1 files changed, 39 insertions, 0 deletions
diff --git a/client/lib/systems/FacingDirection.ts b/client/lib/systems/FacingDirection.ts
new file mode 100644
index 0000000..fbb4c7c
--- /dev/null
+++ b/client/lib/systems/FacingDirection.ts
@@ -0,0 +1,39 @@
+import {
+  ComponentNames,
+  Velocity,
+  FacingDirection as FacingDirectionComponent,
+} from "../components";
+import type { Entity } from "../entities";
+import { System, SystemNames } from "./";
+
+export class FacingDirection extends System {
+  constructor() {
+    super(SystemNames.FacingDirection);
+  }
+
+  public update(
+    _dt: number,
+    entityMap: Map<number, Entity>,
+    componentEntities: Map<string, Set<number>>
+  ) {
+    componentEntities
+      .get(ComponentNames.FacingDirection)
+      ?.forEach((entityId) => {
+        const entity = entityMap.get(entityId);
+        if (!entity.hasComponent(ComponentNames.Velocity)) {
+          return;
+        }
+
+        const velocity = entity.getComponent<Velocity>(ComponentNames.Velocity);
+        const facingDirection = entity.getComponent<FacingDirectionComponent>(
+          ComponentNames.FacingDirection
+        );
+
+        if (velocity.dCartesian.dx > 0) {
+          entity.addComponent(facingDirection.facingRightSprite);
+        } else if (velocity.dCartesian.dx < 0) {
+          entity.addComponent(facingDirection.facingLeftSprite);
+        }
+      });
+  }
+}