Tangets

LoadMesh("knot.mesh");
source_coord_set = SuggestMeshTangentVectorSourceCoordSet("knot.mesh", VES_TANGENT);
index = SuggestMeshTangentVectorIndex("knot.mesh", VES_TANGENT);
BuildMeshTangentVectors("knot.mesh", VES_TANGENT, source_coord_set, index);
knot_entity = CreateEntity("knot.mesh");
SetEntityMaterial(knot_entity, "knot");
knot_node = CreateRootChildSceneNode(0, 0, 0, 0, 0, 0);
AttachEntityToSceneNode(knot_entity, knot_node);