gig-line/Docs/build.md

# Build

Fresh-checkout build procedure. Completed 2026-11-07 after the pinned engine was installed and a blank `Game/GigLine` build was packaged and launch-tested.

## Constraints

- Engine installation is external to the repository. Record its path and exact version in [toolchain.md](toolchain.md).
- Build output (`Binaries/`, `Intermediate/`, `Saved/`, `DerivedDataCache/`) is never committed.
- Large content is LFS-tracked, so a fresh clone needs `git lfs install && git lfs pull` before any build.

## Engine

Pinned install: **Unreal Engine 5.8.4** (CL 58902052, promoted build) at `/run/media/system/DATA/Engines/UE_5.8.4`. The engine bundles **no** Linux clang; the system clang (23.1.4, Fedora 45) is the game-code toolchain. Game targets must use `BuildSettingsVersion.V7` to share the installed editor's build environment.

## Fresh-checkout build

```bash
git clone <remote> gig-line && cd gig-line
git lfs install && git lfs pull
Tools/check-lfs.sh                 # must pass before any content build

# Compile the project's editor target (first build also proves the toolchain)
cd /run/media/system/DATA/Engines/UE_5.8.4
Engine/Build/BatchFiles/Linux/Build.sh GigLineEditor Linux Development \
  -project="$PWD/../../Documents/06-games/gig-line/Game/GigLine/GigLine.uproject" \
  -WaitMutex
# Expected tail: "Result: Succeeded"; module binary lands in
# Game/GigLine/Binaries/Linux/libUnrealEditor-GigLine.so

# Open in the editor (GUI, Vulkan)
./Engine/Binaries/Linux/UnrealEditor \
  /run/media/system/DATA/Documents/06-games/gig-line/Game/GigLine/GigLine.uproject
```

Adapt the `-project=` path to the actual checkout location.

## Package a Linux build

```bash
cd /run/media/system/DATA/Engines/UE_5.8.4
Engine/Build/BatchFiles/RunUAT.sh BuildCookRun \
  -project="/run/media/system/DATA/Documents/06-games/gig-line/Game/GigLine/GigLine.uproject" \
  -noP4 -platform=Linux -clientconfig=Development \
  -cook -allmaps -build -stage -pak \
  -archive -archivedirectory="/run/media/system/DATA/Builds/GigLine" \
  -unattended
# Expected: "BUILD SUCCESSFUL" (~1 min for the blank project; archive ~1.1 GiB)
# Launch test (plain, no -map): /run/media/system/DATA/Builds/GigLine/Linux/GigLine.sh
```

**Launch test must open the DemoMap.** A plain `./GigLine.sh` should load `/Game/Hollywood/DemoMap` (set via `DefaultEngine.ini` `GameMapsSettings`). If it instead opens `/Engine/Maps/Templates/OpenWorld`, the game shows an empty non-interactive "stuck" scene — check that `GameDefaultMap` is in `DefaultEngine.ini`, not `DefaultGame.ini`. Confirm the loaded map in the engine log: `.../Linux/GigLine/Saved/Logs/GigLine.log` (`LoadMap: /Game/Hollywood/DemoMap`). The archive directory is deliberately **outside** the repository; never archive into the checkout.

## Headless content checks

Both content-acceptance tests run headless and are the template for all asset import verification:

```bash
# Static-mesh scale test (Blender export -> Unreal import -> measure)
#   Blender: Tools/scale_test_export.py, Unreal: Tools/ue_scale_test_import.py
# MPFB character (generate -> rig -> bake -> export -> skeletal import)
#   Blender: Tools/mpfb_character_export.py, Unreal: Tools/ue_character_import.py

# Unreal side of any test:
./Engine/Binaries/Linux/UnrealEditor-Cmd \
  /run/media/system/DATA/Documents/06-games/gig-line/Game/GigLine/GigLine.uproject \
  -run=pythonscript -script=<repo>/Tools/<script>.py -nullrhi -unattended -nopause -stdout
# Note: 5.8 swallows Python print() in the commandlet; scripts write result files to /tmp.
```

## Content pipeline (current)

The hero block and the demo level are built by a fixed sequence. Each step writes a result file under `/tmp/gigline/`; read it, because the commandlet's own stdout can be swallowed.

| Step | Tool | Output |
| --- | --- | --- |
| OSM blockout | `Art/blender/blockout/blosm_blockout.py` | `Art/blender/blockout/blockout-*.blend` |
| Terrain | `Art/blender/terrain/terrain_from_dem.py` | `Art/blender/terrain/terrain-*.blend` |
| Street | `Art/blender/street/street_mesh.py` | `Art/blender/street/street-*.blend` |
| Site assembly | `Art/blender/site/site_assembly.py` | `Art/blender/site/site-*.blend` |
| Site export | `Art/blender/site/export_site_fbx.py` | six FBXs, one per mesh |
| Hero façade | `Tools/hero_facade_build.py` | `Art/blender/hero/hero-facade-*.blend` + JSON report |
| Site import | `Tools/ue_import_site.py` | `/Game/Hollywood/Site/*` |
| Hero import | `Tools/ue_hero_facade_import.py` | `/Game/Hollywood/ElCapitan/SM_HeroFacade` |
| Demo map | `Tools/ue_build_demo_map.py` | `/Game/Hollywood/DemoMap` |
| Review shots | `Tools/ue_build_review_map.py` + `Tools/render_screenshots.sh` | `Screenshots/` |

Two rules that the pipeline enforces rather than documents:

- **One conversion.** Metres to Unreal centimetres happens only in `Geo/tools/osm_common.py::to_unreal_local`. Sidecars (`<asset>.geo.json`) record the result and `Geo/tools/asset_metadata.py audit` re-derives it.
- **Collision is decided at import,** not later: terrain, road and sidewalks are complex-as-simple; kerbs and props stay simple. A simple hull over a kerbed street ramps straight across the kerb.

## Known engine quirks (2026-11-07)

- One handled `PSOPrecache` ensure fires at packaged-build exit only; not blocking.
- Interchange 5.8 does not create material/texture assets for skeletal FBX imports — `Tools/ue_character_import.py` finishes that chain explicitly.
- Android Turnkey status errors and datarouter DNS warnings in logs are benign.

## Packaged Linux build

- 2026-11-07: blank `Game/GigLine` Development build packaged via the command above; 1.1 GiB archive at `/run/media/system/DATA/Builds/GigLine/Linux`; `GigLine.sh` launched on the desktop session, Vulkan swapchain created, 759 frames rendered across a 60 s smoke test. Controls document to be written with the first playable (`0.1.0` Gameplay section).