Refactor Default class to use pointers instead of indices.

This in order to make it easier to append the default tree to another tree.

PiperOrigin-RevId: 649812975
Change-Id: I2915ac7e37957e45eadc24d6caaf7beea236bf29

src/user/user_api.cc

@@ -440,7 +440,7 @@ mjsPlugin* mjs_addPlugin(mjSpec* s) {
 mjsDefault* mjs_addDefault(mjSpec* s, const char* classname, const mjsDefault* parent) {
   mjCModel* modelC = static_cast<mjCModel*>(s->element);
   mjCDef* parentC = parent ? static_cast<mjCDef*>(parent->element) :
-                             static_cast<mjCModel*>(s->element)->Defaults(0);
+                             static_cast<mjCModel*>(s->element)->Default();
   mjCDef* def = modelC->AddDefault(classname, parentC);
   if (def) {
     return &def->spec;
@@ -480,7 +480,7 @@ mjsDefault* mjs_findDefault(mjSpec* s, const char* classname) {
 // get default[0] from model
 mjsDefault* mjs_getSpecDefault(mjSpec* s) {
   mjCModel* modelC = static_cast<mjCModel*>(s->element);
-  mjCDef* def = modelC->Defaults(0);
+  mjCDef* def = modelC->Default();
   if (!def) {
     return nullptr;
   }

src/user/user_composite.cc

@@ -560,7 +560,7 @@ bool mjCComposite::MakeParticle(mjCModel* model, mjsBody* body, char* error, int
 
       // create tendon
       mjsTendon* ten = mjs_addTendon(&model->spec, &def[mjCOMPKIND_TENDON].spec);
-      mjs_setDefault(ten->element, &model->Defaults(0)->spec);
+      mjs_setDefault(ten->element, &model->Default()->spec);
       mjs_setString(ten->name, txt0);
       ten->group = 4;
       mjs_wrapSite(ten, txt1);
@@ -568,7 +568,7 @@ bool mjCComposite::MakeParticle(mjCModel* model, mjsBody* body, char* error, int
 
       // add equality constraint
       mjsEquality* eq = mjs_addEquality(&model->spec, &def[mjCOMPKIND_TENDON].spec);
-      mjs_setDefault(eq->element, &model->Defaults(0)->spec);
+      mjs_setDefault(eq->element, &model->Default()->spec);
       eq->type = mjEQ_TENDON;
       mjs_setString(eq->name1, mjs_getString(ten->name));
     }
@@ -674,7 +674,7 @@ bool mjCComposite::MakeGrid(mjCModel* model, mjsBody* body, char* error, int err
 
         // create tendon
         mjCTendon* ten = model->AddTendon(def + mjCOMPKIND_TENDON);
-        ten->def = model->Defaults(0);
+        ten->def = model->Default();
         mju::sprintf_arr(txt, "%sT%d_%d_%d", prefix.c_str(), i, ix, iy);
         ten->name = txt;
         ten->WrapSite(txt1);
@@ -682,7 +682,7 @@ bool mjCComposite::MakeGrid(mjCModel* model, mjsBody* body, char* error, int err
 
         // add equality constraint
         mjsEquality* eq = mjs_addEquality(&model->spec, &def[mjCOMPKIND_TENDON].spec);
-        mjs_setDefault(eq->element, &model->Defaults(0)->spec);
+        mjs_setDefault(eq->element, &model->Default()->spec);
         eq->type = mjEQ_TENDON;
         mjs_setString(eq->name1, ten->name.c_str());
       }
@@ -1045,7 +1045,7 @@ mjsBody* mjCComposite::AddRopeBody(mjCModel* model, mjsBody* body, int ix, int i
 
     // add constraint
     mjsEquality* eq = mjs_addEquality(&model->spec, &def[mjCOMPKIND_TWIST].spec);
-    mjs_setDefault(eq->element, &model->Defaults(0)->spec);
+    mjs_setDefault(eq->element, &model->Default()->spec);
     eq->type = mjEQ_JOINT;
     mjs_setString(eq->name1, mjs_getString(jnt->name));
   }
@@ -1063,7 +1063,7 @@ mjsBody* mjCComposite::AddRopeBody(mjCModel* model, mjsBody* body, int ix, int i
 
     // add constraint
     mjsEquality* eq = mjs_addEquality(&model->spec, &def[mjCOMPKIND_STRETCH].spec);
-    mjs_setDefault(eq->element,  &model->Defaults(0)->spec);
+    mjs_setDefault(eq->element,  &model->Default()->spec);
     eq->type = mjEQ_JOINT;
     mjs_setString(eq->name1, mjs_getString(jnt->name));
   }
@@ -1131,7 +1131,7 @@ bool mjCComposite::MakeBox(mjCModel* model, mjsBody* body, char* error, int erro
 
   // fixed tendon for all joints
   mjCTendon* ten = model->AddTendon(def + mjCOMPKIND_TENDON);
-  ten->def = model->Defaults(0);
+  ten->def = model->Default();
   mju::sprintf_arr(txt, "%sT", prefix.c_str());
   ten->name = txt;
 
@@ -1185,7 +1185,7 @@ bool mjCComposite::MakeBox(mjCModel* model, mjsBody* body, char* error, int erro
 
           // add fix constraint
           mjsEquality* eq = mjs_addEquality(&model->spec, &def[mjCOMPKIND_JOINT].spec);
-          mjs_setDefault(eq->element,  &model->Defaults(0)->spec);
+          mjs_setDefault(eq->element,  &model->Default()->spec);
           eq->type = mjEQ_JOINT;
           mjs_setString(eq->name1, mjs_getString(jnt->name));
 
@@ -1219,7 +1219,7 @@ bool mjCComposite::MakeBox(mjCModel* model, mjsBody* body, char* error, int erro
 
   // finalize fixed tendon
   mjsEquality* eqt = mjs_addEquality(&model->spec, &def[mjCOMPKIND_TENDON].spec);
-  mjs_setDefault(eqt->element, &model->Defaults(0)->spec);
+  mjs_setDefault(eqt->element, &model->Default()->spec);
   eqt->type = mjEQ_TENDON;
   mjs_setString(eqt->name1, ten->name.c_str());
 
@@ -1245,7 +1245,7 @@ void mjCComposite::MakeShear(mjCModel* model) {
 
       // create tendon
       mjCTendon* ten = model->AddTendon(def + mjCOMPKIND_SHEAR);
-      ten->def = model->Defaults(0);
+      ten->def = model->Default();
       ten->WrapSite(txt1);
       ten->WrapSite(txt2);
 
@@ -1255,7 +1255,7 @@ void mjCComposite::MakeShear(mjCModel* model) {
 
       // equality constraint
       mjsEquality* eq = mjs_addEquality(&model->spec, &def[mjCOMPKIND_SHEAR].spec);
-      mjs_setDefault(eq->element, &model->Defaults(0)->spec);
+      mjs_setDefault(eq->element, &model->Default()->spec);
       eq->type = mjEQ_TENDON;
       mjs_setString(eq->name1, txt);
     }

src/user/user_flexcomp.cc

@@ -517,7 +517,7 @@ bool mjCFlexcomp::Make(mjSpec* spec, mjsBody* body, char* error, int error_sz) {
   // create edge equality constraint
   if (equality) {
     mjsEquality* pe = mjs_addEquality(&model->spec, &def.spec);
-    mjs_setDefault(pe->element, &model->Defaults(0)->spec);
+    mjs_setDefault(pe->element, &model->Default()->spec);
     pe->type = mjEQ_FLEX;
     pe->active = true;
     mjs_setString(pe->name1, name.c_str());

src/user/user_mesh.cc

@@ -149,7 +149,7 @@ mjCMesh::mjCMesh(mjCModel* _model, mjCDef* _def) {
 
   // set model, def
   model = _model;
-  def = (_def ? _def : (_model ? _model->Defaults(0) : 0));
+  def = (_def ? _def : (_model ? _model->Default() : 0));
 
   // in case this body is not compiled
   CopyFromSpec();

src/user/user_model.cc

@@ -807,8 +807,6 @@ mjCDef* mjCModel::FindDefault(string name) {
 
 // add default class to array
 mjCDef* mjCModel::AddDefault(string name, mjCDef* parent) {
-  int parentid = parent ? parent->id : 0;
-
   // check for repeated name
   int thisid = (int)defaults_.size();
   for (int i=0; i<thisid; i++) {
@@ -823,14 +821,14 @@ mjCDef* mjCModel::AddDefault(string name, mjCDef* parent) {
   def->id = thisid;
 
   // initialize contents
-  if (parentid>=0 && parentid<thisid) {
-    defaults_[parentid]->CopyFromSpec();
-    *def = *defaults_[parentid];
-    defaults_[parentid]->childid.push_back(thisid);
+  if (parent && parent->id<thisid) {
+    parent->CopyFromSpec();
+    *def = *parent;
+    parent->child.push_back(def);
   }
-  def->parentid = parentid;
+  def->parent = parent;
   def->name = name;
-  def->childid.clear();
+  def->child.clear();
 
   return def;
 }

src/user/user_model.h

@@ -223,7 +223,7 @@ class mjCModel : public mjCModel_, private mjSpec {
   std::string get_meshdir() const { return meshdir_; }
   std::string get_texturedir() const { return texturedir_; }
 
-  mjCDef* Defaults(int i) const { return defaults_[i]; }
+  mjCDef* Default() const { return defaults_[0]; }
   int NumDefaults() const { return defaults_.size(); }
 
   const std::vector<std::pair<const mjpPlugin*, int>>& ActivePlugins() const {

src/user/user_objects.cc

@@ -518,8 +518,8 @@ int mjCBoundingVolumeHierarchy::MakeBVH(
 mjCDef::mjCDef() {
   name.clear();
   id = 0;
-  parentid = -1;
-  childid.clear();
+  parent = nullptr;
+  child.clear();
   mjs_defaultJoint(&joint_.spec);
   mjs_defaultGeom(&geom_.spec);
   mjs_defaultSite(&site_.spec);
@@ -565,8 +565,8 @@ void mjCDef::Compile(const mjCModel* model) {
 mjCDef& mjCDef::operator=(const mjCDef& other) {
   if (this != &other) {
     name = other.name;
-    parentid = other.parentid;
-    childid = other.childid;
+    parent = other.parent;
+    child = other.child;
     joint_ = other.joint_;
     geom_ = other.geom_;
     site_ = other.site_;
@@ -1691,7 +1691,7 @@ mjCJoint::mjCJoint(mjCModel* _model, mjCDef* _def) {
 
   // set model, def
   model = _model;
-  def = (_def ? _def : (_model ? _model->Defaults(0) : 0));
+  def = (_def ? _def : (_model ? _model->Default() : 0));
   classname = def ? def->name : "";
 
   // point to local
@@ -1899,7 +1899,7 @@ mjCGeom::mjCGeom(mjCModel* _model, mjCDef* _def) {
 
   // set model, def
   model = _model;
-  def = (_def ? _def : (_model ? _model->Defaults(0) : 0));
+  def = (_def ? _def : (_model ? _model->Default() : 0));
   classname = def ? def->name : "";
 
   // point to local
@@ -2542,7 +2542,7 @@ mjCSite::mjCSite(mjCModel* _model, mjCDef* _def) {
 
   // set model, def
   model = _model;
-  def = (_def ? _def : (_model ? _model->Defaults(0) : 0));
+  def = (_def ? _def : (_model ? _model->Default() : 0));
   classname = def ? def->name : "";
 }
 
@@ -2688,7 +2688,7 @@ mjCCamera::mjCCamera(mjCModel* _model, mjCDef* _def) {
 
   // set model, def
   model = _model;
-  def = (_def ? _def : (_model ? _model->Defaults(0) : 0));
+  def = (_def ? _def : (_model ? _model->Default() : 0));
   classname = def ? def->name : "";
 
   // point to local
@@ -2842,7 +2842,7 @@ mjCLight::mjCLight(mjCModel* _model, mjCDef* _def) {
 
   // set model, def
   model = _model;
-  def = (_def ? _def : (_model ? _model->Defaults(0) : 0));
+  def = (_def ? _def : (_model ? _model->Default() : 0));
   classname = def ? def->name : "";
 
   PointToLocal();
@@ -3887,7 +3887,7 @@ mjCMaterial::mjCMaterial(mjCModel* _model, mjCDef* _def) {
   }
 
   model = _model;
-  def = (_def ? _def : (_model ? _model->Defaults(0) : 0));
+  def = (_def ? _def : (_model ? _model->Default() : 0));
   classname = def ? def->name : "";
 
   PointToLocal();
@@ -3974,7 +3974,7 @@ mjCPair::mjCPair(mjCModel* _model, mjCDef* _def) {
 
   // set model, def
   model = _model;
-  def = (_def ? _def : (_model ? _model->Defaults(0) : 0));
+  def = (_def ? _def : (_model ? _model->Default() : 0));
   classname = def ? def->name : "";
 
   // point to local
@@ -4335,7 +4335,7 @@ mjCEquality::mjCEquality(mjCModel* _model, mjCDef* _def) {
 
   // set model, def
   model = _model;
-  def = (_def ? _def : (_model ? _model->Defaults(0) : 0));
+  def = (_def ? _def : (_model ? _model->Default() : 0));
   classname = def ? def->name : "";
 
   // point to local
@@ -4497,7 +4497,7 @@ mjCTendon::mjCTendon(mjCModel* _model, mjCDef* _def) {
 
   // set model, def
   model = _model;
-  def = (_def ? _def : (_model ? _model->Defaults(0) : 0));
+  def = (_def ? _def : (_model ? _model->Default() : 0));
   classname = def ? def->name : "";
 
   // point to local
@@ -4975,7 +4975,7 @@ mjCActuator::mjCActuator(mjCModel* _model, mjCDef* _def) {
 
   // set model, def
   model = _model;
-  def = (_def ? _def : (_model ? _model->Defaults(0) : 0));
+  def = (_def ? _def : (_model ? _model->Default() : 0));
   classname = def ? def->name : "";
 
   // in case this actuator is not compiled

src/user/user_objects.h

@@ -1635,8 +1635,8 @@ class mjCDef : public mjsElement {
   // identifiers
   std::string name;               // class name
   int id;                         // id of this default
-  int parentid;                   // id of parent class
-  std::vector<int> childid;       // ids of child classes
+  mjCDef* parent;                 // id of parent class
+  std::vector<mjCDef*> child;     // child classes
 
   mjsDefault spec;
 

src/xml/xml_native_writer.cc

@@ -862,7 +862,7 @@ string mjXWriter::Write(char *error, size_t error_sz) {
   Visual(root);
   Statistic(root);
   writingdefaults = true;
-  Default(root, model->Defaults(0));
+  Default(root, model->Default());
   writingdefaults = false;
   Extension(root);
   Custom(root);
@@ -1192,8 +1192,8 @@ void mjXWriter::Default(XMLElement* root, mjCDef* def) {
 
   // pointer to parent defaults
   mjCDef* par;
-  if (def->parentid>=0) {
-    par = model->Defaults(def->parentid);
+  if (def->parent) {
+    par = def->parent;
   } else {
     par = new mjCDef;
   }
@@ -1260,19 +1260,19 @@ void mjXWriter::Default(XMLElement* root, mjCDef* def) {
   if (!elem->FirstAttribute()) section->DeleteChild(elem);
 
   // if top-level class has no members or children, delete it and return
-  if (def->parentid<0 && section->NoChildren() && def->childid.empty()) {
+  if (!def->parent && section->NoChildren() && def->child.empty()) {
     root->DeleteChild(section);
     delete par;
     return;
   }
 
   // add children recursively
-  for (int i=0; i<(int)def->childid.size(); i++) {
-    Default(section, model->Defaults(def->childid[i]));
+  for (int i=0; i<(int)def->child.size(); i++) {
+    Default(section, def->child[i]);
   }
 
   // delete parent defaults if allocated here
-  if (def->parentid<0) {
+  if (!def->parent) {
     delete par;
   }
 }