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
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Time for action – implementing the ability to move the scene


Next it would be good to move the scene around without the need of using the scroll bars. Let us add the functionality for pressing and holding the left mouse button. First, we add two private members to the view: the m_pressed parameter of type bool and the m_lastMousePos element of type QPoint. Then, we reimplement the mousePressEvent() and mouseReleaseEvent() functions as follows:

void MyView::mousePressEvent(QMouseEvent *event) {
  if (Qt::LeftButton == event->button()) {
    m_pressed = true;
    m_lastMousePos = event->pos();
  }
  QGraphicsView::mousePressEvent(event);
}

void MyView::mouseReleaseEvent(QMouseEvent *event) {
  if (Qt::LeftButton == event->button())
    m_pressed = false;
  QGraphicsView::mouseReleaseEvent(event);
}

What just happened?

Within mousePressEvent(), we check whether the left mouse button was pressed. If it was true, we then set m_pressed to true and save the current mouse position in m_lastMousePos...