When migrating plugins from Gazebo-classic to Gazebo, developers will notice that the C++ APIs for both simulators are quite different. Be sure to check the plugin migration tutorial to get a high-level view of the architecture differences before using this guide.
This tutorial is meant to serve as a reference guide for developers migrating functions from the gazebo::phyiscs::Actor class.
If you're trying to use some API which doesn't have an equivalent on Gazebo yet, feel free to ticket an issue.
Actor API
Gazebo-classic's gazebo::physics::Actor provides lots of functionality, which can be divided in these categories:
- Properties: Setting / getting properties
- Example: Actor::GetName / Actor::SetName
- Read family: Getting children and parent
- Example: Actor::GetParentModel
- Write family: Adding children, changing parent
- Example: Actor::RemoveChildren
- Lifecycle: Functions to control the actor's lifecycle
- Example: Actor::Init
- Others: Functions that don't fit any of the categories above
- Example: Actor::PlaceOnEntity
You'll find the Gazebo APIs below on the following headers:
It's worth remembering that most of this functionality can be performed using the EntityComponentManager directly.
As an example the Actor::Pose() is a convienient function for querying the Pose component from the EntityComponentManager, i.e.
The functions presented in the sections below exist for convenience and readability. The items marked as TODO means that the equivalent API is not implemented yet in Gazebo.
Properties
Most of Gazebo-classic's Actor API is related to setting and getting properties that are done via the Entity-Component-System by setting components (properties) into entities such as actors. Note that a number of the public APIs in Classic are inherited from the base Model / Entity class and they may not have equivalents in Gazebo.
| Classic | Gazebo |
|---|---|
| AddType | ecm.CreateComponent<Type>(entity, Type()) |
| AlignBvh | TODO |
| BoundingBox | TODO |
| CollisionBoundingBox | TODO |
| CustomTrajectory | see SetCustomTrajectory |
| DirtyPose | Not supported |
| FillMsg | TODO |
| GetAutoDisable | TODO |
| GetId | gz::sim::Model::Entity |
| GetName | gz::sim::Actor::Name |
| GetPluginCount | TODO |
| GetSaveable | Not supported |
| GetScopedName | gz::sim::scopedName |
| GetSDF | TODO |
| GetSDFDom | TODO |
| GetSelfCollide | TODO |
| GetType | gz::sim::entityType |
| GetWorldEnergy | TODO |
| GetWorldEnergyKinetic | TODO |
| GetWorldEnergyPotential | TODO |
| HasType | gazebo::components::Link::typeId == entityTypeId(entity, ecm) |
| InitialRelativePose | TODO |
| IsActive | TODO |
| IsCanonicalLink | Not applicable. See link API |
| IsSelected | Selection is client-specific, not porting |
| IsStatic | TODO |
| Mesh | TODO |
| Play | TODO |
| PluginInfo | TODO |
| TODO | |
| ProcessMsg | TODO |
| RelativeAngularAccel | TODO |
| RelativeAngularVel | TODO |
| RelativeLinearAccel | TODO |
| RelativeLinearVel | TODO |
| RelativePose | gz::sim::Actor::Pose |
| Scale | TODO |
| ScriptTime | gz::sim::Actor::AnimationTime |
| SDFPoseRelativeToParent | gz::sim::Actor::Pose |
| SDFSemanticPose | gz::sim::Actor::Pose |
| SensorScopedName | TODO |
| SetAngularVel | TODO |
| SetAnimation | use gz::sim::Actor::SetTrajectoryPose |
| SetAutoDisable | TODO |
| SetCollideMode | TODO |
| SetCustomTrajectory | use gz::sim::Actor::SetTrajectoryPose, SetAnimationTime, and SetAnimationName to achieve similar result. |
| SetEnabled | TODO |
| SetGravityMode | TODO |
| SetInitialRelativePose | TODO |
| SetJointAnimation | Not supported |
| SetJointPosition | Not supported |
| SetJointPositions | Not supported |
| SetLaserRetro | TODO |
| SetLinearVel | TODO |
| SetLinkWorldPose | TODO |
| SetName | TODO |
| SetRelativePose | TODO |
| SetSaveable | Not supported |
| SetScale | TODO |
| SetScriptTime | gz::sim::Actor::SetAnimationTime |
| SetSelected | Selection is client-specific, not porting |
| SetSelfCollide | TODO |
| SetState | TODO |
| SetStatic | TODO |
| SetWindMode | TODO |
| SetWorldPose | TODO |
| SetWorldTwist | TODO |
| SkeletonAnimations | TODO |
| Stop | TODO |
| StopAnimation | use gz::sim::Actor::SetTrajectoryPose |
| TypeStr | gz::sim::entityTypeStr |
| UnscaledSDF | TODO |
| UpdateParamenters | TODO |
| URI | TODO |
| WindMode | TODO |
| WorldAngularAccel | TODO |
| WorldAngularVel | TODO |
| WorldLinearAccel | TODO |
| WorldLinearVel | TODO |
| WorldPose | gz::sim::Actor::WorldPose |
Read family
These APIs deal with reading information related to child / parent relationships.
The main difference in these APIs across Gazebo generations is that on classic, they deal with shared pointers to entities, while on Gazebo, they deal with entity IDs.
| Classic | Gazebo |
|---|---|
| GetByName | TODO |
| GetChild | TODO |
| GetChildCollision | TODO |
| GetChildCount | TODO |
| GetChildLink | TODO |
| GetGripper | Not supported |
| GetGripperCount | Not supported |
| GetJoint | Not supported |
| GetJointCount | Not supported |
| GetJoints | Not supported |
| GetLink | TODO |
| GetLinks | TODO |
| GetParent | gz::sim::EntiyComponentManager::ParentEntity |
| GetParentId | gz::sim::EntiyComponentManager::ParentEntity |
| GetParentModel | gz::sim::EntiyComponentManager::ParentEntity |
| GetSensorCount | TODO |
| GetWorld | const gz::sim::worldEntity |
| NestedModel | TODO |
| NestedModels | TODO |
Write family
These functions deal with modifying the entity tree, attaching children to new parents. Note that APIs for changing an Actor's entity tree structure are currently not implemented yet.
| Classic | Gazebo |
|---|---|
| AddChild | TODO |
| AttachStaticModel | TODO |
| DetachStaticModel | TODO |
| RemoveChild | TODO |
| RemoveChildren | TODO |
| RemoveJoint | TODO |
| SetCanonicalLink | TODO |
| SetParent | TODO |
| SetWorld | TODO |
Lifecycle
These functions aren't related to the state of a actor, but perform some processing related to the actor's lifecycle, like initializing, updating or terminating it.
| Classic | Gazebo |
|---|---|
| Fini | N/A |
| Init | N/A |
| Load | gz::sim::SdfEntityCreator::CreateEntities |
| LoadJoints | gz::sim::SdfEntityCreator::CreateEntities |
| LoadPlugins | TODO |
| Reset | TODO |
| ResetCustomTrajectory | TODO |
| ResetPhysicsStates | TODO |
| Update | Entities are updated by systems |
Others
Miscelaneous functions that don't fit the other categories. Most of them involve logic that should be performed from within a system.
| Classic | Gazebo |
|---|---|
| GetJointController | Use this system: gz::sim::systems::JointController |
| GetNearestEntityBelow | Requires a system |
| PlaceOnEntity | Requires a system |
| PlaceOnNearestEntityBelow | Requires a system |