Book Image

Leap Motion Development Essentials

By : Mischa Spiegelmock
Book Image

Leap Motion Development Essentials

By: Mischa Spiegelmock

Overview of this book

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.
Table of Contents (12 chapters)

Refactoring for multithreading


Before continuing further on, perhaps it would be a good time to refactor our virtual MIDI device output functionality into its own class, as the MIDI output routines with the attendant threading code should be encapsulated for maintaining some semblance of clean program structure.

namespace leapmidi {
class Device {
public:
    Device();
    ~Device();
    void init();
    void queueControlMessage(midi_control_index controlIndex, midi_control_value controlValue);

We'll go ahead and create a leapmidi::Device class. Users of our class construct a new Device class and call init() to set up the MIDI virtual device, and then send MIDI control messages using queueControlMessage().

protected:
    void initPacketList();
    void createDevice();

Our earlier MIDI virtual device setup code can go in here.

    pthread_t messageQueueThread;
    void *messageSendingThreadEntry();

This function will be called when our MIDI output thread (kept track of by messageQueueThread) begins...