 = aucun effet, 1 = marches franches ; le fond plat et le plateau ne bougent pas |
+| `Strata` | `layer_height_m`, `sharpness` (0–1), `minimum_slope_degrees`, `full_slope_degrees`, `region_m: Rect2` (vide = partout) | quantifie l'élévation en gradins de `layer_height_m` là où la pente dépasse `minimum_slope_degrees` (plein effet à `full_slope_degrees`) ; `sharpness` 0 = aucun effet, 1 = marches franches ; le fond plat et le plateau ne bougent pas |
 
 Formule : `f = frac(e / h)`, `f' = clamp((f - 0.5) / (1 - s) + 0.5, 0, 1)`,
 `e' = lerp(e, floor(e / h) * h + h * f', w)` avec
 `w = smoothstep(tan(min), tan(full), |gradient|) * masque`.
 
+### 4.3 bis Relief de fond (ajout du 2026-10-06, demande d'Olivier)
+
+Les plateaux cuits avec la seule `Roughness` à 50 m (± 0,6 m) restaient
+plats. `Roughness` prend maintenant un nombre d'octaves et un type fractal
+(`FRACTAL_FBM` roulant, `FRACTAL_RIDGED` à crêtes) : une fréquence de 0,004
+sur cinq octaves donne des mamelons et des cuvettes de 250 m à 15 m en une
+primitive. Le modificateur `SlopeRoughness` (`seed`, `frequency`,
+`amplitude_m`, `minimum_slope_degrees`, `full_slope_degrees`) ajoute un bruit
+à crêtes pondéré par la pente : la roche s'éraille, le sable reste lisse. Les
+deux sites l'utilisent (ondulation ± 2,2 m, roche ± 0,7 m).
+
 ### 4.4 Ce qui ne change pas
 
 Le contrat de données (`SiteTerrainData`, ADR 0012 §2), l'acteur de monde, la
@@ -170,7 +181,10 @@ Plan de masse (nord en haut) :
   (champ de hauteur vu de dessus, roche teintée) et cinq vues en jeu, graybox,
   `terrain_showcase_canyon.png` (gradins et fond ridé), `_crevasse.png`,
   `_boulders.png`, `_spurs.png`, `_escarpment.png` (face de la falaise vue du
-  pied). Le rendu (brouillard, rides en albédo) n'est pas l'objet de ce brief.
+  pied) ; pour le Banc du Vigilant recuit, `zone1_vigilant_tombant.png`
+  (gradins du tombant) et `zone1_vigilant_plateau.png` (plateau ondulé). Le
+  rendu (brouillard, rides en albédo, absence d'ombrage de détail) n'est pas
+  l'objet de ce brief : à ce stade, le relief se lit surtout au sonar.
 
 ## 8. Décisions laissées à Olivier
 
@@ -179,9 +193,11 @@ Plan de masse (nord en haut) :
    couche : à 1 m par cellule, des couches de 4 m sur une paroi à 55° ; une
    paroi à 76° (première cuisson) ne montrait aucun gradin. Les sites de mission restent à 1,5 m sauf décision contraire ; une
    crevasse de 5 m à 1,5 m par cellule n'a que trois cellules de large.
-2. **Strates partout ?** Le modificateur est appliqué au canyon seulement.
-   L'appliquer à la falaise sud du Banc du Vigilant est un changement de
-   recette, donc de `.res`, donc une re-cuisson à valider.
+2. **Strates sur le Banc du Vigilant** : décidé par Olivier le 2026-10-06,
+   appliquées à la rupture et au tombant (bande z ≥ 118 m, couches de 4 m,
+   plein effet dès 40° ; la Saignée, l'Échine et les amers sont hors bande).
+   Le `.res` du site a été recuit ; l'objet secondaire, les débris et les
+   routes restent dans leurs contrats.
 3. **Sites de mission suivants** (U-Boot sous falaise, océanographique en
    canyon) : les primitives sont prêtes ; le plan de masse de chaque site
    reste à proposer et valider séparément.

tests/unit/run_site_baker_tests.gd

@@ -8,7 +8,7 @@ const SiteTerrainData = preload("res://game/domain/sites/site_terrain_data.gd")
 
 const ZONE1_TERRAIN_PATH := "res://content/sites/zone1_vigilant_terrain.res"
 
-const TEST_COUNT := 44
+const TEST_COUNT := 48
 
 var _failures: Array[String] = []
 
@@ -23,6 +23,7 @@ func _init() -> void:
 	_test_outcrop()
 	_test_boulder_field()
 	_test_strata()
+	_test_slope_roughness()
 
 	if _failures.is_empty():
 		print("Site baker unit tests: %d passed, 0 failed." % TEST_COUNT)
@@ -187,7 +188,7 @@ func _test_strata() -> void:
 	recipe.origin_z_m = -10.0
 	recipe.primitives.append(SiteTerrainBaker.SlopedPlane.new(30.0, 1.0, 0.0, 0.0, 0.0))
 	var plain := SiteTerrainBaker.bake(recipe)
-	recipe.modifiers.append(SiteTerrainBaker.Strata.new(2.0, 0.9, 20.0, 35.0, Vector2.ZERO, 0.0))
+	recipe.modifiers.append(SiteTerrainBaker.Strata.new(2.0, 0.9, 20.0, 35.0, Rect2()))
 	var terraced := SiteTerrainBaker.bake(recipe)
 	var flat_cells := 0
 	var riser_cells := 0
@@ -202,17 +203,48 @@ func _test_strata() -> void:
 
 	var flat := _small_recipe()
 	flat.primitives.append(SiteTerrainBaker.SlopedPlane.new(30.3, 0.0, 0.0, 0.0, 0.0))
-	flat.modifiers.append(SiteTerrainBaker.Strata.new(2.0, 0.9, 20.0, 35.0, Vector2.ZERO, 0.0))
+	flat.modifiers.append(SiteTerrainBaker.Strata.new(2.0, 0.9, 20.0, 35.0, Rect2()))
 	var flat_data := SiteTerrainBaker.bake(flat)
 	_expect(is_equal_approx(flat_data.elevations_m[flat_data.index_of(10, 10)], -30.3), "strata leave flat ground alone")
 
 	var identity := _small_recipe()
 	identity.primitives.append(SiteTerrainBaker.SlopedPlane.new(30.0, 1.0, 0.0, 0.0, 0.0))
 	var before := SiteTerrainBaker.bake(identity)
-	identity.modifiers.append(SiteTerrainBaker.Strata.new(2.0, 0.0, 20.0, 35.0, Vector2.ZERO, 0.0))
+	identity.modifiers.append(SiteTerrainBaker.Strata.new(2.0, 0.0, 20.0, 35.0, Rect2()))
 	var after := SiteTerrainBaker.bake(identity)
 	_expect(before.elevations_m == after.elevations_m, "sharpness 0 is the identity")
 
+	# Depth 30.7 keeps the plane off the layer boundaries, where quantisation is the identity.
+	var banded := _small_recipe()
+	banded.primitives.append(SiteTerrainBaker.SlopedPlane.new(30.7, 1.0, 0.0, 0.0, 0.0))
+	var untouched := SiteTerrainBaker.bake(banded)
+	banded.modifiers.append(SiteTerrainBaker.Strata.new(2.0, 0.9, 20.0, 35.0, Rect2(-20.0, 0.0, 40.0, 20.0)))
+	var half := SiteTerrainBaker.bake(banded)
+	var north_same := half.elevations_m[half.index_of(13, 5)] == untouched.elevations_m[untouched.index_of(13, 5)]
+	var south_changed := half.elevations_m[half.index_of(13, 15)] != untouched.elevations_m[untouched.index_of(13, 15)]
+	_expect(north_same and south_changed, "strata stay inside their region")
+
+
+func _test_slope_roughness() -> void:
+	var recipe := _small_recipe()
+	recipe.primitives.append(SiteTerrainBaker.SlopedPlane.new(30.0, 0.0, 0.0, 0.0, 0.0))
+	recipe.primitives.append(SiteTerrainBaker.Blob.new(Vector2(10.0, 10.0), 5.0, 5.0, 12.0))
+	var smooth := SiteTerrainBaker.bake(recipe)
+	recipe.modifiers.append(SiteTerrainBaker.SlopeRoughness.new(5, 0.2, 1.0, 20.0, 40.0))
+	var rough := SiteTerrainBaker.bake(recipe)
+	_expect(rough.elevations_m[rough.index_of(0, 0)] == smooth.elevations_m[smooth.index_of(0, 0)], "slope roughness leaves flat sand untouched")
+	var flank_changed := false
+	for column in range(13, 18):
+		flank_changed = flank_changed or rough.elevations_m[rough.index_of(column, 15)] != smooth.elevations_m[smooth.index_of(column, 15)]
+	_expect(flank_changed, "slope roughness roughens the steep flank")
+	var octaves := _small_recipe()
+	octaves.primitives.append(SiteTerrainBaker.Roughness.new(7, 0.01, 2.0, 5, FastNoiseLite.FRACTAL_RIDGED))
+	var ridged := SiteTerrainBaker.bake(octaves)
+	var within := true
+	for elevation: float in ridged.elevations_m:
+		within = within and absf(elevation) <= 2.0 + 0.001
+	_expect(within, "roughness amplitude bounds the ridged multi-octave noise")
+
 
 func _test_zone1_artefact_is_stable() -> void:
 	var versioned := load(ZONE1_TERRAIN_PATH) as SiteTerrainData

tools/site_terrain_baker.gd

@@ -410,18 +410,28 @@ class Ripples extends Primitive:
 		return amplitude_m * sin(phase) * falloff
 
 
+## Seeded fractal noise added everywhere. frequency is 1 / wavelength of the largest
+## octave; each further octave halves the wavelength and the amplitude, so a low
+## frequency with five octaves gives hummocks, swales and ripple-scale detail at once.
+## FRACTAL_RIDGED makes sharp crests (rock), FRACTAL_FBM rolling ground (sediment).
 class Roughness extends Primitive:
 	var amplitude_m: float
 	var _noise: FastNoiseLite
 
-	func _init(p_seed: int, p_frequency: float, p_amplitude_m: float) -> void:
+	func _init(
+		p_seed: int,
+		p_frequency: float,
+		p_amplitude_m: float,
+		p_octaves: int = 3,
+		p_fractal_type: FastNoiseLite.FractalType = FastNoiseLite.FRACTAL_FBM
+	) -> void:
 		amplitude_m = p_amplitude_m
 		_noise = FastNoiseLite.new()
 		_noise.noise_type = FastNoiseLite.TYPE_SIMPLEX_SMOOTH
 		_noise.seed = p_seed
 		_noise.frequency = p_frequency
-		_noise.fractal_type = FastNoiseLite.FRACTAL_FBM
-		_noise.fractal_octaves = 3
+		_noise.fractal_type = p_fractal_type
+		_noise.fractal_octaves = p_octaves
 
 	func elevation_delta(x_m: float, z_m: float) -> float:
 		return _noise.get_noise_2d(x_m, z_m) * amplitude_m
@@ -437,12 +447,13 @@ class Modifier extends RefCounted:
 ## Quantises steep ground into horizontal ledges layer_height_m apart: the stratified
 ## walls of a canyon or cliff. Flat floors and summits are below minimum_slope_degrees and
 ## stay untouched; the effect is full from full_slope_degrees. sharpness 0 leaves the
-## field unchanged, 1 cuts hard steps. radius_m 0 applies everywhere.
+## field unchanged, 1 cuts hard steps. region_m is a world-space (x, z) rectangle with a
+## hard edge; an empty rectangle applies everywhere. Ledges need two to three cells of
+## wall per layer to be resolved: at 1.5 m per cell, 4 m layers on a 50 degree wall.
 class Strata extends Modifier:
 	var layer_height_m: float
 	var sharpness: float
-	var centre: Vector2
-	var radius_m: float
+	var region_m: Rect2
 	var _minimum_tangent: float
 	var _full_tangent: float
 
@@ -451,21 +462,19 @@ class Strata extends Modifier:
 		p_sharpness: float,
 		p_minimum_slope_degrees: float,
 		p_full_slope_degrees: float,
-		p_centre: Vector2,
-		p_radius_m: float
+		p_region_m: Rect2
 	) -> void:
 		assert(p_layer_height_m > 0.0, "strata need a positive layer height")
 		layer_height_m = p_layer_height_m
 		sharpness = clampf(p_sharpness, 0.0, 0.999)
-		centre = p_centre
-		radius_m = p_radius_m
+		region_m = p_region_m
 		_minimum_tangent = tan(deg_to_rad(p_minimum_slope_degrees))
 		_full_tangent = tan(deg_to_rad(p_full_slope_degrees))
 
 	func modify(x_m: float, z_m: float, elevation_m: float, gradient: Vector2) -> float:
+		if region_m.has_area() and not region_m.has_point(Vector2(x_m, z_m)):
+			return elevation_m
 		var weight := smoothstep(_minimum_tangent, _full_tangent, gradient.length())
-		if radius_m > 0.0:
-			weight *= 1.0 - smoothstep(radius_m * 0.8, radius_m, Vector2(x_m, z_m).distance_to(centre))
 		if weight <= 0.0:
 			return elevation_m
 		var layer := floorf(elevation_m / layer_height_m)
@@ -474,6 +483,39 @@ class Strata extends Modifier:
 		return lerpf(elevation_m, (layer + sharpened) * layer_height_m, weight)
 
 
+## Seeded noise weighted by the local slope: rock faces and ridge flanks get crumbly
+## while flat sand stays smooth. Zero below minimum_slope_degrees, full amplitude from
+## full_slope_degrees.
+class SlopeRoughness extends Modifier:
+	var amplitude_m: float
+	var _noise: FastNoiseLite
+	var _minimum_tangent: float
+	var _full_tangent: float
+
+	func _init(
+		p_seed: int,
+		p_frequency: float,
+		p_amplitude_m: float,
+		p_minimum_slope_degrees: float,
+		p_full_slope_degrees: float
+	) -> void:
+		amplitude_m = p_amplitude_m
+		_noise = FastNoiseLite.new()
+		_noise.noise_type = FastNoiseLite.TYPE_SIMPLEX_SMOOTH
+		_noise.seed = p_seed
+		_noise.frequency = p_frequency
+		_noise.fractal_type = FastNoiseLite.FRACTAL_RIDGED
+		_noise.fractal_octaves = 3
+		_minimum_tangent = tan(deg_to_rad(p_minimum_slope_degrees))
+		_full_tangent = tan(deg_to_rad(p_full_slope_degrees))
+
+	func modify(x_m: float, z_m: float, elevation_m: float, gradient: Vector2) -> float:
+		var weight := smoothstep(_minimum_tangent, _full_tangent, gradient.length())
+		if weight <= 0.0:
+			return elevation_m
+		return elevation_m + _noise.get_noise_2d(x_m, z_m) * amplitude_m * weight
+
+
 class MaterialPatch extends RefCounted:
 	var centre: Vector2
 	var radius_m: float

tools/sites/terrain_showcase_recipe.gd

@@ -73,10 +73,10 @@ static func recipe() -> SiteTerrainBaker.Recipe:
 		SiteTerrainBaker.BoulderField.new(Vector2(-100.0, 130.0), 40.0, 302, 6, 6.0, 9.0, 0.6),
 		SiteTerrainBaker.Ripples.new(Vector2(1.0, 0.3), 3.5, 0.3, BOULDER_FIELD_CENTRE, 110.0),
 
-		# SE — les Éperons: two pitted rock spurs 6-7 m high framing a 20 m sand channel
+		# SE — les Éperons: two pitted rock spurs 7-8 m high framing a 20 m sand channel
 		# littered with small blocks.
-		SiteTerrainBaker.Outcrop.new(WEST_SPUR_CENTRE, 30.0, 60.0, 7.0, 5.0, 401, 7.0, true),
-		SiteTerrainBaker.Outcrop.new(EAST_SPUR_CENTRE, 30.0, 55.0, 6.0, 5.0, 402, 7.0, true),
+		SiteTerrainBaker.Outcrop.new(WEST_SPUR_CENTRE, 30.0, 60.0, 8.0, 5.0, 401, 7.0, true),
+		SiteTerrainBaker.Outcrop.new(EAST_SPUR_CENTRE, 30.0, 55.0, 7.0, 5.0, 402, 7.0, true),
 		SiteTerrainBaker.BoulderField.new(CHANNEL_CENTRE, 50.0, 403, 12, 1.5, 3.0, 0.8),
 
 		# S — la Corniche: sinuous 22 m escarpment, then a 42 degree slope to the 80 m floor,
@@ -86,13 +86,19 @@ static func recipe() -> SiteTerrainBaker.Recipe:
 		SiteTerrainBaker.Outcrop.new(Vector2(40.0, 236.0), 10.0, 9.0, 4.0, 9.0, 503, 2.0, true),
 		SiteTerrainBaker.Outcrop.new(Vector2(130.0, 245.0), 14.0, 11.0, 6.0, 11.0, 504, 2.0, true),
 
-		# Roughness: broad undulation plus cell-scale pitting.
+		# Roughness: hummocks and swales from 250 m down to 15 m, the 50 m texture,
+		# and cell-scale pitting.
+		SiteTerrainBaker.Roughness.new(2026, 0.004, 2.2, 5),
+		SiteTerrainBaker.Roughness.new(2029, 0.012, 1.2, 4),
+		SiteTerrainBaker.Roughness.new(2030, 0.05, 0.6, 3),
 		SiteTerrainBaker.Roughness.new(1933, 0.02, 0.6),
 		SiteTerrainBaker.Roughness.new(2027, 0.15, 0.2),
 	]
 	result.modifiers = [
-		# Strata on the mesa flanks and canyon walls only: 4 m ledges.
-		SiteTerrainBaker.Strata.new(4.0, 0.85, 30.0, 50.0, MESA_CENTRE, 130.0),
+		# Crumbly rock faces, smooth sand. Before the strata so the ledges stay flat.
+		SiteTerrainBaker.SlopeRoughness.new(2028, 0.12, 0.7, 20.0, 40.0),
+		# Strata on the north-west quarter only (mesa flanks and canyon walls): 4 m ledges.
+		SiteTerrainBaker.Strata.new(4.0, 0.85, 30.0, 50.0, Rect2(-256.0, -256.0, 256.0, 256.0)),
 	]
 	return result
 

tools/sites/zone1_vigilant_recipe.gd

@@ -15,6 +15,9 @@ const GROOVE_END := Vector2(-10.0, 120.0)
 const RIDGE_START := Vector2(70.0, -150.0)
 const RIDGE_END := Vector2(80.0, 90.0)
 const BREAK_Z := 125.0
+# Strata apply from here south: past the groove's end cap (120 m) and still 3 m before
+# the break's smoothstep has dropped half a metre.
+const STRATA_START_Z := 118.0
 # The target's centre sits this far up the groove from GROOVE_END, so its 28 m hull
 # stops one groove half-width short of the end cap and rests on the flat groove floor.
 const TARGET_SET_BACK_M := 22.0
@@ -57,8 +60,22 @@ static func recipe() -> SiteTerrainBaker.Recipe:
 		SiteTerrainBaker.Blob.new(Vector2(25.0, 198.0), 6.3, 6.3, 2.0),
 		# Les Rides: sand ripples near the vessel only.
 		SiteTerrainBaker.Ripples.new(Vector2(1.0, 0.35), 9.0, 0.45, Vector2(0.0, -220.0), 90.0),
-		# Deterministic roughness everywhere.
+		# Deterministic roughness everywhere: the original 50 m texture, plus hummocks
+		# and swales from 250 m down to 15 m (five octaves) so the plateau is never flat.
 		SiteTerrainBaker.Roughness.new(1933, 0.02, 0.6),
+		SiteTerrainBaker.Roughness.new(1934, 0.004, 2.2, 5),
+		SiteTerrainBaker.Roughness.new(1936, 0.012, 1.2, 4),
+		# Hummocks of 20 m down to 5 m, the scale the pilot sees through the fog.
+		SiteTerrainBaker.Roughness.new(1937, 0.05, 0.6, 3),
+	]
+	result.modifiers = [
+		# La rupture et le tombant are a carbonate drop-off: 4 m strata on the break
+		# (full effect) and fainter ledges on the 35 degree talus below. The band starts
+		# south of the target hull and of la Saignée's end cap, so neither changes.
+		# Crumbly rock on every slope steeper than the sand rule, smooth sand elsewhere.
+		# Before the strata so the ledges stay flat.
+		SiteTerrainBaker.SlopeRoughness.new(1935, 0.12, 0.7, 20.0, 40.0),
+		SiteTerrainBaker.Strata.new(4.0, 0.85, 25.0, 40.0, Rect2(-384.0, STRATA_START_Z, 768.0, 384.0 - STRATA_START_Z)),
 	]
 	result.material_patches = [
 		SiteTerrainBaker.MaterialPatch.new(Vector2(140.0, 40.0), 28.0, SonarMaterial.Value.ROCK),
@@ -90,9 +107,9 @@ static func definition(terrain: SiteTerrainData) -> DiveSiteDefinition:
 		_on_seabed(field, &"decoy_coaster", SitePlacement.Kind.WRECK_DECOY,
 			Vector2(140.0, 40.0), -0.6, Vector3(26.0, 6.0, 8.0), 1.2),
 		_on_seabed(field, &"secondary_item", SitePlacement.Kind.SECONDARY_ITEM,
-			Vector2(-6.0, 157.0), 0.0, Vector3(1.0, 1.0, 1.0), 0.0),
+			Vector2(-6.0, 160.0), 0.0, Vector3(1.0, 1.0, 1.0), 0.0),
 		_on_seabed(field, &"debris_1", SitePlacement.Kind.DEBRIS,
-			Vector2(-12.0, 134.0), 0.4, Vector3(3.0, 2.0, 2.0), 0.3),
+			Vector2(-12.0, 136.0), 0.4, Vector3(3.0, 2.0, 2.0), 0.3),
 		_on_seabed(field, &"debris_2", SitePlacement.Kind.DEBRIS,
 			Vector2(-10.0, 139.0), 1.2, Vector3(6.0, 2.5, 2.5), 0.4),
 		_on_seabed(field, &"debris_3", SitePlacement.Kind.DEBRIS,
@@ -110,7 +127,7 @@ static func definition(terrain: SiteTerrainData) -> DiveSiteDefinition:
 		_route(&"safe_ridge", 32.0, [
 			Vector3(0.0, -14.0, -210.0), Vector3(70.0, -16.0, -200.0), Vector3(76.0, -16.0, -100.0),
 			Vector3(78.0, -16.0, 0.0), Vector3(76.0, -18.0, 80.0), Vector3(40.0, -24.0, 105.0),
-			Vector3(0.0, -26.0, 100.0), Vector3(-14.0, -30.0, 98.0),
+			Vector3(0.0, -24.0, 100.0), Vector3(-14.0, -30.0, 98.0),
 		]),
 		_route(&"risky_groove", 48.0, [
 			Vector3(0.0, -14.0, -210.0), Vector3(-60.0, -20.0, -150.0), Vector3(-50.0, -31.0, -100.0),