transcience/tests/unit/test_emitters.gd

extends GutTest
## Emitters are the authoring surface for every enemy and boss, so their shapes
## are asserted directly rather than eyeballed in game.

var pool: BulletPool
var ctx: EmitContext


func before_each() -> void:
	pool = BulletPool.new()
	ctx = EmitContext.new()
	ctx.pool = pool
	ctx.origin = Vector2.ZERO
	ctx.rng = RandomNumberGenerator.new()
	ctx.rng.seed = 1


func _angles() -> Array[float]:
	var out: Array[float] = []
	for i in pool.high_water:
		if pool.alive[i] == 1:
			out.append(pool.vel[i].angle())
	return out


func test_ring_emits_the_requested_count() -> void:
	var e := RingEmitter.new()
	e.count = 8
	e.fire(ctx)
	assert_eq(pool.live_count, 8)


func test_closed_ring_is_evenly_spaced_with_no_duplicate_at_the_seam() -> void:
	var e := RingEmitter.new()
	e.count = 8
	e.arc_deg = 360.0
	e.spin_per_shot_deg = 0.0
	e.fire(ctx)
	var angles := _angles()
	angles.sort()
	for i in range(1, angles.size()):
		assert_almost_eq(angles[i] - angles[i - 1], TAU / 8.0, 0.001)


func test_spin_advances_with_shot_index() -> void:
	var e := RingEmitter.new()
	e.count = 1
	e.spin_per_shot_deg = 30.0
	e.fire(ctx)
	var first := _angles()[0]
	pool.clear()
	ctx.shot_index = 1
	e.fire(ctx)
	assert_almost_eq(_angles()[0] - first, deg_to_rad(30.0), 0.001)


func test_should_fire_respects_interval_and_window() -> void:
	var e := RingEmitter.new()
	e.start_tick = 10
	e.end_tick = 40
	e.interval = 10
	assert_false(e.should_fire(9), "not armed before start_tick")
	assert_true(e.should_fire(10))
	assert_false(e.should_fire(15))
	assert_true(e.should_fire(30))
	assert_false(e.should_fire(50), "not armed after end_tick")


func test_shot_index_matches_the_number_of_shots_so_far() -> void:
	var e := RingEmitter.new()
	e.start_tick = 10
	e.interval = 10
	assert_eq(e.shot_index_at(10), 0)
	assert_eq(e.shot_index_at(30), 2)


func test_aimed_spread_centres_on_the_target() -> void:
	var e := AimedSpreadEmitter.new()
	e.count = 3
	e.spread_deg = 30.0
	ctx.has_target = true
	ctx.target = Vector2(100.0, 0.0)
	e.fire(ctx)
	var angles := _angles()
	angles.sort()
	assert_eq(angles.size(), 3)
	assert_almost_eq(angles[1], 0.0, 0.001, "the middle shot must point at the target")
	assert_almost_eq(angles[2] - angles[0], deg_to_rad(30.0), 0.001)


func test_aimed_spread_falls_back_when_nobody_is_alive() -> void:
	var e := AimedSpreadEmitter.new()
	e.count = 1
	ctx.has_target = false
	e.fire(ctx)
	assert_eq(pool.live_count, 1, "an emitter with no target must still be safe to fire")


func test_wall_leaves_a_gap_of_the_requested_width() -> void:
	var e := WallGapEmitter.new()
	e.count = 20
	e.gap_width = 3
	e.fire(ctx)
	assert_eq(pool.live_count, 17)


func test_wall_gap_slides_between_shots() -> void:
	var e := WallGapEmitter.new()
	e.count = 20
	e.gap_width = 3
	e.gap_step = 5
	e.fire(ctx)
	var first_xs: Array = []
	for i in pool.high_water:
		if pool.alive[i] == 1:
			first_xs.append(snappedf(pool.pos[i].x, 0.01))
	pool.clear()
	ctx.shot_index = 1
	e.fire(ctx)
	var second_xs: Array = []
	for i in pool.high_water:
		if pool.alive[i] == 1:
			second_xs.append(snappedf(pool.pos[i].x, 0.01))
	assert_ne(first_xs, second_xs, "the safe lane must move so it cannot be camped")


func test_arc_sweep_emits_every_arm() -> void:
	var e := ArcSweepEmitter.new()
	e.arms = 3
	e.bullets_per_arm = 4
	e.fire(ctx)
	assert_eq(pool.live_count, 12)


func test_arc_sweep_angle_changes_over_the_phase() -> void:
	var e := ArcSweepEmitter.new()
	e.arms = 1
	e.bullets_per_arm = 1
	e.sweep_period = 4.0
	e.sweep_deg = 90.0
	ctx.local_tick = 0
	e.fire(ctx)
	var a0 := _angles()[0]
	pool.clear()
	ctx.local_tick = 30
	e.fire(ctx)
	assert_ne(snappedf(a0, 0.001), snappedf(_angles()[0], 0.001))


# --- Muzzles against geometry -----------------------------------------------
# An emitter places bullets away from its shooter, and BulletPool samples
# geometry once per tick, so it never sees that jump. A curtain spans the whole
# arena and an arc sweep's outer arms sit 100px out -- both were spawning shots
# on the far side of cover. Both boss arenas are built out of cover: the vault's
# barricades exist precisely so there is no clean firing lane, and the hall has
# pillars.

func _walled_world(kind: MapGrid.Kind) -> SimWorld:
	var g := MapGrid.new(30, 20, MapGrid.Kind.FLOOR)
	for ty in 20:
		g.set_tile(15, ty, kind)
	var w := SimWorld.new(1)
	w.set_map(g)
	return w


func _ctx_for(w: SimWorld, at: Vector2) -> EmitContext:
	var ctx := EmitContext.new()
	ctx.pool = w.pool
	ctx.origin = at
	ctx.target = at + Vector2(0.0, 200.0)
	ctx.has_target = true
	ctx.rng = w.rng
	ctx.bounds = Rect2(at - Vector2(320.0, 320.0), Vector2(640.0, 640.0))
	return ctx


## Bullets born strictly beyond the barrier column, which spans one tile.
func _past_the_barrier(w: SimWorld) -> int:
	var beyond: float = w.map.origin.x + 16.0 * MapGrid.TILE
	var n := 0
	for i in w.pool.high_water:
		if w.pool.alive[i] != 0 and w.pool.pos[i].x >= beyond:
			n += 1
	return n


func _fire_once(w: SimWorld, em: BulletEmitter, at: Vector2) -> void:
	var ctx := _ctx_for(w, at)
	ctx.local_tick = 0
	ctx.shot_index = 0
	em.fire(ctx)


func test_a_curtain_does_not_spawn_through_a_barricade() -> void:
	# A curtain spans its bounds, so most of it is nowhere near the shooter --
	# which is exactly how it was reaching the far side of the room.
	var em := WallGapEmitter.new()
	em.count = 16
	em.speed = 100.0
	var open_world := _walled_world(MapGrid.Kind.FLOOR)
	var at := Vector2(open_world.map.origin.x + 14.0 * MapGrid.TILE,
		open_world.map.tile_centre(14, 10).y)
	_fire_once(open_world, em, at)
	assert_gt(_past_the_barrier(open_world), 0,
		"with nothing in the way the curtain reaches across the room")

	var blocked := _walled_world(MapGrid.Kind.BARRICADE)
	_fire_once(blocked, em, at)
	assert_eq(_past_the_barrier(blocked), 0,
		"a barricade stops bullets, so it has to stop them being born past it")
	assert_gt(blocked.pool.live_count, 0,
		"and the near half of the curtain still fires")


func test_an_arc_sweeps_outer_arms_do_not_reach_through_a_wall() -> void:
	var em := ArcSweepEmitter.new()
	em.arms = 4
	em.arm_spacing = 26.0
	em.muzzle_offset = 26.0
	em.speed = 100.0
	var at_open := _walled_world(MapGrid.Kind.FLOOR)
	# Flush against the barrier, sweeping into it.
	var at := Vector2(at_open.map.origin.x + 15.0 * MapGrid.TILE - 20.0,
		at_open.map.tile_centre(10, 10).y)
	_fire_once(at_open, em, at)
	var reach_open := _past_the_barrier(at_open)

	var blocked := _walled_world(MapGrid.Kind.WALL)
	_fire_once(blocked, em, at)
	assert_gt(reach_open, 0, "the arms do reach past a tile when nothing stops them")
	assert_eq(_past_the_barrier(blocked), 0, "and must not when something does")


func test_no_boss_ever_spawns_a_bullet_inside_its_own_arena_s_cover() -> void:
	# The gameplay statement, against the real arenas. Both are authored around
	# cover -- the vault's barricades exist so that knowing where the Cantor is
	# does not hand you a firing lane, and the hall has pillars -- and a spawner
	# that ignores geometry quietly cancels all of it.
	for dungeon in [Dungeons.STANDARD, Dungeons.VAULT]:
		var inst := Instance.make_dungeon(2, 4242, 1, dungeon)
		var w := inst.world
		var bait := w.add_player(1, "bait")
		bait.pos = inst.boss_spawn + Vector2(90.0, 0.0)
		var offenders := 0
		for _t in 900:
			w.step()
			for slot in w.pool.spawn_log:
				if w.map.bullet_blocked(w.pool.pos[slot]):
					offenders += 1
		assert_eq(offenders, 0,
			"%s spawned %d bullet(s) inside its own arena's cover"
				% [dungeon, offenders])


## The Cantor's strike_point avoids the room's EDGE and knows nothing about the
## barricades and pillars inside it, so a volley can be marked on top of cover.
## What lands there is nothing at all -- which is cover doing its job, and is
## pinned here so it stays a known shape rather than a surprise.
func test_a_strike_marked_on_cover_is_a_dud_rather_than_a_shot_through_it() -> void:
	var g := MapGrid.new(20, 20, MapGrid.Kind.FLOOR)
	g.set_tile(10, 10, MapGrid.Kind.BARRICADE)
	var w := SimWorld.new(1)
	w.set_map(g)
	var em := TelegraphedStrikeEmitter.new()
	em.burst_count = 8
	em.blast_radius = 40.0
	em.speed = 100.0
	var ctx := _ctx_for(w, g.tile_centre(2, 2))
	# Burst centred on the barricade: nothing may come out of it, and nothing
	# may appear on the far side of it either.
	em._burst(ctx, g.tile_centre(10, 10))
	assert_eq(w.pool.live_count, 0,
		"a burst inside cover stays inside it, and dies there")