39 lines
1.4 KiB
Markdown
39 lines
1.4 KiB
Markdown
---
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id: kw-enter
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name: enter
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category: scenes
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kind: keyword
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tokens: enter
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sig: on enter { … }
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tip: The scene-entry hook — runs once as a scene becomes active.
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order: 3
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---
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`enter` names the body of a scene's entry hook, written `on enter { … }`. It runs <b>once</b> each time the scene becomes active — at boot for the `start` scene (right after the `Start` phase), and on every `become Name` that switches into it. This is where a scene builds what it owns: spawn its models, reset its counters, set the tilemap, open a menu. It is a lifecycle hook, not a phase, so it may not contain `phase` handlers; the scene's ongoing behaviour goes in its `layer` handlers instead.
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```ludic
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program EnterHookExample {
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property Position { column: int = 0, row: int = 0 }
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model Player { Position }
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state EnterHookExampleState {
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score: int = 0
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}
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scene Overworld start {
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on enter (enter_hook_example_st: mut EnterHookExampleState) {
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enter_hook_example_st.score = 0
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spawn Player { Position { column: 5, row: 5 } }
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}
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layer World {
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handler DrawWorld phase Render {
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Screen.clear(Color.MidnightBlue)
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for (current_position) in query [Position, {Player}] {
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Screen.fill_rectangle(x: current_position.column * 16, y: current_position.row * 16, width: 16, height: 16, color: Color.LimeGreen)
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}
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Screen.show()
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}
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}
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}
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}
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```
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