babylon.js how to get access to a mesh outside of it's function

问题

I just cant get access to the babylon mesh. Everytime I try to run the code I get this error.

I've tried it with two different approaches:

Example 1:

var carTest;
BABYLON.SceneLoader.ImportMesh("", "assets/", "car.obj", scene, function(object) {
        carTest = object[0];
    });
carTest.position.x = 10;

Example 2:

var carTest = BABYLON.SceneLoader.ImportMesh("", "assets/", "car.obj", scene);
carTest.position.x = 10;

回答1:

In your example 2, The BABYLON.SceneLoader.ImportMesh return Nullable<ISceneLoaderPlugin | ISceneLoaderPluginAsync>, and both of them do not have property name as position.
Thus, carTest.position would be undefined.

carTest.position.x = 10 => undefined.x = 10;

will throw error.

In your first example, BABYLON.SceneLoader.ImportMesh is a synchronized function, although there is another function name ImportMeshAsync in BABYLON.SceneLoader...

I have not used BABYLON before.
But basically, according to BABYLON API, the difference between ImportMesh and ImportMeshAsync is the returned type.

so,

[Improvement]

move carTest.position.x = 10; in your onSuccess callback.

BABYLON
  .SceneLoader
  .ImportMesh("", "assets/", "car.obj", scene, function(object) {
        carTest = object[0];
        carTest.position.x = 10;
    });

回答2:

When call SceneLoader, the carTest object only are set when return the onlyne (function), then the object are not ready in the next line (carTest do not exist at this time).

You need await to use carTest object when SceneLoader are finish.

回答3:

Instead of using the synchron method with callback function you could use the async function if you know the concept of async / await.

Example:

const data = await SceneLoader.ImportMeshAsync("", "assets/", "car.obj", scene);
const carMeshes = data.meshes;

If you know there is only one with children you could access [0] otherwise you may need to merger the meshes. Depends on what you want to do.

来源：https://stackoverflow.com/questions/62018719/babylon-js-how-to-get-access-to-a-mesh-outside-of-its-function

标签

javascript

babylonjs