Class: Darkholme::System

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

Overview

Updated every frame by the engine, a System manipulates and uses the data contained within a component

Direct Known Subclasses

IteratingSystem

Class Attribute Summary collapse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Class Attribute Details

.family ⇒ Object (readonly)

Returns the value of attribute family.



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# File 'lib/darkholme/system.rb', line 6

def family
  @family
end

Instance Attribute Details

#engine ⇒ Object

Returns the value of attribute engine.



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# File 'lib/darkholme/system.rb', line 25

def engine
  @engine
end

Class Method Details

.has_family(*component_classes) ⇒ Family

Set the family for a System. Call this from the body of the class.

Examples:

Standard usage

class MySystem < Darkholme::System
  has_family MyComponent, AnotherComponent, LastComponent
end

Parameters:

  • component_classes (Array<Class>) —

    List of component classes the system is

Returns:

  • (Family) —

    The family for the classes



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# File 'lib/darkholme/system.rb', line 19

def has_family(*component_classes)
  @family = Family.for(*component_classes)
end

Instance Method Details

#added_to_engine(engine) ⇒ Object

Callback called after the system has been added to an Engine

Parameters:

  • engine (Engine) —

    The engine the system was added to



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# File 'lib/darkholme/system.rb', line 38

def added_to_engine(engine)
  self.engine = engine
end

#entities ⇒ Array<Entity>

An Array of all the entities this system is interested in

Returns:

  • (Array<Entity>) —

    All the entities with matching components



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# File 'lib/darkholme/system.rb', line 52

def entities
  engine.entities_for_family(family)
end

#family ⇒ Family

Get the system’s Family instance

Returns:

  • (Family) —

    The system’s family, as defined by #has_family



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# File 'lib/darkholme/system.rb', line 59

def family
  self.class.family
end

#removed_from_engine(engine) ⇒ Object

Callback called after the system has been removed from an Engine

Parameters:

  • engine (Engine) —

    The engine the system was removed from



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# File 'lib/darkholme/system.rb', line 45

def removed_from_engine(engine)
  self.engine = nil if self.engine == engine
end

#update(delta) ⇒ Object

Called once per frame by the engine. This must be overriden by the subclass.

Parameters:

  • delta (Float) —

    Difference in time between the last frame and this one

Raises:

  • (NotImplementedError) 


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# File 'lib/darkholme/system.rb', line 31

def update(delta)
  raise NotImplementedError.new("You must override #update(delta)")
end