From 3c786441bbfdfbb88e52fcaff4f09a9edb0e3397 Mon Sep 17 00:00:00 2001
From: kolaflash <kolaflash@GAMBIT>
Date: Thu, 8 Jan 2026 14:12:40 +0100
Subject: [PATCH] WIP

---
 dev/main.tsx              |  8 ++++++--
 engine/Scene.ts           | 34 ++++++++++++++++++++++++++++++++--
 scenes/testScene/index.ts |  4 +++-
 3 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/dev/main.tsx b/dev/main.tsx
index ee3162d..51d5853 100644
--- a/dev/main.tsx
+++ b/dev/main.tsx
@@ -11,6 +11,7 @@ import { ZoomScanIcon } from "#/dev/icons/ZoomScan.tsx";
 import {
 	currentScene,
 	type SceneData,
+	sceneChangedHandlers,
 	sceneGraph,
 	setScene,
 } from "#/engine/Scene.ts";
@@ -71,10 +72,13 @@ const DevTools: Component<{ gameContainer: HTMLElement }> = ({
 	const setCurrentScene = async (items: ItemsRef): Promise<void> => {
 		const name = items.find((ref) => ref.item.isActive)!.item.label;
 		await setScene(name);
-		setSceneData(currentScene.data);
-		setEntities(mapSceneEntities(currentScene.data));
 	};
 
+	sceneChangedHandlers.add((data) => {
+		setSceneData(data);
+		setEntities(mapSceneEntities(data));
+	});
+
 	const setActiveEntity = (items: ItemsRef): void => {
 		const activeRef = items.find((ref) => ref.item.isActive)!;
 		const instances = currentScene.entityInstanceMap.get(
diff --git a/engine/Scene.ts b/engine/Scene.ts
index 84a2e93..ab2cd71 100644
--- a/engine/Scene.ts
+++ b/engine/Scene.ts
@@ -33,12 +33,20 @@ export type Scene = {
 };
 
 export type Process = (ctx: CanvasRenderingContext2D, delta: number) => void;
+export type PreProcess = () => void;
+export type PostProcess = () => void;
 
-export type SceneChangeCallback = (from: Scene, to: Scene) => void;
+export type SceneChangeHandler = (to: SceneData, from: SceneData) => void;
+
+const sceneProcessMap = new Map<string, Process>();
+const scenePreProcessMap = new Map<string, PreProcess>();
+const scenePostProcessMap = new Map<string, PostProcess>();
 
 const sceneDataMap = new Map<string, SceneData>();
-const sceneProcessMap = new Map<string, Process>();
 const sceneEntiyMap = new Map<string, EntityInstanceMap>();
+
+export const sceneChangedHandlers = new Set<SceneChangeHandler>();
+
 export const sceneGraph: Graph<string> = new Map();
 
 export const [loadScene, sceneCache] = useWithAsyncCache(
@@ -112,6 +120,8 @@ export function useScene(data: SceneData): {
 		names: T,
 	) => (name: T[number]) => Promise<void>;
 	process: (fn: Process) => void;
+	preProcess: (fn: PreProcess) => void;
+	postProcess: (fn: PreProcess) => void;
 } {
 	sceneDataMap.set(data.name, data);
 	sceneEntiyMap.set(data.name, new Map());
@@ -133,6 +143,12 @@ export function useScene(data: SceneData): {
 				animateEntities(ctx, delta);
 			});
 		},
+		preProcess(fn): void {
+			scenePreProcessMap.set(data.name, fn);
+		},
+		postProcess(fn): void {
+			scenePostProcessMap.set(data.name, fn);
+		},
 	};
 }
 
@@ -148,10 +164,24 @@ export async function setScene(name: string): Promise<void> {
 	const process = sceneProcessMap.get(name)!;
 	const entityInstanceMap = sceneEntiyMap.get(name)!;
 
+	const preProcess = scenePreProcessMap.get(name);
+	if (preProcess) {
+		preProcess();
+	}
+
+	const postProcess = scenePostProcessMap.get(currentScene.data.name);
+	if (postProcess) {
+		postProcess();
+	}
+
 	currentScene.data = data;
 	self.dispatchEvent(new Event("resize"));
 
 	currentScene.process = process;
 
 	currentScene.entityInstanceMap = entityInstanceMap;
+
+	for (const handler of sceneChangedHandlers.values()) {
+		handler(data, currentScene.data);
+	}
 }
diff --git a/scenes/testScene/index.ts b/scenes/testScene/index.ts
index f2a8c4d..2595e24 100644
--- a/scenes/testScene/index.ts
+++ b/scenes/testScene/index.ts
@@ -1,8 +1,10 @@
 import { useScene } from "#/engine/Scene.ts";
 import data from "./data.json";
 
-const { process, linkScenes } = useScene(data);
+const { process, preProcess, linkScenes } = useScene(data);
 
 linkScenes(["fooScene", "fuzzScene"] as const);
 
+preProcess(() => {});
+
 process((_ctx, _delta) => {});