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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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alex de18d2c91d K: the research-event roll costs one or two RNG words, not one 
Every Coverage note in this repo said RollResearchEvent draws "exactly one
NextFloat". That is the cost of REACHING its branch. When the roll beats the
odds, the plague path draws a SECOND word (NextInt) to pick an owned system and
posts EVENT_PLAGUE_OUTBREAK, and the rebellion path allocates an AIRebellion at
ServerPlayer+0x3b8 and cancels the current research. Nothing has caught this
because the branch has not fired in three sessions.

Corrected in research.h (two Coverage entries plus the scope comment, and the
branch entry raised to Risk::High), research.cpp, tech_effects.h and
tech_effects.cpp. Ours still models the first word only; the branch stays
declared unmodelled, now accurately.

Header regenerated from sots-re bb0f990 (750 entries) - lane K's map of the
combat-done tail: the autosave and save-file writer, the bankruptcy limits, the
turn-results accumulator and outbox, and the encounter-block callees.
2026-09-08 08:51:15 -04:00
cmake m0: binkw32 proxy shim, minhook, trace hook on Application::Initialize; build/deploy tooling 2026-09-07 17:22:15 -04:00
docs lane T merge fixups: name the roll-succeeded branch instead of its FUN_ id (clean-room); mark describe_i32 maybe_unused so the shim cross-builds 2026-09-08 08:13:39 -04:00
include/generated K: the research-event roll costs one or two RNG words, not one 2026-09-08 08:51:15 -04:00
src K: the research-event roll costs one or two RNG words, not one 2026-09-08 08:51:15 -04:00
tests T: hook for Game::ServerPlayer::ProcessTurn, with the prediction committed first 2026-09-08 08:08:47 -04:00
third_party mars/vfs: gob ZIP reader + native override, miniz 3.1.2; oracle-verified 8352+2035 entries 2026-09-07 17:40:51 -04:00
tools b4: colony + movement hooks; 22 formula corrections (growth curve has no capacity term, range margin +0.05f, ties-to-even rounding); 3 verified signatures 2026-09-08 00:57:55 -04:00
.gitignore init commit 2026-09-07 17:07:54 -04:00
CMakeLists.txt T: hook for Game::ServerPlayer::ProcessTurn, with the prediction committed first 2026-09-08 08:08:47 -04:00
CMakePresets.json m0: binkw32 proxy shim, minhook, trace hook on Application::Initialize; build/deploy tooling 2026-09-07 17:22:15 -04:00
CONTRIBUTING.md CONTRIBUTING: cmake >=3.25 requirement and the uv workaround 2026-09-08 05:13:31 -04:00
LICENSE init commit 2026-09-07 17:07:54 -04:00
README.md b3: research hook + RNG-snapshot compare design; fix draw mapping to y/(2^32-1), NextInt inclusive, float32 odds, spend floor, decay constants 2026-09-07 23:14:08 -04:00

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 + .effect readers (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 checks
  • mars/vfs — .gob (ZIP) archive reader + loose-file override; entry counts and bytes verified against unzip
  • mars/stream — the game's self-describing save/serialization format (reader, writer, typed shapes) + gzip; three real saves round-trip byte-identical
  • mars/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 reference
  • game/design — ship-design assembly/fit/tech-gating rules and derived stats; validates all 127 stock designs from real saves

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)
  • include/generated/sots_addresses.h — binary facts (RVAs/prototypes), generated from the RE repo
  • tests/ — host tests; real-data tests skip unless $SOTS_DATA_DIR is set
  • tools/ — build (MinGW i686 cross) and deploy scripts

Planning, findings, and verification evidence are tracked in the private RE repo (sots-re).