Set unused inherited opaque pointers to nullptr.

PiperOrigin-RevId: 652444674
Change-Id: I3e82b1e1ae029f2f01ddcdf5ce2ccb45624e7062

src/user/user_mesh.cc

@@ -202,13 +202,13 @@ void mjCMesh::PointToLocal() {
   spec.plugin.name = &plugin_name;
   spec.plugin.instance_name = &plugin_instance_name;
   spec.info = &info;
-  file = &file_;
-  content_type = &content_type_;
-  uservert = &vert_;
-  usernormal = &normal_;
-  userface = &face_;
-  usertexcoord = &texcoord_;
-  userfacetexcoord = &facetexcoord_;
+  file = nullptr;
+  content_type = nullptr;
+  uservert = nullptr;
+  usernormal = nullptr;
+  userface = nullptr;
+  usertexcoord = nullptr;
+  userfacetexcoord = nullptr;
 }
 
 
@@ -1993,16 +1993,16 @@ void mjCSkin::PointToLocal() {
   spec.vertid = &spec_vertid_;
   spec.vertweight = &spec_vertweight_;
   spec.info = &info;
-  file = &spec_file_;
-  material = &spec_material_;
-  vert = &spec_vert_;
-  texcoord = &spec_texcoord_;
-  face = &spec_face_;
-  bodyname = &spec_bodyname_;
-  bindpos = &spec_bindpos_;
-  bindquat = &spec_bindquat_;
-  vertid = &spec_vertid_;
-  vertweight = &spec_vertweight_;
+  file = nullptr;
+  material = nullptr;
+  vert = nullptr;
+  texcoord = nullptr;
+  face = nullptr;
+  bodyname = nullptr;
+  bindpos = nullptr;
+  bindquat = nullptr;
+  vertid = nullptr;
+  vertweight = nullptr;
 }
 
 
@@ -2399,11 +2399,11 @@ void mjCFlex::PointToLocal() {
   spec.texcoord = &spec_texcoord_;
   spec.elem = &spec_elem_;
   spec.info = &info;
-  material = &material_;
-  vertbody = &vertbody_;
-  vert = &vert_;
-  texcoord = &texcoord_;
-  elem = &elem_;
+  material = nullptr;
+  vertbody = nullptr;
+  vert = nullptr;
+  texcoord = nullptr;
+  elem = nullptr;
 }