poem-loop

This module is a configurable event loop for visualizations, demos, experiments, art, and poems. It provides an update and draw event, as well as updatedone and drawdone. It uses the raf module for the requestAnimationFrame.

Part of the programming-poem module series.

Usage

Its primary intended use is with Browserify.

From the command line:

npm install poem-loop --save

Then in your code:

var loop = require('poem-loop')( configuration );

loop.start();

loop.emitter.on('update', function( e ) {
	box.position.x += e.dt;
	gameClock.text( e.elapsed );
});

loop.emitter.on('draw', function( e ) {
	renderer.render();
});

Event object

The event object has the following values.

• dt - The change in time in milliseconds.
• unitDt - The change in time as a unit interval (0-1). Assumes 1 is equal to 16.6666 milliseconds.
• now - The current Date.now() in milliseconds.
• elapsed - The elapsed game time in milliseconds, starts at 0. Does not increment when the loop is stopped.

Configuration

The loop can be configured.

var loop = require('poem-loop')({
	emitter: poemEmitter,
	customizeEvent : function( event ) {
		event.mousePosition = getMousePosition();
		return event;
	}
});

emitter

A node.js EventEmitter. If one is set, it is used by the loop. Otherwise a new EventEmitter is created.

customizeEvent

A function that customizes the event object that is passed to the update and draw event. It gets passed the object and should return the object.

Interface

loop.start()

Start the loop.

loop.stop()

Stops the loop but doesn't reset the elapsed time.

loop.reset()

Resets the elapsed time.

loop.emitter

The event emitter.