Upgrade UrdfRobot, CoreUtils, SimulationController plugins

[RachithP]

• Migrate UrdfRobot plugin to support Unreal Engine 5
  • Add new pendulum urdf robot
  • Stabilize fetch robot
  • Update example application - open loop control of fetch robot
• Add new InputActionComponent to support every pawn to add it's own set of keyboard input mappings
• Add new StandaloneComponent that simplifies usage of custom components such as ActorHitEventComponent
• Add new ClassRegistrationUtils functionality to simplify creating different agent types during runtime

[mikeroberts3000]

Some clean-up and interface refinements to do but otherwise this PR is looking very good. Comment here when you think all items are addressed and it is ready to review again.

[mikeroberts3000]

I've decided that the rules and conventions around CreateDefaultSubcomponent vs NewComponent, SetupAttachment vs no SetupAttachment, and RegisterComponent vs no RegisterComponent are too confusing. I propose to add the following functions to Unreal.h, and to use them throughout the code where appropriate.

template <typename TComponent>
TComponent* Unreal::createComponentInsideOwnerConstructor(const std::string& name, AActor* parent)
{
    // CreateDefaultSubobject is required when inside the constructor of the owner AActor (either directly or indirectly via
    // the constructor of a child component). SetRootComponent is required to attach the newly created root component to its
    // owner AActor.
    SP_ASSERT(parent);
    TComponent* component = CreateDefaultSubobject<TComponent>(Unreal::toFName(name));
    SP_ASSERT(component);
    parent->SetRootComponent(component);
}

template <typename TComponent>
TComponent* Unreal::createComponentInsideOwnerConstructor(const std::string& name, UActorComponent* parent)
{
    // CreateDefaultSubobject is required when inside the constructor of the owner AActor (either directly or indirectly via
    // the constructor of a child component). SetupAttachment is required to connect the newly created component to its
    // parent component.
    SP_ASSERT(parent);
    TComponent* component = CreateDefaultSubobject<TComponent>(Unreal::toFName(name));
    SP_ASSERT(component);
    component->SetupAttachment(parent);
}

template <typename TComponent>
TComponent* Unreal::createComponentOutsideOwnerConstructor(const std::string& name, AActor* parent)
{
    // NewObject and RegisterComponent are required when outside the constructor of the owner AActor (either directly or
    // indirectly via the constructor of a child component). SetRootComponent is required to attach the newly created root
    // component to its owner AActor. The Unreal codebase usually calls SetRootComponent before calling RegisterComponent
    // so we follow the same convention convention here.
    TComponent* component = NewObject<TComponent>(parent, Unreal::toFName(name));
    SP_ASSERT(component);
    parent->SetRootComponent(component);
    component->RegisterComponent();
}

template <typename TComponent>
TComponent* Unreal::createComponentOutsideOwnerConstructor(const std::string& name, UActorComponent* parent)
{
    // NewObject and RegisterComponent are required when outside the constructor of the owner AActor (either directly or
    // indirectly via the constructor of a child component). SetupAttachment is required to attach the newly created
    // component to its parent UActorComponent. The Unreal codebase usually calls SetupAttachment before calling
    // RegisterComponent so we follow the same convention convention here.
    SP_ASSERT(parent);
    TComponent* component = NewObject<TComponent>(parent, Unreal::toFName(name));
    SP_ASSERT(component);
    component->SetupAttachment(parent);
    component->RegisterComponent();
}

Does the behavior of each function look correct to you?

[RachithP]

I've decided that the rules and conventions around CreateDefaultSubcomponent vs NewComponent, SetupAttachment vs no SetupAttachment, and RegisterComponent vs no RegisterComponent are too confusing. I propose to add the following functions to Unreal.h, and to use them throughout the code where appropriate.

template <typename TComponent>
TComponent* Unreal::createComponentInsideOwnerConstructor(const std::string& name, AActor* parent)
{
    // CreateDefaultSubobject is required when inside the constructor of the owner AActor (either directly or indirectly via
    // the constructor of a child component). SetRootComponent is required to attach the newly created root component to its
    // owner AActor.
    SP_ASSERT(parent);
    TComponent* component = CreateDefaultSubobject<TComponent>(Unreal::toFName(name));
    SP_ASSERT(component);
    parent->SetRootComponent(component);
}

template <typename TComponent>
TComponent* Unreal::createComponentInsideOwnerConstructor(const std::string& name, UActorComponent* parent)
{
    // CreateDefaultSubobject is required when inside the constructor of the owner AActor (either directly or indirectly via
    // the constructor of a child component). SetupAttachment is required to connect the newly created component to its
    // parent component.
    SP_ASSERT(parent);
    TComponent* component = CreateDefaultSubobject<TComponent>(Unreal::toFName(name));
    SP_ASSERT(component);
    component->SetupAttachment(parent);
}

template <typename TComponent>
TComponent* Unreal::createComponentOutsideOwnerConstructor(const std::string& name, AActor* parent)
{
    // NewObject and RegisterComponent are required when outside the constructor of the owner AActor (either directly or
    // indirectly via the constructor of a child component). SetRootComponent is required to attach the newly created root
    // component to its owner AActor. The Unreal codebase usually calls SetRootComponent before calling RegisterComponent
    // so we follow the same convention convention here.
    TComponent* component = NewObject<TComponent>(parent, Unreal::toFName(name));
    SP_ASSERT(component);
    parent->SetRootComponent(component);
    component->RegisterComponent();
}

template <typename TComponent>
TComponent* Unreal::createComponentOutsideOwnerConstructor(const std::string& name, UActorComponent* parent)
{
    // NewObject and RegisterComponent are required when outside the constructor of the owner AActor (either directly or
    // indirectly via the constructor of a child component). SetupAttachment is required to attach the newly created
    // component to its parent UActorComponent. The Unreal codebase usually calls SetupAttachment before calling
    // RegisterComponent so we follow the same convention convention here.
    SP_ASSERT(parent);
    TComponent* component = NewObject<TComponent>(parent, Unreal::toFName(name));
    SP_ASSERT(component);
    component->SetupAttachment(parent);
    component->RegisterComponent();
}

Does the behavior of each function look correct to you?

Yes, I think these behaviors are correct. I'll update the code with these changes.

[mikeroberts3000]

As discussed in our meeting today, CreateDefaultSubject is a public method on UObject, not a free function like NewObject, so the code snippet above needs to be modified slightly.

template <typename TComponent>
TComponent* Unreal::createComponentInsideOwnerConstructor(AActor* parent, const std::string& name)
{
    return createComponentInsideOwnerConstructor(parent, parent, name); // assume parent is owner
}

template <typename TComponent>
TComponent* Unreal::createComponentInsideOwnerConstructor(UObject* owner, AActor* parent, const std::string& name)
{
    // CreateDefaultSubobject is required when inside the constructor of the owner AActor (either directly or indirectly via
    // the constructor of a child component). SetRootComponent is required to attach the newly created root component to its
    // owner AActor.
    SP_ASSERT(owner);
    SP_ASSERT(parent);
    TComponent* component = owner->CreateDefaultSubobject<TComponent>(Unreal::toFName(name));
    SP_ASSERT(component);
    parent->SetRootComponent(component);
    return component;
}

[RachithP]

As discussed in our meeting today, CreateDefaultSubject is a public method on UObject, not a free function like NewObject, so the code snippet above needs to be modified slightly.

template <typename TComponent>
TComponent* Unreal::createComponentInsideOwnerConstructor(AActor* parent, const std::string& name)
{
    return createComponentInsideOwnerConstructor(parent, parent, name); // assume parent is owner
}

template <typename TComponent>
TComponent* Unreal::createComponentInsideOwnerConstructor(UObject* owner, AActor* parent, const std::string& name)
{
    // CreateDefaultSubobject is required when inside the constructor of the owner AActor (either directly or indirectly via
    // the constructor of a child component). SetRootComponent is required to attach the newly created root component to its
    // owner AActor.
    SP_ASSERT(owner);
    SP_ASSERT(parent);
    TComponent* component = owner->CreateDefaultSubobject<TComponent>(Unreal::toFName(name));
    SP_ASSERT(component);
    parent->SetRootComponent(component);
    return component;
}

Thanks! For some reason I kept thinking that CreateDefaultSubobject function was a static function! 🙈