三个 js - 纹理加载 - 异步 / 等待

Question

我做了一个绘图课：

export class Drawing {
    constructor(texture) {        
        const material = new MeshBasicMaterial({
            color: 0xffffff,
            map: texture
        });
        this.mesh = new Mesh(new PlaneGeometry(texture.image.naturalWidth / 20, texture.image.naturalHeight / 20), material);
    }

    setPosition(x, y, z) {
        this.mesh.position.x = x;
        this.mesh.position.y = y;
        this.mesh.position.z = z;
    }
}

我想访问 texture.image 属性以设置 PlaneGeometry。因此，在调用绘图对象之前，我会执行一些异步/等待调用来加载纹理（绘图调用是在 World 构造函数中进行的）：

let world;
let raycasterDown;
let prevTime = performance.now();
const direction = new Vector3();
const globalInputs = new GlobalInputs();
const textureLoader = new TextureLoader();

const promiseTextureBack = (pathName) => {
    return new Promise((resolve) => {
        resolve(textureLoader.load(pathName));
    });
}

const allTexturesPromises = [];
drawingPaths.map(pathName => {          //drawingPaths is an array of string
    allTexturesPromises.push(promiseTextureBack(pathName));
});

const loadingWorld = async () => {
    const allTextures = await Promise.all(allTexturesPromises); 
    console.log(allTextures[0]);
    world = new World(allTextures);
    document.body.appendChild(world.renderer.domElement);
    world.instructions.addEventListener('click', function () {
        world.controls.lock();
    });
    world.controls.addEventListener('lock', function () {
        world.instructions.style.display = 'none';
        world.blocker.style.display = 'none';
    });

    world.controls.addEventListener('unlock', function () {
        world.blocker.style.display = 'block';
        world.instructions.style.display = '';
    });
}

init();

function init() {
    loadingWorld();
    raycasterDown = new Raycaster(new Vector3(), new Vector3(0, -1, 0), 0, 10);
    document.addEventListener('keydown', (event) => {
        globalInputs.onKeyDown(event);
    });

    document.addEventListener('keyup', (event) => {
        globalInputs.onKeyUp(event);
    });
    window.addEventListener('resize', onWindowResize);
    animate();
}

尽管如此，

    console.log(allTextures[0]) 

在 loadingWorld 中返回：

而且图像仍然未定义...我很确定问题来自：

textureLoader.load(pathName)

我愿意接受任何建议！

Answer 1

load method 接受回调。它不会返回您可以调用 resolve 的任何内容。而不是所有这些promiseTextureBack 代码，只需使用返回承诺的loadAsync method：

const allTexturesPromises = drawingPaths.map(pathName => {  
    return textureLoader.load(pathName);
});