Add AddFreeJoint and remove isfree from AddJoint.

PiperOrigin-RevId: 604597442
Change-Id: I2fe03cf0f9a59b425080cc5cc12b236fea9c020d

src/user/user_composite.cc

@@ -456,7 +456,7 @@ bool mjCComposite::MakeParticle(mjCModel* model, mjCBody* body, char* error, int
     // add slider joints if none defined
     if (!add[mjCOMPKIND_PARTICLE]) {
       for (int i=0; i<3; i++) {
-        mjCJoint* jnt = b->AddJoint(&defjoint[mjCOMPKIND_JOINT][0], false);
+        mjCJoint* jnt = b->AddJoint(&defjoint[mjCOMPKIND_JOINT][0]);
         jnt->def = body->def;
         jnt->type = mjJNT_SLIDE;
         mjuu_setvec(jnt->pos, 0, 0, 0);
@@ -468,7 +468,7 @@ bool mjCComposite::MakeParticle(mjCModel* model, mjCBody* body, char* error, int
     // add user-specified joints
     else {
       for (auto defjnt : defjoint[mjCOMPKIND_PARTICLE]) {
-        mjCJoint* jnt = b->AddJoint(&defjnt, false);
+        mjCJoint* jnt = b->AddJoint(&defjnt);
         jnt->def = body->def;
       }
     }

src/user/user_objects.cc

@@ -659,16 +659,25 @@ mjCFrame* mjCBody::AddFrame(mjCFrame* _frame) {
 
 
 
-// create new joint and add it to body
-//  _def==NULL means no defaults, unlike all others which inherit from body
-mjCJoint* mjCBody::AddJoint(mjCDef* _def, bool isfree) {
-  // create joint
-  mjCJoint* obj = new mjCJoint(model, _def ? _def : (isfree ? NULL : def));
+// create new free joint (no default inheritance) and add it to body
+mjCJoint* mjCBody::AddFreeJoint() {
+  // create free joint, don't inherit from defaults
+  mjCJoint* obj = new mjCJoint(model, NULL);
+  obj->type = mjJNT_FREE;
 
-  // set free type if specified
-  if (isfree) {
-    obj->type = mjJNT_FREE;
-  }
+  // set body pointer, add
+  obj->body = this;
+
+  joints.push_back(obj);
+  return obj;
+}
+
+
+
+// create new joint and add it to body
+mjCJoint* mjCBody::AddJoint(mjCDef* _def) {
+  // create joint
+  mjCJoint* obj = new mjCJoint(model, _def ? _def : def);
 
   // set body pointer, add
   obj->body = this;

src/user/user_objects.h

@@ -229,7 +229,8 @@ class mjCBody : public mjCBase {
   // API for adding objects to body
   mjCBody*    AddBody(mjCDef* = 0);
   mjCFrame*   AddFrame(mjCFrame* = 0);
-  mjCJoint*   AddJoint(mjCDef* = 0, bool isfree = false);
+  mjCJoint*   AddJoint(mjCDef* = 0);
+  mjCJoint*   AddFreeJoint();
   mjCGeom*    AddGeom(mjCDef* = 0);
   mjCSite*    AddSite(mjCDef* = 0);
   mjCCamera*  AddCamera(mjCDef* = 0);

src/xml/xml_native_reader.cc

@@ -3045,7 +3045,7 @@ void mjXReader::Body(XMLElement* section, mjCBody* pbody, mjCFrame* frame) {
       }
 
       // create free joint without defaults
-      mjCJoint* pjoint = pbody->AddJoint(NULL, true);
+      mjCJoint* pjoint = pbody->AddFreeJoint();
       pjoint->SetFrame(frame);
 
       // save defaults after creation, to make sure writing is ok