atlas::scene Class Reference

Constructs a scene that defines an area where game objects are part of contained within an atlas::world. More...

#include <scene.hpp>

Public Member Functions
	scene (const std::string &p_name, event::event_bus &p_bus)
game_object	entity (std::string_view p_name)
	Retrieves if an entity already exists within the registry, create new entity otherwise.
game_object	entity (uint64_t p_id)
	Retrieves if an entity already exists within the registry, create new entity otherwise.
template<typename UEventType , typename UObject , typename UCallback >
void	subscribe (UObject *p_instance, const UCallback &p_callback)
	subscribes an event to the event::bus to get invoked when publishers notify all subscribers when an update is incoming
template<typename... Comps, typename... Args>
flecs::query_builder< Comps... >	query_builder (Args &&... args) const
	queries components, returning entities (game objects) that contain those components queried with.
uint32_t	children_count (const game_object &p_parent)
bool	defer_begin ()
	Defer operations until end of frame. When this operation is invoked while iterating, operations inbetween the defer_begin() and defer_end() operations are executed at the end of the frame.
bool	defer_end ()
std::string	name () const
event::event_bus *	event_handle () const
	operator flecs::world & ()
	Requires to return flecs::world is returned by reference to prevent making copies of flecs::world.

Detailed Description

Constructs a scene that defines an area where game objects are part of contained within an atlas::world.

Scenes are fundamentally building blocks that a game object may reside in. Composing of variety of properties such as sky lights, game objects, cameras, etc.

Which can represent corresponding resources that can be related to specific levels/scenes.

Scenes are apart of another container referred to as the world which helps manages these scenes and consider them as contexts that can be switched/toggled based on users transforms.

Constructor & Destructor Documentation

scene()

atlas::scene::scene	(	const std::string &	p_name,
		event::event_bus &	p_bus
	)

Parameters

p_name	is the name given to this scene
p_bus	is the globalized event bus that is given access to the scene to subscribe events to it.

Member Function Documentation

children_count()

uint32_t atlas::scene::children_count

(

const game_object &

p_parent

)

Returns

the number of children entities

Example Usage:

 ++
 
atlas::scene scene("New Scene");
 
// creating obj1 (parent) and obj2 (child)
atlas::game_object obj1 = scene.create("Parent");
 
atlas::game_object obj2 = scene.create("Chlid");
 
// obj2 is the child of obj1
// As obj1 is a parent node
 
obj2.child_of(obj1);
 
// Returns 1
uint32_t obj1_children = scene.children_count(obj1);

defer_begin()

bool atlas::scene::defer_begin ( )

inline

Defer operations until end of frame. When this operation is invoked while iterating, operations inbetween the defer_begin() and defer_end() operations are executed at the end of the frame.

This operation is thread safe.

Returns

true if world changed from non-deferred mode to deferred mode.

defer_end()

bool atlas::scene::defer_end ( )

inline

End block of operations to defer. See defer_begin().

This operation is thread safe.

Returns

true if world changed from deferred mode to non-deferred mode.

entity() [1/2]

game_object atlas::scene::entity

(

std::string_view

p_name

)

Retrieves if an entity already exists within the registry, create new entity otherwise.

Parameters

p_name

is a string to set the name of the entity

entity() [2/2]

game_object atlas::scene::entity

(

uint64_t

p_id

)

Retrieves if an entity already exists within the registry, create new entity otherwise.

Parameters

p_entity_id

is the ID to retrieve an entity if it exists, otherwise returns a new entity.

event_handle()

event::event_bus * atlas::scene::event_handle ( ) const

inline

Returns

the event::bus handle for subscribing events

name()

std::string atlas::scene::name ( ) const

inline

Returns

the name of the scene

query_builder()

template<typename... Comps, typename... Args>

flecs::query_builder< Comps... > atlas::scene::query_builder ( Args &&...  args ) const

inline

queries components, returning entities (game objects) that contain those components queried with.

Queries are a feature flecs allows us to do. Which query component parameters and gives us archetypes back.

Archetypes are list of entities that contain those list of parameters

Template Parameters

...Comps
...Args

Parameters

...

args

Returns

flecs::query_builder<Comps...>

Example Usage:

 ++
auto query_physics = query_builder<atlas::transform,
atlas::physics_body>().build();
 
query_physics.each([](flecs::entity, atlas::transform&,
atlas::physics_body&){
     // do stuff
});

subscribe()

template<typename UEventType , typename UObject , typename UCallback >

void atlas::scene::subscribe ( UObject *  p_instance, const UCallback &  p_callback  )

inline

subscribes an event to the event::bus to get invoked when publishers notify all subscribers when an update is incoming

Template Parameters

UEventType
UObject
UCallback

Parameters

p_instance	is the object instance to specify where the callback belongs to
p_callback	is the callback that contains an arbitrary task that gets invoked when incoming updates occur from the publisher

---

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

• TheAtlasEngine/atlas/core/scene/scene.hpp