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.
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Reads the whole colony output chain off the instruction stream (every range disassembled to the next function start) and compares two of its functions against the running game. The population -> output law is linear and is carried by the executable: output points per head are typeOutputModifier x 1.8 / 500000, and the three-row population-type table is built in code rather than loaded, so the imperial (1.0) and civilian (0.33f) modifiers are facts about the binary. A system's total output is a SUM of three terms, not one multiplicative chain. The station bonus scales only the imperial term and morale only the civilian one, so OutputModifiers no longer carries either; they belong to GroupOutputInputs. The function previously described as the base-output term is the over-harvest RESOURCE demand, and it is corrected in place. Live on VM140, both hooks in compare mode over two species and two workloads: GroupOutput 13,105 calls / 0 divergences; ComputeTotalOutput 11,252 calls / 1 divergence of one ulp, in a value its caller rounds to an integer. Both functions declare a whole-object Guard: 0 undeclared writes in 24,357 calls, which is what makes the side-effect-free claim a measurement. sim::Narrow forces the double rounding a 32-bit x87 build otherwise skips; without it every civilian row came out one ulp low. Also fixes ComputeBankruptcyLimits' elimination divisor, which was the decimal -0.15 rather than the image's widened float -0.15000000596046448. The two disagree for every maximum income divisible by 3 and for essentially every empire above ~3,000,000. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01ARBgSooAfokKUy6wKUKEyZ |
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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).