lib/darkholme/system.rb in darkholme-0.9.1 vs lib/darkholme/system.rb in darkholme-1.0.0

@@ -1,32 +1,62 @@
 module Darkholme
+  # Updated every frame by the engine, a System manipulates and uses the
+  # data contained within a component
   class System
     class << self
       attr_reader :family
 
+      # Set the family for a System. Call this from the body of the
+      # class.
+      #
+      # @param component_classes [Array<Class>] List of component classes the system is
+      #
+      # @example Standard usage
+      #   class MySystem < Darkholme::System
+      #     has_family MyComponent, AnotherComponent, LastComponent
+      #   end
+      #
+      # @return [Family] The family for the classes
       def has_family(*component_classes)
-        @family = Family.for(*component_classes) 
+        @family = Family.for(*component_classes)
       end
     end
 
+    # @!attribute engine [Engine] The engine this system belongs to
     attr_accessor :engine
 
+    # Called once per frame by the engine. This must be overriden
+    # by the subclass.
+    #
+    # @param delta [Float] Difference in time between the last frame and this one
     def update(delta)
       raise NotImplementedError.new("You must override #update(delta)")
     end
 
+    # Callback called after the system has been added to an Engine
+    #
+    # @param engine [Engine] The engine the system was added to
     def added_to_engine(engine)
       self.engine = engine
     end
 
+    # Callback called after the system has been removed from an Engine
+    #
+    # @param engine [Engine] The engine the system was removed from
     def removed_from_engine(engine)
       self.engine = nil if self.engine == engine
     end
 
+    # An Array of all the entities this system is interested in
+    #
+    # @return [Array<Entity>] All the entities with matching components
     def entities
       engine.entities_for_family(family)
     end
 
+    # Get the system's Family instance
+    #
+    # @return [Family] The system's family, as defined by #has_family
     def family
       self.class.family
     end
   end
 end