OpenRA3/docs/ARCHITECTURE.md

# Architecture & Master Plan

OpenRA3 is a from-scratch, portable re-implementation of **Command & Conquer:
Red Alert 3** (SAGE 2.0) in **pure C++26** — C++ modules, `import std;`, no
scripting language, no managed runtime, no other programming language anywhere
in the tree. It is built with Clang + libc++ on Linux and cross-compiled to
Windows with llvm-mingw.

This document is two things at once:

1. the **layer architecture** (how the modules sit on top of one another), and
2. the **master plan** — the complete Red Alert 3 feature set decomposed three
   levels deep into **Module → Function → Feature**, each tagged with its
   implementation status and target milestone.

The decomposition is the contract: every feature RA3 has is either implemented,
being implemented, or explicitly planned here. Nothing is silently dropped.

> **Scope.** Offline only. Single-player campaign, skirmish, Commander's
> Challenge and LAN lockstep — never an online service, matchmaking, EA account
> or GameSpy/Steam integration. The simulation is deterministic and
> self-contained. No game assets or binaries are shipped; the engine reads the
> user's own install at runtime.

---

## 1. Principles

Same five rules as the rest of the tree, restated because the plan is written
against them:

1. **Pure C++.** One language. No Lua, no JS, no C#, no Python at runtime.
   Python is allowed *only* in offline build tooling (`tools/`, cmake helper
   scripts), never linked into `openra3`.
2. **No raw owning pointers.** Ownership is `std::unique_ptr`; cross-references
   are non-owning views (`thing *`, handles, indices).
3. **Portable simulation.** No platform API in the foundation or simulation
   layers. All platform concerns live behind `display` / `audio` / `video`.
4. **Determinism.** Anything that can diverge between runs (RNG, iteration
   order, float accumulation, hash order) is explicit, seeded and testable.
5. **RE-traceable.** Every structure or constant taken from the retail
   `ra3_1.12.game` (image base `0x400000`) or from the GPLv3 SAGE 1.0 reference
   cites its origin. No asserted fact without a source.

---

## 2. Layer architecture

Each layer may import the ones below it, never the ones above. The `ra3`
umbrella module re-exports the SDK; applications import `ra3` only.

```
   L6  tooling / apps     openra3 (CLI)        tools/ (offline, Python allowed)
                                  |  import ra3
   ---------------------------------------------------------------------------
                                  v
   L5  meta               ra3.i18n    ra3.mod    ra3.net (deferred)
                                  |
   L4  match services     ra3.match   ra3.replay  ra3.save
                                  |
   L3  presentation       ra3.client ── ra3.render ── ra3.audio ── ra3.video
                                  |             \        |
                                  |              \       v
                                  |             ra3.display (backend pick)
                                  |              /     |      \        \
                                  v          ra3.ui  ra3.vulkan  ra3.dx   ra3.webgpu / ra3.wasmgl
                                  |          (SDL3)  (Vulkan)   (D3D11/12) (wasm workers)
   ---------------------------------------------------------------------------
                                  v
   L2  simulation         ra3.logic  ra3.modules  ra3.combat  ra3.movement
                          ra3.economy ra3.ai ra3.script ra3.powers ra3.shroud
                                  |
   L1  data & assets      ra3.data ── ra3.assets ── ra3.map ── ra3.terrain
                                  |                      |
                                  v                      v
                          ra3.fs (BIG4 / RefPack / install)
                                  |
   L0  foundation         ra3.core (types, math, containers, RNG, message bus)
```

The current concrete modules (`ra3.core`, `ra3.logic`, `ra3.data`,
`ra3.skirmish`, `ra3.fs`, `ra3.map`, `ra3.terrain`, `ra3.models`, `ra3.render`, `ra3.ui.*`,
`ra3.vulkan.*`, `ra3.dx.*`, `ra3.webgpu.*`, `ra3.wasmgl.*`, `ra3.display`, `ra3.game`, `ra3.client`, and the
vendored `ender.log`) are the **seeds** of the
target modules below. `ra3.skirmish` and `ra3.game` will be absorbed into
`ra3.ai` / `ra3.match`; new modules are added as their subsystems are recovered.

### Status legend

| Tag | Meaning |
| --- | --- |
| `[x]` | implemented and tested on `main` |
| `[~]` | partially implemented / works for the happy path |
| `[ ]` | planned, not started |
| `(vX.Y)` | target milestone (see the roll-up in §5) |
| `!!` | needs reverse engineering before it can be built |

| Function tag | Meaning |
| --- | --- |
| `D` | **done** — the function's features are largely present |
| `P` | **partial** — some features present |

---

## 3. Master plan — Module → Function → Feature

### M00 `ra3.core` — foundation vocabulary `[D]`

Mirrors SAGE `GameEngine/Common`. Everything else speaks this.

- **F1 Types & math** `[D]`
  - `[x]` `real` (float), `int32`/`uint32`/`uint16`/`uint8`, `bool` aliases
  - `[x]` `coord2d` / `coord3d` vectors, dot/cross/length/normalize
  - `[x]` `rgb_color` / `argb_color`, packing and lerp
  - `[x]` geometry: `segment`, `triangle`, `plane`, ray/segment intersection
  - `[ ]` fixed-point helpers for replay-stable accumulation `(v0.4)`
  - `[ ]` matrix / quaternion (needed by W3D models) `(v0.6)`
  - `[ ]` `KindOf` flag bitset (SAGE object taxonomy) `(v0.4)`
- **F2 Containers** `[D]`
  - `[x]` `ascii_string` + `make_name_key` (case-folded hash for data lookup)
  - `[x]` intrusive doubly linked list (message stream node layout)
  - `[x]` deterministic iteration-order map (insertion-ordered)
  - `[ ]` object pool / arena for per-frame allocations `(v0.4)`
  - `[ ]` interned string table `(v0.5)`
- **F3 Deterministic RNG** `[D]`
  - `[x]` seedable `random` stream (`game_logic` random)
  - `[ ]` independent per-player / per-subsystem streams `(v0.4)`
  - `[ ]` shuffle / weighted-pick primitives `(v0.4)`
- **F4 Message stream** `[D]`
  - `[x]` command bus with retail node layout (`appendMessage` `0x0060c4a0`)
  - `[x]` ordered per-frame command drain
  - `[ ]` command argument blocks (build/target/waypoint payloads) `(v0.4)`
  - `[ ]` network/replay source tagging `(v0.4)`
- **F5 Diagnostics** `[~]`
  - `[x]` logging sink + assert macro
  - `[ ]` scoped profiling timers, per-subsystem counters `(v0.4)`
  - `[ ]` structured crash/report capture `(v0.8)`
- **F6 Serialization primitives** `[~]`
  - `[x]` little-endian byte reader/writer
  - `[ ]` chunked binary reader/writer with versioning `(v0.5)`
  - `[ ]` stable content hashing (replay/desync checks) `(v0.4)`
- **F7 Localization primitives** `[~]` (see M26)
  - `[x]` UTF-16 unit access, CSF low-byte `^0xFF` decode
  - `[ ]` placeholder substitution, plural/gender rules `(v0.5)`

### M01 `ra3.fs` — containers & install `[D]`

- **F1 BIG archive** `[D]`
  - `[x]` `BIG4` header parse (`fileSize` LE, `fileCount`/offsets BE) + name index
  - `[x]` payload read on demand (index-only resident memory)
  - `[ ]` `BIGF` (RefPack whole-archive) variant `!!` `(v0.5)`
  - `[ ]` write support (pack/repack, used by tooling) `(v0.8)`
- **F2 RefPack codec** `[D]`
  - `[x]` decode: 2/3/4-byte commands, long-literal, stop opcode
  - `[x]` `refpack_output_size` without full decompress
  - `[ ]` encode (for tooling round-trips) `(v0.8)`
- **F3 Install locator** `[D]`
  - `[x]` `--game-dir` / `$RA3_GAME_DIR` / `C:\Red Alert 3` defaults
  - `[ ]` registry / Steam / EA-app discovery `(v0.5)`
  - `[ ]` Uprising as an optional content source `(v0.5)`
- **F4 Virtual file system** `[~]`
  - `[x]` layered archive mounts (loose files → `*.big`)
  - `[ ]` patch/language precedence rules (newest `Lang-*.big` wins) `(v0.5)`
  - `[ ]` case-insensitive lookup + path normalisation `(v0.5)`
- **F5 Extraction targets** `[D]`
  - `[x]` `openra3 extract` dumps maps/terrain to `assets/`
  - `[ ]` full asset dump via `ra3tools` integration as a build target `(v0.5)`

### M02 `ra3.data` — data schema & balance `[P]`

- **F1 Data schema** `[ ]` `!!`
  - `[ ]` SAGE INI parser (`#include`, `#define`, inheritance) `(v0.5)`
  - `[ ]` XML rule schema
  - `[ ]` `.manifest` compiled-blob schema `!!` `(v0.5)`
- **F2 Compiled asset blobs** `[ ]` `!!`
  - `[ ]` `global.bin` deserialisation `(v0.5)`
  - `[ ]` `static.*.bin` deserialisation `(v0.5)`
  - `[ ]` version/dependency validation `(v0.5)`
- **F3 Balance tables** `[~]`
  - `[x]` damage types, `ArmorTemplate` percentages
  - `[x]` weapon target masks, weapon definitions
  - `[x]` unit/structure build costs, times, prerequisites
  - `[x]` ore economy constants
  - `[ ]` read these from the install instead of pinned constants `(v0.5)`
- **F4 Object definitions** `[ ]`
  - `[ ]` `ThingTemplate`/`ObjectTemplate` inheritance graph `(v0.5)`
  - `[ ]` module descriptor lists (per-object update/draw module sets)
  - `[ ]` `WeaponTemplate`/`ArmorTemplate`/`LocomotorTemplate` stores
- **F5 Faction & player templates** `[~]`
  - `[x]` Allied / Soviet / Empire side flags (`2/4/8`), match templates
  - `[ ]` commander/sub-commander definitions `(v0.7)`
  - `[ ]` build/upgrade unlock trees per faction `(v0.5)`
- **F6 Rules & settings** `[ ]`
  - `[ ]` skirmish options (cash, crates, superweapons, speed, limits)
  - `[ ]` bonus crate effect table
  - `[ ]` AI personality tables
  - `[ ]` map-specific rule overrides (`map.ini`)
- **F7 Validation** `[ ]`
  - `[ ]` schema diagnostics with source location
  - `[ ]` cross-reference integrity (missing templates/refs)

### M03 `ra3.assets` — runtime asset manager `[ ]`

- **F1 Textures** `[~]`
  - `[x]` TGA decode (`ra3.render`); 256×256 terrain cells
  - `[ ]` DDS / DXT compressed textures `(v0.5)`
  - `[ ]` atlas + mip generation, gutter padding (GPU) `[~]`
  - `[ ]` async upload / streaming `(v0.6)`
- **F2 Models** `[~]`
  - `[x]` compiled `W3DMesh` decode (vertex buffer + D3D9 declaration + triangle list) from the BAB static/worldbuilder stream
  - `[x]` embedded DDS textures (DXT1/3/5 + uncompressed RGB) → ARGB
  - `[x]` `W3DHierarchy` decode + static bind-pose skinning (bone-space vertices)
  - `[ ]` W3D container/hierarchy animation, LOD sets, collision meshes `!!` `(v0.6)`
- **F3 Animation** `[ ]` `!!`
  - `[ ]` W3D animation chunks, bone poses `(v0.6)`
  - `[ ]` blend trees / transition animations
- **F4 Audio** `[ ]` `!!`
  - `[ ]` audio container + codec decode `(v0.7)`
  - `[ ]` cue/event tables (unit responses, weapon foley)
- **F5 Fonts & glyphs** `[ ]`
  - `[ ]` bitmap/vector font load; CJK coverage `(v0.5)`
- **F6 Asset registry** `[ ]`
  - `[ ]` cache with ref counting, eviction `(v0.6)`
  - `[ ]` name-key lookup into the data schema
- **F7 UI art (`.apt`)** `[ ]` `!!`
  - `[ ]` RA3 interface art decode (HUD/command bar) `(v0.7)`

### M04 `ra3.map` — map catalog & loader `[D]`

- **F1 Catalog** `[D]`
  - `[x]` scan `MapsMultiplayer.big` for main map entries
  - `[ ]` campaign + challenge map catalog `(v0.7)`
- **F2 Compiled map (`CkMp`)** `[D]`
  - `[x]` double unwrap (`BIG4` RefPack → `EAR\0` → RefPack → `CkMp`)
  - `[x]` name table + chunk list (`{index,version,size,data}`)
  - `[ ]` full typed chunk dispatch for all chunk kinds `(v0.5)`
- **F3 Start positions** `[~]`
  - `[x]` `Player_N_Start` waypoint scan → `coord3d`
  - `[ ]` `MPPositionList` layout for maps without waypoints `!!` `(v0.5)`
- **F4 Metadata** `[~]`
  - `[x]` display names from `gamestrings.csf` (`MAP:<ID>`)
  - `[ ]` player count, size, supported game modes `(v0.5)`
- **F5 Map rules** `[ ]`
  - `[ ]` `map.ini` override application `(v0.5)`
- **F6 Preview art** `[~]`
  - `[x]` `<map>_art.tga` overview decode (`--thumbnail`)
- **F7 Validation & fallback** `[D]`
  - `[x]` reject degenerate extractions, fall back to built-in test map
  - `[ ]` integrity/version checks with actionable errors `(v0.5)`

### M05 `ra3.terrain` — terrain `[P]`

- **F1 Heightmap** `[D]`
  - `[x]` `HeightMapData` v6 (grid, border, `u16` elevations, scale)
  - `[ ]` multi-resolution / LOD height sampling `(v0.6)`
- **F2 Blend tiles** `[D]`
  - `[x]` `BlendTileData` v27: tile grid, blends/three-way/cliff tables
  - `[x]` `BlendDescription` parse; `secondaryTile` decode
  - `[x]` retail `Terrain.fx` blend ramp (`blend_factor`, axis flags)
- **F3 Terrain textures** `[D]`
  - `[x]` `art\terrain\*.tga` from `Terrain.big` / `Core11.big`
  - `[x]` cell atlas with replicated gutter (GPU bleeding fix)
  - `[ ]` continuous 32 px / Morton layout (kill residual grid lines) `(v0.4)`
- **F4 Water** `[ ]` `!!`
  - `[ ]` water height/type, sea level `(v0.6)`
  - `[ ]` animated waves + shoreline blending `(v0.6)`
  - `[ ]` shroud-aware water rendering `(v0.6)`
- **F5 Cliffs & roads** `[ ]` `!!`
  - `[x]` `CliffTextures` table parsed
  - `[ ]` cliff mesh + `CliffTextureMapping` UV remap `(v0.6)`
  - `[ ]` roads and bridges (passability + render) `(v0.6)`
- **F6 Terrain lighting** `[ ]`
  - `[ ]` per-vertex normals, cell lighting, global light `(v0.6)`
- **F7 Terrain queries** `[~]`
  - `[x]` height lookup (render)
  - `[ ]` passability grid (ground/naval/amphibious/air) `(v0.4)`
  - `[ ]` buildability grid (flatness, slope, water) `(v0.4)`

### M06 `ra3.logic` — simulation core `[P]`

- **F1 Objects & things** `[~]`
  - `[x]` `thing` → `object` with pluggable `update_module`s
  - `[x]` global object registry with stable ids
  - `[ ]` handle/reference system (survives deletion) `(v0.4)`
  - `[ ]` object destruction lifecycle + death dispatch `(v0.4)`
- **F2 Players & teams** `[~]`
  - `[x]` `player` / `player_list`
  - `[x]` money (`std::vector<Money*>`) and power fields
  - `[x]` team assignment and relations
  - `[ ]` diplomacy matrix, ally vision sharing `(v0.5)`
- **F3 Partition manager** `[~]`
  - `[x]` spatial grid, neighborhood queries
  - `[ ]` cell-resolution + large-object multi-cell registration `(v0.4)`
- **F4 Game loop** `[~]`
  - `[x]` 30 Hz deterministic step with frame counter
  - `[x]` `prepare_new_game` / `start_new_game` two-phase start
  - `[ ]` per-tick module scheduling with stable ordering `(v0.4)`
- **F5 Commands** `[~]`
  - `[x]` `message_stream` bus
  - `[ ]` typed commands (build, attack, move, ability, sell, repair) `(v0.4)`
  - `[ ]` command validation + feedback (insufficient funds, etc.) `(v0.4)`
- **F6 Determinism** `[~]`
  - `[x]` seeded logic random
  - `[ ]` replay-hash of state per tick `(v0.4)`
  - `[ ]` float determinism policy / fixed-point where required `(v0.4)`
- **F7 Victory / defeat** `[~]`
  - `[x]` team-wipe / base-destruction win condition
  - `[ ]` surrender, disconnection, timed, objective victories `(v0.5)`
  - `[ ]` score / stats accumulation `(v0.8)`

### M07 `ra3.modules` — object update & draw modules `[P]`

- **F1 Module system** `[~]`
  - `[x]` update modules attached to objects with a simple order
  - `[ ]` module descriptor data-binding (from `ThingTemplate`) `(v0.5)`
  - `[ ]` interface queries (get WeaponModule / ContainModule on demand) `(v0.4)`
- **F2 Locomotor** `[ ]`
  - `[ ]` movement state machine (idle/moving/attacking) `(v0.4)`
- **F3 Weapon module** `[~]`
  - `[x]` simple weapons on units, auto-target + fire
  - `[ ]` multi-weapon slots, turret aiming/rotation `(v0.4)`
  - `[ ]` reload/clip, deploy/undeploy states `(v0.6)`
- **F4 Contain** `[ ]`
  - `[ ]` transport passenger slots, load/unload `(v0.4)`
  - `[ ]` garrison of civilian structures `(v0.6)`
  - `[ ]` paradrop / airdrop `(v0.6)`
- **F5 Production** `[~]`
  - `[x]` pay-as-you-go build queue on a factory
  - `[ ]` per-factory queues, rally points, queue reordering `(v0.4)`
  - `[ ]` building placement → production handoff `(v0.4)`
- **F6 Power** `[~]`
  - `[x]` power production/consumption fields
  - `[ ]` brownout/blackout effects on radar + build speed `(v0.4)`
- **F7 Upgrades** `[ ]`
  - `[ ]` upgrade research, unlock dependent modules/weapons `(v0.5)`
- **F8 Experience / veterancy** `[ ]`
  - `[ ]` XP from kills, ranks (veteran/elite/heroic), bonuses `(v0.6)`
  - `[ ]` chevron rendering `(v0.6)`
- **F9 Special abilities** `[~]`
  - `[ ]` secondary ability slots with cooldown, target/area types `(v0.6)`
  - `[ ]` toggle/instant/targeted ability kinds `(v0.6)`
- **F10 Stealth / disguise / detection** `[ ]`
  - `[ ]` stealth states, detection radius, decloak on fire `(v0.6)`
  - `[ ]` disguise (spy-like) and detection interaction `(v0.6)`
- **F11 Structure modules** `[~]`
  - `[x]` base structures, destruction
  - `[ ]` construction/assembly animation, sell, repair `(v0.4)`
  - `[ ]` walls/gates if present, defensive structures `(v0.6)`
- **F12 Resource modules** `[~]`
  - `[x]` harvester ↔ refinery ore cycle
  - `[ ]` ore field spread/depletion, multiple miners, dock queue `(v0.4)`
- **F13 Shroud modules** `[ ]`
  - `[ ]` per-object shroud reveal / clearance `(v0.4)`
- **F14 Draw modules** `[ ]`
  - `[ ]` model draw, animation, particles, construction ghost, temp effects `(v0.6)`

### M08 `ra3.combat` — weapons, warheads, damage `[P]`

- **F1 Weapons** `[~]`
  - `[x]` damage, range, rate of fire, target masks
  - `[ ]` clip/burst, scatter, arc, continuous beam `(v0.4)`
  - `[ ]` primary vs secondary weapon selection `(v0.4)`
- **F2 Warheads** `[~]`
  - `[x]` damage type + armor multiplier resolution
  - `[ ]` radius/falloff, affects mask, death type on kill `(v0.4)`
- **F3 Armor** `[~]`
  - `[x]` `ArmorTemplate` percentage table
  - `[ ]` armor upgrades and per-state armor `(v0.6)`
- **F4 Damage application** `[~]`
  - `[x]` damage resolution against armor
  - `[ ]` conditional modifiers (from above, in air, moving) `(v0.4)`
  - `[ ]` friendly-fire policy, self-damage `(v0.4)`
- **F5 Projectiles** `[ ]`
  - `[ ]` ballistic / laser / missile / beam / homing / arcing `(v0.4)`
  - `[ ]` projectile draw + impact VFX hook `(v0.6)`
- **F6 Targeting** `[~]`
  - `[x]` simple nearest/in-range acquisition
  - `[ ]` priority scans (attack-move, guard, force-attack) `(v0.4)`
  - `[ ]` re-targeting, leash, target ground `(v0.4)`
- **F7 Special effects** `[ ]`
  - `[ ]` EMP/stun, flame/radiation DoT, mind-control, shrink/grow `(v0.7)`
- **F8 Death & corpses** `[ ]`
  - `[ ]` death types, wrecks, gibs, salvage, rebuild `(v0.6)`

### M09 `ra3.movement` — locomotion & pathfinding `[ ]`

- **F1 Locomotors** `[ ]`
  - `[ ]` ground / air / naval / amphibious / hover / teleport `!!` `(v0.4)`
  - `[ ]` turn rates, acceleration, braking, banking `(v0.6)`
- **F2 Pathfinding** `[ ]`
  - `[ ]` grid A* over the passability grid `(v0.4)`
  - `[ ]` hierarchical / jump-point refinement `(v0.6)`
  - `[ ]` dynamic obstacle integration (buildings, units) `(v0.6)`
- **F3 Steering & flocking** `[ ]`
  - `[ ]` separation, avoidance, group cohesion `(v0.6)`
  - `[ ]` formation slots (line/wedge/box) `(v0.6)`
- **F4 Orders & waypoints** `[~]`
  - `[x]` straight-line move toward a target (skirmish)
  - `[ ]` waypoint queues, queued orders with shift `(v0.4)`
  - `[ ]` guard / patrol / attack-move / stop / scatter `(v0.4)`
- **F5 Collision & crush** `[ ]`
  - `[ ]` unit-unit collision, pushing, crush damage `(v0.6)`
- **F6 Naval & amphibious** `[ ]`
  - `[ ]` water-only movement, amphibious land↔water transition `!!` `(v0.6)`
- **F7 Transport & airdrop** `[ ]`
  - `[ ]` boarding/unloading, airdrop descent `(v0.6)`

### M10 `ra3.economy` — resources, power, construction `[P]`

- **F1 Ore / resource** `[~]`
  - `[x]` ore fields and harvester↔refinery cycle
  - `[ ]` ore spread/regrowth, depletion, ore density `(v0.4)`
- **F2 Power** `[~]`
  - `[x]` power balance fields
  - `[ ]` brownout/blackout consequences `(v0.4)`
- **F3 Construction** `[~]`
  - `[x]` pay-as-you-go queue, tech prerequisites, build times
  - `[ ]` build-radius rules (structures must be in base vicinity) `(v0.4)`
  - `[ ]` low-power build-speed penalty `(v0.4)`
- **F4 Placement** `[ ]`
  - `[ ]` placement grid, footprint validation, green/red ghost `(v0.4)`
  - `[ ]` adjacency bonuses / prerequisite-adjacent structures `(v0.6)`
- **F5 Repair & sell** `[ ]`
  - `[ ]` structure repair over time, cost, sell refund `(v0.4)`
  - `[ ]` unit repair pads if present `(v0.6)`
- **F6 Rally points** `[ ]`
  - `[ ]` factory rally, rally preview, waypoint rally `(v0.6)`
- **F7 Income modifiers** `[ ]`
  - `[ ]` bonus crates (cash/units/repair/heal, `random_bonus_crates`) `(v0.5)`

### M11 `ra3.ai` — computer opponents `[P]`

- **F1 Skirmish AI** `[~]`
  - `[x]` simple build AI (base, ore, a couple of unit types)
  - `[ ]` data-driven build orders per faction `(v0.5)`
  - `[ ]` economy management (expand, defend harvesters) `(v0.5)`
- **F2 Attack management** `[~]`
  - `[x]` send units at the enemy base
  - `[ ]` attack force assembly, waves, retreat/regroup `(v0.5)`
  - `[ ]` targeting priorities (harvesters, key structures) `(v0.6)`
- **F3 Team AI / diplomacy** `[ ]`
  - `[ ]` allied coordination, shared attacks, base defense `(v0.6)`
- **F4 Difficulty & personalities** `[ ]`
  - `[ ]` easy/normal/hard modifiers, AI cheating options `(v0.5)`
  - `[ ]` commander personalities (aggressive/turtle/air/naval) `(v0.7)`
- **F5 Scouting** `[ ]`
  - `[ ]` exploration, map awareness, threat response `(v0.6)`
- **F6 Superweapon usage** `[ ]`
  - `[ ]` AI powers/power targeting `(v0.7)`
- **F7 Script hooks** `[ ]`
  - `[ ]` AI cooperation with script triggers (campaign) `(v0.7)`

### M12 `ra3.script` — triggers & missions `[ ]`

- **F1 Trigger system** `[ ]` `!!`
  - `[ ]` conditions (elapsed, object in region, destroyed, flag) `(v0.7)`
  - `[ ]` actions (spawn, order, reveal, camera, dialog, win/lose) `(v0.7)`
- **F2 Script engine** `[ ]` `!!`
  - `[ ]` SAGE script language / mission script parse `(v0.7)`
  - `[ ]` timers, counters, flags, per-player state `(v0.7)`
- **F3 Campaign missions** `[ ]`
  - `[ ]` mission objectives, sequential phases, briefing `(v0.8)`
  - `[ ]` three faction campaigns (Allied/Soviet/Empire) `(v0.8)`
- **F4 Reinforcements & spawns** `[ ]`
  - `[ ]` scripted spawns, cinematic units, capture `(v0.8)`
- **F5 Tutorials** `[ ]`
  - `[ ]` tutorial message gates, camera lock/unlock actions `(v0.8)`
- **F6 Co-op** `[ ]`
  - `[ ]` co-op commander missions `(v0.9)`

### M13 `ra3.powers` — superweapons & support powers `[ ]`

- **F1 Superweapons** `[ ]` `!!`
  - `[ ]` Allied Chronosphere `(v0.7)`
  - `[ ]` Soviet Vacuum Imploder `(v0.7)`
  - `[ ]` Empire Psionic Decimator `(v0.7)`
  - `[ ]` charge timer, targeting, ready state, HUD `(v0.7)`
- **F2 Support powers** `[ ]`
  - `[ ]` per-faction powers (spy satellite, air support, etc.) `(v0.7)`
  - `[ ]` cooldowns, targeting types, cost `(v0.7)`
- **F3 Commander's Challenge powers** `[ ]`
  - `[ ]` challenge-mode power loadouts `(v0.8)`

### M14 `ra3.shroud` — fog of war & radar `[ ]`

- **F1 Shroud** `[ ]`
  - `[ ]` per-player unexplored grid `(v0.4)`
- **F2 Fog of war** `[ ]`
  - `[ ]` explored-but-unseen dimming `(v0.4)`
- **F3 Reveal sources** `[ ]`
  - `[ ]` units/structures reveal radius, abilities, spy satellite `(v0.6)`
- **F4 Radar / minimap** `[ ]`
  - `[ ]` radar texture, unit blips, radar-offline on low power `(v0.6)`
- **F5 Shroud ↔ logic** `[ ]`
  - `[ ]` targetability gating, option for AI to ignore shroud `(v0.4)`

### M15 `ra3.client` — game client & shell `[P]`

- **F1 Game client** `[~]`
  - `[x]` `game_client` facade owning the sim, driving the frame loop
  - `[ ]` sim/present decoupling, interpolation, catch-up `(v0.6)`
- **F2 Tactical view / camera** `[~]`
  - `[x]` controls: wheel zoom, edge scroll, clamped pan, open on player start
  - `[x]` camera tuning table (`cameraMinHeight` …) + lock actions
  - `[ ]` retail perspective camera, pitch/yaw, FOV (needs 3D terrain) `(v0.6)`
- **F3 Selection** `[ ]`
  - `[ ]` click select, drag-box, double-click type select `(v0.6)`
  - `[ ]` control groups (Ctrl+N), type filters, select-all-of-type `(v0.6)`
- **F4 Orders** `[ ]`
  - `[ ]` contextual right-click orders, force-attack, force-move `(v0.6)`
  - `[ ]` order queue with shift, formation move `(v0.6)`
- **F5 Command bar** `[ ]` `!!`
  - `[ ]` build/production palettes, ability buttons, portraits `(v0.7)`
  - `[ ]` tooltips, cost/time, cooldown sweep, disabled states `(v0.7)`
- **F6 HUD** `[ ]`
  - `[x]` minimal match-state overlay (units, start markers)
  - `[ ]` resource/power readouts, objectives, notifications `(v0.7)`
  - `[ ]` EVA voice announcements hook `(v0.7)`
- **F7 Shell menus** `[~]`
  - `[x]` map list by localized name + full render/skirmish options; console fallback
  - `[ ]` main menu, skirmish setup, faction/team/color pickers `(v0.7)`
  - `[ ]` options (video/audio/keybinds), pause, load/save, credits `(v0.8)`
- **F8 Feedback & cursors** `[ ]`
  - `[ ]` action cursor, placement ghost, move/attack markers `(v0.6)`

### M16 `ra3.render` — renderer & RHI `[P]`

- **F1 RHI** `[ ]`
  - `[ ]` device/queue/swapchain abstraction over Vulkan `(v0.6)`
  - `[ ]` buffers, textures, samplers, descriptor sets, pipelines `(v0.6)`
  - `[ ]` `present_terrain` is the seam where this lands today `[~]`
- **F2 Render graph** `[ ]`
  - `[ ]` pass scheduling, barriers, transient/aliased resources `(v0.6)`
- **F3 Terrain render** `[~]`
  - `[x]` top-down software + GPU heightfield with blend ramp + gutter atlas
  - `[ ]` perspective terrain mesh, LOD, cliff `(v0.6)`
  - `[x]` water surface in the raymarch: SAGE `Water.frag` port (ocean/river) `[~]`
- **F4 Model render** `[~]`
  - `[x]` static map-object triangle soup, world-space, depth-tested over the terrain (Vulkan + software)
  - `[x]` bind-pose skinning (bone-space vertices) + ground-decal depth bias
  - `[ ]` animated W3D draw, materials, team colors `!!` `(v0.6)`
  - `[ ]` shadows, decals, ground marks `(v0.6)`
- **F5 VFX** `[ ]`
  - `[ ]` particle systems, beams, muzzle flashes, explosions `(v0.6)`
  - `[ ]` shader effect graph (retail `.fxo` parity where feasible) `!!` `(v0.7)`
- **F6 Sky & atmosphere** `[ ]`
  - `[ ]` skybox, fog, weather, time-of-day `(v0.7)`
- **F7 HUD render** `[ ]`
  - `[ ]` 2D art layer, fonts, minimap/radar texture `(v0.7)`
- **F8 Software renderer** `[D]`
  - `[x]` ARGB framebuffer, blit/line/circle/text, TGA decode, BMP encode
  - `[x]` map compositing, grid, markers; headless output
- **F9 Post-processing** `[ ]`
  - `[x]` underwater tint/fog in the terrain pass (retail `UnderwaterDeferred.fx`) `[~]`
  - `[ ]` bloom, color grading, AA, resolution scaling `(v0.7)`

### M16b shader porting status (retail `Data\Shaders.big` → `*.fxo`)

The retail set is **88 compiled effects** (`Core12\shaders\compiled`, duplicated
in `Misc`/`Shaders`; `Core5`/`Core8` ship only `terrain`; plus a 60-byte
`null` stub). OpenRA3 implements the static-map subset only:

- **Ported (approximate stand-ins, shared by all backends):** `Terrain.fx`
  (`terrain.*`), the opaque diffuse subset of `BuildingsGeneric.fx` /
  `BasicW3D.fx` / `ObjectsGeneric.fx` (`object.*`), and the SAGE water model
  `Ocean.fx` (+ `OceanDisplacement`/`OceanNoVertexTexture`/`RiverWater`/
  `RiverReflection`/`UnderwaterDeferred`, folded into the `terrain.*` water
  branch — see `docs/REVERSE_ENGINEERING.md`). The retail water flow and bump
  maps (`art/terrain/ra3_deepocean.tga`, `ra3_deepocean_nrm.tga`) ride as the
  last two terrain-atlas layers, so no backend adds a binding.
- **Not ported:** all faction/variant model shaders (`buildings*`, `objects*`,
  `basicw3d*`, `defaultw3d*`, `normalmapped`, `tree`/`treesway`), instances/
  animation (`infantry*`), particles and beams (`cpuparticle`, `gpuparticle*`,
  `swarmparticle`, `laser*`, `lightning`, `fx*`, `tracer`, `trail`,
  `connectionline`, `linerenderers`, `stream`, `rain`, `simple*`), shadows and
  ground decals (`shadow`, `decal`, `outlines`, `occlusion`, `terraintracks`),
  post-processing (`postfx_*`), and the 2D/misc shaders (`render2d`, `video`,
  `bootupscreen`, `debug`, `errormissing`, `rotateenvironmentmap`,
  `distortingobject`). The shared retail includes `shadowmap.fxh`, `ssao.fxh`,
  `macrotexture.fxh`, `gamma.fxh` are likewise absent (`skinning.fxh` is done at
  bind pose only).

### M17 `ra3.ui` — platform layer & backends `[D]`

- **F1 Display abstraction** `[D]`
  - `[x]` shared primitives + interactive loops + `ui_event` mapping in the base
  - `[x]` backends implement primitives only (SDL/Vulkan cannot drift)
- **F2 SDL3 backend** `[D]`
  - `[x]` window, streaming-texture blit, input polling
  - `[ ]` gamepad support `(v0.8)`
- **F3 Backend selection (`ra3.display`)** `[D]`
  - `[x]` preferred backend + ordered fallback (Vulkan / D3D11 / D3D12 / SDL)
  - `[x]` in-game Renderer option; report failure for offscreen fallback
- **F4 Input mapping** `[~]`
  - `[x]` keyboard/mouse state, modifier masks
  - `[ ]` rebindable keybinds, mouse capture, scroll wheel events `(v0.6)`
- **F5 Window modes** `[ ]`
  - `[ ]` windowed/fullscreen/borderless, resize, multi-monitor `(v0.6)`
- **F6 Null/headless backend** `[D]`
  - `[x]` returns false so the tree builds and runs without SDL3/Vulkan

### M18 `ra3.vulkan` — Vulkan backend `[P]`

- **F1 Device & swapchain** `[~]`
  - `[x]` embedded SPIR-V, SDL3 surface, present path
  - `[ ]` formal RHI integration (see M16 F1) `(v0.6)`
- **F2 Terrain presentation** `[D]`
  - `[x]` GPU heightfield raymarch, mipmapped atlas, gutter, retail blend ramp
- **F3 Materials & pipelines** `[~]`
  - `[x]` static-model pipeline (vertex/index buffers, texture array, depth test)
  - `[ ]` particle/HUD pipelines `(v0.6)`
- **F4 Null fallback** `[D]`
  - `[x]` report failure when no Vulkan loader is present

### M18b `ra3.dx` — Direct3D 11 / 12 backend `[P]`

- **F1 Device & swapchain** `[D]`
  - `[x]` SDL3 window → HWND, DXGI flip-model swapchain, resize
  - `[x]` runtime HLSL via `d3dcompiler_47` (no build-time shader compiler)
- **F2 2D image path** `[D]`
  - `[x]` BGRA scene texture + fullscreen-triangle blit (D3D11/D3D12)
- **F3 Terrain presentation** `[D]`
  - `[x]` GPU heightfield raymarch (HLSL port of `terrain.frag`), D3D11 and D3D12
- **F4 Root signatures / PSOs (D3D12)** `[~]`
  - `[x]` root constants, descriptor tables, static samplers, barriers
  - `[ ]` shared RHI with Vulkan (see M16 F1) `(v0.6)`
- **F5 Null fallback** `[D]`
  - `[x]` non-Windows builds link a stub that fails `init`

### M18d `ra3.wasmgl` — SDL-free wasm worker backend `[P]`

- **F1 Device & canvas** `[D]`
  - `[x]` Emscripten-only; engine runs on a plain Web Worker, WebGL2 on an
    OffscreenCanvas transferred by the page (no SDL, no `PROXY_TO_PTHREAD`)
  - `[x]` `specialHTMLTargets['#canvas']` lets `emscripten_webgl_create_context` find
    the worker's OffscreenCanvas
- **F2 2D image path** `[D]`
  - `[x]` GLSL ES BGRA texture + fullscreen triangle (`.bgra` swizzle)
- **F3 Terrain presentation** `[D]`
  - `[x]` GPU heightfield raymarch (GLSL ES), including the `GL_R16`
    (`0x822A`) heightmap and `GL_RGBA16` cell textures
- **F4 On-demand assets** `[D]`
  - `[x]` `assets.manifest.json` (from `scripts/make_web_manifest.py`) is embedded;
    the worker registers every file with `FS.createLazyFile`, so only opened files
    are fetched (a map pulls just its map + tiles)
- **F5 Input** `[D]`
  - `[x]` page owns DOM listeners and posts events to the worker's exported
    `openra3_*` functions (no DOM callbacks in the worker)
- **F6 Null fallback** `[D]`
  - `[x]` non-Emscripten builds link a stub that fails `init`

### M18e `ra3.webgpu` — WebGPU wasm backend `[P]`

- **F1 Device & surface** `[D]`
  - `[x]` Emscripten `emdawnwebgpu` port (Dawn C++ wrapper); the worker pre-creates
    the device (`Module.preinitializedWebGPUDevice`) and a surface is configured on
    the transferred OffscreenCanvas
- **F2 WGSL shaders** `[D]`
  - `[x]` web WebGPU is WGSL-only, so the scene/terrain shaders are WGSL ports
    (the Vulkan SPIR-V blobs cannot be reused); the uniform layout and terrain data
    plumbing are shared with Vulkan/WebGL
- **F3 Terrain** `[D]`
  - `[x]` GPU heightfield raymarch in WGSL (R16Uint heightmap, RGBA16Uint cell
    record, RGBA8 atlas)
- **F4 Selection & fallback** `[D]`
  - `[x]` preferred wasm backend; falls back to `ra3.wasmgl` when no adapter is
    available
- **F5 Null fallback** `[D]`
  - `[x]` non-Emscripten builds link a stub that fails `init`

### M19 `ra3.audio` — audio `[ ]`

- **F1 SFX** `[ ]`
  - `[ ]` 3D positional sound from cues/events `(v0.7)`
- **F2 Music** `[ ]`
  - `[ ]` streaming music, playlists, combat stingers `(v0.7)`
- **F3 Voice & EVA** `[ ]`
  - `[ ]` unit response lines, announcer (EVA) events `(v0.7)`
- **F4 Mixer** `[ ]`
  - `[ ]` buses (master/sfx/music/voice), volume, ducking, reverb `(v0.7)`
- **F5 Codecs** `[ ]` `!!`
  - `[ ]` decode RA3 audio formats `(v0.7)`

### M20 `ra3.video` — movies & cutscenes `[ ]`

- **F1 Movie playback** `[ ]` `!!`
  - `[ ]` intro/briefing/ending video decode + playback `(v0.8)`
  - `[ ]` skip, subtitles, aspect handling `(v0.8)`
- **F2 In-engine cutscenes** `[ ]`
  - `[ ]` scripted camera + unit animation sequences `(v0.8)`

### M21 `ra3.match` — game setup & match rules `[P]`

- **F1 Game setup** `[~]`
  - `[x]` map + two players + seed defaults
  - `[ ]` faction/color/team/start-slot selection, AI personalities `(v0.7)`
- **F2 Rules & options** `[ ]`
  - `[ ]` starting cash, crates on/off, superweapons on/off, speed, limits `(v0.7)`
- **F3 Match flow** `[~]`
  - `[x]` `prepare_new_game` / `start_new_game` split mirroring retail
  - `[ ]` loading progress, in-game start countdown `(v0.7)`
- **F4 Factions** `[~]`
  - `[x]` Allied / Soviet / Empire player templates
  - `[ ]` full faction tech trees and rosters `(v0.5)`
- **F5 Victory & scoring** `[~]`
  - `[x]` team-wipe victory
  - `[ ]` full victory conditions, post-match score screen `(v0.8)`

### M22 `ra3.replay` — recording & playback `[ ]`

- **F1 Recorder** `[ ]`
  - `[ ]` capture command stream + seed + map id per match `(v0.4)`
- **F2 Replay format** `[ ]`
  - `[ ]` self-describing header, command log, checksums `(v0.4)`
  - `[ ]` compatibility with retail `.RA3Replay` playback `!!` `(v0.9)`
- **F3 Playback** `[ ]`
  - `[ ]` deterministic re-simulation, speed control, seek `(v0.4)`
- **F4 Golden replays** `[ ]`
  - `[ ]` curated replay corpus as a regression test `(v0.4)`
- **F5 Observer / spectator** `[ ]`
  - `[ ]` watch live or recorded matches, fog option `(v0.9)`

### M23 `ra3.save` — save/load & profiles `[ ]`

- **F1 Save / load** `[ ]`
  - `[ ]` full simulation state serialization (objects, modules, queues) `(v0.8)`
  - `[ ]` versioned saves with migration `(v0.8)`
- **F2 Profiles** `[ ]`
  - `[ ]` player profile, stats, progress/unlocks `(v0.8)`
- **F3 Options persistence** `[ ]`
  - `[ ]` settings, keybinds, last-used skirmish config `(v0.7)`
- **F4 Checkpoints** `[ ]`
  - `[ ]` campaign checkpoint save/restore `(v0.9)`

### M24 `ra3.mod` — data packages `[ ]`

- **F1 Data packages** `[ ]`
  - `[ ]` load order, override precedence, loose-file mounting `(v0.8)`
- **F2 Content discovery** `[ ]`
  - `[ ]` scan user mod dirs and additional `.big` archives `(v0.8)`
- **F3 Mod validation** `[ ]`
  - `[ ]` schema + reference checks, actionable errors `(v0.8)`

### M25 `ra3.net` — LAN lockstep `[ ]` *(deferred, offline-only)*

- **F1 Lockstep** `[ ]`
  - `[ ]` deterministic lockstep over LAN, command-exchange only `(v1.0)`
- **F2 Lobby & sync** `[ ]`
  - `[ ]` lobby, slot/team assignment, start sync `(v1.0)`
- **F3 Desync detection** `[ ]`
  - `[ ]` state-hash comparison, desync report `(v1.0)`

> No online service, matchmaking, EA account or third-party network
> integration — ever. LAN only.

### M26 `ra3.i18n` — localization `[P]`

- **F1 CSF strings** `[~]`
  - `[x]` parse `gamestrings.csf` (UTF-16 units, low byte `^0xFF`)
  - `[x]` map display-name lookup (`MAP:<ID>`)
  - `[ ]` full string-table load for all UI text `(v0.5)`
- **F2 Language selection** `[~]`
  - `[x]` newest `Lang-English*.big` wins
  - `[ ]` all supported languages, fallback chain `(v0.5)`
- **F3 Fonts & shaping** `[ ]`
  - `[ ]` glyph coverage, CJK/RTL shaping where applicable `(v0.6)`
- **F4 Substitution** `[ ]`
  - `[ ]` placeholders, numbers, plurals `(v0.5)`

### M27 `apps` — applications `[D]`

- **F1 CLI** `[D]`
  - `[x]` `menu` / `menu-preview` / `maps` / `skirmish` / `render` / `extract`
  - `[ ]` `replay`, `benchmark`, `validate-data` subcommands `(v0.5)`
- **F2 Extraction pipeline** `[~]`
  - `[x]` `extract` → `assets/` (maps, terrain)
  - `[ ]` full asset dump (models/textures/audio/movies) as a build target `(v0.5)`
- **F3 Diagnostics** `[ ]`
  - `[ ]` headless render/benchmark modes for CI `(v0.4)`

### M28 `tools` — offline tooling `[~]`

*(Python is permitted here; it is never linked into `openra3`.)*

- **F1 Reference fetch** `[D]`
  - `[x]` sparse-clone SAGE 1.0 reference into git-ignored `reference/`
- **F2 Ghidra workflow** `[D]`
  - `[x]` MCP-driven recovery loop + recovered symbol map (see RE doc)
  - `[ ]` automated structure/table extractors `(v0.5)`
- **F3 Format inspectors** `[ ]`
  - `[ ]` BIG/RefPack/CkMp/W3D/APT dumpers `(v0.5)`
- **F4 CI & packaging** `[D]`
  - `[x]` GitLab CI builds both targets → test → package

---

## 4. Cross-cutting invariants

These hold across **every** module above and are enforced in review:

1. **Language** — runtime code is C++ only. Build tooling may use Python.
2. **Ownership** — no raw owning pointers; `unique_ptr` for ownership, handles or
   `thing *` views for references.
3. **Layering** — a module imports only lower layers. `ra3.core` imports no
   engine module and no platform API.
4. **Determinism** — RNG, iteration, hashing and float use are explicit and
   seedable; the logic step must be bit-reproducible for a given input stream.
5. **RE-traceable** — retail structure/constant changes cite an address in
   [`REVERSE_ENGINEERING.md`](REVERSE_ENGINEERING.md).
6. **Offline** — no online service; LAN lockstep (M25) is the only networking,
   and only command exchange.
7. **No bundled assets** — game data is read from the user's install; nothing
   from it is committed. The tree builds and runs in CI on a built-in test map.

---

## 5. Milestone mapping

The plan rolls up to these releases:

| Milestone | Modules advanced | Delivers |
| --- | --- | --- |
| `v0.3.x` (done) | M00, M01, M04, M05(F1–F3), M06, M07(partial), M08(partial), M10(partial), M16(F3,F8), M17, M18 | minimal deterministic skirmish, real terrain, Vulkan present, menu |
| `v0.4.0` | M05(F4–F7), M06, M07, M08, M09(F1,F2,F4), M14, M22(F1–F4) | real update modules: locomotor, projectiles/warheads, placement, shroud, pathfinding, replay |
| `v0.5.0` | M02, M03, M04(F3,F4), M08, M10(F3,F4), M11(F1,F2), M26 | data-driven content: deserialise `.bin`/`.manifest`, real rosters, maps, strings |
| `v0.6.0` | M03(F1–F3), M07(F4,F6,F8,F14), M09(F2–F7), M16(F1,F2,F4,F5), M18(F3), M15(F1–F4,F8) | full renderer: perspective terrain, W3D models, in-game client + input |
| `v0.7.0` | M13, M15(F5–F7), M19, M11(F4–F6), M20, M21 | HUD/command bar, audio, superweapons, Commander's Challenge |
| `v0.8.0` | M12, M20(F1), M23, M24, M21(F5) | campaigns, cutscenes, save/load, mods |
| `v0.9.0` | M22(F2,F5), M12(F6), M25 | retail replay playback, co-op, LAN lockstep |
| `v1.0.0` | all | feature-complete offline RA3 |

---

## 6. Design rules

The five rules the codebase is held to (restated from §1, with the concrete
consequences that trip people up):

1. **No raw owning pointers.** Ownership is `std::unique_ptr`; the partition
   manager and object registry hold non-owning `thing *` views only.
2. **Portable simulation.** No platform APIs in `ra3.core` / simulation
   modules. All platform concerns live behind `display`.
3. **Determinism.** Anything that can diverge between runs (random, iteration
   order) is explicit and seedable.
4. **RE-traceable.** Where a structure or constant comes from the retail
   binary, the address is cited in the comment.
5. **No bundled assets, no online.** Game data is read from the user's install
   and never committed; there is no networking or online service.

---

## 7. Where to start

- New to the codebase: read this plan top-to-bottom (§3 is the feature set,
  §5 the near-term order of work).
- Picking up a feature: find its **Function** above, take the lowest-numbered
  unmet `[ ]` **Feature**, and cite its supporting retail address.
- Reverse engineering a subsystem: follow the loop in
  [`REVERSE_ENGINEERING.md`](REVERSE_ENGINEERING.md); the `!!` tags above mark
  the functions that still need a recovery pass before they can be built.