feat: graphical trait

packages/entity/traits/graphical.js

@@ -0,0 +1,52 @@
+import {compose} from '@avocado/core';
+import {Container} from '@avocado/graphics';
+
+import {simpleState, Trait} from '../trait';
+
+const decorate = compose(
+);
+
+class GraphicalBase extends Trait {
+
+  static defaultParams() {
+    return {
+      trackPosition: true,
+    };
+  }
+
+  static defaultState() {
+    return {};
+  }
+
+  constructor(entity) {
+    super(entity);
+    this._container = new Container();
+  }
+
+  get container() {
+    return this._container;
+  }
+
+  listeners() {
+    const trackPosition = this.params.get('trackPosition');
+    if (!trackPosition || !this._container.isValid) {
+      return {};
+    }
+    return {
+      traitAdded: (trait) => {
+        if ('positioned' === trait.constructor.type()) {
+          this._container.position = this.entity.position;
+        }
+      },
+      xChanged: (x) => {
+        this._container.x = x;
+      },
+      yChanged: (y) => {
+        this._container.y = y;
+      },
+    }
+  }
+
+}
+
+export class Graphical extends decorate(GraphicalBase) {}

packages/entity/traits/registry.js

@@ -22,6 +22,9 @@ registerTrait(Directional);
 import {Existent} from './existent';
 registerTrait(Existent);
 
+import {Graphical} from './graphical';
+registerTrait(Graphical);
+
 import {Mobile} from './mobile';
 registerTrait(Mobile);