Add compiler C API for mjmSite.

PiperOrigin-RevId: 604573450
Change-Id: I6ba7fcece0942ddc0d109413ba5684b2df3fab96

src/user/CMakeLists.txt

@@ -13,6 +13,8 @@
 # limitations under the License.
 
 set(MUJOCO_USER_SRCS
+    user_api.cc
+    user_api.h
     user_composite.cc
     user_composite.h
     user_flexcomp.cc

src/user/user_api.cc

@@ -0,0 +1,110 @@
+// Copyright 2021 DeepMind Technologies Limited
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "user/user_api.h"
+#include <string>
+#include <vector>
+
+#include <mujoco/mujoco.h>
+#include "user/user_model.h"
+#include "user/user_objects.h"
+
+
+
+// create model
+void* mjm_createModel() {
+  mjCModel* modelC = new mjCModel();
+  return modelC;
+}
+
+
+
+// delete model
+void mjm_deleteModel(void* model) {
+  mjCModel* modelC = static_cast<mjCModel*>(model);
+  delete modelC;
+}
+
+
+
+// add body to body
+void* mjm_addBody(void* body, void* def) {
+  mjCDef* defC = static_cast<mjCDef*>(def);
+  mjCBody* bodyC = static_cast<mjCBody*>(body);
+  return bodyC->AddBody(defC);
+}
+
+
+
+// add site to body
+mjmSite* mjm_addSite(void* body, void* def) {
+  mjCDef* defC = static_cast<mjCDef*>(def);
+  mjCSite* siteC = static_cast<mjCBody*>(body)->AddSite(defC);
+  return &siteC->spec;
+}
+
+
+
+// get object of given type
+void* mjm_findObject(void* model, mjtObj type, const char* name) {
+  mjCModel* modelC = static_cast<mjCModel*>(model);
+  return modelC->FindObject(type, std::string(name));
+}
+
+
+
+// set parent frame of dest
+void mjm_setFrame(void* dest, void* frame) {
+  mjCFrame* frameC = static_cast<mjCFrame*>(frame);
+  mjCBase* baseC = static_cast<mjCBase*>(dest);
+  baseC->SetFrame(frameC);
+}
+
+
+
+// set string
+void mjm_setString(mjString dest, const char* text) {
+  std::string* str = reinterpret_cast<std::string*>(dest);
+  *str = std::string(text);
+}
+
+
+
+// set double array
+void mjm_setDouble(mjDouble dest, const double* array, int size) {
+  std::vector<double>* v = reinterpret_cast<std::vector<double>*>(dest);
+  v->assign(size, 0.0);
+  for (int i = 0; i < size; ++i) {
+    (*v)[i] = array[i];
+  }
+}
+
+
+
+// get string
+const char* mjm_getString(const mjString source) {
+  std::string* str = reinterpret_cast<std::string*>(source);
+  return str->c_str();
+}
+
+
+
+// get double array
+const double* mjm_getDouble(const mjDouble source, int* size) {
+  std::vector<double>* v = reinterpret_cast<std::vector<double>*>(source);
+  if (size) {
+    *size = v->size();
+  }
+  return v->data();
+}

src/user/user_api.h

@@ -0,0 +1,92 @@
+// Copyright 2021 DeepMind Technologies Limited
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef MUJOCO_SRC_USER_USER_API_H_
+#define MUJOCO_SRC_USER_USER_API_H_
+
+#include <mujoco/mjexport.h>
+#include <mujoco/mjmodel.h>
+
+typedef struct _mjString* mjString;
+typedef struct _mjDouble* mjDouble;
+typedef struct _mjElement* mjElement;
+
+
+
+//---------------------------------- Public structs ------------------------------------------------
+typedef struct _mjmOrientation {
+  double axisangle[4];            // rotation axis and angle
+  double xyaxes[6];               // x and y axes
+  double zaxis[3];                // z axis (use minimal rotation)
+  double euler[3];                // euler rotations
+  double fullinertia[6];          // non-axis-aligned inertia matrix
+} mjmOrientation;
+
+typedef struct _mjmSite {
+  mjElement element;              // only used internally, do not modify
+  mjString name;                  // name
+  mjString classname;             // class name
+  mjString info;                  // message appended to errors
+  mjtGeom type;                   // geom type for rendering
+  int group;                      // group id, used for visualization
+  double size[3];                 // geom size for rendering
+  double pos[3];                  // position
+  double quat[4];                 // orientation
+  mjString material;              // name of material for rendering
+  mjDouble userdata;              // user data
+  float rgba[4];                  // rgba when material is omitted
+  double fromto[6];               // alternative for capsule, cylinder, box, ellipsoid
+  mjmOrientation alt;             // alternative orientation specification
+} mjmSite;
+
+//---------------------------------- Public API ----------------------------------------------------
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Create model.
+MJAPI void* mjm_createModel();
+
+// Delete model.
+MJAPI void mjm_deleteModel(void* model);
+
+// Add body to body.
+MJAPI void* mjm_addBody(void* body, void* def);
+
+// Add site to body.
+MJAPI mjmSite* mjm_addSite(void* body, void* def);
+
+// Find object of given type.
+MJAPI void* mjm_findObject(void* model, mjtObj type, const char* name);
+
+// Copy input text to destination string.
+MJAPI void mjm_setString(mjString dest, const char* text);
+
+// Copy input array to destination vector.
+MJAPI void mjm_setDouble(mjDouble dest, const double* array, int size);
+
+// Get const pointer to mjString data.
+MJAPI const char* mjm_getString(mjString source);
+
+// Get const pointer to mjDouble data and its size.
+MJAPI const double* mjm_getDouble(mjDouble source, int* size);
+
+// Set frame.
+MJAPI void mjm_setFrame(void* dest, void* frame);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // MUJOCO_SRC_USER_USER_API_H_

src/user/user_objects.cc

@@ -43,6 +43,7 @@
 #include "engine/engine_util_solve.h"
 #include "engine/engine_util_spatial.h"
 #include "engine/engine_vfs.h"
+#include "user/user_api.h"
 #include "user/user_model.h"
 #include "user/user_util.h"
 
@@ -1931,25 +1932,35 @@ mjCSite::mjCSite(mjCModel* _model, mjCDef* _def) {
   spec.group = 0;
   mjuu_setvec(spec.quat, 1, 0, 0, 0);
   mjuu_setvec(spec.pos, 0, 0, 0);
-  spec.material = nullptr;
+  spec_material_.clear();
   spec.rgba[0] = spec.rgba[1] = spec.rgba[2] = 0.5f;
   spec.rgba[3] = 1.0f;
   spec.fromto[0] = mjNAN;
-  spec.userdata = nullptr;
+  spec_userdata_.clear();
+  spec.alt.axisangle[0] = spec.alt.xyaxes[0] = spec.alt.zaxis[0] =
+      spec.alt.euler[0] = spec.alt.fullinertia[0] = mjNAN;
 
   // clear internal variables
   body = 0;
   matid = -1;
 
-  // initialize private attributes
-  CopyFromSpec();
-
   // reset to default if given
   if (_def) {
     _def->site.CopyFromSpec();
     *this = _def->site;
   }
 
+  // point to local, not to default
+  spec.element = (mjElement)this;
+  spec.name = (mjString)&name;
+  spec.info = (mjString)&info;
+  spec.classname = (mjString)&classname;
+  spec.material = (mjString)&spec_material_;
+  spec.userdata = (mjDouble)&spec_userdata_;
+
+  // initialize private attributes in case object won't be compiled
+  CopyFromSpec();
+
   // set model, def
   model = _model;
   def = (_def ? _def : (_model ? _model->defaults[0] : 0));
@@ -1961,8 +1972,13 @@ void mjCSite::CopyFromSpec() {
   *static_cast<mjmSite*>(this) = spec;
   userdata_ = spec_userdata_;
   material_ = spec_material_;
-  userdata = userdata_.data();
-  material = material_.data();
+  userdata = (mjDouble)&userdata_;
+  material = (mjString)&material_;
+  mju_copy4(alt_.axisangle, alt.axisangle);
+  mju_copy(alt_.xyaxes, alt.xyaxes, 6);
+  mju_copy3(alt_.zaxis, alt.zaxis);
+  mju_copy3(alt_.euler, alt.euler);
+  mju_copy(alt_.fullinertia, alt.fullinertia, 6);
 }
 
 
@@ -2034,7 +2050,7 @@ void mjCSite::Compile(void) {
 
   // alternative orientation
   else {
-    const char* err = alt.Set(quat, 0, model->degree, model->euler);
+    const char* err = alt_.Set(quat, 0, model->degree, model->euler);
     if (err) {
       throw mjCError(this, "orientation specification error '%s' in site %d", err, id);
     }

src/user/user_objects.h

@@ -24,11 +24,10 @@
 #include <utility>
 #include <vector>
 
-#include "lodepng.h"
-
 #include <mujoco/mjtnum.h>
 #include <mujoco/mjmodel.h>
 #include <mujoco/mjplugin.h>
+#include "user/user_api.h"
 
 // forward declarations of all mjC/X classes
 class mjCError;
@@ -109,18 +108,12 @@ class [[nodiscard]] mjCError {
 
 
 // alternative specifications of frame orientation
-class mjCAlternative {
+class mjCAlternative : public mjmOrientation {
  public:
   mjCAlternative();                               // constuctor
   const char* Set(double* quat, double* inertia,  // set frame quat and diag. inertia
                   bool degree,                    //  angle format: degree/radian
                   const char* sequence);          //  euler sequence format: "xyz"
-
-  double axisangle[4];            // rotation axis and angle
-  double xyaxes[6];               // x and y axes
-  double zaxis[3];                // z axis (use minimal rotation)
-  double euler[3];                // euler rotations
-  double fullinertia[6];          // non-axis-aligned inertia matrix
 };
 
 
@@ -458,19 +451,6 @@ class mjCGeom : public mjCBase {
 //------------------------- class mjCSite ----------------------------------------------------------
 // Describes a site on a body
 
-typedef struct _mjmSite {
-  mjtGeom type;                   // geom type for rendering
-  int group;                      // group id, used for visualization
-  double size[3];                 // geom size for rendering
-  double pos[3];                  // position
-  double quat[4];                 // orientation
-  char* material;                 // name of material for rendering
-  double* userdata;               // user data
-  float rgba[4];                  // rgba when material is omitted
-  double fromto[6];               // alternative for capsule, cylinder, box, ellipsoid
-  mjCAlternative alt;             // alternative orientation specification
-} mjmSite;
-
 class mjCSite : public mjCBase, private mjmSite {
   friend class mjCDef;
   friend class mjCBody;
@@ -481,30 +461,30 @@ class mjCSite : public mjCBase, private mjmSite {
  public:
   mjmSite spec;                   // variables set by user
 
-  void set_material(std::string _material) {
-    spec_material_ = _material;
-    spec.material = spec_material_.data();
-  }
-  void set_userdata(std::vector<double> _userdata) {
-    spec_userdata_ = _userdata;
-    spec.userdata = spec_userdata_.data();
-  }
-  std::vector<double>& get_userdata() { return userdata_; }
-  std::string& get_material() { return material_; }
+  // use strings from mjCBase rather than mjStrings from mjmSite
+  using mjCBase::name;
+  using mjCBase::classname;
+  using mjCBase::info;
+
+  // used by mjXWriter and mjCModel
+  const std::vector<double>& get_userdata() { return userdata_; }
+  const std::string& get_material() { return material_; }
 
-  // variables computed by 'compile' and 'mjCBody::addSite'
  private:
   mjCSite(mjCModel* = 0, mjCDef* = 0);    // constructor
   void Compile(void);                     // compiler
   void CopyFromSpec();                    // copy spec into attributes
 
+  mjCAlternative alt_;
+  mjCAlternative spec_alt_;
+
   // variable-size data
   std::string material_;
   std::vector<double> userdata_;
-
   std::string spec_material_;
   std::vector<double> spec_userdata_;
 
+  // variables computed by 'compile' and 'mjCBody::addSite'
   mjCBody* body;                  // site's body
   int matid;                      // material id for rendering
 };