Book Image

HTML5 Web Application Development By Example : Beginner's guide

By : Jody Gustafson
Book Image

HTML5 Web Application Development By Example : Beginner's guide

By: Jody Gustafson

Overview of this book

HTML5's new features have made it a real application development platform with widespread adoption throughout the industry for this purpose. Being able to create one application that can run on virtually any device from phone to desktop has made it the first choice among developers. Although JavaScript has been around for a while now, it wasn't until the introduction of HTML5 that we have been able to create dynamic, feature-rich applications rivaling those written for the desktop. HTML5 Web Application Development By Example will give you the knowledge you need to build rich, interactive web applications from the ground up, incorporating the most popular HTML5 and CSS3 features available right now. This book is full of tips, tools, and example applications that will get you started writing your own applications today. HTML5 Web Application Development By Example shows you how to write web applications using the most popular HTML5 and CSS3 features. This book is a practical, hands-on guide with numerous real-world and relevant examples. You will learn how to use local storage to save an application's state and incorporate CSS3 to make it look great. You will also learn how to use custom data attributes to implement data binding. We'll use the new Canvas API to create a drawing application, then use the Audio API to create a virtual piano, before turning it all into a game. The time to start using HTML5 is now. And HTML5 Web Application Development by Example will give you the tips and know-how to get started.
Table of Contents (18 chapters)
HTML5 Web Application Development By Example Beginner's guide
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Creating an audio sequencer


Before we can play the game, we need some way to play songs on the piano by playing back notes in a certain order, at the correct time, and at the correct speed. We will create an object called AudioSequencer that takes an array of musical event objects and turns them into music.

To implement our audio sequencer we need to define a format for our music events. We will roughly follow the MIDI format, but much more simplified. MIDI is the standard to record and play back music events. Each event contains information about how and when to play notes, or turn notes off.

Our event object will contain three fields:

  • deltaTime: The amount of time to wait before executing the event.

  • event: This is an integer event code that determines what the event does. It can be one of the following:

    • Turn a note on

    • Turn a note off

    • Cue point will be at the beginning of a song

    • End of track will signal that the song is over

  • note: This is the note to play. It contains the octave and note, and...