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- Herausgeber: Packt Publishing
- Kategorie: Fachliteratur
- Sprache: Englisch
Leap Motion is a company developing advanced motion sensing technology for human–computer interaction. Originally inspired by the level of difficulty of using a mouse and keyboard for 3D modeling, Leap Motion believe that moulding virtual clay should be as easy as moulding clay in your hands. Leap Motion now focus on bringing this motion sensing technology closer to the real world.
Leap Motion Development Essentials explains the concepts and practical applications of gesture input for developers who want to take full advantage of Leap Motion technology. This guide explores the capabilities available to developers and gives you a clear overview of topics related to gesture input along with usable code samples.
Leap Motion Development Essentials shows you everything you need to know about the Leap Motion SDK, from creating a working program with gesture input to more sophisticated applications covering a range of relevant topics. Sample code is provided and explained along with details of the most important and central API concepts.
This book teaches you the essential information you need to design a gesture-enabled interface for your application, from specific gesture detection to best practices for this new input. You will be given guidance on practical considerations along with copious runnable demonstrations of API usage which are explained in step-by-step, reusable recipes.
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Seitenzahl: 136
Veröffentlichungsjahr: 2013
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Table of Contents
Leap Motion Development Essentials
Leap Motion Development Essentials
Copyright © 2013 Packt Publishing
All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.
Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.
Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.
First published: October 2013
Production Reference: 1211013
Published by Packt Publishing Ltd.
Livery Place
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Birmingham B3 2PB, UK.
ISBN 978-1-84969-772-9
www.packtpub.com
Cover Image by Suresh Mogre (<[email protected]>)
Credits
Author
Mischa Spiegelmock
Reviewers
Shaun Walker
Carlos Zinato
Acquisition Editors
Erol Staveley
Rebecca Youe
Commissioning Editor
Mohammed Fahad
Technical Editors
Vrinda Nitesh Bhosale
Pratik More
Amit Ramadas
Project Coordinator
Suraj Bist
Proofreader
Bernadette Watkins
Indexer
Hemangini Bari
Production Coordinator
Manu Joseph
Cover Work
Manu Joseph
About the Author
Mischa Spiegelmock is an accomplished software engineer from the San Francisco Bay Area. Slightly infamous from light-hearted technical pranks from his youth, he is now a respectable CTO at a healthcare software startup. His passions are architecting elegant and useful programs and sharing his insights into software design with others in a straightforward and entertaining fashion.
This book would not exist without the extremely passionate people at Leap Motion, whose vision and heroic efforts to improve the interactions between humans and computers should be commended. Special mention to Elizabeth Ruscitto for taking the time to provide me with informative answers to my queries. I would also like to thank Hep Svadja Hepic Photography, for the amazing pictures.
About the Reviewers
Shaun Walker is a software and web developer from Tasmania, Australia. He enjoys tinkering with electronics, listening to music, playing computer games, and working on small projects that generally never get finished.
Shaun has a Bachelor's degree in Computing, majoring in Human Interface Technology, part of the HITLab, an International collaboration effort between a few universities around the world. His areas of focus during his studies were in augmented reality, virtual reality, and gesture-based interactions.
With a history in corporate IT support, working on network integration, software and web development, his main employment is with a Brisbane-based medical start-up.
Ramblings by Shaun can be found at his blog at http://theshaun.com or on Twitter @theshaun.
Carlos Zinato, aged 25, is from São Paulo, Brazil. Currently, he's living in Miami Beach, FL, developing mobile apps and games, playing bass guitar, and getting to know people and places.
Working with tools such as Objective-C, Leap Motion, Titanium, and Unity3D, Carlos makes mobile apps and games and this is what he loves to do.
Carlos is currently aiming to keep making awesome apps and games with skilled friends and teams. He not only cares about the money but, more importantly, about the knowledge. Carlos wants to keep working with brilliant people that enhance his job, his life, and his pocket.
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Preface
Once in a great while, a revolutionary and exciting new way of interacting with technology comes along. Leap Motion makes natural gesture-based interfaces a reality, and gives software developers access to a large and powerful set of features and capabilities. This guide is for software engineers who wish to get an overview of the Leap Software Development Kit modules, types and interfaces in C++ along with some guidelines for getting the most out of your Leap device and creating usable, gestural software interfaces.
What this book covers
Chapter 1, Leap Motion SDK – A Quick Start, explores how to begin using the Leap C++ SDK right away, with a sample mouse control program. It covers how to receive frame updates and read finger position data.
Chapter 2, Real Talk – Real Time, guides you through writing a multithreaded MIDI controller, which uses a blocking OS call without sacrificing responsiveness.
Chapter 3, Actual Gestures, covers a high-level discussion of gesture interfaces and a look at the available Leap SDK recognizers. It also covers creating an interface to manipulate Windows OS.
Chapter 4, Leap and the Web, teaches you how to create Leap-enabled web pages, using JavaScript with the LeapJS library, with no additional installation or configuration.
Chapter 5, HTML5 Antics in 3D, combines LeapJS, WebGL, and Three.js together to manipulate objects in 3D space in a web page using Leap Motion.
What you need for this book
You will need a working knowledge of basic C++ and a compiler. Additional demonstration operating system-specific code is provided for Mac OS X APIs, but neither OS X nor familiarity with it is a requirement. An understanding of basic geometry and concepts such as vectors is useful for spatial manipulations.
Who this book is for
This book is for developers with an interest in using the Leap Motion input device with their software. This book gives a broad overview of most of the available functionality in the Leap SDK, which can be transferred to any of the supported language interfaces, as the data types and routines are nearly identical.
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Chapter 1. Leap Motion SDK – A Quick Start
The Leap Motion is a peripheral input device that allows users to interact with the software through hand gestures. This chapter will explain the features and software interface exposed by the Leap Motion SDK, which will allow us to take advantage of the hand motion input.
An overview of the SDK
The Leap device uses a pair of cameras and an infrared pattern projected by LEDs to generate an image of your hands with depth information. A very small amount of processing is done on the device itself, in order to keep the cost of the units low.
The images are post-processed on your computer to remove noise, and to construct a model of your hands, fingers, and pointy tools that you are holding.
As an application developer, you can make use of this data via the Leap software developer kit, which contains a powerful high-level API for easily integrating gesture input into your applications. Because developers do not want to go to, the trouble of processing raw input in the form of depth-mapped images skeleton models and point cloud data, the SDK provides abstracted models that report what your user is doing with their hands. With the SDK you can write applications that make use of some familiar concepts:
Quick start
Congratulations on your purchase of a genuine fine quality Leap Motion gesture input device! This handy guide will walk you through the assembly, proper usage, and care of your Leap Motion.
To get started, remove your Leap Motion SDK and Leap Motion™ device from the box and unpack the shared object files and headers from their shrink-wrap. Gently place your SDK in a handy directory and fire up your favorite IDE to begin.
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We'll get things going right away with a short C++ application to illustrate how to interact with the Leap SDK to receive events and input.
To interact with the Leap software, we will begin by creating a subclass of Leap::Listener and defining the callback methods we wish to receive. While it is possible to poll the controller for the current frame, generally you will want to make your program as responsive as possible which is most easily accomplished by acting on input events immediately via callbacks. In case you're wondering, the primary available callback methods are:
Let's implement our onConnect handler real quick so that we can verify that the controller driver and SDK are communicating with the device properly. If everything is working as it should be, the following code should cause a message to be emitted on stdout when the device is plugged in to a USB port:
We can display a friendly contrived greeting to ourselves when the program is run with the controller connected and the driver software is running. This will cause breathless anticipation in your users as they prepare themselves to experience the magic and wonder of this fantastic new input technology.
