feat(tools): Outcrop and BoulderField primitives with forced rock material

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

tools/site_terrain_baker.gd

@@ -243,6 +243,110 @@ class Escarpment extends Primitive:
 		return -(step + slope)
 
 
+## Flat-topped elliptical mound (or, with a negative height, a flat-bottomed pit) whose
+## flank spans wall_width_m inside a noise-roughened outline. With rock_top the whole
+## mound above 30 % of its height is rock, sommet plat compris.
+class Outcrop extends Primitive:
+	var centre: Vector2
+	var radius_x_m: float
+	var radius_z_m: float
+	var height_m: float
+	var wall_width_m: float
+	var edge_amplitude_m: float
+	var rock_top: bool
+	var _noise: FastNoiseLite
+	var _mean_radius_m: float
+
+	func _init(
+		p_centre: Vector2,
+		p_radius_x_m: float,
+		p_radius_z_m: float,
+		p_height_m: float,
+		p_wall_width_m: float,
+		p_edge_seed: int,
+		p_edge_amplitude_m: float,
+		p_rock_top: bool
+	) -> void:
+		centre = p_centre
+		radius_x_m = p_radius_x_m
+		radius_z_m = p_radius_z_m
+		height_m = p_height_m
+		wall_width_m = p_wall_width_m
+		edge_amplitude_m = p_edge_amplitude_m
+		rock_top = p_rock_top
+		_noise = edge_noise(p_edge_seed, p_edge_amplitude_m)
+		_mean_radius_m = (p_radius_x_m + p_radius_z_m) * 0.5
+
+	func elevation_delta(x_m: float, z_m: float) -> float:
+		var dx := (x_m - centre.x) / radius_x_m
+		var dz := (z_m - centre.y) / radius_z_m
+		var edge_distance := (sqrt(dx * dx + dz * dz) - 1.0) * _mean_radius_m
+		edge_distance += edge_offset(_noise, edge_amplitude_m, x_m, z_m)
+		return height_m * (1.0 - smoothstep(-wall_width_m, 0.0, edge_distance))
+
+	func material_at(x_m: float, z_m: float) -> int:
+		if rock_top and absf(elevation_delta(x_m, z_m)) > 0.3 * absf(height_m):
+			return SonarMaterial.Value.ROCK
+		return NO_MATERIAL
+
+
+## count half-ellipsoid boulders scattered uniformly in a disc by a seeded generator.
+## Boulders combine by maximum, so overlapping blocks never pile into one mound, and every
+## cell they cover is rock.
+class BoulderField extends Primitive:
+	var centre: Vector2
+	var radius_m: float
+	var height_ratio: float
+	var _boulders := PackedVector3Array()  # x, z, radius
+	var _reach_m: float
+
+	func _init(
+		p_centre: Vector2,
+		p_radius_m: float,
+		p_seed: int,
+		p_count: int,
+		p_boulder_radius_min_m: float,
+		p_boulder_radius_max_m: float,
+		p_height_ratio: float
+	) -> void:
+		centre = p_centre
+		radius_m = p_radius_m
+		height_ratio = p_height_ratio
+		_reach_m = p_radius_m + p_boulder_radius_max_m
+		var generator := RandomNumberGenerator.new()
+		generator.seed = p_seed
+		for _index in p_count:
+			var distance := p_radius_m * sqrt(generator.randf())
+			var angle := TAU * generator.randf()
+			var boulder_radius := generator.randf_range(p_boulder_radius_min_m, p_boulder_radius_max_m)
+			_boulders.append(Vector3(
+				p_centre.x + distance * cos(angle),
+				p_centre.y + distance * sin(angle),
+				boulder_radius
+			))
+
+	func boulders() -> PackedVector3Array:
+		return _boulders
+
+	func elevation_delta(x_m: float, z_m: float) -> float:
+		if Vector2(x_m, z_m).distance_to(centre) > _reach_m:
+			return 0.0
+		var highest := 0.0
+		for boulder in _boulders:
+			var dx := x_m - boulder.x
+			var dz := z_m - boulder.y
+			var squared := dx * dx + dz * dz
+			var radius_squared := boulder.z * boulder.z
+			if squared < radius_squared:
+				highest = maxf(highest, boulder.z * height_ratio * sqrt(1.0 - squared / radius_squared))
+		return highest
+
+	func material_at(x_m: float, z_m: float) -> int:
+		if elevation_delta(x_m, z_m) > 0.0:
+			return SonarMaterial.Value.ROCK
+		return NO_MATERIAL
+
+
 class Step extends Primitive:
 	var point: Vector2
 	var normal: Vector2