Make a seed reproduce a run, and give the sector-2 boss teeth

Adding a per-sector breakdown to the balance bench turned up two things.

A seed reproduced nothing
The same seed, run three times in one process: won, lost at sector 4, lost at
sector 5. Boss patterns and enemy behaviour drew from the module-level `random`
rather than from the run's own generator, so nothing about a fight was
reproducible. Nothing crashed and no test failed -- the game just was not
deterministic, which means the balance figures in the previous commit were
reporting run-to-run noise as if it were the effect of a change, and a seed in
a bug report reproduced nothing.

Every roll that decides how a fight goes now comes from the run's RNG: boss
drift, spiral phase, wall gaps, rain, beam comb order, turret sides, pod and
turret stagger, enemy station, drift and fire cadence, pickup scatter.
Particles, shake and the starfield stay on the global generator deliberately --
they cannot change an outcome, and threading a seeded generator through the
particle pool would be churn for no property gained.

test_determinism.py fingerprints a patrol and all five bosses, driven twice from
one seed with a fixed input weave, with the global generator deliberately
disturbed in between so a leaked roll cannot accidentally line up. Its first
version passed with the bug reintroduced: it traced only the sector-2 boss, and
HIVE MOTHER has no walls, so a wall's roll leaking changed nothing it could
see. Tracing all five, the same injected bug fails SENTINEL, BULWARK and WARDEN.

Its sanity check -- a different seed must change the trace -- also had to be
loosened from one alternate seed to several. LANCE's opening rolls exactly one
die, its drift direction, so four seeds in a row can legitimately produce an
identical fight. Requiring one specific seed to differ was testing the seed
rather than the game.

HIVE MOTHER was the weakest of the five
Per sector, at PILOT: SENTINEL 2.3 hull, HIVE MOTHER 1.0, LANCE 3.2, BULWARK
5.1, WARDEN 6.3 -- and half of HIVE MOTHER's fights ended without a scratch, on
the boss most players meet second. Escorts alone are not a pattern: they are
enemies, and enemies are the thing a player is already good at. Its wall guns
are up from the first phase, escorts come down the flanks as well as out of the
bays, and it keeps firing while they close instead of waiting its turn.

Also corrected: the map figures in the READMEs were measured before REST_CHANCE
went from 0.45 to 0.55 and did not match the shipped code. On the code as it
stands: 0.54 repair bays a sector, 54% of sectors offering one, 12% forcing it.

The win-rate table in pc/README.md still carries the figures measured on the
non-deterministic build. A 24-seed run on this build is in flight and those
numbers land in the next commit.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AKLqS4PgnCXrzKHDH8Cnzy

Author: softpython2884

README.md

@@ -37,7 +37,7 @@ spirales, peignes de rayons, escortes, modules destructibles et canons sur les
 murs de l'arène. Les motifs sont denses mais jamais aléatoires : ils sont faits
 pour être lus, et chaque boss ménage une **fenêtre** où tout se tait, le temps
 de riposter. La carte, elle, est un vrai choix — un atelier de réparation n'est
-proposé que dans 42 % des secteurs, sur une seule branche, jamais avant le boss.
+proposé que dans 54 % des secteurs, sur une seule branche, jamais avant le boss.
 Zoom toujours entier, arène de taille fixe quelle que soit la résolution, et
 20 effets sonores synthétisés au démarrage (aucun fichier audio) —
 [à écouter](docs/nova-sound-demo.wav). Le tir étant automatique, `M` fait le

pc/README.md

@@ -260,9 +260,9 @@ Les nœuds spéciaux sont maintenant posés **un par un**, pas par colonne :
 
 | | avant | maintenant |
 |---|---|---|
-| Ateliers par secteur | 1,87 | **0,41** |
-| Secteurs qui en proposent un | 100 % | **42 %** |
-| Toutes les routes en croisent un | 100 % | **11 %** |
+| Ateliers par secteur | 1,87 | **0,54** |
+| Secteurs qui en proposent un | 100 % | **54 %** |
+| Toutes les routes en croisent un | 100 % | **12 %** |
 | Atelier juste avant le boss | 100 % | **0 %** |
 
 Quand les deux sont présents, **le marchand et l'atelier sont dans la même

pc/nova/boss.py

@@ -90,13 +90,13 @@ def draw(self, surf, top):
 class Pod:
     """A turret bolted to a boss. Armours the core while it lives."""
 
-    def __init__(self, offset_x, offset_y, hp):
+    def __init__(self, offset_x, offset_y, hp, rng):
         self.ox = offset_x
         self.oy = offset_y
         self.hp = hp
         self.max_hp = hp
         self.flash = 0.0
-        self.fire_t = random.uniform(0.5, 1.6)
+        self.fire_t = rng.uniform(0.5, 1.6)
         self.w = 11
         self.h = 7
         self.x = 0.0
@@ -123,14 +123,14 @@ class Turret:
 
     ARM = 1.05
 
-    def __init__(self, side, y, hp):
+    def __init__(self, side, y, hp, rng):
         self.side = side                # -1 left wall, +1 right wall
         self.y = y
         self.hp = hp
         self.max_hp = hp
         self.flash = 0.0
         self.t = 0.0
-        self.fire_t = self.ARM + random.uniform(0.15, 0.8)
+        self.fire_t = self.ARM + rng.uniform(0.15, 0.8)
         self.w = 9
         self.h = 11
 
@@ -194,17 +194,22 @@ def _clamp(v, lo, hi):
 
 
 class Boss:
-    def __init__(self, index, sector, hp, x, y, fire_bonus=0.0):
+    def __init__(self, index, sector, hp, x, y, fire_bonus=0.0, rng=None):
         self.index = index % BOSS_COUNT
         self.sector = sector
         self.fire_bonus = fire_bonus
+        # Every roll a boss makes comes from here. Left on the module-level
+        # `random`, a seeded run was not reproducible at all: the same seed
+        # won once and lost the next two times, and every balance figure
+        # measured against it was noise wearing a number's clothes.
+        self.rng = rng or random
         self.hp = hp
         self.max_hp = hp
         self.x = x
         self.y = y
         self.t = 0.0
         self.fire_t = 1.2
-        self.drift = random.choice((-1, 1)) * 34.0
+        self.drift = self.rng.choice((-1, 1)) * 34.0
         self.flash = 0.0
         self.phase = 0
         self.w = 37
@@ -220,11 +225,12 @@ def __init__(self, index, sector, hp, x, y, fire_bonus=0.0):
         self.cycle = 0              # alternates attacks within a phase
         self.storming = True
         self.burst_t = self.STORM[0][0]
-        self.spin = random.uniform(0.0, math.tau)
+        self.spin = self.rng.uniform(0.0, math.tau)
         self.stream_t = 0.0
         if self.index in (BULWARK, WARDEN):
             pod_hp = max(8, hp // 6)
-            self.pods = [Pod(-34, 5, pod_hp), Pod(34, 5, pod_hp)]
+            self.pods = [Pod(-34, 5, pod_hp, self.rng),
+                         Pod(34, 5, pod_hp, self.rng)]
 
     # -- helpers ----------------------------------------------------------
     @property
@@ -406,7 +412,7 @@ def wall(self, combat, gap=56, speed=90, step=15):
         stop shooting and go somewhere -- and it asks it in a way nobody can
         misread.
         """
-        hole = random.uniform(data.PLAY_L + gap, data.PLAY_R - gap)
+        hole = self.rng.uniform(data.PLAY_L + gap, data.PLAY_R - gap)
         x = data.PLAY_L + 6
         while x < data.PLAY_R - 6:
             if abs(x - hole) > gap / 2:
@@ -421,9 +427,9 @@ def rain(self, combat, count, speed=122):
         Pressure rather than a threat: it takes space away without ever
         chasing anyone, which is what makes the aimed attacks land."""
         for _ in range(count):
-            x = random.uniform(data.PLAY_L + 8, data.PLAY_R - 8)
+            x = self.rng.uniform(data.PLAY_L + 8, data.PLAY_R - 8)
             combat.shots.append(ent.EnemyBullet(
-                x, data.TOP + 2, random.uniform(-16, 16), speed, 2))
+                x, data.TOP + 2, self.rng.uniform(-16, 16), speed, 2))
         combat.audio.play("enemy_shoot", 0.5, throttle=0.08)
 
     def deploy_turrets(self, combat, phase, hp=None):
@@ -433,9 +439,10 @@ def deploy_turrets(self, combat, phase, hp=None):
         self.deployed = phase
         arena = data.BOT - data.TOP
         hp = hp or max(6, self.max_hp // 11)
-        side = random.choice((-1, 1))
+        side = self.rng.choice((-1, 1))
         for f, s in ((0.34, side), (0.60, -side)):
-            self.turrets.append(Turret(s, data.TOP + arena * f, hp))
+            self.turrets.append(
+                Turret(s, data.TOP + arena * f, hp, self.rng))
         combat.audio.play("boss_warn", 0.45)
 
     def cast_beams(self, combat, comb=False):
@@ -448,14 +455,15 @@ def cast_beams(self, combat, comb=False):
             start = data.PLAY_L + span * 0.13
             step = (span * 0.74) / (n - 1)
             order = list(range(n))
-            if random.random() < 0.5:
+            if self.rng.random() < 0.5:
                 order.reverse()
             for i, slot in enumerate(order):
                 self.beams.append(Beam(start + slot * step, width,
                                        delay=i * 0.32))
         elif self.phase >= 1:
             self.beams.append(Beam(tx, width))
-            self.beams.append(Beam(tx + random.choice((-78, 78)), width))
+            self.beams.append(
+                Beam(tx + self.rng.choice((-78, 78)), width))
         else:
             self.beams.append(Beam(tx, width))
         combat.audio.play("boss_warn", 0.5)
@@ -498,27 +506,38 @@ def act_sentinel(self, dt, combat):
                 self.spray(combat, self.scaled(5, 7), 0.17, 134)
 
     def act_hive(self, dt, combat):
-        """The bays are the threat, and from phase 1 the walls are too."""
+        """The bays are the threat, and the walls are armed from the start.
+
+        Measured as the weakest of the five by a distance -- 1.0 hull a fight
+        and half of them finished without a scratch, on the boss most players
+        meet second. The reason is that escorts alone are not a pattern: they
+        are enemies, and enemies are the thing a player is already good at.
+        So they come down the flanks as well as out of the bays, the wall guns
+        are up from the first phase, and the boss keeps firing while they
+        close instead of politely waiting its turn.
+        """
+        self.deploy_turrets(combat, 0)
         self.spawn_t -= dt
         if self.spawn_t <= 0:
-            self.spawn_t = (3.4, 2.6, 1.9)[self.phase]
+            self.spawn_t = (3.0, 2.4, 1.8)[self.phase]
             wave = (3, 4, 5)[self.phase]
             for i in range(wave):
-                kind = data.RUSHER_ID if (i % 2 and self.phase) else data.GRUNT_ID
+                kind = data.RUSHER_ID if i % 2 else data.GRUNT_ID
                 combat.spawn_escort(kind,
                                     self.x + (i - (wave - 1) / 2.0) * 18,
                                     self.y + 12)
+            if self.phase >= 1:
+                # down the flanks, where nobody is looking
+                for x in (data.PLAY_L + 26, data.PLAY_R - 26):
+                    combat.spawn_escort(data.RUSHER_ID, x, data.TOP + 8)
             combat.audio.play("jump", 0.5)
-        if self.phase >= 1:
-            self.deploy_turrets(combat, 1)
         self.fire_t -= dt
         if self.fire_t <= 0:
-            self.fire_t = self.fire_rate() * 1.2
+            self.fire_t = self.fire_rate()
             self.cycle += 1
+            self.rain(combat, self.scaled(5, 9))
             if self.cycle % 2:
-                self.rain(combat, self.scaled(4, 7))
-            else:
-                self.spray(combat, self.scaled(3, 5), 0.28, 108)
+                self.spray(combat, self.scaled(3, 5), 0.26, 112)
 
     def act_lance(self, dt, combat):
         """Charge, telegraph, fire -- one beam, then two, then a comb that

pc/nova/combat.py

@@ -78,7 +78,7 @@ def __init__(self, run, kind, art, audio=None):
             # One boss per sector, cycling once the campaign is behind you.
             self.boss = boss_mod.Boss(sector, sector, self.boss_hp(),
                                       (data.PLAY_L + data.PLAY_R) / 2,
-                                      data.TOP - 20, run.fire_bonus)
+                                      data.TOP - 20, run.fire_bonus, self.rng)
             self.tag = self.boss.name
             self.intro_t = 2.6
             self.audio.play("boss_warn")
@@ -120,7 +120,7 @@ def spawn_wave(self, dt):
         self.budget -= data.ENEMY_COST[kind]
         hp = data.ENEMY_HP[kind] + self.run.sector
         x = self.rng.uniform(data.PLAY_L + 24, data.PLAY_R - 24)
-        e = ent.Enemy(kind, x, data.TOP - 14, hp, self.run.sector)
+        e = ent.Enemy(kind, x, data.TOP - 14, hp, self.run.sector, self.rng)
         self.enemies.append(e)
         gap = max(0.28, 0.85 - self.run.sector * 0.06) * self.rng.uniform(0.6, 1.4)
         self.spawn_t = gap
@@ -130,7 +130,7 @@ def spawn_escort(self, kind, x, y):
         arrive in numbers and the boss is the real fight."""
         hp = max(1, data.ENEMY_HP[kind] + self.run.sector - 1)
         e = ent.Enemy(kind, max(data.PLAY_L + 12, min(data.PLAY_R - 12, x)),
-                      y, hp, self.run.sector)
+                      y, hp, self.run.sector, self.rng)
         e.score = data.ENEMY_SCORE[kind] // 2
         self.enemies.append(e)
         self.particles.burst(x, y, 10, 90, (data.WHITE, data.ORANGE), 0.3)
@@ -152,19 +152,21 @@ def kill_enemy(self, e):
         if big:
             self.flash.pop(data.WHITE, 0.55)
             for _ in range(14):
-                self.pickups.append(ent.Pickup(e.x + self.rng.uniform(-24, 24),
-                                               e.y + self.rng.uniform(-10, 10)))
+                self.pickups.append(ent.Pickup(
+                    e.x + self.rng.uniform(-24, 24),
+                    e.y + self.rng.uniform(-10, 10), rng=self.rng))
         else:
             n = 1 + (self.rng.random() < 0.45)
             for _ in range(n):
-                self.pickups.append(ent.Pickup(e.x, e.y))
+                self.pickups.append(ent.Pickup(e.x, e.y, rng=self.rng))
             # A hull patch every eleventh kill sounds modest until you count
             # the kills: at eighteen a fight it healed more than the fight
             # cost, so a sector's worth of patrols left the ship *fuller* than
             # it started and nothing that happened on the way to the boss
             # could matter. Measured at 0.09: -0.13 hull per patrol.
             if self.rng.random() < 0.03:
-                self.pickups.append(ent.Pickup(e.x, e.y, kind=1))
+                self.pickups.append(ent.Pickup(e.x, e.y, kind=1,
+                                               rng=self.rng))
 
     def hurt_player(self, p):
         if p.invuln > 0:
@@ -368,7 +370,8 @@ def kill_boss(self):
                              drag=1.2, gravity=40)
         for _ in range(16):
             self.pickups.append(ent.Pickup(b.x + self.rng.uniform(-30, 30),
-                                           b.y + self.rng.uniform(-10, 10)))
+                                           b.y + self.rng.uniform(-10, 10),
+                                           rng=self.rng))
         # escorts do not outlive their carrier
         for e in list(self.enemies):
             self.kill_enemy(e)

pc/nova/entities.py

@@ -61,11 +61,12 @@ class Pickup:
 
     __slots__ = ("x", "y", "vx", "vy", "kind", "life")
 
-    def __init__(self, x, y, kind=0):
+    def __init__(self, x, y, kind=0, rng=None):
         self.x = x
         self.y = y
-        self.vx = random.uniform(-24, 24)
-        self.vy = random.uniform(-40, -8)
+        rng = rng or random
+        self.vx = rng.uniform(-24, 24)
+        self.vy = rng.uniform(-40, -8)
         self.kind = kind          # 0 crystal, 1 hull
         self.life = 11.0
 
@@ -183,18 +184,20 @@ def take_hit(self):
 
 class Enemy:
     __slots__ = ("x", "y", "kind", "hp", "max_hp", "t", "fire_t", "anchor",
-                 "drift", "w", "h", "flash", "phase", "score")
+                 "drift", "w", "h", "flash", "phase", "score", "rng")
 
-    def __init__(self, kind, x, y, hp, sector):
+    def __init__(self, kind, x, y, hp, sector, rng=None):
         self.kind = kind
         self.x = x
         self.y = y
         self.hp = hp
         self.max_hp = hp
-        self.t = random.uniform(0, 6.0)
-        self.fire_t = random.uniform(0.4, 1.8)
-        self.anchor = data.TOP + 40 + random.uniform(0, (data.BOT - data.TOP) * 0.28)
-        self.drift = random.choice((-1, 1)) * random.uniform(30, 62)
+        self.rng = rng or random
+        self.t = self.rng.uniform(0, 6.0)
+        self.fire_t = self.rng.uniform(0.4, 1.8)
+        self.anchor = data.TOP + 40 + self.rng.uniform(
+            0, (data.BOT - data.TOP) * 0.28)
+        self.drift = self.rng.choice((-1, 1)) * self.rng.uniform(30, 62)
         self.flash = 0.0
         self.phase = 0
         self.score = data.ENEMY_SCORE[kind]
@@ -256,7 +259,7 @@ def wants_to_fire(self, dt, haste=1.0):
             rate *= max(0.32, 1.0 - (self.t - 40.0) * 0.022)
         self.fire_t -= dt
         if self.fire_t <= 0:
-            self.fire_t = rate * random.uniform(0.75, 1.3)
+            self.fire_t = rate * self.rng.uniform(0.75, 1.3)
             return True
         return False
 

pc/tests/run_all.py

@@ -7,6 +7,7 @@
 
 HERE = os.path.dirname(os.path.abspath(__file__))
 SUITE = [("full runs", "test_run.py"),
+         ("determinism", "test_determinism.py"),
          ("sound catalogue", "test_audio.py"),
          ("gamepad mapping", "test_gamepad.py"),
          ("frame budget", "test_perf.py")]