iOS Games Router

You MUST use this skill for ANY game development, SpriteKit, SceneKit, RealityKit, or interactive simulation work.

When to Use

Use this router when:

Building a new SpriteKit game or prototype (2D)
Building a 3D game with SceneKit or RealityKit
Implementing physics (collisions, contacts, forces, joints)
Setting up game architecture (scenes, layers, cameras, ECS)
Debugging SpriteKit, SceneKit, or RealityKit issues
Optimizing game performance (draw calls, node counts, entity counts, batching)
Managing game loop, delta time, or pause handling
Implementing touch/input handling in a game context
Integrating SpriteKit or RealityKit with SwiftUI
Working with particle effects, texture atlases, or 3D models
Looking up SpriteKit, SceneKit, or RealityKit API details
Migrating from SceneKit to RealityKit
Building AR games with RealityKit

Routing Logic

SpriteKit (2D)

Architecture, patterns, and best practices → /skill axiom-spritekit

Scene graph model, coordinate systems, anchor points
Physics engine: bitmask discipline, contact detection, body types
Actions system: sequencing, grouping, named actions, timing
Input handling: touches, coordinate conversion
Performance: draw calls, batching, object pooling, SKShapeNode trap
Game loop: frame cycle, delta time, pause handling
Scene transitions and data passing
SwiftUI integration (SpriteView, UIViewRepresentable)
Metal integration (SKRenderer)
Anti-patterns and code review checklist
Pressure scenarios with push-back templates

API reference and lookup → /skill axiom-spritekit-ref

All 16 node types with properties and performance notes
SKPhysicsBody creation methods and properties
Complete SKAction catalog (movement, rotation, scaling, fading, composition, physics)
Texture and atlas management
SKConstraint types and SKRange
SKView configuration and scale modes
SKEmitterNode properties and presets
SKRenderer setup and SKShader syntax

Troubleshooting and diagnostics → /skill axiom-spritekit-diag

Physics contacts not firing (6-branch decision tree)
Objects tunneling through walls (5-branch)
Poor frame rate (4 top branches, 12 leaves)
Touches not registering (6-branch)
Memory spikes and crashes (5-branch)
Coordinate confusion (5-branch)
Scene transition crashes (5-branch)

Automated scanning → Launch spritekit-auditor agent or /axiom:audit spritekit (physics bitmasks, draw call waste, node accumulation, action memory leaks, coordinate confusion, touch handling, missing object pooling, missing debug overlays)

SceneKit (3D — Deprecated)

SceneKit is soft-deprecated as of iOS 26. Use for maintenance of existing code only. New 3D projects should use RealityKit.

Maintenance and migration planning → /skill axiom-scenekit

Scene graph architecture, coordinate system, transforms
Rendering: SCNView, SceneView (deprecated), SCNViewRepresentable
Geometry, PBR materials, shader modifiers
Lighting, animation (SCNAction, SCNTransaction, CAAnimation bridge)
Physics: bodies, collision categories, contact delegate
Asset pipeline: Model I/O, USD/DAE/SCN formats
ARKit integration (legacy ARSCNView)
Migration decision tree (when to migrate vs maintain)
Anti-patterns and pressure scenarios

API reference and migration mapping → /skill axiom-scenekit-ref

Complete SceneKit → RealityKit concept mapping table
Scene graph API: SCNScene, SCNNode, SCNGeometry
Materials: lighting models, PBR properties, shader modifiers
Lighting: all light types with properties
Camera: SCNCamera properties
Physics: body types, shapes, joints
Animation: SCNAction catalog, timing functions
Constraints: all constraint types

RealityKit (3D — Modern)

For non-game 3D content display (product viewers, AR try-on, spatial computing), the ios-graphics router also routes to these RealityKit skills.

Architecture, ECS, and best practices → /skill axiom-realitykit

Entity-Component-System mental model and paradigm shift
Entity hierarchy, transforms, world-space queries
Built-in and custom components, component lifecycle
System protocol, update ordering, event handling
SwiftUI integration: RealityView, Model3D, attachments
AR on iOS: AnchorEntity types, SpatialTrackingSession
Interaction: ManipulationComponent, gestures, hit testing
Materials: SimpleMaterial, PBR, Unlit, Occlusion, ShaderGraph, Custom
Physics: collision shapes, groups/filters, events, forces
Animation: transform, USD playback, playback control
Audio: spatial, ambient, channel
Performance: instancing, component churn, shape optimization
Multiplayer: synchronization, ownership
Anti-patterns and code review checklist
Pressure scenarios

API reference and lookup → /skill axiom-realitykit-ref

Entity API: properties, hierarchy, subclasses
Complete component catalog with all properties
MeshResource generators
ShapeResource types and performance
System protocol and EntityQuery
Scene events catalog
RealityView API: initializers, content, gestures
Model3D API
Material system: all types with full property listings
Animation timing functions and playback control
Audio components and playback
RealityRenderer (Metal integration)

Troubleshooting and diagnostics → /skill axiom-realitykit-diag

Entity not visible (8-branch decision tree)
Anchor not tracking (6-branch)
Gesture not responding (6-branch)
Performance problems (7-branch)
Material looks wrong (6-branch)
Physics not working (6-branch)
Multiplayer sync issues (5-branch)

Decision Tree

Building/designing a 2D SpriteKit game? → axiom-spritekit
How to use a specific SpriteKit API? → axiom-spritekit-ref
SpriteKit broken or performing badly? → axiom-spritekit-diag
Maintaining existing SceneKit code? → axiom-scenekit
SceneKit API reference or migration mapping? → axiom-scenekit-ref
Building new 3D game or experience? → axiom-realitykit
How to use a specific RealityKit API? → axiom-realitykit-ref
RealityKit entity not visible, gestures broken, performance? → axiom-realitykit-diag
Migrating SceneKit to RealityKit? → axiom-scenekit (migration tree) + axiom-scenekit-ref (mapping table)
Building AR game? → axiom-realitykit
Physics contacts not working (SpriteKit)? → axiom-spritekit-diag (Symptom 1)
Frame rate dropping (SpriteKit)? → axiom-spritekit-diag (Symptom 3)
Coordinate/position confusion (SpriteKit)? → axiom-spritekit-diag (Symptom 6)
Need the complete action list? → axiom-spritekit-ref (Part 3)
Physics body setup reference? → axiom-spritekit-ref (Part 2)
Entity not visible (RealityKit)? → axiom-realitykit-diag (Symptom 1)
Gesture not responding (RealityKit)? → axiom-realitykit-diag (Symptom 3)
Want automated SpriteKit code scan? → spritekit-auditor (Agent)

Anti-Rationalization

Thought	Reality
"SpriteKit is simple, I don't need a skill"	Physics bitmasks default to 0xFFFFFFFF and cause phantom collisions. The bitmask checklist catches this in 2 min.
"I'll just use SKShapeNode, it's quick"	Each SKShapeNode is a separate draw call. 50 of them = 50 draw calls. axiom-spritekit has the pre-render-to-texture pattern.
"I can figure out the coordinate system"	SpriteKit uses bottom-left origin (opposite of UIKit). Anchor points add another layer. axiom-spritekit-diag Symptom 6 resolves in 5 min.
"Physics is straightforward"	Three different bitmask properties, modification rules inside callbacks, and tunneling edge cases. axiom-spritekit Section 3 covers all gotchas.
"The performance is fine on my device"	Performance varies dramatically across devices. axiom-spritekit Section 6 has the debug overlay checklist.
"SceneKit is fine for our new project"	SceneKit is soft-deprecated iOS 26. No new features, only security patches. axiom-scenekit has the migration decision tree.
"I'll learn RealityKit later"	Every line of SceneKit is migration debt. axiom-scenekit-ref has the concept mapping table so the transition is concrete, not abstract.
"ECS is overkill for a simple 3D app"	You're already using ECS — Entity + ModelComponent. axiom-realitykit shows how to scale from simple to complex.
"I don't need collision shapes for taps"	RealityKit gestures require CollisionComponent. axiom-realitykit-diag diagnoses this in 2 min vs 30 min guessing.
"I'll just use a Timer for game updates"	Timer-based updates miss frames and aren't synchronized with rendering. axiom-realitykit has the System pattern.

Critical Patterns

axiom-spritekit:

PhysicsCategory struct with explicit bitmasks (default 0xFFFFFFFF causes phantom collisions)
Camera node pattern for viewport + HUD separation
SKShapeNode pre-render-to-texture conversion
[weak self] in all SKAction.run closures
Delta time with spiral-of-death clamping

axiom-spritekit-ref:

Complete node type table (16 types with batching behavior)
Physics body creation methods (circle cheapest, texture most expensive)
Full action catalog with composition patterns
SKView debug overlays and scale mode matrix

axiom-spritekit-diag:

5-step bitmask checklist (2 min vs 30-120 min guessing)
Debug overlays as mandatory first diagnostic step
Tunneling prevention flowchart
Memory growth diagnosis via showsNodeCount trending

axiom-scenekit:

Migration decision tree (new project → RealityKit, existing → maintain or migrate)
USDZ asset conversion before migration (xcrun scntool)
SceneView deprecation and SCNViewRepresentable replacement
Pressure scenarios for "just use SceneKit" rationalization

axiom-scenekit-ref:

Complete SceneKit → RealityKit concept mapping table
All material lighting models and properties
Full constraint catalog

axiom-realitykit:

ECS mental shift table (scene graph thinking → ECS thinking)
Custom component registration (registerComponent())
Read-modify-write pattern for component updates
CollisionComponent required for all interaction
System-based updates instead of timers

axiom-realitykit-ref:

Complete component catalog with all properties
MeshResource generators and ShapeResource types
Scene events catalog
Material system with all PBR properties

axiom-realitykit-diag:

Entity visibility checklist (8 branches, 2-5 min vs 30-60 min)
Gesture debugging (CollisionComponent first check)
Performance diagnosis (entity count, resource sharing, component churn)
Physics constraint: entities must share an anchor

Example Invocations

User: "I'm building a SpriteKit game" → Invoke: /skill axiom-spritekit

User: "My physics contacts aren't firing" → Invoke: /skill axiom-spritekit-diag

User: "How do I create a physics body from a texture?" → Invoke: /skill axiom-spritekit-ref

User: "Frame rate is dropping in my game" → Invoke: /skill axiom-spritekit-diag

User: "How do I set up SpriteKit with SwiftUI?" → Invoke: /skill axiom-spritekit

User: "What action types are available?" → Invoke: /skill axiom-spritekit-ref

User: "Objects pass through walls" → Invoke: /skill axiom-spritekit-diag

User: "I need to build a 3D game" → Invoke: /skill axiom-realitykit

User: "How do I add a 3D model to my SwiftUI app?" → Invoke: /skill axiom-realitykit

User: "My RealityKit entity isn't showing up" → Invoke: /skill axiom-realitykit-diag

User: "How do I set up physics in RealityKit?" → Invoke: /skill axiom-realitykit-ref

User: "I'm migrating from SceneKit to RealityKit" → Invoke: /skill axiom-scenekit + /skill axiom-scenekit-ref

User: "What's the RealityKit equivalent of SCNNode?" → Invoke: /skill axiom-scenekit-ref

User: "Should I use SceneKit for my new 3D project?" → Invoke: /skill axiom-scenekit

User: "Tap gestures don't work on my RealityKit entity" → Invoke: /skill axiom-realitykit-diag

User: "How do I set up ECS in RealityKit?" → Invoke: /skill axiom-realitykit

User: "My AR content isn't tracking" → Invoke: /skill axiom-realitykit-diag

User: "What materials are available in RealityKit?" → Invoke: /skill axiom-realitykit-ref

User: "How do I animate entities in RealityKit?" → Invoke: /skill axiom-realitykit-ref

User: "Memory keeps growing during gameplay" → Invoke: /skill axiom-spritekit-diag

User: "What particle emitter settings should I use for fire?" → Invoke: /skill axiom-spritekit-ref

User: "Can you scan my SpriteKit code for common issues?" → Invoke: spritekit-auditor agent

axiom-ios-games