Component Model

PocketEngine gameplay code is built around Lua component tables.

Declaring a component type

Each component type lives in resources/component_types/*.lua and is declared as a global table whose name matches the file name.

Mover = {
    speed = 4.0,
    target_names = {},
}

Instance fields automatically provided by the engine

Every live component instance receives:

• self.actor
• self.key
• self.enabled

The instance keeps its own state, while functions and default values are looked up through the component type table.

Lifecycle callbacks

The runtime recognizes these callback names when they exist on a component:

• OnStart()
• OnUpdate()
• OnLateUpdate()
• OnDestroy()
• OnCollisionEnter(collision)
• OnCollisionExit(collision)
• OnTriggerEnter(collision)
• OnTriggerExit(collision)

Authoring defaults vs runtime overrides

A component property can come from three places:

1. the Lua component type default
2. scene/template overrides stored in JSON
3. runtime edits applied to the live instance

PocketEngine now uses the same array-aware property writer for both:

• scene/template override application
• live runtime property editing

so arrays and scalars stay consistent across editor and runtime.

Arrays

Arrays must stay homogeneous:

• bool[]
• int[]
• double[]
• string[]

Good:

frames = {"sprite://images/Run.png?row=1&column=1",
          "sprite://images/Run.png?row=1&column=2"}

Not supported:

• mixed-type tables
• nested tables as property values
• map-like tables as serialized component properties

Built-in component names

These component types are built into the engine and can be added from Lua or the editor:

• Transform
• SpriteRenderer
• Rigidbody
• ParticleSystem