Chapter 1, Getting Started with AI Sandbox, begins with learning the overview of how projects are set up as well as how the Lua script interacts with C++ code. Here, the beginnings of the AI sandbox are built from open source technologies, starting with a framework that integrates Lua, Ogre3D, OpenSteer, and Bullet Physics.

Chapter 2, Creating and Moving Agents, starts off with examples of the lowest layer of AI interaction with the world, local steering, and movement. Here, agent seeking, avoiding, and group movement are introduced into the sandbox through the use of the OpenSteer library.

Chapter 3, Character Animations, continues with the AI sandbox by exposing Ogre3D's animation playback and resource handling of Lua scripts. Low-level structures for controlling animation clips, animation state machines, and layered animations are integrated into the sandbox.

Chapter 4, Mind Body Control, combines animation handling with local steering and agent movement. Two different approaches toward mind and body interactions will be implemented. The first will focus on the latency between agent decisions and actions, while the second approach will focus on the perceived quality of the agent's actions.

Chapter 5, Navigation, builds up from local movement and moves on to long distance movement and planning. Navigation mesh generation provided by the Recast library will be integrated into the AI sandbox in order to allow A* pathfinding provided by the Detour library.

Chapter 6, Decision Making, adds intelligence to the choices the AI agents make. Different data structures and approaches to creating modular and reusable decision logic are covered through Lua scripts. Decision trees, finite state machines, and behavior trees are integrated into the sandbox.

Chapter 7, Knowledge Representation, adds the ability to store long-term and short-term information for individual agents. A centralized approach to storing and propagating agent knowledge about the world is exposed to Lua.

Chapter 8, Perception, exposes the services that are available to agents for them to query information about the world. Approaches toward visual- and communication-based information is integrated into the sandbox.

Chapter 9, Tactics, exposes a high-level spatial knowledge of the environment to the sandbox. Through a grid-based representation of the world, different knowledge sources are combined in order to give you an accurate tactical view of the environment for decision making.

The AI sandbox solution and project files are built automatically through Premake, which is the utility program. Visual Studio 2008, 2010, 2012, and 2013 were tested for compatibility with each of the included demos. With the large number of dependencies the sandbox builds from the source, the project setup is only supported from Visual Studio.

The open source Lua IDE, which is Decoda, is used to write and debug Lua scripts within the sandbox. While other Lua script editors can be used, the sandbox natively exposes information that allows seamless Lua debugging within Decoda.

This book is aimed at programmers who are looking to understand all the facets involved with the creation of the game AI. You should be comfortable with C or C++ and the Lua programming language. While no direct C or C++ knowledge is required, being able to fully debug into the sandbox allows for extending the existing functionality. A combination of both functional and object-oriented Lua will be used by the sandbox, and both approaches will be explained. Additional understanding of modern game engines will be useful but is not required.

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "The LuaScriptUtilities header defines the metatable name of the vector type."

A block of code is set as follows:

local function CallCallbacks(callbacks, stateName, looping)
    for index = 1, #callbacks do
        callbacks[index].callback(
            stateName, looping, callbacks[index].data);
    end
end

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "Open the Settings menu under the Project menu."

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