HTML and CSS Reference
In-Depth Information
Supporting Components
The last core piece of functionality necessary to bootstrap Quintus is adding in component support. As described
earlier in the section “Using Inheritance in Game Engines,” components make it simpler to create small pieces
of reusable functionality that can be mixed and matched among the various sprites and objects that need it.
Crafty.js
a popular, mature HTML5 Game engine based entirely around a component-entity architec-
ture, as discussed in Chapter 26, “Using an HTML5 Game Engine,” and was the inspiration for the Quintus
component methods.
Designing the Component API
As usual, think about the API first and how you want to use components in the game. Components need to be
added and removed from sprites quickly and concisely. They should be accessible from the objects but also not
overly pollute the object's namespace.
Listing 9-13
shows and example of how you could define and use com-
ponents.
Listing 9-13:
Imagining a component system
var exGame = Quintus();
var player = new exGame.GameObject();
exGame.register('sword',{
added: function() {
// When whatever we are registered with triggers
// a fire event, call the attack method
this.entity.bind('fire',this,'attack');
},
attack: function() {
// Code to attack
},
// Methods copied directly over to the entity
extend: {
attack: function() {
this.sword.attack();
}
}
});
// Add the sword component
player.add('sword');
// Calls attack via event
player.trigger('fire');
// Call attack directly from extended event
player.attack();
// Remove the sword component
