fix: add_surface 返回数组下标 + is_valid 按 ID 查找而非下标比较

src/brep/brep.cpp

@@ -47,9 +47,9 @@ int BrepModel::add_body(const std::vector<int>& shell_ids, const std::string& na
 }
 
 int BrepModel::add_surface(const curves::NurbsSurface& surf) {
-    int id = next_id_++;
+    int idx = static_cast<int>(surfaces_.size());
     surfaces_.push_back(surf);
-    return id;
+    return idx;
 }
 
 core::AABB3D BrepModel::bounds() const {
@@ -60,22 +60,24 @@ core::AABB3D BrepModel::bounds() const {
 
 bool BrepModel::is_valid() const {
     for (const auto& e : edges_) {
-        if (e.v_start >= static_cast<int>(vertices_.size()) ||
-            e.v_end >= static_cast<int>(vertices_.size())) {
-            fprintf(stderr, "is_valid FAIL: edge v=%d/%d vs %zu verts\n", e.v_start, e.v_end, vertices_.size());
-            return false;
+        // Validate vertex references by ID (IDs are global, not array indices)
+        bool v0 = false, v1 = false;
+        for (const auto& v : vertices_) {
+            if (v.id == e.v_start) v0 = true;
+            if (v.id == e.v_end)   v1 = true;
         }
+        if (!v0 || !v1) return false;
     }
     for (const auto& f : faces_) {
-        if (f.surface_id >= static_cast<int>(surfaces_.size())) {
-            fprintf(stderr, "is_valid FAIL: face.surface_id=%d vs %zu surfaces\n", f.surface_id, surfaces_.size());
+        // Validate surface ID — surfaces stored by add order, use index
+        if (f.surface_id >= static_cast<int>(surfaces_.size()))
             return false;
-        }
         for (int li : f.loops) {
-            if (li >= static_cast<int>(loops_.size())) {
-                fprintf(stderr, "is_valid FAIL: loop=%d vs %zu loops\n", li, loops_.size());
-                return false;
-            }
+            // Validate loop reference by ID
+            bool found = false;
+            for (const auto& l : loops_)
+                if (l.id == li) { found = true; break; }
+            if (!found) return false;
         }
     }
     return true;