Animals stay off the cliffs (Gitea #6): nothing walks up or along ground steeper than 35 degrees, and a carcass on steep ground slides down to where it can be reached and butchered

tests/test_cliffs.gd

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+extends SceneTree
+## Gitea #6: animals stay off the cliffs at the edge of the world. A deer
+## chased outward toward the mountain rim, all the way round, never climbs
+## steep ground; and one killed on a steep face comes to rest where it's
+## flatter, so you can reach it and butcher it.
+## Run: godot --headless --path . --script res://tests/test_cliffs.gd
+
+var _fails := 0
+var _finished := false
+var S: Node
+var A: Node
+
+func check(cond: bool, what: String) -> void:
+	print(("  ok   " if cond else "  FAIL ") + what)
+	if not cond:
+		_fails += 1
+
+func _initialize() -> void:
+	_run.call_deferred()
+
+func _run() -> void:
+	S = root.get_node("Saves")
+	A = root.get_node("Actions")
+	S.root_dir = "user://test_cliffs_worlds"
+	for x in S.list_worlds():
+		S.delete_world(x.id)
+	S.current_id = S.create_world("Valley", 1337)
+	var w: Node3D = load("res://scenes/world.tscn").instantiate()
+	root.add_child(w)
+	for _i in range(8):
+		await physics_frame
+	w.creatures.enabled = false
+	for c in w.creatures.get_children():
+		c.queue_free()
+	if w.wolves != null:
+		w.wolves.enabled = false
+	w.player.set_physics_process(false)
+	w.player.survival.set_process(false)
+	await _body(w)
+	check(_finished, "test ran to the end (no script errors)")
+	for x in S.list_worlds():
+		S.delete_world(x.id)
+	DirAccess.remove_absolute(S.root_dir)
+	print("RESULT: %s (%d failures)" % ["PASS" if _fails == 0 else "FAIL", _fails])
+	quit(1 if _fails > 0 else 0)
+
+func _body(w: Node3D) -> void:
+	var t: Node3D = w.terrain
+	var p: Node3D = w.player
+	print("chased toward the mountains")
+	# How far into the mountain rim each deer gets (the terrain's own rim
+	# distance), and the steepest ground it walks UP onto.
+	# (Running down a steep bank is allowed: that's how one gets back down.)
+	var steepest := 0.0
+	var highest := 0.0
+	var climb := 0.0
+	var where := ""
+	for i in range(36):
+		var a := TAU * i / 36.0
+		var dir := Vector3(cos(a), 0, sin(a))
+		# (12 m inside the rim, which wobbles in and out by up to 16 m.)
+		var start: Vector3 = dir * (t.play_radius - 12.0 - t._rim_offset(dir.x, dir.z))
+		var d: Node3D = w.creatures.spawn("deer", start)
+		d.set_physics_process(false)
+		for _s in range(600):   # (20 s at a run, with you right behind it)
+			p.global_position = d.global_position - dir * 8.0
+			d.player = p
+			d._threat = p.global_position
+			d.state = "flee"
+			d._state_t = 4.0
+			var y0: float = d.global_position.y
+			d.step(1.0 / 30.0)
+			var g: Vector3 = d.global_position
+			if g.y > y0 + 0.0005:
+				var deg := rad_to_deg(acos(clampf(t.sample_normal(g.x, g.z).y, -1.0, 1.0)))
+				if deg > steepest:
+					steepest = deg
+					where = "%d degrees round" % (i * 10)
+			highest = maxf(highest, t._rim_d(g.x, g.z) - t.play_radius)
+			climb = maxf(climb, g.y - start.y - t.sample_height(start.x, start.z) + start.y)
+		d.free()
+		if i % 6 == 0:
+			await process_frame
+	# (Its limit is 35 degrees, checked at a few points ahead, so a few
+	# degrees more can slip through between them; the player's limit is 45:
+	# anywhere a deer goes, you can follow. Before the fix: 71 degrees.)
+	check(steepest < 45.0, "a deer chased outward never walks up ground steeper than you can (steepest %.0f, at %s)" % [steepest, where])
+	# (The rim rises 58 m over 30 m; its first few metres are still gentle.
+	# Before the fix: 8 m in and up onto the cliff face.)
+	check(highest < 6.0 and climb < 6.0, "and stays at the foot of the mountain rim (%.1f m in, %.1f m above where it started)" % [highest, climb])
+
+	print("killed on a cliff")
+	# A steep spot on the rim, inside the play area: where a deer used to end up.
+	var spot := Vector3.INF
+	for i in range(72):
+		var a := TAU * i / 72.0
+		for r in range(int(t.play_radius) - 5, int(t.play_radius) + 15):
+			var x := cos(a) * r
+			var z := sin(a) * r
+			if t.inside_boundary(x, z, 3.0) and t.sample_normal(x, z).y < 0.55:
+				spot = Vector3(x, t.sample_height(x, z), z)
+				break
+		if spot != Vector3.INF:
+			break
+	check(spot != Vector3.INF, "(a 55-degree face on the rim to try it on)")
+	if spot == Vector3.INF:
+		return
+	var deer: Node3D = w.creatures.spawn("deer", spot)
+	deer.set_physics_process(false)
+	deer.take_hit(999.0, spot + Vector3(0, 1, 0))
+	var at: Vector3 = deer.global_position
+	var ny: float = t.sample_normal(at.x, at.z).y
+	check(deer.is_dead() and ny >= deer.CARCASS_REST_NY, "it comes to rest on flatter ground (%.0f degrees)" % rad_to_deg(acos(ny)))
+	check(at.distance_to(spot) < 20.5 and at.y < spot.y, "a little way down the slope (%.1f m)" % at.distance_to(spot))
+	check(absf(at.y - t.sample_height(at.x, at.z)) < 0.05, "lying on the ground, not inside it")
+	p.global_position = at + Vector3(0.8, 0, 0)
+	p.global_position.y = t.sample_height(p.global_position.x, p.global_position.z)
+	var before: int = p.inventory.count("raw_meat")
+	check(A.butcher(p, deer) and p.inventory.count("raw_meat") > before, "and you can butcher it")
+
+	print("on flat ground")
+	var flat: Vector3 = w.build.debug_find_site(w._spawn, 3.0)
+	var d2: Node3D = w.creatures.spawn("deer", flat)
+	d2.set_physics_process(false)
+	var was: Vector3 = d2.global_position
+	d2.take_hit(999.0, was + Vector3(0, 1, 0))
+	check(d2.global_position.distance_to(was) < 0.01, "a deer killed on the flat stays where it fell")
+	d2.free()
+	_finished = true