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Copy pathobjFromCode.ts
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Copy pathobjFromCode.ts
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194 lines (174 loc) · 7.46 KB
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import * as THREE from 'three';
import {OBJLoader} from 'three/examples/jsm/loaders/OBJLoader.js';
import {MTLLoader} from 'three/examples/jsm/loaders/MTLLoader.js';
import {OrbitControls} from 'three/examples/jsm/controls/OrbitControls.js';
import {createContext, makeCleanup, disposeObject3D, setSceneBackground, BG_DARK} from './helper';
import {createParamPanel} from '../utils/paramPanel';
import type {Lesson} from './types';
// 从磁盘读取真实生成的文件：?url 拿到可加载地址，?raw 拿到文本内容
import objUrl from '../assets/OBJFormat/box-from-code.obj?url';
import objRaw from '../assets/OBJFormat/box-from-code.obj?raw';
import mtlRaw from '../assets/OBJFormat/box-from-code.mtl?raw';
/**
* 演示：用代码直接生成 OBJ 文本 → 再解析回 Three.js 网格显示；
* 并提供复选框，勾选时用 MTLLoader 加载配套的 MTL 材质文件。
*/
let raf = 0;
function create(container: HTMLElement): () => void {
const ctx = createContext(container);
const {scene, renderer} = ctx;
setSceneBackground(ctx, BG_DARK);
const camera = new THREE.PerspectiveCamera(50, 1, 0.1, 100);
camera.position.set(3, 2.5, 4);
const controls = new OrbitControls(camera, renderer.domElement);
controls.enableDamping = true;
scene.add(new THREE.AmbientLight(0xffffff, 0.6));
const dir = new THREE.DirectionalLight(0xffffff, 1.4);
dir.position.set(5, 8, 6);
scene.add(dir);
// 1) 直接加载磁盘上生成的 OBJ 文件（box-from-code.obj）
// 注意：每次运行 `npm run gen:obj_and_mtl` 后刷新页面，形状都会跟着变化。
let currentObj: THREE.Object3D | null = null;
// 给模型所有网格开启双面渲染（从内部也能看到面）
const applyDoubleSide = (root: THREE.Object3D) => {
root.traverse((o) => {
const mesh = o as THREE.Mesh;
if (mesh.isMesh) {
const mat = mesh.material as THREE.Material | THREE.Material[];
if (Array.isArray(mat)) mat.forEach((m) => (m.side = THREE.DoubleSide));
else if (mat) mat.side = THREE.DoubleSide;
}
});
};
// 默认：加载磁盘 OBJ（不套 MTL，Three.js 给默认白色）
const loader = new OBJLoader();
loader.load(objUrl, (loaded) => {
currentObj = loaded;
applyDoubleSide(currentObj);
scene.add(currentObj);
});
// 2) 右上角参数面板：勾选「加载 MTL 材质」时加载配套 MTL 并应用到模型
let mtlLoaded = false;
const loadMtlModel = () => {
const mtlLoader = new MTLLoader();
mtlLoader.load(objUrl.replace(/\.obj(\?.*)?$/, '.mtl'), (materials) => {
materials.preload();
// 关键：仍然加载「同一份磁盘 OBJ」文件，只是套上 MTL 材质，
// 这样形状与默认显示完全一致，只是换了材质颜色。
const objLoader = new OBJLoader();
objLoader.setMaterials(materials);
objLoader.load(objUrl, (loaded) => {
if (currentObj) {
scene.remove(currentObj);
disposeObject3D(currentObj);
}
currentObj = loaded;
applyDoubleSide(currentObj);
scene.add(currentObj);
mtlLoaded = true;
});
});
};
const loadPlainModel = () => {
loader.load(objUrl, (loaded) => {
if (currentObj) {
scene.remove(currentObj);
disposeObject3D(currentObj);
}
currentObj = loaded;
applyDoubleSide(currentObj);
scene.add(currentObj);
mtlLoaded = false;
});
};
const paramPanel = createParamPanel({
container,
controls: [
{
key: 'loadMtl',
label: '加载 MTL 材质',
type: 'checkbox',
min: 0,
max: 1,
step: 1,
value: 0,
desc: '勾选后用 MTLLoader 加载 box-from-code.mtl 并应用到模型',
},
],
defaults: {loadMtl: 0},
resettable: false,
onChange: (key, value) => {
if (key !== 'loadMtl') return;
if (value >= 0.5 && !mtlLoaded) loadMtlModel();
else if (value < 0.5 && mtlLoaded) loadPlainModel();
},
});
// 2.5) 把生成的 OBJ 源码渲染到右侧说明面板
const objMount = document.querySelector<HTMLElement>('#obj-source-mount');
if (objMount) {
const pre = document.createElement('pre');
pre.textContent = objRaw;
pre.style.cssText =
'background:#0d1117;color:#c9d1d9;padding:12px;border-radius:6px;' +
'overflow:auto;max-height:320px;font-size:12px;line-height:1.5;margin:8px 0;';
objMount.appendChild(pre);
}
// 把 MTL 源码渲染到右侧说明面板
const mtlMount = document.querySelector<HTMLElement>('#mtl-source-mount');
if (mtlMount) {
const pre = document.createElement('pre');
pre.textContent = mtlRaw;
pre.style.cssText =
'background:#0d1117;color:#c9d1d9;padding:12px;border-radius:6px;' +
'overflow:auto;max-height:320px;font-size:12px;line-height:1.5;margin:8px 0;';
mtlMount.appendChild(pre);
}
function onResize(w: number, h: number) {
camera.aspect = w / h;
camera.updateProjectionMatrix();
}
ctx.onResize(onResize);
onResize(ctx.getSize().width, ctx.getSize().height);
const tick = () => {
raf = requestAnimationFrame(tick);
controls.update();
renderer.render(scene, camera);
};
tick();
return makeCleanup(ctx, () => {
cancelAnimationFrame(raf);
controls.dispose();
paramPanel.remove();
if (currentObj) disposeObject3D(currentObj);
});
}
export const objFromCode: Lesson = {
id: 'obj_and_mtl_loader',
title: 'OBJ 与 MTL 格式',
description: `
<h3>OBJ 与 MTL 格式</h3>
<p>OBJ 是 Wavefront 的纯文本 3D 模型格式，核心元素：</p>
<ul>
<li><code>v x y z</code> 顶点位置</li>
<li><code>vt u v</code> 纹理坐标（可选）</li>
<li><code>vn x y z</code> 顶点法线（可选）</li>
<li><code>f a b c</code> 面（索引从 1 开始）</li>
<li><code>mtllib</code> 引用材质库（.mtl 文件）</li>
<li><code>usemtl</code> 为后续面指定材质名</li>
</ul>
<p>MTL 是与 OBJ 配套的材质库文件，用 <code>newmtl</code> 定义材质，字段如
<code>Ka</code>/<code>Kd</code>/<code>Ks</code>（环境/漫反射/高光色）、<code>Ns</code>（高光指数）、<code>d</code>（不透明度）。</p>
<p>因为本质是文本，<b>任何代码都能直接拼出 OBJ / MTL</b>。本例：</p>
<ol>
<li>运行生成脚本（<code>scripts/generate-obj-and-mtl.mjs</code>，即 <code>npm run gen:obj_and_mtl</code>）由代码构造一个立方体的 OBJ 文本；</li>
<li>用官方 <code>OBJLoader</code> 把该文本解析回 Three.js 网格并实时显示；</li>
<li>勾选左上角"加载 MTL 材质"复选框，用 <code>MTLLoader</code> 加载配套的
<code>box-from-code.mtl</code> 并应用到模型（漫反射蓝色）。</li>
</ol>
<h4>生成的 OBJ 源码</h4>
<div id="obj-source-mount"></div>
<h4>配套的 MTL 源码</h4>
<div id="mtl-source-mount"></div>
`,
create,
};