From-scratch reimplementation of the Sword of the Stars (2006) engine. Clean-room; engine code only — bring your own game copy. Planning/RE evidence live in sots-re.
d3ee45364b
`ComputeBudget` takes a system's money from two different functions. Projected mode
calls `ComputeMaxIncome`, which lane E1 closed 25/25 against the BnkEl oracle. The
TURN calls `ComputeOutput` with the system's own rate sliders, where the build queue,
the ship-repair pass and the infrastructure -> terraform -> money cascade are all
live and E1's proof that the cascades are zero does not apply.
Read from the instruction stream, both ranges disassembled to the next function start:
* `sim::ComputeSystemOutput` -- the channel algebra of `ComputeOutputFromRates`, with
every rounding site (round-half-even per channel, truncating for the construction
and money slots) and the association of every x87 sum as the original has them.
* `sim::IdealSuitability` -- the owner's own field, the server's species baseline for
an independent colony, and the per-system `dsu` override.
* `sim::RepairShipsInOrbit` -- the round robin, which is provably equivalent to
`points - min(points, demand)`: the per-pass share is at least 1, so the only early
exit needs every remaining cost to be zero.
* two corrections to `ConstructionPoints` and `SplitLeftover`: the station bonus is
ignored unless strictly positive and its association is `k x (b x cons) + cons`, and
the leftover weights sum as `wi + (wf + wt)`.
The load-bearing fact: the leftover construction points come back to the TRADE
channel, so a colony with an empty build queue earns the same money whichever way its
sliders point. The engine now runs both paths on every load and reports the
difference; on the 11-save corpus every delta decomposes to the unit into the build
queue's points priced through the money chain.
P01/P02 move from blocked to partial and are committed:
turn1-state -> turn2-state 209 -> 157 closed 52 regressed 0 (was 51 / 0)
turn2-state -> turn3-state 108 -> 86 closed 22 regressed 0 (was 21 / 0)
One leaf per pair, and it is the easy one: the independent colony, whose population
does not grow and whose orders the turn does not change. The human's savings are
still short by the civilian growth `S11` does not commit, and the AI's by its own
orders. The ship-repair demand is taken as 0 because `Ship::RepairCost` is unread.
sots-re: findings/subsystems/output-turn-path.md, ghidra/addresses.d/lane-c3.json
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| cmake | ||
| docs | ||
| include/generated | ||
| src | ||
| tests | ||
| third_party | ||
| tools | ||
| .gitignore | ||
| CMakeLists.txt | ||
| CMakePresets.json | ||
| CONTRIBUTING.md | ||
| LICENSE | ||
| README.md | ||
sots-engine
A from-scratch, functional reimplementation of the engine behind Sword of the Stars (2006). Not a byte-for-byte decompilation: behavior-equivalent code, built up one verified piece at a time (OpenRCT2-style) until the tree can build the whole application on its own.
Bring your own game. This repository contains engine code only. Game data, assets, saves, and
the original binaries are never included; tests and tools read an owner-supplied copy via
$SOTS_DATA_DIR. See CONTRIBUTING.md for the clean-room rules.
Status
Phase 2. M0 done — the shim frontend (src/shim/, a proxy binkw32.dll the original game
loads) builds, deploys, hooks, and logs from a real game launch. Engine code accrues under
src/mars/ and src/game/; each module is oracle-verified against the owner's game data before merge:
mars/parse— brace-block +.effectreaders (1,531/1,531 files agree with the reference)mars/text— flat key/value tables, id manifests, CSV (64/64 files agree)game/sim— strategic formulas (economy, research, colonies, movement) as pure functions; 356 hand-computed checksmars/vfs—.gob(ZIP) archive reader + loose-file override; entry counts and bytes verified againstunzipmars/stream— the game's self-describing save/serialization format (reader, writer, typed shapes) + gzip; three real saves round-trip byte-identicalmars/rng— MT19937 with save-state load/store; layout confirmed against real saves, draw mappings read off the binary (docs/mars-rng.md)game/data— typed catalogs (weapons, ship sections, turrets, id registries, tech tree, strings) with cross-reference checks; 229k values agree with the referencegame/design— ship-design assembly/fit/tech-gating rules and derived stats; validates all 127 stock designs from real savesapp— the standalone:sots_turnloads a save, runs one strategic turn over the published phase order of all three turn drivers, and writes a save. 14 of the 44 turn-driver phases are modelled; every phase that is not appears in the run log as a named no-op. How far it is from the byte-match, and what stands in the way, is indocs/S-standalone.md
Build: cmake --preset host && cmake --build --preset host && ctest --preset host (Linux);
tools/sync-build.sh cross-builds the shim on the lab box and stages it for deployment.
Layout (grows with the work)
src/shim/— binkw32 proxy + hooks + old-vs-new compare harness (frontend #1)src/mars/,src/game/— the engine and game reimplementation (accruing)src/app/— the standalone turn driver (frontend #2): load a save, run a turn, write a saveinclude/generated/sots_addresses.h— binary facts (RVAs/prototypes), generated from the RE repotests/— host tests; real-data tests skip unless$SOTS_DATA_DIRis settools/— build (MinGW i686 cross) and deploy scripts
Planning, findings, and verification evidence are tracked in the private RE repo (sots-re).