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 – rotating and scaling a picture by pinching


Start a new Qt Quick UI project. In the QML file, delete everything but the external item. Then, add an image to the UI and make it centered in its parent:

Image {
  id: image
  anchors.centerIn: parent
  source: "wilanow.jpg"
}

Now, we will add a PinchArea element. This kind of item can be used in two ways–either by manually implementing signal handlers onPinchStarted, onPinchUpdated, and onPinchFinished to have total control over the functionality of the gesture or by using a simplified interface similar to the drag property of MouseArea. Since the simplified interface does exactly what we want, there is no need to handle pinch events manually. Let's add the following declaration to the file:

PinchArea {
  anchors.fill: parent
  pinch {
    target: image
    minimumScale: 0.2; maximumScale: 2.0
    minimumRotation: -90; maximumRotation: 90
  }
}

You'll get an output similar to the following screenshot:

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Our simple...