Bergson

What is Bergson?

Bergson is the scheduling system for Flocking and Aconite. It provides a variety of clocks driven by different sources (such as requestAnimationFrame, the Web Audio API, and setInterval), and a priority queue-based scheduler that allows you to queue up one-time and repeating function calls.

Bergson provides a very low-level API for scheduling, and is intended for library developers to build their own rhythmic and pattern-based abstractions on top of.

Examples

Creating a Scheduler with the requestAnimationFrame Clock

var scheduler = berg.scheduler({
    components: {
        clock: {
            type: "berg.clock.requestAnimationFrame",
            options: {
                freq: 60
            }
        }
    }
});

scheduler.start();

Scheduling one-time events

scheduler.schedule({
    type: "once",
    time: 30            // 30 seconds from now
    callback: function (now) {
        // Do something in the future.
    }
});

Scheduling repeating events

scheduler.schedule({
    type: "repeat",
    time: 5,            // Start repeating five seconds from now.
    freq: 2,            // Repeat every two seconds.
    end: 20,            // Stop repeating 20 seconds from now.
    callback: function (now) {
        // Do something repeatedly.
    }
});

Listening for Clock Events Directly

scheduler.clock.events.onTick.addListener(function (time, rate) {
    // Do something every time the clock ticks.
});

Bergson API

Scheduler API

Score Event Specifications

A score event specification is a JSON-type (i.e. plain old, non-prototypal) object that describes the event to be scheduled. It can contain the following properties.

Scheduler Model

For more information on interacting with models, see the Infusion documentation about the Change Applier.

Scheduler Members

Scheduler Methods

Clock API

Clock Members

Clock Methods

Clock Events

Types of Clocks

Building and Testing Bergson

Prerequisites

Bergson uses Node.js, npm, Grunt, and Testem for its build and test tooling. Here's how to get set up:

1. Install the [Node.js](https://nodejs.org/en/) LTS release
3. Install Grunt: <code>npm install -g grunt-cli</code>
4. Install Testem: <code>npm install -g testem</code>

How to Build Bergson

To download all of Bergson's dependencies, build them, and then build Bergson itself, run the following commands:

npm install
grunt

Running Bergson's Test Suite

Bergson's test suite can be run on both Node.js and all of the browsers installed on your computer using Testem:

npm test

If you'd like to run only the Node.js tests, run:

npm run node-test

Or if you only want to run the browser tests:

npm run browser-test

Alternatively, if you'd like to only run the tests in one browser, you can open the test suite tests/unit/all-tests.html file by hand in your browser.

Community

Bergson is supported by the Flocking community and uses its forums:

Mailing List

The Flocking mailing list is the place to ask questions, share code, and request new features.

Chat

Flocking has an IRC channel, which can also be used to ask questions about Bergson. Join #flocking on irc.freenode.net.

Credits and License

Bergson is written and maintained by Colin Clark. It is dually licensed under the MIT and GPL 2.0 licenses.