Class: Draco::Entity

Inherits:
Object
  • Object
show all
Defined in:
lib/draco.rb

Overview

Public: A general purpose game object that consists of a unique id and a collection of Components.

Defined Under Namespace

Classes: ComponentStore

Constant Summary collapse

@@next_id = 
1

Class Attribute Summary collapse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(args = {}) ⇒ Entity

Public: Initialize a new Entity.

args - A Hash of arguments to pass into the components.

Examples

class Player < Draco::Entity
  component Position, x: 0, y: 0
end

Player.new(position: {x: 100, y: 100})



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# File 'lib/draco.rb', line 75

def initialize(args = {})
  @id = args.fetch(:id, @@next_id)
  @@next_id = [@id + 1, @@next_id].max
  @subscriptions = []

  setup_components(args)
  after_initialize
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args, &block) ⇒ Object

Signature

<underscored_component_name>

underscored_component_name - The component to access the data from

Public: Get the component associated with this Entity. This method will be available for each component.

Examples

class Creature < Draco::Entity
  component CreatureStats, strength: 10
end

creature = Creature.new
creature.creature_stats

Returns the Component instance.



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# File 'lib/draco.rb', line 195

def method_missing(method, *args, &block)
  component = components[method.to_sym]
  return component if component

  super
end

Class Attribute Details

.default_components ⇒ Object (readonly)

Internal: Returns the default components for the class.



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# File 'lib/draco.rb', line 55

def default_components
  @default_components
end

Instance Attribute Details

#components ⇒ Object (readonly)

Public: Returns the Array of the Entity’s components



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# File 'lib/draco.rb', line 62

def components
  @components
end

#id ⇒ Object (readonly)

Public: Returns the Integer id of the Entity.



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# File 'lib/draco.rb', line 59

def id
  @id
end

Class Method Details

.component(component, defaults = {}) ⇒ Object

Public: Adds a default component to the Entity.

component - The class of the Component to add by default. defaults - The Hash of default values for the Component data. (default: {})

Examples

component(Visible)

component(Position, x: 0, y: 0)

Returns nothing.



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# File 'lib/draco.rb', line 40

def self.component(component, defaults = {})
  @default_components[component] = defaults
end

.inherited(sub) ⇒ Object

Internal: Resets the default components for each class that inherites Entity.

sub - The class that is inheriting Entity.

Returns nothing.



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# File 'lib/draco.rb', line 23

def self.inherited(sub)
  super
  sub.instance_variable_set(:@default_components, {})
end

.Tag(name) ⇒ Object

Public: Creates a tag Component. If the tag already exists, return it.

name - The string or symbol name of the component.

Returns a class with subclass Draco::Component.



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# File 'lib/draco.rb', line 49

def self.Tag(name) # rubocop:disable Naming/MethodName
  Draco::Tag(name)
end

Instance Method Details

#after_component_added(component) ⇒ Object

Public: Callback run after a component is added.

component - The component that was added.

Returns the added component.



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# File 'lib/draco.rb', line 128

def after_component_added(component)
  @subscriptions.each { |sub| sub.component_added(self, component) }
  component
end

#after_component_removed(component) ⇒ Object

Public: Callback run after a component is deleted.

component - The component that was removed.

Returns the removed component.



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# File 'lib/draco.rb', line 147

def after_component_removed(component)
  @subscriptions.each { |sub| sub.component_removed(self, component) }
  component
end

#after_initialize ⇒ Object

Public: Callback run after the entity is initialized.

This is empty by default but is present to allow plugins to tie into.

Returns nothing.



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# File 'lib/draco.rb', line 103

def after_initialize; end

#before_component_added(component) ⇒ Object

Public: Callback run before a component is added.

component - The component that will be added.

Returns the component to add.



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# File 'lib/draco.rb', line 119

def before_component_added(component)
  component
end

#before_component_removed(component) ⇒ Object

Public: Callback run before a component is deleted.

component - The component that will be removed.

Returns the component to remove.



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# File 'lib/draco.rb', line 138

def before_component_removed(component)
  component
end

#inspect ⇒ Object

Public: Returns a String representation of the Entity.



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# File 'lib/draco.rb', line 166

def inspect
  serialize.to_s
end

#respond_to_missing?(method, _include_private = false) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/draco.rb', line 202

def respond_to_missing?(method, _include_private = false)
  !!components[method.to_sym] or super
end

#serialize ⇒ Object

Public: Serializes the Entity to save the current state.

Returns a Hash representing the Entity.



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# File 'lib/draco.rb', line 155

def serialize
  serialized = { class: self.class.name.to_s, id: id }

  components.each do |component|
    serialized[Draco.underscore(component.class.name.to_s).to_sym] = component.serialize
  end

  serialized
end

#setup_components(args) ⇒ Object

Internal: Sets up the default components for the class.

args - A hash of arguments to pass into the generated components.

Returns nothing.



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# File 'lib/draco.rb', line 89

def setup_components(args)
  @components = ComponentStore.new(self)

  self.class.default_components.each do |component, default_args|
    arguments = default_args.merge(args[Draco.underscore(component.name.to_s).to_sym] || {})
    @components << component.new(arguments)
  end
end

#subscribe(subscriber) ⇒ Object

Public: Subscribe to an Entity’s Component updates.

subscriber - The object to notify when Components change.

Returns nothing.



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# File 'lib/draco.rb', line 110

def subscribe(subscriber)
  @subscriptions << subscriber
end

#to_s ⇒ Object

Public: Returns a String representation of the Entity.



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# File 'lib/draco.rb', line 171

def to_s
  serialize.to_s
end