Book Image

Unity 2018 Artificial Intelligence Cookbook - Second Edition

By : Jorge Palacios
Book Image

Unity 2018 Artificial Intelligence Cookbook - Second Edition

By: Jorge Palacios

Overview of this book

Interactive and engaging games come with intelligent enemies, and this intellectual behavior is combined with a variety of techniques collectively referred to as Artificial Intelligence. Exploring Unity's API, or its built-in features, allows limitless possibilities when it comes to creating your game's worlds and characters. This cookbook covers both essential and niche techniques to help you take your AI programming to the next level. To start with, you’ll quickly run through the essential building blocks of working with an agent, programming movement, and navigation in a game environment, followed by improving your agent's decision-making and coordination mechanisms – all through hands-on examples using easily customizable techniques. You’ll then discover how to emulate the vision and hearing capabilities of your agent for natural and humanlike AI behavior, and later improve the agents with the help of graphs. This book also covers the new navigational mesh with improved AI and pathfinding tools introduced in the Unity 2018 update. You’ll empower your AI with decision-making functions by programming simple board games, such as tic-tac-toe and checkers, and orchestrate agent coordination to get your AIs working together as one. By the end of this book, you’ll have gained expertise in AI programming and developed creative and interactive games.
Table of Contents (12 chapters)

Blending behaviors by weight

The blending techniques allow you to add behaviors and mix them without creating new scripts every time you need a new type of hybrid agent.

This is one of the most powerful techniques in this chapter, and it's probably the most widely-used behavior-blending approach because of its power and the low cost of implementation.

Getting ready

We must add a new member variable to our AgentBehaviour class called weight and preferably assign a default value. In this case, this is 1.0f. We should refactor the Update function to incorporate weight as a parameter for the Agent class's SetSteering function. All in all, the new AgentBehaviour class should look something like this:

public class AgentBehaviour : MonoBehaviour 
{ 
    public float weight = 1.0f; 
 
    // ... the rest of the class 
 
    public virtual void Update () 
    { 
        agent.SetSteering(GetSteering(), weight); 
   } 
}

How to do it...

We just need to change the SetSteering function's signature and definition:

public void SetSteering (Steering steering, float weight) 
{ 
    this.steering.linear += (weight * steering.linear); 
    this.steering.angular += (weight * steering.angular); 
} 

How it works...

The weights are used to amplify the steering behavior result, and they're added to the main steering structure.

There's more...

The weights don't necessarily need to add up to 1.0f. The weight parameter is a reference for defining the relevance that the steering behavior will have among other parameters.

See also

In this project, there is an example of avoiding walls, which is worked out using weighted blending.