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.
b39bb290e3
`ComputeBudget`'s savings-interest term is now compared against the running game at
a treasury the corpus actually contains. Three runs on VM146 from turn1-state.sav:
A (widened floats, as shipped) 3,895 calls, 0 diverged, 0 undeclared writes
B (exact decimals, the control) 2,718 calls, 1,359 diverged
The game fills savingsInterest with 499 at a treasury of 50,000, and with 380 at
38,100 -- the exact decimals pay 500 and 381. Every divergence in B lands on a
treasury that is a multiple of 100 and no other state diverges at all, which is
exactly the arithmetic. G3's rule-23 reading is now measured, not inferred, and the
one-money error is shown to propagate into `available` and `researchMoney` too.
The control also settles why the earlier 4,437-call green run was green: slot 5 IS
diffed and the harness CAN see it, so that run simply presented no boundary state.
Coverage is therefore reported as distinct states, not calls: 5 distinct treasuries,
2 of them on the boundary.
Two further rule-23 constants found in the same routine by an operand-width sweep,
corrected, and honestly marked UNVERIFIED because no reference turn can see them:
- the research-yield factor is a widened 0.85f while its two neighbours in the
same product are exact doubles. Boundary: research money a multiple of 40,000;
the run presented 9 distinct values and none is.
- the three research modifiers are summed in single precision, not double.
Boundary: two of the three non-zero; the corpus has shrm = TRM = 0.
Both are pinned by boundary cases in test_economy.cpp that fail with the decimals.
Also verified live, in the same run:
- T31's difficulty-column recovery. The live ServerPlayer+0xf9 / NPC flags on all
eight players are exactly what lane PL's save-only inversion claims, including
the awkward system-owning player that is still ambiguous because it is an NPC.
- BANKRUPTCY_PROTECTION_LIMIT_FACTOR reads 3.29999995 = (float)3.3. Its file image
is zero because the loader fills it at run time, so lane PL-3 had to assume the
value; it is now measured and the assumption was right.
Falsified, and recorded as such: the difficulty-mods record does NOT sit inline at
ServerPlayer+0x36c -- that field is a heap pointer on all eight players. The row IS
reachable from a ServerPlayer (which corrects the hook's standing coverage note),
but the fitted {3.0,1.5}/{1.0,1.0} pair remains unverified. The hook logs the
pointer and does not follow it.
The `verified` column stays 0, deliberately. Every phase this compare touches is
Partial for reasons upstream of it, and promoting one because part of it was checked
is the drift app_test_catalog exists to catch. What moved is models; see
docs/L5-live-verification.md for each one with its coverage.
Gates run separately: clean-room OK, host ctest 54/54, CT111 shim cross-build exit 0.
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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).