Add validation for player start gamepad camera look binding

src/document/scene-document-validation.ts

@@ -9,6 +9,7 @@ import type { ModelInstance } from "../assets/model-instances";
 import { isModelInstanceCollisionMode } from "../assets/model-instances";
 import {
   isPlayerStartColliderMode,
+  isPlayerStartGamepadCameraLookBinding,
   isPlayerStartGamepadBinding,
   isPlayerStartKeyboardBindingCode,
   isPlayerStartNavigationMode,
@@ -1254,6 +1255,21 @@ function validatePlayerStartEntity(
     );
   }
 
+  if (
+    !isPlayerStartGamepadCameraLookBinding(
+      entity.inputBindings?.gamepad.cameraLook
+    )
+  ) {
+    diagnostics.push(
+      createDiagnostic(
+        "error",
+        "invalid-player-start-camera-look-gamepad-binding",
+        "Player Start camera-look gamepad binding must be a supported standard-gamepad camera input.",
+        `${path}.inputBindings.gamepad.cameraLook`
+      )
+    );
+  }
+
   if (!isPlayerStartColliderMode(entity.collider.mode)) {
     diagnostics.push(
       createDiagnostic(