Added the element type mjOBJ_SPEC for mjSpec.

PiperOrigin-RevId: 742678572
Change-Id: I95a382ac58b5bc88c2aa5c07210549a1d5e2f538

doc/includes/references.h

@@ -607,7 +607,8 @@ typedef enum mjtObj_ {            // type of MujoCo object
 
   // meta elements, do not appear in mjModel
   mjOBJ_FRAME         = 100,      // frame
-  mjOBJ_DEFAULT                   // default
+  mjOBJ_DEFAULT,                  // default
+  mjOBJ_MODEL                     // entire model
 
 } mjtObj;
 typedef enum mjtConstraint_ {     // type of constraint

include/mujoco/mjmodel.h

@@ -269,7 +269,8 @@ typedef enum mjtObj_ {            // type of MujoCo object
 
   // meta elements, do not appear in mjModel
   mjOBJ_FRAME         = 100,      // frame
-  mjOBJ_DEFAULT                   // default
+  mjOBJ_DEFAULT,                  // default
+  mjOBJ_MODEL                     // entire model
 
 } mjtObj;
 

python/mujoco/introspect/enums.py

@@ -288,6 +288,7 @@ ENUMS: Mapping[str, EnumDecl] = dict([
              ('mjNOBJECT', 26),
              ('mjOBJ_FRAME', 100),
              ('mjOBJ_DEFAULT', 101),
+             ('mjOBJ_MODEL', 102),
          ]),
      )),
     ('mjtConstraint',

src/engine/engine_io.c

@@ -2143,6 +2143,7 @@ static int numObjects(const mjModel* m, mjtObj objtype) {
   case mjOBJ_DEFAULT:
   case mjOBJ_FRAME:
   case mjOBJ_UNKNOWN:
+  case mjOBJ_MODEL:
     return -1;
   case mjOBJ_BODY:
   case mjOBJ_XBODY:

src/user/user_model.cc

@@ -166,7 +166,7 @@ static void processlist(mjListKeyMap& ids, vector<T*>& list,
 // constructor
 mjCModel::mjCModel() {
   mjs_defaultSpec(&spec);
-  elemtype = mjOBJ_UNKNOWN;
+  elemtype = mjOBJ_MODEL;
   spec_comment_.clear();
   spec_modelfiledir_.clear();
   spec_meshdir_.clear();

unity/Runtime/Bindings/MjBindings.cs

@@ -320,6 +320,7 @@ public enum mjtObj : int{
   mjNOBJECT = 26,
   mjOBJ_FRAME = 100,
   mjOBJ_DEFAULT = 101,
+  mjOBJ_MODEL = 102,
 }
 public enum mjtConstraint : int{
   mjCNSTR_EQUALITY = 0,