# Introduction and Goals

Gig Line is a Linux-first Unreal Engine 5 game that reconstructs a walkable (and eventually drivable) stretch of Hollywood Boulevard around 6840 Hollywood Blvd / El Capitan Entertainment Centre. The initial release (`0.1.0`) delivers a first-person walking demo of the south-side block between Highland Avenue and Orange Drive, plus north-side buildings within 50 m of the frontage.

## Requirements Overview

| ID | Description |
| --- | --- |
| F-1 | Walk both sides of Hollywood Blvd in the demo area without falling through geometry |
| F-2 | First-person movement (WASD + mouse look), jump, reset (R), pause (Escape) |
| F-3 | Fixed daytime lighting and atmosphere (sun, sky, fog, exposure) |
| F-5 | Designated street crossing with zebra markings at signalised crossings |
| F-6 | Building façades recognisable against reference photography |
| F-7 | Terrain, road, and sidewalk follow real-world DEM elevation |
| F-8 | 60 FPS at 1440p on the documented workstation and quality preset |

Full requirements and progress are in [TODO.md](../../TODO.md); version direction is in [ROADMAP.md](../../ROADMAP.md).

## Quality Goals

| Priority | Quality Goal | Scenario |
| --- | --- | --- |
| 1 | **Visual realism** | Renders read as the reference photographs: façade identity, proportion, material and light — judged side by side, shot against photo |
| 2 | **Geographic fidelity** | Building placement and street scale match the measured data and the photographs |
| 3 | **Terrain walkability** | Zero raycast holes across both sidewalks and the carriageway (84-sample transect passes) |
| 4 | **Build reproducibility** | Fresh checkout + documented engine path produces a runnable Linux build |
| 5 | **Provenance** | Every committed asset has recorded provenance |
| 6 | **Performance efficiency** | 60 FPS at 2560×1440 on RTX 5070 Ti, documented preset, no frame generation |

**How the order is used.** It decides trade-offs. When realism and performance disagree, realism wins and the cost is paid — but never by silently shipping a frame rate below the floor. The 60 FPS figure is a **budget that must still be met**, so the response to "realism costs too much frame time" is to cut the realism feature deliberately, record the cut, and keep the floor — not to let frames slip. Walkability outranks realism in one direction only: a beautiful block the player falls through is not a demo.

## Stakeholders

| Role | Contact | Expectations |
| --- | --- | --- |
| Owner / Director | zwitschi | Sets scope, approves screenshots, cuts release tags |
| AI coding agents | multiple sessions | Read `AGENTS.md`, `TODO.md`, `ROADMAP.md`, and this document for architecture constraints; never commit directly to `main` |
| Players | end users | Walk the demo at 60 FPS without falling through the world; see a recognisable Hollywood block |