Hippo Game Requirements

Functional Requirements

Core Gameplay

• The game must allow up to 4 Hippo players, each positioned at one edge of the screen (top, bottom, left, right).
• Hippos must be able to slide along their edge (left-right for horizontal edges, up-down for vertical edges).
• Hippos can catch Food and traps launched during the game.
• Food and traps must be visually distinct with clear icons.
• Food spawning must be continuous to ensure smooth gameplay.
• Fairness: Food spawning logic must ensure all players have equal opportunities to catch the AAC-selected food.
• Food may spawn from different points on the map (not just the center) for variety.
• Presenter/Spectator view must mirror the hippo player view to support joint attention.

AAC Game Conductor Role

• An AAC (Augmentative and Alternative Communication) user acts as the Game Conductor.
• The AAC user must be able to:
  • Choose the type of food or trap.
  • Launch the selected object into the play area.
  • Use verbs and modifiers such as "eat," "don’t eat," "more" to create simple commands.
• The AAC board must:
  • Provide audio feedback (speech output) for every button press.
  • Support customizable categories to limit options (e.g., max ~10 visible items).
  • Be optimized for touchscreen use with large buttons and simple folder navigation.

Object Types

• Food is catchable for points.
• Traps (burn, freeze, grow) negatively affect Hippos.
• Catching the wrong food or trap should trigger visual and audio effects (e.g., a hippo "freeze" animation for freeze verb).

Scoring & Feedback

• Hippos earn points for catching correct food.
• Provide fun, animated feedback for events (catch, trap effects).
• Leaderboard must be visual:
  • Use hippo colors, icons, or progress bars instead of text labels or numbers.
• Game must have a clear progress indicator or game over screen.

Spectator Mode

• A spectator mode must allow observers to watch gameplay in real time.
• Spectators should see:
  • Player hippos
  • Current food/trap state
  • Visual leaderboard

---

Facilitator/Admin Features

• Provide a facilitator panel to:
• Pre-configure game rooms with specific settings.

---

Research & Data Logging

• The game must log key actions with timestamps, including:
  • AAC user selections (e.g., "User clicked Apple").
  • Player catches (correct/wrong food).
  • Trap interactions.
• Logs should be stored in the database (Postgres) and be exportable (CSV/JSON) for research use.

---

Non-Functional Requirements

Accessibility

• Autism-friendly design:
  • Low sensory load: plain, non-distracting background.
  • High contrast between hippos, food, and background.
  • Optional muted/low-sound mode.
• AAC interface must be simple, large-buttoned, and optimized for touchscreens.
• Game mode and role selection must be icon-based, avoiding text or dropdown menus.

Usability

• Must work on desktop, laptop, or tablet.
• Controls must be intuitive for touchscreens and desktops:
  • Touchscreen: swipe or large on-screen buttons.
  • Desktop: arrow keys or alternative visual controls.
• UI must minimize text where possible, relying on icons and colors.

Performance

• Game must run smoothly (≥ 30 FPS) even with multiple objects on screen.
• Use real-time synchronization via WebSockets with movement interpolation to reduce jitter.
• Physics (bounce, expiration, collisions) must remain accurate and lightweight.

Reliability

• Game state must not crash or freeze during normal play.
• Players should be able to reconnect without breaking game state.

Maintainability

• Code must be modular and well-structured, especially for:
  • Movement strategies
  • Food/trap spawning logic
  • AAC interface
• Include unit tests for critical features (movement, spawning, scoring, WebSocket state sync).

---