feat: add lookAtEntity field to Billboard component

packages/@dcl/playground-assets/etc/playground-assets.api.md

@@ -2514,6 +2514,7 @@ export namespace PBAvatarShape {
 // @public (undocumented)
 export interface PBBillboard {
     billboardMode?: BillboardMode | undefined;
+    lookAtEntity?: number | undefined;
 }
 
 // @public (undocumented)

test/ecs/components/Billboard.spec.ts

@@ -1,4 +1,4 @@
-import { Engine, components, BillboardMode } from '../../../packages/@dcl/ecs/src'
+import { Engine, components, BillboardMode } from '../../../packages/@dcl/ecs/src'
 import { testComponentSerialization } from './assertion'
 
 describe('Generated Billboard ProtoBuf', () => {
@@ -10,4 +10,23 @@ describe('Generated Billboard ProtoBuf', () => {
       billboardMode: BillboardMode.BM_Y
     })
   })
+
+  it('should serialize/deserialize Billboard with lookAtEntity', () => {
+    const newEngine = Engine()
+    const Billboard = components.Billboard(newEngine)
+
+    testComponentSerialization(Billboard, {
+      billboardMode: BillboardMode.BM_Y,
+      lookAtEntity: 512
+    })
+  })
+
+  it('should serialize/deserialize Billboard with only lookAtEntity (no explicit mode)', () => {
+    const newEngine = Engine()
+    const Billboard = components.Billboard(newEngine)
+
+    testComponentSerialization(Billboard, {
+      lookAtEntity: 1024
+    })
+  })
 })

test/snapshots/production-bundles/billboard.ts

@@ -52,6 +52,10 @@ function createBillboards() {
   const plane4 = createPlaneTexture(12, 3, 8)
   createPlaneTexture(4, 3, 8)
 
+  // Target entity for look_at_entity demonstration
+  const targetEntity = engine.addEntity()
+  Transform.create(targetEntity, { position: { x: 8, y: 3, z: 4 } })
+
   Billboard.create(plane1, {
     billboardMode: BillboardMode.BM_Y
   })
@@ -62,6 +66,13 @@ function createBillboards() {
   Billboard.create(plane5, {
     billboardMode: BillboardMode.BM_Y
   })
+
+  // Billboard that faces a specific entity instead of the camera
+  const plane6 = createPlaneTexture(4, 3, 4)
+  Billboard.create(plane6, {
+    billboardMode: BillboardMode.BM_Y,
+    lookAtEntity: targetEntity
+  })
 }
 
 function createTextShape(text: string, position: Vector3, textColor: Color4) {