Build Mobile Threejs Games

---
name: build-mobile-threejs-games
description: Build, tune, or test a Three.js game for mobile web. Use for touch
  movement, action controls, target selection, touch inventory, safe areas,
  portrait/landscape layouts, responsive HUD, battery/performance budgets, and
  real mobile browser QA.
---

# Build Mobile Three.js Games

Treat mobile as a primary control and performance surface.

## Controls

Provide a clear movement control, reachable primary actions, target selection, cancel/reset paths, and non-drag alternatives for inventory. Keep controls out of unsafe areas, avoid overlapping action zones, and show feedback for held, unavailable, and queued actions.

## Responsive HUD

Design for representative portrait and landscape viewports. Keep vital status, target data, inventory, tooltips, and dialogs legible without covering the playfield. Support orientation changes without resetting gameplay state.

## Performance and QA

Use device-appropriate quality defaults and adaptive decorative effects. Test touch targets, multi-touch, long sessions, audio unlock, pause/background return, reduced motion, low-end quality, and actual mobile-size viewports in the repository-approved browser.