feat: implement Signal v1.0

Author: fraxken

packages/editors/model/src/PlayerBehavior.ts

@@ -6,14 +6,19 @@ import {
   Input,
   type InputDevicePreference,
   SceneProperty,
-  SceneActorComponent
+  SceneActorComponent,
+  Signal,
+  type SignalEvent
 } from "@jolly-pixel/engine";
 
 export interface PlayerProperties extends BehaviorProperties {
   speed: number;
 }
 
 export class PlayerBehavior extends Behavior<PlayerProperties> {
+  @Signal()
+  onPlayerPunch: SignalEvent;
+
   @SceneProperty({ type: "number" })
   speed = 0.05;
 
@@ -33,9 +38,6 @@ export class PlayerBehavior extends Behavior<PlayerProperties> {
   }
 
   awake() {
-    console.log({
-      isTouchpadAvailable: this.actor.gameInstance.input.isTouchpadAvailable()
-    });
     this.actor.threeObject.rotateX(-Math.PI / 2);
 
     this.model.animation.setClipNameRewriter((name) => name.slice(name.indexOf("|") + 1).toLowerCase());
@@ -68,6 +70,7 @@ export class PlayerBehavior extends Behavior<PlayerProperties> {
     }
     else if (input.isMouseButtonDown("left")) {
       this.model.animation.play("punch_jab");
+      this.onPlayerPunch.emit();
     }
     else {
       this.model.animation.play("idle_loop");

packages/engine/src/actor/Signal.ts

@@ -0,0 +1,74 @@
+// Import Third-party Dependencies
+import "reflect-metadata";
+
+// CONSTANTS
+const kActorComponentSignalKey = Symbol("ActorComponentSignalKey");
+
+export interface SignalMetadata {
+  signals: Set<string>;
+}
+
+export type SignalListener<T extends unknown[]> = (...args: T[]) => void;
+
+export class SignalEvent<T extends unknown[] = []> {
+  private listeners: SignalListener<T>[] = [];
+
+  emit(...args: T) {
+    this.listeners.forEach((listener) => {
+      listener(...args as any);
+    });
+  }
+
+  connect(
+    listener: SignalListener<T>
+  ) {
+    this.listeners.push(listener);
+  }
+
+  disconnect(
+    listener: SignalListener<T>
+  ) {
+    const index = this.listeners.indexOf(listener);
+    if (index !== -1) {
+      this.listeners.splice(index, 1);
+    }
+  }
+
+  clear() {
+    this.listeners = [];
+  }
+}
+
+export function Signal(): PropertyDecorator {
+  return function fn(
+    object: Object,
+    propertyName: string | symbol
+  ): void {
+    const metadata = getActorComponentMetadata(object);
+    if (metadata) {
+      metadata.signals.add(propertyName.toString());
+    }
+    else {
+      const metadata = createActorComponentMetadata();
+      metadata.signals.add(propertyName.toString());
+
+      Reflect.defineMetadata(
+        kActorComponentSignalKey,
+        metadata,
+        object
+      );
+    }
+  };
+}
+
+function createActorComponentMetadata(): SignalMetadata {
+  return {
+    signals: new Set<string>()
+  };
+}
+
+export function getActorComponentMetadata(
+  object: Object
+): SignalMetadata | undefined {
+  return Reflect.getMetadata(kActorComponentSignalKey, object);
+}

packages/engine/src/actor/index.ts

@@ -1,3 +1,8 @@
 export * from "./Actor.js";
 export * from "./ActorComponent.js";
 export * from "./ActorTree.js";
+export {
+  Signal,
+  SignalEvent,
+  type SignalListener
+} from "./Signal.js";

packages/engine/src/components/script/BehaviorDecorators.ts

@@ -81,7 +81,8 @@ export type SceneActorComponentType =
   | typeof SpriteRenderer
   | typeof TextRenderer
   | typeof TiledMapRenderer
-  | typeof ActorComponent;
+  | typeof ActorComponent
+  | any;
 
 export function SceneActorComponent(
   classObject: SceneActorComponentType

packages/engine/src/components/script/BehaviorInitializer.ts

@@ -7,6 +7,10 @@ import {
   Input,
   type InputListenerMetadata
 } from "../../controls/Input.class.js";
+import {
+  SignalEvent,
+  getActorComponentMetadata
+} from "../../actor/Signal.js";
 import { Behavior } from "./Behavior.js";
 import {
   getBehaviorMetadata,
@@ -68,11 +72,26 @@ export class BehaviorInitializer {
   }
 
   load(): void {
+    this.#bindSignalHandlers();
     this.#resolveProperties();
     this.#resolveActorComponents();
     this.#resolveInputListeners();
   }
 
+  #bindSignalHandlers() {
+    const metadata = getActorComponentMetadata(
+      Object.getPrototypeOf(this.#behavior)
+    );
+    if (!metadata) {
+      return;
+    }
+
+    const { signals } = metadata;
+    for (const propertyName of signals) {
+      this.#behavior[propertyName] = new SignalEvent();
+    }
+  }
+
   #resolveInputListeners(): void {
     const { input } = this.#behavior.actor.gameInstance;