OpenGL Game Development by Example

340 Pages·2016·4.715 MB·English

by  Robert Madsen, Stephen Madsen

OpenGL Game Development
By Example
Design and code your own 2D and 3D games efficiently
using OpenGL and C++
Robert Madsen
Stephen Madsen
BIRMINGHAM - MUMBAI
OpenGL Game Development By Example
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First published: March 2016
Production reference: 1010316
Published by Packt Publishing Ltd.
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Birmingham B3 2PB, UK.
ISBN 978-1-78328-819-9
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Credits
Authors Project Coordinator
Robert Madsen Paushali Desai
Stephen Madsen
Proofreader
Safis Editing
Reviewers
Artemis Tsouflidou
Simon W. J. Vanhauwaert Indexer
Monica Ajmera Mehta
Pantelis Lekakis
Graphics
Commissioning Editor
Disha Haria
Julian Ursell
Production Coordinator
Acquisition Editor
Nilesh Mohite
Shaon Basu
Cover Work
Content Development Editor
Nilesh Mohite
Siddhesh Salvi
Technical Editor
Parag Topre
Copy Editor
Priyanka Ravi
About the Authors
Robert Madsen is an accomplished game programmer, with dozens of published
games to his credit. He started programming in 1979, and he has been a programmer
for all of his professional life. He entered the game industry in 2004, and he founded
SynapticSwitch, LLC in 2010. As studio director, he continues to code while also
managing the broader needs of an independent game development studio.
Stephen Madsen completed his degree in game development from Full Sail Real
World Education in 2007, beginning his first job as a game programmer in 2008.
He then joined SynapticSwitch, LLC as the lead software engineer in 2012. He has
developed and published many titles on the mobile, console, and personal computer
platforms with OpenGL being the foundational rendering technology for most of
these platforms.
About the Reviewers
Artemis Tsouflidou is a game developer based in London, and she has experience
in gameplay programming. She studied computer engineering at the University of
Thessaly in Greece, and she continued her studies at Goldsmiths University where
she earned a master's degree in computer games. She is interested in programming
and game development.
Simon W. J. Vanhauwaert is a Belgian game development programmer. He
graduated in digital arts and entertainment, and he is currently professionally
employed in the UK.
Pantelis Lekakis has been in the game industry for 4 years now, and he has been
actively programming and developing his own projects since 2002.
His experience lies in rendering and game engines, and he has worked with various
versions of Direct3D and OpenGL.
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Table of Contents
Preface ix
Chapter 1: Building the Foundation 1
Introducing the development environment 1
A quick look at Visual Studio 3
Start screen 3
The Solution Explorer panel 4
The Standard Toolbar panel 4
The code window 5
The output window 6
Starting your project 6
The game loop 7
The game structure 7
Initialization 8
The game loop 8
Shutdown 9
Creating the game structure 9
Port of access 11
The Windows message loop 11
Introducing OpenGL 13
What is OpenGL? 13
The other GL 14
Downloading OpenGL 14
Adding OpenGL to the project 15
Linking to the OpenGL library 15
Summary 17
Chapter 2: Your Point of View 19
Plotting your revenge 20
The OpenGL coordinate system 20
Making your point 21
Understanding the code 23
[ i ]
Table of Contents
Running the program 26
Stretching your point 27
Getting primitive 29
A triangle by any other name 29
A primitive example 30
From triangles to models 32
Introducing textures 33
Using textures to fill the triangles 33
A matter of reference 35
Hanging out in the quad 36
Coding the quad 37
Rendering a texture 38
Loading the texture 38
Texture wrapping 39
Creating a textured quad 42
Putting the pieces together 43
Summary 44
Chapter 3: A Matter of Character 45
Spritely speaking 45
Sprites versus non-sprites 46
Flipbook animation 46
Framed animation 47
Creating sprites 47
Working with PNGs 47
Linking to the SOIL library 50
Including the SOIL header file 51
Opening an image file 51
Coding a sprite class 52
Creating sprite frames 58
Saving each frame 59
Loading a sprite from individual textures 59
Creating a sprite sheet 60
Loading a sprite sheet 61
Loading our sprites 61
Rendering 65
Adding a render to the game loop 65
Implementing the main Render function 66
Implementing Render in the Sprite class 67
UV mapping 69
One more detail 70
A moving example 70
Adding update to the game loop 71
Implementing the main Update call 71
[ ii ]
Table of Contents
Implementing Update in the Sprite class 72
Character movement 73
Using delta time 73
Calculating delta time 74
Flipping 75
Scrolling the background 76
Using an atlas 77
Summary 78
Chapter 4: Control Freak 79
A penny for your input 79
The keyboard input 80
Using the mouse 80
Touch 81
Other inputs 81
Someone is listening 82
The WndProc event listener 82
Handling the message queue 84
Handling mouse and keyboard inputs 85
Creating the Input class 86
Virtual key codes 87
Querying for input 88
Implementing the Input class 89
Adding input to the game loop 90
Processing our input 91
Changes to the Sprite class 94
Graphical User Interface 95
Creating a button 95
Enhancing the Input class 95
Adding UI elements to the list 96
Checking each UI element 97
Pushing your buttons 98
Adding our pauseButton 99
State management 100
Creating a state manager 101
Pausing the game 101
Summary 104
Chapter 5: Hit and Run 105
Out of bounds! 105
Getting anchored 106
Collision rectangles 110
[ iii ]