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Diffstat (limited to 'lib/felecs/entity_manager.rb')
| -rw-r--r-- | lib/felecs/entity_manager.rb | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/lib/felecs/entity_manager.rb b/lib/felecs/entity_manager.rb new file mode 100644 index 0000000..a457ed2 --- /dev/null +++ b/lib/felecs/entity_manager.rb @@ -0,0 +1,160 @@ +# frozen_string_literal: true + +module FelECS + class Entities + # Creating a new Entity + # @param components [Components] Can be any number of components, identical duplicates will be automatically purged however different components from the same component manager are allowed. + # @return [Entity] + def initialize(*components) + # Add each component + add(*components) + self.class._data.push self + end + + # A hash that uses component manager constant names as keys, and where the values of those keys are arrays that contain the the components attached to this entity. + # @return [Hash<Component_Manager, Array<Integer>>] + def components + @components ||= {} + end + + # A single component from a component manager. Use this if you expect the component to only belong to one entity and you want to access it. Access the component using either parameter notation or array notation. Array notation is conventional for better readablility. + # @example + # @entity.component[@component_manager] # array notation(the standard) + # @entity.component(@component_manager) # method notation + # @param manager [ComponentManager] If you pass nil you can then use array notation to access the same value. + # @return [Component] + def component(manager = nil) + if manager.nil? + FelECS::Entities.component_redirect.entity = self + FelECS::Entities.component_redirect + else + if components[manager].nil? + raise "This entity(#{self}) doesnt have any components of this type: #{manager}" + elsif components[manager].length > 1 + Warning.warn("This entity has MANY of this component but you called the method that is intended for having a single of this component type.\nYou may have a bug in your logic.") + end + + components[manager].first + end + end + + # Removes this Entity from the list and purges all references to this Entity from other Components, as well as its data. + # @return [Boolean] +true+ + def delete + components.each do |_component_manager, component_array| + component_array.reverse_each do |component| + component.entities.delete(self) + end + end + FelECS::Entities._data.delete self + @components = {} + true + end + + # Add any number components to the Entity. + # @param components_to_add [Component] Any number of components created from any component manager + # @return [Boolean] +true+ + def add(*components_to_add) + components_to_add.each do |component| + if components[component.class].nil? + components[component.class] = [component] + component.entities.push self + check_systems component, :addition_triggers + elsif !components[component.class].include? component + components[component.class].push component + component.entities.push self + check_systems component, :addition_triggers + end + end + true + end + + # triggers every system associated with this component's trigger + # @return [Boolean] +true+ + # @!visibility private + def check_systems(component, trigger_type) + component_calls = component.class.send(trigger_type) + component.send(trigger_type).each do |system| + component_calls |= [system] + end + component_calls.sort_by(&:priority).reverse.each(&:call) + true + end + + # Remove a component from the Entity + # @param components_to_remove [Component] A component created from any component manager + # @return [Boolean] +true+ + def remove(*components_to_remove) + components_to_remove.each do |component| + check_systems component, :removal_triggers if component.entities.include? self + component.entities.delete self + components[component.class].delete component + components.delete component.class if components[component.class].empty? + end + true + end + + # Export all data into a JSON String which can then be saved into a file + # TODO: This function is not yet complete + # @return [String] A JSON formatted String + # def to_json() end + + class << self + # Makes component managers behave like arrays with additional + # methods for managing the array + # @!visibility private + def respond_to_missing?(method, *) + if _data.respond_to? method + true + else + super + end + end + + # Makes component managers behave like arrays with additional + # methods for managing the array + # @!visibility private + def method_missing(method, *args, **kwargs, &block) + if _data.respond_to? method + _data.send(method, *args, **kwargs, &block) + else + super + end + end + + # Fancy method redirection for when the `component` method is called + # in an Entity + # WARNING: This method will not correctly work with multithreading + # @!visibility private + def component_redirect + if @component_redirect + else + @component_redirect = Object.new + @component_redirect.instance_variable_set(:@entity, nil) + @component_redirect.define_singleton_method(:entity) do + instance_variable_get(:@entity) + end + @component_redirect.define_singleton_method(:entity=) do |value| + instance_variable_set(:@entity, value) + end + @component_redirect.define_singleton_method(:[]) do |component_manager| + entity.component(component_manager) + end + end + @component_redirect + end + + # @return [Array<Entity>] Array of all Entities that exist + # @!visibility private + def _data + @data ||= [] + end + + # Creates a new entity using the data from a JSON string + # TODO: This function is not yet complete + # @param json_string [String] A string that was exported originally using the {FelECS::Entities#to_json to_json} function + # @param opts [Keywords] What values(its {FelECS::Entities#id ID} or the {FelECS::ComponentManager#id component IDs}) should be overwritten TODO: this might change + # def from_json(json_string, **opts) end + end + end +end |