59 lines
2.8 KiB
TypeScript
59 lines
2.8 KiB
TypeScript
import { LoadingManager, type Material, type Mesh, type Texture } from 'three';
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import { OBJExporter } from 'three/addons/exporters/OBJExporter.js';
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import { ColladaLoader } from 'three/addons/loaders/ColladaLoader.js';
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const TRANSPARENT_PIXEL = 'data:image/gif;base64,R0lGODlhAQABAAD/ACwAAAAAAQABAAACADs=';
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/**
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* 将 Collada 几何转换为 MuJoCo WASM 可读取的 OBJ。
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* ColladaLoader 会先统一为 Y-up；额外旋转到 MuJoCo 使用的 Z-up，并烘焙节点变换与单位缩放。
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*/
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export function convertDaeToObj(data: Uint8Array, path: string): Uint8Array {
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const manager = new LoadingManager();
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// 转换只需要几何。拦截贴图 URL，避免为浏览器内存文件发起无效网络请求。
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manager.setURLModifier(() => TRANSPARENT_PIXEL);
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const loader = new ColladaLoader(manager);
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const text = new TextDecoder('utf-8').decode(data);
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const xml = new DOMParser().parseFromString(text, 'application/xml');
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if (xml.querySelector('parsererror')) throw new Error('Collada XML 格式无效');
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const upAxis =
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xml.getElementsByTagName('up_axis')[0]?.textContent?.trim().toUpperCase() ?? 'Y_UP';
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// 禁用 ColladaLoader 自带的 Z-up → Y-up 旋转，改为直接统一到 MuJoCo 的 Z-up。
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if (upAxis === 'Z_UP') xml.getElementsByTagName('up_axis')[0]!.textContent = 'Y_UP';
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const normalized = new XMLSerializer().serializeToString(xml);
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const result = loader.parse(normalized, path.slice(0, path.lastIndexOf('/') + 1));
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if (!result?.scene) throw new Error('Collada 文件无法解析');
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const scene = result.scene;
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if (upAxis === 'Y_UP') scene.rotation.x += Math.PI / 2;
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else if (upAxis === 'X_UP') scene.rotation.y -= Math.PI / 2;
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scene.updateMatrixWorld(true);
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let meshCount = 0;
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scene.traverse((object) => {
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const mesh = object as Mesh;
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if (!mesh.isMesh) return;
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meshCount += 1;
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const materials = Array.isArray(mesh.material) ? mesh.material : [mesh.material];
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for (const material of materials) if (material) material.name = '';
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});
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if (!meshCount) throw new Error('Collada 文件不包含可转换的三角网格');
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try {
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const output = new OBJExporter().parse(scene);
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if (!/^v\s/m.test(output) || !/^f\s/m.test(output))
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throw new Error('Collada 文件未生成有效三角面');
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return new TextEncoder().encode(output);
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} finally {
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scene.traverse((object) => {
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const mesh = object as Mesh;
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if (!mesh.isMesh) return;
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mesh.geometry?.dispose();
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const materials: Material[] = Array.isArray(mesh.material) ? mesh.material : [mesh.material];
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for (const material of materials) {
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for (const value of Object.values(material))
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if (value && typeof value === 'object' && (value as Texture).isTexture)
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(value as Texture).dispose();
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material.dispose();
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}
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});
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}
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}
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