cc0c164574
- ItemManager(uint seed, ...) refuses seed 0 and seeds Random from it. - RunStart.ItemSeed(galaxy, step) is public (formula unchanged), refuses a zero result; named steps ArenaStep, StageStep, ContinueStep and NoRunSeed. - Continue seeds the item stream from the saved run's seed (ContinueStep); a scene with no galaxy uses NoRunSeed. - Zone's unpack scatter draws SimulationDice.For(CombatSeed, ScatterStream, 1-based pack ordinal), never the item stream. - Loadout's scratch manager and AetherDb's catalog command take fixed seeds; every test and Editor construction gains 1u (mechanical rewrite). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
43 lines
2.1 KiB
C#
43 lines
2.1 KiB
C#
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
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using Random = CultMath.Random;
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// Structured simulation seeds: the one place a zone seed, a stream and an ordinal become a generator. Every
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// draw is a pure function of its arguments, never of a shared stream, so one roll cannot perturb another.
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public static class SimulationDice
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{
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public const uint LootStream = 1;
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public const uint MineStream = 2;
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// A pilot's own decisions, ordinal Agent.Id: its preferred engagement range and its patrol circuit. AI behaviour
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// never rides ItemManager.Random, so minting items cannot change how a pilot fights.
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public const uint CombatSampleStream = 3;
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public const uint PatrolStream = 4;
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// Generation placement of an unpacked ship packed at the origin, ordinal its 1-based index in the pack, on the zone's
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// seed (CombatSeed): the run seed feeds drops and mines only (ruling run-seed-drops-only), and placement never rides
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// ItemManager.Random.
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public const uint ScatterStream = 5;
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// 9.1 (docs/fire-control-cut.md): fmix32, MurmurHash3's 32-bit finalizer -- xor-shift, multiply,
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// xor-shift, multiply, xor-shift. Diffuses a structured seed (a zone seed XORed with a small,
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// low-bits-only id) across every bit before the first xorshift draw reads it, so two seeds that differ
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// only in their low bits still land on uncorrelated first outputs. Caller-side mixing only --
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// CultMath.Random itself is unchanged. FireControl.Commit's per-shot seed is built on this verbatim.
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public static uint Mix(uint seed)
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{
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seed ^= seed >> 16;
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seed *= 0x85ebca6bu;
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seed ^= seed >> 13;
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seed *= 0xc2b2ae35u;
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seed ^= seed >> 16;
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return seed;
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}
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// The generator for the `ordinal`th roll of `stream` in the zone identified by `zoneSeed`.
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public static Random For(uint zoneSeed, uint stream, uint ordinal)
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{
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var seed = Mix(Mix(zoneSeed ^ Mix(stream)) ^ ordinal);
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return new Random(seed == 0 ? 1u : seed);
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}
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}
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