redshift/src/process/loop.js

A JavaScript UX framework. Handles animation, UI physics and user input tracking.

/*
    The loop
*/
"use strict";

var Timer = require('./timer.js'),
    tick = require('./tick.js'),
    Loop = function () {
        this.timer = new Timer();
    };
    
Loop.prototype = {
    
    /*
        [boolean]: Current status of animation loop
    */
    isRunning: false,
    
    /*
        Fire all active processes once per frame
    */
    frame: function () {
        var self = this;
        
        tick(function () {
            var framestamp = self.timer.update(), // Currently just measuring in ms - will look into hi-res timestamps
                isActive = self.callback.call(self.scope, framestamp, self.timer.getElapsed());

            if (isActive) {
                self.frame(true);
            } else {
                self.stop();
            }
        });
    },
    
    /*
        Start loop
    */
    start: function () {
        // Make sure we're not already running a loop
        if (!this.isRunning) {
            this.timer.clock();
            this.isRunning = true;
            this.frame();
        }
    },
    
    /*
        Stop the loop
    */
    stop: function () {
        this.isRunning = false;
    },
    
    /*
        Set the callback to run every frame
        
        @param [Object]: Execution context
        @param [function]: Callback to fire
    */
    setCallback: function (scope, callback) {
        this.scope = scope;
        this.callback = callback;
    }
 
};

module.exports = new Loop();