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.
f177a5fdd0
The two derived words the per-player turn record's ship census counts by, and the design serializers that three lanes had been told did not exist. HOW DESIGNS PERSIST. Game::ShipDesign derives from Game::ShipDesignDef and reaches IStreamable through adjustor thunks, so a design is written by TWO serializers: the base emits FAIDes/DHide/DWep/DName and exactly three section frames (command, mission, engine on the wire), the derived one appends Dtc, the Dwgv flag and, only when that flag is set, a weapon-group frame. The earlier "the writer makes no stream call at all" note named an address that is in no vftable at all. Corrected in shapes.h. THREE sections, not five. The "two reserved slots" were Dtc and Dwgv swept into the section list by the reference reader's catch-all tail; the constructor builds a three-element array. design.h's comment is corrected and the fixture loader now accepts 3-5 raw_slots so old fixtures still load; the array keeps five inert entries deliberately, since touching the slot enum reaches rules.cpp and another lane's tests for no behavioural gain. DWep and Dwgv are bools, not ints -- both writers call the bool primitive. With four-character tags a bool item and an int item are the same size on the wire and 0/1 the same bytes, so no save can tell them apart. Byte-neutral: the typed round trip is still byte-identical on all 11 saves at 100% named coverage. HULL SIZE is the section_class of the last resolved section in memory slot order, mapped Destroyer/Cruiser/Dreadnought -> 0/1/2 case-insensitively, with absent or unrecognised meaning 0 rather than an error. The DEFENCE-PLATFORM flag is one bit of a 64-bit role-flag word OR-ed across the design's sections. Neither is on the wire; both are rebuilt from the section catalog. MEASURED, not assumed: the new game_design_census test rebuilds the six census counters per player and compares them against the record the game archived for each save's own frame. 11 saves, 503 designs, 480 leaves, 0 mismatched, 0 ships with an unresolvable design, 0 designs where first- and last-resolved section disagree on hull size. COVERAGE IS THIN AND THE TEST SAYS SO: only 32 of the 480 leaves are nonzero, and three of the six census leaves (both cruiser rows and dreadnought platforms) are never exercised by any save in the corpus -- the test prints the per-leaf nonzero counts and names them unexercised rather than verified. Nothing is wired into the turn record: src/app is another lane's this cycle, so this is evaluated and reported, not written. host ctest 43/43 (was 42/42; +1, skips cleanly without the env). With a data root set, game_data_realdata and mars_text_realdata fail identically on main -- both are the absent Locale/EN/Strings.csv, not this change. clean-room OK. Reference readers fixed openly in the RE repo: save_reader 49/49, design rules 32/32, stock_designs.json regenerated (raw_slots 5->3 and dWep int->bool are the only field changes across all 127 designs). |
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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).