Book Image

Game Programming Using Qt: Beginner's Guide

By : Lorenz Haas, Witold Wysota, Witold Wysota, Lorenz Haas
Book Image

Game Programming Using Qt: Beginner's Guide

By: Lorenz Haas, Witold Wysota, Witold Wysota, Lorenz Haas

Overview of this book

Qt is the leading cross-platform toolkit for all significant desktop, mobile, and embedded platforms and is becoming more popular by the day, especially on mobile and embedded devices. Despite its simplicity, it's a powerful tool that perfectly fits game developers’ needs. Using Qt and Qt Quick, it is easy to build fun games or shiny user interfaces. You only need to create your game once and deploy it on all major platforms like iOS, Android, and WinRT without changing a single source file. The book begins with a brief introduction to creating an application and preparing a working environment for both desktop and mobile platforms. It then dives deeper into the basics of creating graphical interfaces and Qt core concepts of data processing and display before you try creating a game. As you progress through the chapters, you’ll learn to enrich your games by implementing network connectivity and employing scripting. We then delve into Qt Quick, OpenGL, and various other tools to add game logic, design animation, add game physics, and build astonishing UI for the games. Towards the final chapters, you’ll learn to exploit mobile device features such as accelerators and sensors to build engaging user experiences. If you are planning to learn about Qt and its associated toolsets to build apps and games, this book is a must have.
Table of Contents (18 chapters)
Game Programming Using Qt
About the Authors
About the Reviewers

Time for action – writing the OOP conform code using QSignalMapper

A more elegant way that does not rely on sender() would be to use QSignalMapper and a local hash, in which all replies that are connected to that slot are stored. So, whenever you call QNetworkAccessManager::get(), store the returned pointer in a member variable of the QHash<int, QNetworkReply*> type and set up the mapper. Let's assume that we have the following member variables and that they are set up properly:

QNetworkAccessManager *m_nam;
QSignalMapper *m_mapper;
QHash<int, QNetworkReply*> m_replies;

Then, you connect the finished() signal of a reply this way:

QNetworkReply *reply = m_nam->get(QNetworkRequest(QUrl(/*...*/)));
connect(reply, SIGNAL(finished()), m_mapper, SLOT(map()));
int id = /* unique id, not already used in m_replies*/;
m_replies.insert(id, reply);
m_mapper->setMapping(reply, id);

What just happened?

First, we posted the request and fetched the pointer to QNetworkReply with reply. Then...