# Quality Requirements

## Quality Requirements Overview

| Category | Requirement | Priority |
| --- | --- | --- |
| Performance efficiency | 60 FPS at 2560×1440, documented preset, no frame generation | 1 |
| Reliability / Terrain | Zero raycast holes across sidewalks and carriageway (84-sample transect) | 1 |
| Accuracy / Fidelity | Building placement matches reference photography within ~1 m | 2 |
| Accuracy / Fidelity | Street scale (lane width, sidewalk width) within ~10 cm of measured profile | 2 |
| Usability | WASD + mouse look, jump, reset (R), pause (Escape) — no tutorial needed | 2 |
| Compliance | ODbL attribution visible at runtime | 2 |
| Maintainability | Fresh checkout builds with documented engine installation | 2 |
| Portability | Linux build packages and runs; Windows build ships | 3 |

## Quality Scenarios

| ID | Source/Stimulus | Response | Metric |
| --- | --- | --- | --- |
| QS-1 | Player walks both sides of the demo | No fall-through, character stays at ground Z | 0 raycast holes in 84-sample transect |
| QS-2 | Player holds W for 2 s on flat road | Character moves forward | ≥ 200 cm displacement, Z constant within ±5 cm |
| QS-3 | Player presses R | Character teleports to spawn | < 100 cm from `StartLocation` |
| QS-4 | Player presses Escape | Game pauses, cursor appears | `IsGamePaused()` = true |
| QS-5 | Player presses Escape while paused | Game unpauses, cursor hides | `IsGamePaused()` = false |
| QS-6 | Game runs on dev workstation at 1440p | Frame rate stable | ≥ 60 FPS, 99th percentile ≥ 55 FPS |
| QS-7 | Fresh checkout + engine install | Build succeeds | Exit code 0, runnable binary produced |