Merge pull request #2447 from gazebosim/merge_6_7_20240617

Merge 6 -> 7

include/gz/sim/components/Gravity.hh

@@ -36,6 +36,11 @@ namespace components
   /// \brief Store the gravity acceleration.
   using Gravity = Component<math::Vector3d, class GravityTag>;
   GZ_SIM_REGISTER_COMPONENT("gz_sim_components.Gravity", Gravity)
+
+  /// \brief Store the gravity acceleration.
+  using GravityEnabled = Component<bool, class GravityEnabledTag>;
+  GZ_SIM_REGISTER_COMPONENT(
+      "gz_sim_components.GravityEnabled", GravityEnabled)
 }
 }
 }

src/SdfEntityCreator.cc

@@ -618,6 +618,13 @@ Entity SdfEntityCreator::CreateEntities(const sdf::Link *_link)
         linkEntity, components::WindMode(_link->EnableWind()));
   }
 
+  if (!_link->EnableGravity())
+  {
+    // If disable gravity, create a GravityEnabled component to the entity
+    this->dataPtr->ecm->CreateComponent(
+        linkEntity, components::GravityEnabled(false));
+  }
+
   // Visuals
   for (uint64_t visualIndex = 0; visualIndex < _link->VisualCount();
       ++visualIndex)

src/systems/physics/Physics.cc

@@ -1306,6 +1306,15 @@ void PhysicsPrivate::CreateLinkEntities(const EntityComponentManager &_ecm,
           link.SetInertial(inertial->Data());
         }
 
+        // get link gravity
+        const components::GravityEnabled *gravityEnabled =
+            _ecm.Component<components::GravityEnabled>(_entity);
+        if (nullptr != gravityEnabled)
+        {
+          // gravityEnabled set in SdfEntityCreator::CreateEntities()
+          link.SetEnableGravity(gravityEnabled->Data());
+        }
+
         auto constructLinkFeature =
           this->entityModelMap.EntityCast<ConstructSdfLinkFeatureList>(
             _parent->Data());