An object that stores and manages updates to all the component arrays instantiated for this ECS World. More...

#include <ecs_world.hpp>

Classes
struct	getComponentTypeName
	Helper function for retrieving the component type string defined as part of the component. More...

struct	getComponentTypeName< std::shared_ptr< TComponent > >
	A specialization of getComponentTypeName for components which are wrapped in shared pointers. More...

Public Member Functions
	ComponentManager (std::weak_ptr< ECSWorld > world)
	Construct a new Component Manager object.

Private Member Functions
ComponentManager	instantiate (std::weak_ptr< ECSWorld > world) const
	Constructs a new component manager and associates it with the world passed in as argument. Creates a fresh, but empty, set of component arrays.

template<typename TComponent>
void	registerComponentArray ()
	A method to allow a new component type to register itself with the ECS system for this project.

template<typename TComponent>
std::shared_ptr< ComponentArray< TComponent > >	getComponentArray () const
	Get the (specialized) Component Array object.

std::shared_ptr< BaseComponentArray >	getComponentArray (const std::string &componentTypeName) const
	Get the Component Array object.

template<typename TComponent>
ComponentType	getComponentType () const
	Get the component type ID for a given component type.

ComponentType	getComponentType (const std::string &typeName) const
	Get the component type ID for a given component type string.

Signature	getSignature (EntityID entityID)
	Get the component signature for a given entity.

template<typename TComponent>
void	addComponent (EntityID entityID, const TComponent &component)
	Adds a component entry for this entity in the array specified.

void	addComponent (EntityID entityID, const nlohmann::json &jsonComponent)
	Adds a component entry for this entity in the array specified (in the JSON description).

template<typename TComponent>
void	removeComponent (EntityID entityID)
	Removes the component of the type specified from the entity.

void	removeComponent (EntityID entityID, const std::string &type)
	Removes the component of the type specified from the entity.

template<typename TComponent>
bool	hasComponent (EntityID entityID) const
	Tests whether an entity has a component of a particular type.

bool	hasComponent (EntityID entityID, const std::string &type)
	Tests whether an entity has a component of a particular type.

template<typename TComponent>
TComponent	getComponent (EntityID entityID, float simulationProgress=1.f) const
	Get the component value for this entity.

template<typename TComponent>
void	updateComponent (EntityID entityID, const TComponent &newValue)
	Updates a component belonging to an entity with its new value.

void	updateComponent (EntityID entityID, const nlohmann::json &componentProperties)
	Updates a component belonging to an entity with its new value(described in JSON).

template<typename TComponent>
void	copyComponent (EntityID to, EntityID from)
	Copies a component value from one component to another within the same component array.

void	copyComponents (EntityID to, EntityID from)
	Copies all components from one entity and updates or adds them to the other.

void	copyComponents (EntityID to, EntityID from, ComponentManager &other)
	Copies all components from one entity and updates or adds them to the other, where the source entity may belong to a different ECS World.

void	handleEntityDestroyed (EntityID entityID)
	Handles component arrays specific side effect of entity destruction.

void	handlePreSimulationStep ()
	Callback for the start of a simulation step, where the contents of every component's `next` member is copied into its `previous` member.

void	unregisterAll ()
	Unregisters all component arrays associated with this manager, as part of the destruction process for the world this component manager belongs to.

Private Attributes
std::unordered_map< std::string, std::size_t >	mNameToComponentHash {}
	Maps each component type name to its corresponding hash.

std::unordered_map< std::size_t, ComponentType >	mHashToComponentType {}
	Maps a component's type hash to its ComponentType.

std::unordered_map< std::size_t, std::shared_ptr< BaseComponentArray > >	mHashToComponentArray {}
	Maps the hash of a component type to its corresponding ComponentArray.

std::unordered_map< EntityID, Signature >	mEntityToSignature {}
	Stores the component signature of each entity.

std::weak_ptr< ECSWorld >	mWorld
	Holds a reference to the ECS world this component manager manages component arrays for.

Friends
class	ECSWorld

Detailed Description

An object that stores and manages updates to all the component arrays instantiated for this ECS World.

Constructor & Destructor Documentation

◆ ComponentManager()

ToyMaker::ComponentManager::ComponentManager ( std::weak_ptr< ECSWorld > world )

inlineexplicit

Construct a new Component Manager object.

Parameters

world The world to which this component manager belongs.

Member Function Documentation

◆ addComponent() [1/2]

void ComponentManager::addComponent	(	EntityID	entityID,
		const nlohmann::json &	jsonComponent )

private

Adds a component entry for this entity in the array specified (in the JSON description).

Parameters

entityID	The entity to which the component is being added.
jsonComponent	The value of the added component, described in JSON.

◆ addComponent() [2/2]

template<typename TComponent>

void ToyMaker::ComponentManager::addComponent	(	EntityID	entityID,
		const TComponent &	component )

private

Adds a component entry for this entity in the array specified.

Template Parameters

TComponent The type of component being added.

Parameters

entityID	The entity to which the component is being added.
component	The value of the added component.

◆ copyComponent()

template<typename TComponent>

void ToyMaker::ComponentManager::copyComponent	(	EntityID	to,
		EntityID	from )

private

Copies a component value from one component to another within the same component array.

Template Parameters

TComponent The type of component being copied.

Parameters

to	The entity to which the component is copied.
from	The entity the component is copied from.

◆ copyComponents() [1/2]

void ComponentManager::copyComponents	(	EntityID	to,
		EntityID	from )

private

Copies all components from one entity and updates or adds them to the other.

Parameters

to	The entity to which the copied components will be added or updated.
from	The entity from which the components will be copied.

◆ copyComponents() [2/2]

void ComponentManager::copyComponents	(	EntityID	to,
		EntityID	from,
		ComponentManager &	other )

private

Copies all components from one entity and updates or adds them to the other, where the source entity may belong to a different ECS World.

Parameters

to	The entity to which the copied components will be added or updated.
from	The entity from which components will be copied.
other	The component manager belonging to the same world as `from`.

◆ getComponent()

template<typename TComponent>

TComponent ToyMaker::ComponentManager::getComponent	(	EntityID	entityID,
		float	simulationProgress = 1.f ) const

private

Get the component value for this entity.

Template Parameters

TComponent The type of component value to retrieve.

Parameters

entityID	The entity whose component is being retrieved.
simulationProgress	Progress towards the next simulation tick, a value between 0.0 and 1.0.

Returns: TComponent A copy of the entity's component.

◆ getComponentArray() [1/2]

template<typename TComponent>

std::shared_ptr< ComponentArray< TComponent > > ToyMaker::ComponentManager::getComponentArray ( ) const

inlineprivate

Get the (specialized) Component Array object.

Template Parameters

TComponent The type of component whose array is being retrieved.

Returns: std::shared_ptr<ComponentArray<TComponent>> (Specialized) shared pointer to said component array.

◆ getComponentArray() [2/2]

std::shared_ptr< BaseComponentArray > ToyMaker::ComponentManager::getComponentArray ( const std::string & componentTypeName ) const

inlineprivate

Get the Component Array object.

Parameters

componentTypeName The component type string for the desired component array.

Returns: std::shared_ptr<BaseComponentArray> (Unspecialized) shared pointer to said component array.

◆ getComponentType() [1/2]

template<typename TComponent>

ComponentType ToyMaker::ComponentManager::getComponentType ( ) const

private

Get the component type ID for a given component type.

Template Parameters

TComponent The type of the component type ID being retrieved.

Returns: ComponentType The ID of the component type.

◆ getComponentType() [2/2]

ComponentType ComponentManager::getComponentType ( const std::string & typeName ) const

private

Get the component type ID for a given component type string.

Parameters

typeName the component type string for the component type.

Returns: ComponentType The ID of the component type.

◆ getSignature()

Signature ComponentManager::getSignature ( EntityID entityID )

private

Get the component signature for a given entity.

The component signature describes which components are present for a given object. The position of each bit in the signature corresponds to the ComponentType that that bit represents.

1 indicates that a component of that particular type is associated with the entity.
0 indicates that there is no component of that type associated with the entity.

Parameters

entityID The entity whose component signature is being retrieved.

Returns: Signature A bitset representing the presence or absence of specific components for an entity.

See also: ComponentType; mEntityToSignature

◆ handleEntityDestroyed()

void ComponentManager::handleEntityDestroyed ( EntityID entityID )

private

Handles component arrays specific side effect of entity destruction.

Removes entry from every component array belonging to this entity.

Parameters

entityID The entity being destroyed.

◆ handlePreSimulationStep()

void ComponentManager::handlePreSimulationStep ( )

private

Callback for the start of a simulation step, where the contents of every component's next member is copied into its previous member.

Todo: rename to handleSimulationPreStep

◆ hasComponent() [1/2]

template<typename TComponent>

bool ToyMaker::ComponentManager::hasComponent ( EntityID entityID ) const

private

Tests whether an entity has a component of a particular type.

Template Parameters

TComponent The type of component whose existence is being tested.

Parameters

entityID The entity being queried.

Return values

true	The component is present;
false	The component is absent;

See also: bool hasComponent(EntityID entityID, const std::string& type)

◆ hasComponent() [2/2]

bool ComponentManager::hasComponent	(	EntityID	entityID,
		const std::string &	type )

private

Tests whether an entity has a component of a particular type.

Parameters

entityID	The entity being queried.
type	The component type string of the component whose existence is being tested.

Return values

true	The component is present;
false	The component is absent;

See also: template <typename TComponent> bool hasComponent(EntityID entityID) const

◆ instantiate()

ComponentManager ComponentManager::instantiate ( std::weak_ptr< ECSWorld > world ) const

private

Constructs a new component manager and associates it with the world passed in as argument. Creates a fresh, but empty, set of component arrays.

Parameters

world The world to which the new component manager will belong.

Returns: ComponentManager The new component manager constructed, using this component manager as a template

◆ registerComponentArray()

template<typename TComponent>

void ToyMaker::ComponentManager::registerComponentArray ( )

private

A method to allow a new component type to register itself with the ECS system for this project.

Template Parameters

TComponent The type of component being registered.

◆ removeComponent() [1/2]

template<typename TComponent>

void ToyMaker::ComponentManager::removeComponent ( EntityID entityID )

private

Removes the component of the type specified from the entity.

Template Parameters

TComponent The type of component being removed.

Parameters

entityID The entity whose component is being removed.

◆ removeComponent() [2/2]

void ComponentManager::removeComponent	(	EntityID	entityID,
		const std::string &	type )

private

Removes the component of the type specified from the entity.

Parameters

entityID	The entity whose component is being removed.
type	The component type string of the component being removed.

◆ updateComponent() [1/2]

void ComponentManager::updateComponent	(	EntityID	entityID,
		const nlohmann::json &	componentProperties )

private

Updates a component belonging to an entity with its new value(described in JSON).

Parameters

entityID	The entity whose component is being updated.
componentProperties	The new value for the component, described in JSON.

See also: void updateComponent<TComponent>(EntityID entityID, const TComponent& newValue)

◆ updateComponent() [2/2]

template<typename TComponent>

void ToyMaker::ComponentManager::updateComponent	(	EntityID	entityID,
		const TComponent &	newValue )

private

Updates a component belonging to an entity with its new value.

Template Parameters

TComponent The type of component being updated.

Parameters

entityID	The entity whose component is being updated.
newValue	The new value for the component.

See also: void updateComponent(EntityID entityID, const nlohmann::json& componentProperties)

Member Data Documentation

◆ mEntityToSignature

std::unordered_map<EntityID, Signature> ToyMaker::ComponentManager::mEntityToSignature {}

private

Stores the component signature of each entity.

The position of each bit in the signature corresponds to a ComponentType managed by the ComponentManager. A given entity either has or doesn't have a particular component according as the corresponding bit in the signature is set or unset.

See also: ComponentType; Signature; getSignature

◆ mHashToComponentType

std::unordered_map<std::size_t, ComponentType> ToyMaker::ComponentManager::mHashToComponentType {}

private

Maps a component's type hash to its ComponentType.

The hash of a component is provided by the STL type_traits library. The map allows us to retrieve the ECS Type ID (used in entity component signatures) for a type with a particular hash

See also: ComponentType

◆ mNameToComponentHash

std::unordered_map<std::string, std::size_t> ToyMaker::ComponentManager::mNameToComponentHash {}

private

Maps each component type name to its corresponding hash.

See also: mHashToComponentArray

The documentation for this class was generated from the following files:

src/engine/core/ecs_world.hpp
src/engine/core/ecs_world.cpp

Classes

Public Member Functions

Private Member Functions

Private Attributes

Friends

Detailed Description

Constructor & Destructor Documentation

◆ ComponentManager()

Member Function Documentation

◆ addComponent() [1/2]

◆ addComponent() [2/2]

◆ copyComponent()

◆ copyComponents() [1/2]

◆ copyComponents() [2/2]

◆ getComponent()

◆ getComponentArray() [1/2]

◆ getComponentArray() [2/2]

◆ getComponentType() [1/2]

◆ getComponentType() [2/2]

◆ getSignature()

◆ handleEntityDestroyed()

◆ handlePreSimulationStep()

◆ hasComponent() [1/2]

◆ hasComponent() [2/2]

◆ instantiate()

◆ registerComponentArray()

◆ removeComponent() [1/2]

◆ removeComponent() [2/2]

◆ updateComponent() [1/2]

◆ updateComponent() [2/2]

Member Data Documentation

◆ mEntityToSignature

◆ mHashToComponentType

◆ mNameToComponentHash