feat: add browser-based MuJoCo simulation platform

wasm/web_platform/src/project/daeConverter.ts

@@ -0,0 +1,54 @@
+import {LoadingManager,type Material,type Mesh,type Texture} from 'three';
+import {OBJExporter} from 'three/addons/exporters/OBJExporter.js';
+import {ColladaLoader} from 'three/addons/loaders/ColladaLoader.js';
+
+const TRANSPARENT_PIXEL='data:image/gif;base64,R0lGODlhAQABAAD/ACwAAAAAAQABAAACADs=';
+
+/**
+ * 将 Collada 几何转换为 MuJoCo WASM 可读取的 OBJ。
+ * 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。
+ */
+export function convertDaeToObj(data:Uint8Array,path:string):Uint8Array {
+  const manager=new LoadingManager();
+  // 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。
+  manager.setURLModifier(()=>TRANSPARENT_PIXEL);
+  const loader=new ColladaLoader(manager);
+  const text=new TextDecoder('utf-8').decode(data);
+  const xml=new DOMParser().parseFromString(text,'application/xml');
+  if(xml.querySelector('parsererror'))throw new Error('Collada XML 格式无效');
+  const upAxis=xml.getElementsByTagName('up_axis')[0]?.textContent?.trim().toUpperCase()??'Y_UP';
+  // 禁用 ColladaLoader 自带的 Z-up → Y-up 旋转，改为直接统一到 MuJoCo 的 Z-up。
+  if(upAxis==='Z_UP')xml.getElementsByTagName('up_axis')[0]!.textContent='Y_UP';
+  const normalized=new XMLSerializer().serializeToString(xml);
+  const result=loader.parse(normalized,path.slice(0,path.lastIndexOf('/')+1));
+  if(!result?.scene)throw new Error('Collada 文件无法解析');
+  const scene=result.scene;
+  if(upAxis==='Y_UP')scene.rotation.x+=Math.PI/2;
+  else if(upAxis==='X_UP')scene.rotation.y-=Math.PI/2;
+  scene.updateMatrixWorld(true);
+  let meshCount=0;
+  scene.traverse(object=>{
+    const mesh=object as Mesh;
+    if(!mesh.isMesh)return;
+    meshCount+=1;
+    const materials=Array.isArray(mesh.material)?mesh.material:[mesh.material];
+    for(const material of materials)if(material)material.name='';
+  });
+  if(!meshCount)throw new Error('Collada 文件不包含可转换的三角网格');
+  try {
+    const output=new OBJExporter().parse(scene);
+    if(!/^v\s/m.test(output)||!/^f\s/m.test(output))throw new Error('Collada 文件未生成有效三角面');
+    return new TextEncoder().encode(output);
+  } finally {
+    scene.traverse(object=>{
+      const mesh=object as Mesh;
+      if(!mesh.isMesh)return;
+      mesh.geometry?.dispose();
+      const materials:Material[]=Array.isArray(mesh.material)?mesh.material:[mesh.material];
+      for(const material of materials){
+        for(const value of Object.values(material))if(value&&typeof value==='object'&&(value as Texture).isTexture)(value as Texture).dispose();
+        material.dispose();
+      }
+    });
+  }
+}