athility/game-development

Game Development

Orchestrator skill that provides core principles and routes to specialized sub-skills.

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When to Use This Skill

You are working on a game development project. This skill teaches the PRINCIPLES of game development and directs you to the right sub-skill based on context.

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Sub-Skill Routing

Platform Selection

| If the game targets... | Use Sub-Skill | |------------------------|---------------| | Web browsers (HTML5, WebGL) | game-development/web-games | | Mobile (iOS, Android) | game-development/mobile-games | | PC (Steam, Desktop) | game-development/pc-games | | VR/AR headsets | game-development/vr-ar |

Dimension Selection

| If the game is... | Use Sub-Skill | |-------------------|---------------| | 2D (sprites, tilemaps) | game-development/2d-games | | 3D (meshes, shaders) | game-development/3d-games |

Specialty Areas

| If you need... | Use Sub-Skill | |----------------|---------------| | GDD, balancing, player psychology | game-development/game-design | | Multiplayer, networking | game-development/multiplayer | | Visual style, asset pipeline, animation | game-development/game-art | | Sound design, music, adaptive audio | game-development/game-audio |

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Core Principles (All Platforms)

1. The Game Loop

Every game, regardless of platform, follows this pattern:

INPUT  → Read player actions
UPDATE → Process game logic (fixed timestep)
RENDER → Draw the frame (interpolated)

Fixed Timestep Rule:

• Physics/logic: Fixed rate (e.g., 50Hz)
• Rendering: As fast as possible
• Interpolate between states for smooth visuals

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2. Pattern Selection Matrix

| Pattern | Use When | Example | |---------|----------|---------| | State Machine | 3-5 discrete states | Player: Idle→Walk→Jump | | Object Pooling | Frequent spawn/destroy | Bullets, particles | | Observer/Events | Cross-system communication | Health→UI updates | | ECS | Thousands of similar entities | RTS units, particles | | Command | Undo, replay, networking | Input recording | | Behavior Tree | Complex AI decisions | Enemy AI |

Decision Rule: Start with State Machine. Add ECS only when performance demands.

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3. Input Abstraction

Abstract input into ACTIONS, not raw keys:

"jump"  → Space, Gamepad A, Touch tap
"move"  → WASD, Left stick, Virtual joystick

Why: Enables multi-platform, rebindable controls.

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4. Performance Budget (60 FPS = 16.67ms)

| System | Budget | |--------|--------| | Input | 1ms | | Physics | 3ms | | AI | 2ms | | Game Logic | 4ms | | Rendering | 5ms | | Buffer | 1.67ms |

Optimization Priority:

1. Algorithm (O(n²) → O(n log n))
2. Batching (reduce draw calls)
3. Pooling (avoid GC spikes)
4. LOD (detail by distance)
5. Culling (skip invisible)

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5. AI Selection by Complexity

| AI Type | Complexity | Use When | |---------|------------|----------| | FSM | Simple | 3-5 states, predictable behavior | | Behavior Tree | Medium | Modular, designer-friendly | | GOAP | High | Emergent, planning-based | | Utility AI | High | Scoring-based decisions |

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6. Collision Strategy

| Type | Best For | |------|----------| | AABB | Rectangles, fast checks | | Circle | Round objects, cheap | | Spatial Hash | Many similar-sized objects | | Quadtree | Large worlds, varying sizes |

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Anti-Patterns (Universal)

| Don't | Do | |-------|-----| | Update everything every frame | Use events, dirty flags | | Create objects in hot loops | Object pooling | | Cache nothing | Cache references | | Optimize without profiling | Profile first | | Mix input with logic | Abstract input layer |

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Routing Examples

Example 1: "I want to make a browser-based 2D platformer"

→ Start with game-development/web-games for framework selection → Then game-development/2d-games for sprite/tilemap patterns → Reference game-development/game-design for level design

Example 2: "Mobile puzzle game for iOS and Android"

→ Start with game-development/mobile-games for touch input and stores → Use game-development/game-design for puzzle balancing

Example 3: "Multiplayer VR shooter"

→ game-development/vr-ar for comfort and immersion → game-development/3d-games for rendering → game-development/multiplayer for networking

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Remember: Great games come from iteration, not perfection. Prototype fast, then polish.