Move MBP::HydroelasticContactInfoAndBodySpatialForces into internal (R…

…obotLocomotion#12953) MBP has a nested class that is stored in a cache entry. The hash logic associated with the drake::Value type doesn't work well with nested classes of templated classes (it introduces a "namespace" with a template parameter). This clutters up the console with warnings that don't help the end user at all. SO, for now, we'll pull the nested class out and put it in an internal namespace.
tehbelinda · Mar 27, 2020 · 875217a · 875217a
1 parent 65dcc78
commit 875217a
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Showing 2 changed files with 31 additions and 26 deletions.
diff --git a/multibody/plant/multibody_plant.cc b/multibody/plant/multibody_plant.cc
@@ -1186,7 +1186,7 @@ template <typename T>
 void MultibodyPlant<T>::CalcContactResultsContinuousHydroelastic(
     const systems::Context<T>& context,
     ContactResults<T>* contact_results) const {
-  const HydroelasticContactInfoAndBodySpatialForces&
+  const internal::HydroelasticContactInfoAndBodySpatialForces<T>&
       contact_info_and_spatial_body_forces =
           EvalHydroelasticContactForces(context);
   for (const HydroelasticContactInfo<T>& contact_info :
@@ -1415,16 +1415,17 @@ void MultibodyPlant<T>::CalcAndAddContactForcesByPenaltyMethod(
 template <>
 void MultibodyPlant<symbolic::Expression>::CalcHydroelasticContactForces(
     const Context<symbolic::Expression>&,
-    HydroelasticContactInfoAndBodySpatialForces*) const {
+    internal::HydroelasticContactInfoAndBodySpatialForces<
+        symbolic::Expression>*) const {
   throw std::logic_error(
       "This method doesn't support T = symbolic::Expression.");
 }
 
 template <typename T>
 void MultibodyPlant<T>::CalcHydroelasticContactForces(
     const Context<T>& context,
-    HydroelasticContactInfoAndBodySpatialForces* contact_info_and_body_forces)
-    const {
+    internal::HydroelasticContactInfoAndBodySpatialForces<T>*
+        contact_info_and_body_forces) const {
   DRAKE_DEMAND(contact_info_and_body_forces != nullptr);
 
   std::vector<SpatialForce<T>>& F_BBo_W_array =
@@ -2510,15 +2511,16 @@ void MultibodyPlant<T>::DeclareCacheEntries() {
             std::string("Hydroelastic contact info and body spatial forces."),
             [this]() {
               return AbstractValue::Make(
-                  HydroelasticContactInfoAndBodySpatialForces(
+                  internal::HydroelasticContactInfoAndBodySpatialForces<T>(
                       this->num_bodies()));
             },
             [this](const systems::ContextBase& context_base,
                    AbstractValue* cache_value) {
               auto& context = dynamic_cast<const Context<T>&>(context_base);
               auto& contact_info_and_body_spatial_forces_cache =
                   cache_value->get_mutable_value<
-                      HydroelasticContactInfoAndBodySpatialForces>();
+                      internal::HydroelasticContactInfoAndBodySpatialForces<
+                          T>>();
               this->CalcHydroelasticContactForces(
                   context, &contact_info_and_body_spatial_forces_cache);
             },

diff --git a/multibody/plant/multibody_plant.h b/multibody/plant/multibody_plant.h
@@ -46,6 +46,22 @@ struct HydroelasticFallbackCacheData {
   std::vector<geometry::PenetrationAsPointPair<T>> point_pairs;
 };
 
+// Structure used in the calculation of hydroelastic contact forces.
+template <typename T>
+struct HydroelasticContactInfoAndBodySpatialForces {
+  explicit HydroelasticContactInfoAndBodySpatialForces(int num_bodies) {
+    F_BBo_W_array.resize(num_bodies);
+  }
+
+  // Forces from hydroelastic contact applied to the origin of each body
+  // (indexed by BodyNodeIndex) in the MultibodyPlant.
+  std::vector<SpatialForce<T>> F_BBo_W_array;
+
+  // Information used for contact reporting collected through the evaluation
+  // of the hydroelastic model.
+  std::vector<HydroelasticContactInfo<T>> contact_info;
+};
+
 }  // namespace internal
 
 // TODO(amcastro-tri): Add a section on contact models in
@@ -3343,22 +3359,6 @@ class MultibodyPlant : public internal::MultibodyTreeSystem<T> {
   // Friend class to facilitate testing.
   friend class MultibodyPlantTester;
 
-  // Structure used in the calculation of hydroelastic contact forces (see
-  // method that follows).
-  struct HydroelasticContactInfoAndBodySpatialForces {
-    explicit HydroelasticContactInfoAndBodySpatialForces(int num_bodies) {
-      F_BBo_W_array.resize(num_bodies);
-    }
-
-    // Forces from hydroelastic contact applied to the origin of each body
-    // (indexed by BodyNodeIndex) in the MultibodyPlant.
-    std::vector<SpatialForce<T>> F_BBo_W_array;
-
-    // Information used for contact reporting collected through the evaluation
-    // of the hydroelastic model.
-    std::vector<HydroelasticContactInfo<T>> contact_info;
-  };
-
   // This struct stores in one single place all indexes related to
   // MultibodyPlant specific cache entries. These are initialized at Finalize()
   // when the plant declares its cache entries.
@@ -3775,14 +3775,16 @@ class MultibodyPlant : public internal::MultibodyTreeSystem<T> {
   // thrown.
   void CalcHydroelasticContactForces(
       const systems::Context<T>& context,
-      HydroelasticContactInfoAndBodySpatialForces* F_BBo_W_array) const;
+      internal::HydroelasticContactInfoAndBodySpatialForces<T>* F_BBo_W_array)
+      const;
 
   // Eval version of CalcHydroelasticContactForces().
-  const HydroelasticContactInfoAndBodySpatialForces&
+  const internal::HydroelasticContactInfoAndBodySpatialForces<T>&
   EvalHydroelasticContactForces(const systems::Context<T>& context) const {
     return this
         ->get_cache_entry(cache_indexes_.contact_info_and_body_spatial_forces)
-        .template Eval<HydroelasticContactInfoAndBodySpatialForces>(context);
+        .template Eval<
+            internal::HydroelasticContactInfoAndBodySpatialForces<T>>(context);
   }
 
   // Helper method to add the contribution of external actuation forces to the
@@ -4245,7 +4247,8 @@ MultibodyPlant<AutoDiffXd>::CalcPointPairPenetrations(
 template <>
 void MultibodyPlant<symbolic::Expression>::CalcHydroelasticContactForces(
     const systems::Context<symbolic::Expression>&,
-    HydroelasticContactInfoAndBodySpatialForces*) const;
+    internal::HydroelasticContactInfoAndBodySpatialForces<
+        symbolic::Expression>*) const;
 template <>
 void MultibodyPlant<symbolic::Expression>::
     CalcContactResultsContinuousHydroelastic(