Video games are complex, interactive, multimedia software systems. These systems must, in real time, process player input, simulate the interactions of semi-autonomous objects, and generate high-fidelity graphics and audio outputs, all while trying to engage the players. Attempts at building video games can quickly be overwhelmed by the need to be well versed in software development as well as in how to create appealing player experiences. The first challenge can be alleviated with a software library, or game engine, that contains a coherent collection of utilities and objects designed specifically for developing video games. The player engagement goal is typically achieved through careful gameplay design and fine-tuning throughout the video game development process. This book is about the design and development of a game engine; it will focus on implementing and hiding the mundane operations and supporting complex simulations. Through the projects in this book, you will build a practical game engine for developing video games that are accessible across the Internet.