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

Rendering


We did a lot of work creating our sprites, but nothing is going to show up until we actually render the sprites using OpenGL. Rendering is done for every frame of the game. First, an Update function is called to update the state of the game, then everything is rendered to the screen.

Adding a render to the game loop

Let's start by adding a call to Render in the GameLoop RoboRacer.cpp:

void GameLoop()
{
  Render();
}

At this point, we are simply calling the main Render function (implemented in the next section). Every object that can be drawn to the screen will also have a Render method. In this way, the call to render the game will cascade down through every renderable object in the game.

Implementing the main Render function

Now, it is time to implement the main Render function. Add the following code to RoboRacer.cpp:

void Render()
{
  glClear(GL_COLOR_BUFFER_BIT);
  glLoadIdentity();
  
  background->Render();
  robot_left->Render();
  robot_right->Render();
  robot_left_strip...