Tutorial: Old Tam's hut outline beside the fire, pieces snap into it

scripts/core/guide.gd

@@ -120,6 +120,7 @@ func start(w: Node3D, from_saved: Dictionary = {}) -> void:
 	_enter()
 
 func stop() -> void:
+	_clear_outline()
 	active = false
 	world = null
 
@@ -145,7 +146,16 @@ func _enter() -> void:
 	_check()   # (done early? it ticks straight away)
 
 const DemoWolf = preload("res://scripts/creatures/tutorial_wolf.gd")
+const HutOutline = preload("res://scripts/ui/hut_outline.gd")
 var demo_wolf: Node3D = null
+var outline: Node3D = null       ## the hut outline, while the hut step is on
+
+func _clear_outline() -> void:
+	if outline != null and is_instance_valid(outline):
+		outline.queue_free()
+	outline = null
+	if world != null and is_instance_valid(world):
+		world.build.outline = null
 
 ## A step's set-up: the clock, some animals, the demo wolf.
 func _setup(su: Dictionary) -> void:
@@ -168,6 +178,28 @@ func _setup(su: Dictionary) -> void:
 				if world.terrain.inside_boundary(at.x, at.z, 4.0) and world.terrain.sample_height(at.x, at.z) > world.terrain.water_level + 0.3:
 					world.creatures.spawn(String(sp.kind), at)
 					break
+	if String(su.get("outline", "")) == "hut":
+		_clear_outline()
+		# A good spot a few metres from your fire (or from you).
+		# Search out from the fire in small rings, starting far enough out
+		# that the hut (3 m half-width) leaves the fire 2 m clear of its walls.
+		var near: Vector3 = world.player.global_position
+		var step := 4.0
+		var min_dist := 0.0
+		for pc in world.all_pieces():
+			if pc.item_id == "campfire" and pc.global_position.distance_to(near) < 30.0:
+				near = pc.global_position
+				step = 1.5
+				min_dist = 5.0
+		var site: Vector3 = world.build.debug_find_site(near, 3.0, step, min_dist)
+		var yaw: float = world.player.rotation.y
+		var b := Basis(Vector3.UP, yaw)
+		var first: Transform3D = world.build._free_xf("floor", site + b * Vector3(-1, 0, -1), yaw, true)
+		outline = HutOutline.new()
+		outline.name = "HutOutline"
+		world.add_child(outline)
+		outline.setup(world, first)
+		world.build.outline = outline
 	if su.get("demo_wolf", false):
 		if demo_wolf != null and is_instance_valid(demo_wolf):
 			demo_wolf.queue_free()
@@ -200,6 +232,7 @@ func _check() -> void:
 		_advance()
 
 func _advance() -> void:
+	_clear_outline()   # (it was only for the step that's ending)
 	var s := current()
 	done.append(String(s.id))
 	step_done.emit(index, s)
@@ -349,6 +382,11 @@ func find_marker() -> Vector3:
 		for pc in world.all_pieces():
 			if pc.item_id == what.substr(6):
 				cands.append(pc)
+	elif what == "outline":
+		# Wherever the outline still has pieces to build: its middle.
+		if outline != null and is_instance_valid(outline):
+			return outline.center()
+		return Vector3.INF
 	elif what == "lake":
 		# The lake's shore, on your side of it.
 		var c: Vector2 = world.terrain.lake_center