Book Image

OpenGL Game Development By Example

By : Stephen Madsen, Robert Madsen
Book Image

OpenGL Game Development By Example

By: Stephen Madsen, Robert Madsen

Overview of this book

OpenGL is one of the most popular rendering SDKs used to develop games. OpenGL has been used to create everything from 3D masterpieces running on desktop computers to 2D puzzles running on mobile devices. You will learn to apply both 2D and 3D technologies to bring your game idea to life. There is a lot more to making a game than just drawing pictures and that is where this book is unique! It provides a complete tutorial on designing and coding games from the setup of the development environment to final credits screen, through the creation of a 2D and 3D game. The book starts off by showing you how to set up a development environment using Visual Studio, and create a code framework for your game. It then walks you through creation of two games–a 2D platform game called Roboracer 2D and a 3D first-person space shooter game–using OpenGL to render both 2D and 3D graphics using a 2D coordinate system. You'll create sprite classes, render sprites and animation, and navigate and control the characters. You will also learn how to implement input, use audio, and code basic collision and physics systems. From setting up the development environment to creating the final credits screen, the book will take you through the complete journey of creating a game engine that you can extend to create your own games.
Table of Contents (19 chapters)
OpenGL Game Development By Example
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Graphical User Interface


It is now time to turn our attention to the graphical user interface, or GUI. The GUI allows us to control other elements of the game, such as starting or stopping the game, or setting various options.

In this section, you will learn how to create buttons on the screen that can be clicked by the mouse. We'll keep it simple by adding a single button to pause the game. While we are at it, we will learn important lessons about game state.

Creating a button

A button is nothing more than a texture that is being displayed on the screen. However, we have to perform some special coding to detect whether or not the button is being clicked. We will add this functionality to the sprite class so that our buttons are being handled by the same class that handles other image in our game.

We will actually create two buttons: one to Pause and one to Resume. I have used a simple graphics program to create the following two buttons:

I have saved these buttons as, you guessed it, pause.png...