Potential index offset bug in load_mesh.cpp

[lzero1115]

Hi Kemeng, thanks for your excellent work!

When I play around with the simulator, I met a problem when I try to load several .obj meshes. The potential issue may be located in load_mesh.cpp, inside tetrahedra_obj::load_triMesh (around line 301).

Current code:

triangleNum = triangles.size();
set_body_tri_num(gipc::BodyType::FEM, elementNumber);
vertexOffset += vertexNum; // <--- Potential Bug
set_body_point_num(gipc::BodyType::FEM, nodeNumber);