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.
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.
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.
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.
In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.
Code words in text are shown as follows: "We can include other contexts through the use of the include directive."
A block of code is set as follows:
if (frame.hands().empty()) return;
const Leap::Hand firstHand = frame.hands()[0];
const Leap::FingerList fingers = firstHand.fingers();When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:
namespace leapmidi {
typedef double midi_control_value_raw;
typedef unsigned short midi_control_value;New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes, for example, appear in the text like this: "Prepare to be astounded when you point at the middle of your screen and the transfixing message, You are pointing at (0.519522, 0.483496, 0), is revealed".
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