Update XML parsing to store asset path so that assets can be recovered and sent to external renderers

PiperOrigin-RevId: 567347908
Change-Id: I4d8e1abe35be3a67643ff925af709921280856f8

doc/includes/references.h

@@ -861,6 +861,7 @@ struct mjModel_ {
   int nuser_sensor;               // number of mjtNums in sensor_user
   int nnames;                     // number of chars in all names
   int nnames_map;                 // number of slots in the names hash map
+  int npaths;                     // number of chars in all paths
 
   // sizes set after mjModel construction (only affect mjData)
   int nM;                         // number of non-zeros in sparse inertia matrix
@@ -1045,6 +1046,7 @@ struct mjModel_ {
   int*      mesh_graphadr;        // graph data address; -1: no graph         (nmesh x 1)
   mjtNum*   mesh_pos;             // translation applied to asset vertices    (nmesh x 3)
   mjtNum*   mesh_quat;            // rotation applied to asset vertices       (nmesh x 4)
+  int*      mesh_assetpathadr;    // address of asset path for mesh; -1: none (nmesh x 1)
   float*    mesh_vert;            // vertex positions for all meshes          (nmeshvert x 3)
   float*    mesh_normal;          // normals for all meshes                   (nmeshnormal x 3)
   float*    mesh_texcoord;        // vertex texcoords for all meshes          (nmeshtexcoord x 2)
@@ -1251,6 +1253,9 @@ struct mjModel_ {
   int*      name_pluginadr;       // plugin instance name pointers            (nplugin x 1)
   char*     names;                // names of all objects, 0-terminated       (nnames x 1)
   int*      names_map;            // internal hash map of names               (nnames_map x 1)
+
+  // paths
+  char*     paths;                // paths to assets, 0-terminated            (npaths x 1)
 };
 typedef struct mjModel_ mjModel;
 struct mjResource_ {
@@ -1995,6 +2000,7 @@ struct mjvSceneState_ {
     int nwrap;
     int nsensor;
     int nnames;
+    int npaths;
     int nsensordata;
 
     mjOption opt;
@@ -2062,6 +2068,7 @@ struct mjvSceneState_ {
     int* mesh_bvhnum;
     int* mesh_texcoordadr;
     int* mesh_graphadr;
+    int* mesh_assetpathadr;
 
     int* skin_matid;
     int* skin_group;
@@ -2137,6 +2144,7 @@ struct mjvSceneState_ {
     int* name_tendonadr;
     int* name_actuatoradr;
     char* names;
+    char* paths;
   } model;
 
   // fields in mjData that are necessary to re-render a scene

include/mujoco/mjmodel.h

@@ -593,6 +593,7 @@ struct mjModel_ {
   int nuser_sensor;               // number of mjtNums in sensor_user
   int nnames;                     // number of chars in all names
   int nnames_map;                 // number of slots in the names hash map
+  int npaths;                     // number of chars in all paths
 
   // sizes set after mjModel construction (only affect mjData)
   int nM;                         // number of non-zeros in sparse inertia matrix
@@ -777,6 +778,7 @@ struct mjModel_ {
   int*      mesh_graphadr;        // graph data address; -1: no graph         (nmesh x 1)
   mjtNum*   mesh_pos;             // translation applied to asset vertices    (nmesh x 3)
   mjtNum*   mesh_quat;            // rotation applied to asset vertices       (nmesh x 4)
+  int*      mesh_assetpathadr;    // address of asset path for mesh; -1: none (nmesh x 1)
   float*    mesh_vert;            // vertex positions for all meshes          (nmeshvert x 3)
   float*    mesh_normal;          // normals for all meshes                   (nmeshnormal x 3)
   float*    mesh_texcoord;        // vertex texcoords for all meshes          (nmeshtexcoord x 2)
@@ -983,6 +985,9 @@ struct mjModel_ {
   int*      name_pluginadr;       // plugin instance name pointers            (nplugin x 1)
   char*     names;                // names of all objects, 0-terminated       (nnames x 1)
   int*      names_map;            // internal hash map of names               (nnames_map x 1)
+
+  // paths
+  char*     paths;                // paths to assets, 0-terminated            (npaths x 1)
 };
 typedef struct mjModel_ mjModel;
 

include/mujoco/mjvisualize.h

@@ -401,6 +401,7 @@ struct mjvSceneState_ {
     int nwrap;
     int nsensor;
     int nnames;
+    int npaths;
     int nsensordata;
 
     mjOption opt;
@@ -468,6 +469,7 @@ struct mjvSceneState_ {
     int* mesh_bvhnum;
     int* mesh_texcoordadr;
     int* mesh_graphadr;
+    int* mesh_assetpathadr;
 
     int* skin_matid;
     int* skin_group;
@@ -543,6 +545,7 @@ struct mjvSceneState_ {
     int* name_tendonadr;
     int* name_actuatoradr;
     char* names;
+    char* paths;
   } model;
 
   // fields in mjData that are necessary to re-render a scene

include/mujoco/mjxmacro.h

@@ -118,6 +118,7 @@
     X   ( nuser_actuator )     \
     X   ( nuser_sensor )       \
     XMJV( nnames )             \
+    XMJV( npaths )             \
     X   ( nnames_map )         \
     X   ( nM )                 \
     X   ( nD )                 \
@@ -132,6 +133,8 @@
     X   ( narena )             \
     X   ( nbuffer )
 
+    /* nbuffer needs to be the final field */
+
 
 // define symbols needed in MJMODEL_POINTERS (corresponding to number of columns)
 #define MJMODEL_POINTERS_PREAMBLE( m )      \
@@ -296,6 +299,7 @@
     XMJV( int,     mesh_graphadr,         nmesh,         1                    ) \
     X   ( mjtNum,  mesh_pos,              nmesh,         3                    ) \
     X   ( mjtNum,  mesh_quat,             nmesh,         4                    ) \
+    XMJV( int,     mesh_assetpathadr,     nmesh,         1                    ) \
     X   ( float,   mesh_vert,             nmeshvert,     3                    ) \
     X   ( float,   mesh_normal,           nmeshnormal,   3                    ) \
     X   ( float,   mesh_texcoord,         nmeshtexcoord, 2                    ) \
@@ -468,6 +472,7 @@
     X   ( int,     name_pluginadr,        nplugin,       1                    ) \
     XMJV( char,    names,                 nnames,        1                    ) \
     X   ( int,     names_map,             nnames_map,    1                    ) \
+    XMJV( char,    paths,                 npaths,        1                    ) \
 
 //-------------------------------- mjData ----------------------------------------------------------
 

introspect/structs.py

@@ -1070,6 +1070,11 @@ STRUCTS: Mapping[str, StructDecl] = dict([
                  type=ValueType(name='int'),
                  doc='number of slots in the names hash map',
              ),
+             StructFieldDecl(
+                 name='npaths',
+                 type=ValueType(name='int'),
+                 doc='number of chars in all paths',
+             ),
              StructFieldDecl(
                  name='nM',
                  type=ValueType(name='int'),
@@ -2118,6 +2123,13 @@ STRUCTS: Mapping[str, StructDecl] = dict([
                  ),
                  doc='rotation applied to asset vertices       (nmesh x 4)',
              ),
+             StructFieldDecl(
+                 name='mesh_assetpathadr',
+                 type=PointerType(
+                     inner_type=ValueType(name='int'),
+                 ),
+                 doc='address of asset path for mesh; -1: none (nmesh x 1)',
+             ),
              StructFieldDecl(
                  name='mesh_vert',
                  type=PointerType(
@@ -3322,6 +3334,13 @@ STRUCTS: Mapping[str, StructDecl] = dict([
                  ),
                  doc='internal hash map of names               (nnames_map x 1)',  # pylint: disable=line-too-long
              ),
+             StructFieldDecl(
+                 name='paths',
+                 type=PointerType(
+                     inner_type=ValueType(name='char'),
+                 ),
+                 doc='paths to assets, 0-terminated            (npaths x 1)',
+             ),
          ),
      )),
     ('mjThreadPool',
@@ -5554,6 +5573,11 @@ STRUCTS: Mapping[str, StructDecl] = dict([
                              type=ValueType(name='int'),
                              doc='',
                          ),
+                         StructFieldDecl(
+                             name='npaths',
+                             type=ValueType(name='int'),
+                             doc='',
+                         ),
                          StructFieldDecl(
                              name='nsensordata',
                              type=ValueType(name='int'),
@@ -5952,6 +5976,13 @@ STRUCTS: Mapping[str, StructDecl] = dict([
                              ),
                              doc='',
                          ),
+                         StructFieldDecl(
+                             name='mesh_assetpathadr',
+                             type=PointerType(
+                                 inner_type=ValueType(name='int'),
+                             ),
+                             doc='',
+                         ),
                          StructFieldDecl(
                              name='skin_matid',
                              type=PointerType(
@@ -6428,6 +6459,13 @@ STRUCTS: Mapping[str, StructDecl] = dict([
                              ),
                              doc='',
                          ),
+                         StructFieldDecl(
+                             name='paths',
+                             type=PointerType(
+                                 inner_type=ValueType(name='char'),
+                             ),
+                             doc='',
+                         ),
                      ),
                  ),
                  doc='',

python/mujoco/structs.cc

@@ -234,6 +234,7 @@ MjModelWrapper::MjWrapper(raw::MjModel* ptr)
       MJMODEL_POINTERS,
       text_data_bytes(ptr->text_data, ptr->ntextdata),
       names_bytes(ptr->names, ptr->nnames),
+      paths_bytes(ptr->paths, ptr->npaths),
       indexer_(ptr, owner_) {
   bool is_newly_inserted = false;
   {
@@ -255,6 +256,7 @@ MjModelWrapper::MjWrapper(MjModelWrapper&& other)
       MJMODEL_POINTERS,
       text_data_bytes(ptr_->text_data, ptr_->ntextdata),
       names_bytes(ptr_->names, ptr_->nnames),
+      paths_bytes(ptr_->paths, ptr_->npaths),
       indexer_(ptr_, owner_) {
   bool is_newly_inserted = false;
   {
@@ -1509,10 +1511,11 @@ This is useful for example when the MJB is not available as a file on disk.)"));
   MJMODEL_INTS
 #undef X
 
-#define X(dtype, var, dim0, dim1)                        \
+#define X(dtype, var, dim0, dim1)                             \
-  if constexpr (std::string_view(#var) != "text_data" &&     \
+  if constexpr (std::string_view(#var) != "text_data" &&      \
-                std::string_view(#var) != "names") { \
+                std::string_view(#var) != "names" &&          \
-    DefinePyArray(mjModel, #var, &MjModelWrapper::var);  \
+                std::string_view(#var) != "paths") {          \
+    DefinePyArray(mjModel, #var, &MjModelWrapper::var);       \
   }
   MJMODEL_POINTERS
 #undef X
@@ -1527,6 +1530,11 @@ This is useful for example when the MJB is not available as a file on disk.)"));
         // Return the full bytes array of concatenated names
         return m.names_bytes;
       });
+  mjModel.def_property_readonly(
+      "paths", [](const MjModelWrapper& m) -> const auto& {
+        // Return the full bytes array of concatenated paths
+        return m.paths_bytes;
+      });
 
 #define XGROUP(MjModelGroupedViews, field, nfield, FIELD_XMACROS)             \
   mjModel.def(                                                                \

python/mujoco/structs.h

@@ -477,6 +477,7 @@ class MjWrapper<raw::MjModel> : public WrapperBase<raw::MjModel> {
   // TODO(nimrod): Exclude text_data and names from the MJMODEL_POINTERS macro.
   pybind11::bytes text_data_bytes;
   pybind11::bytes names_bytes;
+  pybind11::bytes paths_bytes;
 
  protected:
   explicit MjWrapper(raw::MjModel* ptr);

src/engine/engine_io.c

@@ -450,7 +450,7 @@ mjModel* mj_makeModel(int nq, int nv, int nu, int na, int nbody, int nbvh, int n
                       int ntuple, int ntupledata, int nkey, int nmocap, int nplugin,
                       int npluginattr, int nuser_body, int nuser_jnt, int nuser_geom,
                       int nuser_site, int nuser_cam, int nuser_tendon, int nuser_actuator,
-                      int nuser_sensor, int nnames) {
+                      int nuser_sensor, int nnames, int npaths) {
   intptr_t offset = 0;
 
   // allocate mjModel
@@ -519,6 +519,7 @@ mjModel* mj_makeModel(int nq, int nv, int nu, int na, int nbody, int nbvh, int n
                      + nskin + nhfield + ntex + nmat + npair + nexclude + neq
                      + ntendon  + nu + nsensor + nnumeric + ntext + ntuple
                      + nkey + nplugin);
+  m->npaths = npaths;
 
 #define X(name)                                    \
   if ((m->name) < 0) {                             \
@@ -597,7 +598,7 @@ mjModel* mj_copyModel(mjModel* dest, const mjModel* src) {
                         src->ntuple, src->ntupledata, src->nkey, src->nmocap, src->nplugin,
                         src->npluginattr, src->nuser_body, src->nuser_jnt, src->nuser_geom,
                         src->nuser_site, src->nuser_cam, src->nuser_tendon, src->nuser_actuator,
-                        src->nuser_sensor, src->nnames);
+                        src->nuser_sensor, src->nnames, src->npaths);
   }
   if (!dest) {
     mjERROR("failed to make mjModel. Invalid sizes.");
@@ -762,7 +763,7 @@ mjModel* mj_loadModel(const char* filename, const mjVFS* vfs) {
                    ints[28], ints[29], ints[30], ints[31], ints[32], ints[33], ints[34],
                    ints[35], ints[36], ints[37], ints[38], ints[39], ints[40], ints[41],
                    ints[42], ints[43], ints[44], ints[45], ints[46], ints[47], ints[48],
-                   ints[49], ints[50], ints[51], ints[52]);
+                   ints[49], ints[50], ints[51], ints[52], ints[53]);
   if (!m || m->nbuffer != sizes[getnsize()-1]) {
     mju_closeResource(r);
     mju_warning("Corrupted model, wrong size parameters");
@@ -1791,7 +1792,8 @@ const char* mj_validateReferences(const mjModel* m) {
   X(name_numericadr,    nnumeric,      nnames       , 0                      ) \
   X(name_textadr,       ntext,         nnames       , 0                      ) \
   X(name_tupleadr,      ntuple,        nnames       , 0                      ) \
-  X(name_keyadr,        nkey,          nnames       , 0                      )
+  X(name_keyadr,        nkey,          nnames       , 0                      ) \
+  X(mesh_assetpathadr,  nmesh,         npaths       , 0                      )
 
   #define X(adrarray, nadrs, ntarget, numarray) {             \
     int *nums = (numarray);                                   \

src/engine/engine_io.h

@@ -62,7 +62,7 @@ mjModel* mj_makeModel(int nq, int nv, int nu, int na, int nbody, int nbvh, int n
                       int ntuple, int ntupledata, int nkey, int nmocap, int nplugin,
                       int npluginattr, int nuser_body, int nuser_jnt, int nuser_geom,
                       int nuser_site, int nuser_cam, int nuser_tendon, int nuser_actuator,
-                      int nuser_sensor, int nnames);
+                      int nuser_sensor, int nnames, int npaths);
 
 // copy mjModel; allocate new if dest is NULL
 MJAPI mjModel* mj_copyModel(mjModel* dest, const mjModel* src);

src/user/user_model.cc

@@ -275,6 +275,7 @@ void mjCModel::Clear(void) {
   ntupledata = 0;
   npluginattr = 0;
   nnames = 0;
+  npaths = 0;
   memory = -1;
   nstack = -1;
   nemax = 0;
@@ -1002,6 +1003,18 @@ void mjCModel::SetSizes(void) {
   for (int i=0; i<nkey; i++)     nnames += (int)keys[i]->name.length() + 1;
   for (int i=0; i<nplugin; i++)  nnames += (int)plugins[i]->name.length() + 1;
 
+  // npaths
+  npaths = 0;
+  for (int i=0; i<nmesh; i++) {
+    if (meshes[i]->file().empty()) {
+      continue;
+    }
+    npaths += (int)meshes[i]->file().length() + 1;
+  }
+  if (npaths == 0) {
+    npaths = 1;
+  }
+
   // nemax
   for (int i=0; i<neq; i++)
     if (equalities[i]->type==mjEQ_CONNECT) {
@@ -1197,7 +1210,6 @@ void mjCModel::LengthRange(mjModel* m, mjData* data) {
 }
 
 
-
 // process names from one list: concatenate, compute addresses
 template <class T>
 static int namelist(vector<T*>& list, int adr, int* name_adr, char* names, int* map) {
@@ -1313,6 +1325,30 @@ void mjCModel::CopyNames(mjModel* m) {
 }
 
 
+void mjCModel::CopyPaths(mjModel* m) {
+  // start with 0 address.
+  size_t adr = 0;
+  m->paths[0] = 0;
+
+  for (unsigned int i=0; i<meshes.size(); i++) {
+    if (meshes[i]->file().empty()) {
+      m->mesh_assetpathadr[i] = -1;
+      continue;
+    }
+    m->mesh_assetpathadr[i] = adr;
+
+    // copy path
+    size_t path_size = meshes[i]->file().size();
+    memcpy(m->paths+adr, meshes[i]->file().c_str(), path_size);
+    adr += path_size;
+
+    // append 0
+    m->paths[adr] = 0;
+    adr++;
+  }
+}
+
+
 
 // copy objects inside kinematic tree
 void mjCModel::CopyTree(mjModel* m) {
@@ -2703,7 +2739,7 @@ void mjCModel::TryCompile(mjModel*& m, mjData*& d, const mjVFS* vfs) {
                    nnumeric, nnumericdata, ntext, ntextdata,
                    ntuple, ntupledata, nkey, nmocap, nplugin, npluginattr,
                    nuser_body, nuser_jnt, nuser_geom, nuser_site, nuser_cam,
-                   nuser_tendon, nuser_actuator, nuser_sensor, nnames);
+                   nuser_tendon, nuser_actuator, nuser_sensor, nnames, npaths);
   if (!m) {
     throw mjCError(0, "could not create mjModel");
   }
@@ -2712,6 +2748,7 @@ void mjCModel::TryCompile(mjModel*& m, mjData*& d, const mjVFS* vfs) {
   m->opt = option;
   m->vis = visual;
   CopyNames(m);
+  CopyPaths(m);
   CopyTree(m);
 
   // assign plugin slots and copy plugin config attributes
@@ -2918,7 +2955,8 @@ bool mjCModel::CopyBack(const mjModel* m) {
       neq!=m->neq || ntendon!=m->ntendon || nwrap!=m->nwrap || nsensor!=m->nsensor ||
       nnumeric!=m->nnumeric || nnumericdata!=m->nnumericdata || ntext!=m->ntext ||
       ntextdata!=m->ntextdata || nnames!=m->nnames || nM!=m->nM || nD!=m->nD ||
-      nB!=m->nB || nemax!=m->nemax || nconmax!=m->nconmax || njmax!=m->njmax) {
+      nB!=m->nB || nemax!=m->nemax || nconmax!=m->nconmax || njmax!=m->njmax ||
+      npaths!=m->npaths) {
     errInfo = mjCError(0, "incompatible models in CopyBack");
     return false;
   }

src/user/user_model.h

@@ -182,6 +182,7 @@ class mjCModel {
   void AutoSpringDamper(mjModel*);// automatic stiffness and damping computation
   void LengthRange(mjModel*, mjData*); // compute actuator lengthrange
   void CopyNames(mjModel*);       // copy names, compute name addresses
+  void CopyPaths(mjModel*);       // copy paths, compute path addresses
   void CopyObjects(mjModel*);     // copy objects outside kinematic tree
   void CopyTree(mjModel*);        // copy objects inside kinematic tree
 
@@ -235,6 +236,7 @@ class mjCModel {
   int ntupledata;                 // number of objects in all tuple fields
   int npluginattr;                // number of chars in all plugin config attributes
   int nnames;                     // number of chars in all names
+  int npaths;                     // number of chars in all paths
   int nM;                         // number of non-zeros in sparse inertia matrix
   int nD;                         // number of non-zeros in sparse dof-dof matrix
   int nB;                         // number of non-zeros in sparse body-dof matrix

src/xml/xml.cc

@@ -321,6 +321,7 @@ mjCModel* mjParseXML(const char* filename, const mjVFS* vfs, char* error, int er
       // this is separate from the Parser to allow multiple URDFs to be loaded.
       model->strippath = true;
       model->fusestatic = true;
+      model->discardvisual = true;
 
       parser.SetModel(model);
       parser.Parse(root);

src/xml/xml_urdf.cc

@@ -87,9 +87,6 @@ void mjXURDF::Parse(
   int id_parent, id_child;
   urPrefix = prefix;
 
-  // set compiler defaults suitable for URDF
-  model->discardvisual = true;
-
   // parse MuJoCo sections (not part of URDF)
   XMLElement* mjc = FindSubElem(root, "mujoco");
   if (mjc) {

test/user/user_mesh_test.cc

@@ -375,6 +375,9 @@ TEST_F(MjCMeshTest, SaveMeshOnce) {
   const std::string xml_path = GetTestDataFilePath(kCubePath);
   std::array<char, 1024> error;
   mjModel* model = mj_loadXML(xml_path.c_str(), 0, error.data(), error.size());
+  // Confirm the mesh file is loaded and stored in paths
+  EXPECT_EQ(
+      std::string(&model->paths[model->mesh_assetpathadr[0]]), "cube.obj");
   std::string saved_xml = SaveAndReadXml(model);
   EXPECT_THAT(saved_xml, Not(testing::HasSubstr("vertex")));
   mj_deleteModel(model);

unity/Runtime/Bindings/MjBindings.cs

@@ -5095,6 +5095,7 @@ public unsafe struct mjModel_ {
   public int nuser_sensor;
   public int nnames;
   public int nnames_map;
+  public int npaths;
   public int nM;
   public int nD;
   public int nB;
@@ -5249,6 +5250,7 @@ public unsafe struct mjModel_ {
   public int* mesh_graphadr;
   public double* mesh_pos;
   public double* mesh_quat;
+  public int* mesh_assetpathadr;
   public float* mesh_vert;
   public float* mesh_normal;
   public float* mesh_texcoord;
@@ -5421,6 +5423,7 @@ public unsafe struct mjModel_ {
   public int* name_pluginadr;
   public char* names;
   public int* names_map;
+  public char* paths;
 }
 
 [StructLayout(LayoutKind.Sequential)]
@@ -5944,6 +5947,7 @@ public unsafe struct model {
   public int nwrap;
   public int nsensor;
   public int nnames;
+  public int npaths;
   public int nsensordata;
   public mjOption_ opt;
   public mjVisual_ vis;
@@ -6002,6 +6006,7 @@ public unsafe struct model {
   public int* mesh_bvhnum;
   public int* mesh_texcoordadr;
   public int* mesh_graphadr;
+  public int* mesh_assetpathadr;
   public int* skin_matid;
   public int* skin_group;
   public float* skin_rgba;
@@ -6070,6 +6075,7 @@ public unsafe struct model {
   public int* name_tendonadr;
   public int* name_actuatoradr;
   public char* names;
+  public char* paths;
 }
 
 [StructLayout(LayoutKind.Sequential)]