Search icon CANCEL
Subscription
0
Cart icon
Your Cart (0 item)
Close icon
You have no products in your basket yet
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Free Learning
Arrow right icon
Practical Game AI Programming
Practical Game AI Programming

Practical Game AI Programming: Unleash the power of Artificial Intelligence to your game

eBook
$9.99 $43.99
Paperback
$54.99
Subscription
Free Trial
Renews at $19.99p/m

What do you get with Print?

Product feature icon Instant access to your digital eBook copy whilst your Print order is Shipped
Product feature icon Paperback book shipped to your preferred address
Product feature icon Download this book in EPUB and PDF formats
Product feature icon Access this title in our online reader with advanced features
Product feature icon DRM FREE - Read whenever, wherever and however you want
OR
Modal Close icon
Payment Processing...
tick Completed

Shipping Address

Billing Address

Shipping Methods
Table of content icon View table of contents Preview book icon Preview Book

Practical Game AI Programming

Possibility and Probability Maps

In this chapter, we'll be talking about possibility and probability maps, understanding how and where they are used. We'll also be learning the best practices for creating an AI that reacts to the player and that also chooses the best options, as we look to create a character that can make decisions as a human would.

As we saw previously, video games used to rely heavily on predetermining the behavior of what the AI could do in different scenarios that were either created by the game itself or by the player's actions. This method has been present since day one and is still being used today, making it an extremely valuable method for creating quality AI characters. Before explaining, in detail, what each of the maps do, and before demonstrating how to create them in order to develop good AI behavior, it's always good to have...

Game states

To understand how to create possibility or probability maps we need to first acknowledge the principle aspect necessary to create them, which is called game states, or simply states. We call game states to the actions that are predetermined throughout different occasions in the game, and those actions can be applied to both the player or to the enemy character. Some examples can be simple behavior, such as run, jump, or attack, and those states can be expanded a little more, for example when the character is in the air and cannot attack or if the character has low magical energy and cannot perform a magic attack. In these cases, the character goes from one state to another or can't perform one if it's doing another.

Possibility maps

Now let's take a deeper look at the possibility maps that we encountered in the examples in the first chapter, from the chess machine to the Metal Gear Solid video game. As we can see, it's a technique that is still being used today, and it is almost impossible to create a game AI without it.

As the name suggests, possibility maps allow the programmer to define the possibilities available to the player or the AI character within the game. Everything that is possible inside the game needs to be planned and coded, but what happens when you allow the character to do a lot of things can they do them all at the same time? If played during different stages of the game, can they react in the same way at all of the stages? To allow, and restrain, the possible actions, we also need to think about the possible scenarios that can occur in the game, and when you...

Defining the states

Let's define what triggers each state and how the AI should choose the correct state in different scenarios. The PASSIVE state will be the default state, and the game will start in that position until the player comes across our character. The DEFENSIVE state will be used in two different situations if the player comes from the right side and if he has already confronted the player and has low HP. Finally, the AGGRESSIVE state will be activated if the player comes from the left side or has already arrived at the middle area:

public class Enemy : MonoBehaviour {
private int Health = 100;
private bool statePassive;
private bool stateAggressive;
private bool stateDefensive;
private bool triggerL;
private bool triggerR;
private bool triggerM;
// Use this for initialisation
void Start () {
statePassive = true;
}
// Update is called once per frame
void Update ...

Probability maps

A probability map is a more complex and detailed version of a possibility map because it relies on probabilities in order to change the behavior of the character, rather than a simple on or off trigger. Its similarity with the possibility map is that it's also required for planning ahead the possible states for our character. This time, however, we add to it a percentage, using which the AI will calculate what behavior he will be using. Imagine the next example using the situation that we previously created for the possibility map our enemy AI could be more aggressive in the daytime than at night. For that, we create a statement that explains to our enemy that if it's night time, there is a lesser chance of seeing the player character, and for that reason it will choose a more defensive approach instead of an aggressive one. Or, simply, we could define...

Summary

This chapter has described possibility and probability maps and we have learned how to let the AI take decisions for itself according to the player actions. Possibility and probability maps is the foundation of an AI character and now we can explore this technique to create new and unique artificial intelligence for our games. In the next chapter, we'll learn how the AI should behave according to the different options that it has on that moment instead of using a possibility map. We want the character to analyze the situation and think about what to do, taking in consideration many factors, such as health, distance, weapon, bullets, and any other relevant factors.

Left arrow icon Right arrow icon
Download code icon Download Code

Key benefits

  • Move beyond using libraries to create smart game AI, and create your own AI projects from scratch
  • Implement the latest algorithms for AI development and in-game interaction
  • Customize your existing game AI and make it better and more efficient to improve your overall game performance

Description

The book starts with the basics examples of AI for different game genres and directly jumps into defining the probabilities and possibilities of the AI character to determine character movement. Next, you’ll learn how AI characters should behave within the environment created. Moving on, you’ll explore how to work with animations. You’ll also plan and create pruning strategies, and create Theta algorithms to find short and realistic looking game paths. Next, you’ll learn how the AI should behave when there is a lot of characters in the same scene. You'll explore which methods and algorithms, such as possibility maps, Forward Chaining Plan, Rete Algorithm, Pruning Strategies, Wall Distances, and Map Preprocess Implementation should be used on different occasions. You’ll discover how to overcome some limitations, and how to deliver a better experience to the player. By the end of the book, you think differently about AI.

Who is this book for?

This book is for game developers with a basic knowledge of game development techniques and some basic programming techniques in C# or C++.

What you will learn

  • Get to know the basics of how to create different AI for different type of games
  • Know what to do when something interferes with the AI choices and how the AI should behave if that happens
  • Plan the interaction between the AI character and the environment using Smart Zones or Triggering Events
  • Use animations correctly, blending one animation into another and rather than stopping one animation and starting another
  • Calculate the best options for the AI to move using Pruning Strategies, Wall Distances, Map Preprocess Implementation, and Forced Neighbours
  • Create Theta algorithms to the AI to find short and realistic looking paths
  • Add many characters into the same scene and make them behave like a realistic crowd
Estimated delivery fee Deliver to Egypt

Standard delivery 10 - 13 business days

$12.95

Premium delivery 3 - 6 business days

$34.95
(Includes tracking information)

Product Details

Country selected
Publication date, Length, Edition, Language, ISBN-13
Publication date : Jun 30, 2017
Length: 348 pages
Edition : 1st
Language : English
ISBN-13 : 9781787122819
Vendor :
Unity Technologies
Languages :
Tools :

What do you get with Print?

Product feature icon Instant access to your digital eBook copy whilst your Print order is Shipped
Product feature icon Paperback book shipped to your preferred address
Product feature icon Download this book in EPUB and PDF formats
Product feature icon Access this title in our online reader with advanced features
Product feature icon DRM FREE - Read whenever, wherever and however you want
OR
Modal Close icon
Payment Processing...
tick Completed

Shipping Address

Billing Address

Shipping Methods
Estimated delivery fee Deliver to Egypt

Standard delivery 10 - 13 business days

$12.95

Premium delivery 3 - 6 business days

$34.95
(Includes tracking information)

Product Details

Publication date : Jun 30, 2017
Length: 348 pages
Edition : 1st
Language : English
ISBN-13 : 9781787122819
Vendor :
Unity Technologies
Languages :
Tools :

Packt Subscriptions

See our plans and pricing
Modal Close icon
$19.99 billed monthly
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Simple pricing, no contract
$199.99 billed annually
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Choose a DRM-free eBook or Video every month to keep
Feature tick icon PLUS own as many other DRM-free eBooks or Videos as you like for just $5 each
Feature tick icon Exclusive print discounts
$279.99 billed in 18 months
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Choose a DRM-free eBook or Video every month to keep
Feature tick icon PLUS own as many other DRM-free eBooks or Videos as you like for just $5 each
Feature tick icon Exclusive print discounts

Frequently bought together


Stars icon
Total $ 147.97
Practical Game AI Programming
$54.99
Game Development Patterns and Best Practices
$48.99
Game Physics Cookbook
$43.99
Total $ 147.97 Stars icon
Banner background image

Table of Contents

10 Chapters
Different Problems Require Different Solutions Chevron down icon Chevron up icon
Possibility and Probability Maps Chevron down icon Chevron up icon
Production System Chevron down icon Chevron up icon
Environment and AI Chevron down icon Chevron up icon
Animation Behaviors Chevron down icon Chevron up icon
Navigation Behavior and Pathfinding Chevron down icon Chevron up icon
Advanced Pathfinding Chevron down icon Chevron up icon
Crowd Interactions Chevron down icon Chevron up icon
AI Planning and Collision Avoidance Chevron down icon Chevron up icon
Awareness Chevron down icon Chevron up icon
Get free access to Packt library with over 7500+ books and video courses for 7 days!
Start Free Trial

FAQs

What is the delivery time and cost of print book? Chevron down icon Chevron up icon

Shipping Details

USA:

'

Economy: Delivery to most addresses in the US within 10-15 business days

Premium: Trackable Delivery to most addresses in the US within 3-8 business days

UK:

Economy: Delivery to most addresses in the U.K. within 7-9 business days.
Shipments are not trackable

Premium: Trackable delivery to most addresses in the U.K. within 3-4 business days!
Add one extra business day for deliveries to Northern Ireland and Scottish Highlands and islands

EU:

Premium: Trackable delivery to most EU destinations within 4-9 business days.

Australia:

Economy: Can deliver to P. O. Boxes and private residences.
Trackable service with delivery to addresses in Australia only.
Delivery time ranges from 7-9 business days for VIC and 8-10 business days for Interstate metro
Delivery time is up to 15 business days for remote areas of WA, NT & QLD.

Premium: Delivery to addresses in Australia only
Trackable delivery to most P. O. Boxes and private residences in Australia within 4-5 days based on the distance to a destination following dispatch.

India:

Premium: Delivery to most Indian addresses within 5-6 business days

Rest of the World:

Premium: Countries in the American continent: Trackable delivery to most countries within 4-7 business days

Asia:

Premium: Delivery to most Asian addresses within 5-9 business days

Disclaimer:
All orders received before 5 PM U.K time would start printing from the next business day. So the estimated delivery times start from the next day as well. Orders received after 5 PM U.K time (in our internal systems) on a business day or anytime on the weekend will begin printing the second to next business day. For example, an order placed at 11 AM today will begin printing tomorrow, whereas an order placed at 9 PM tonight will begin printing the day after tomorrow.


Unfortunately, due to several restrictions, we are unable to ship to the following countries:

  1. Afghanistan
  2. American Samoa
  3. Belarus
  4. Brunei Darussalam
  5. Central African Republic
  6. The Democratic Republic of Congo
  7. Eritrea
  8. Guinea-bissau
  9. Iran
  10. Lebanon
  11. Libiya Arab Jamahriya
  12. Somalia
  13. Sudan
  14. Russian Federation
  15. Syrian Arab Republic
  16. Ukraine
  17. Venezuela
What is custom duty/charge? Chevron down icon Chevron up icon

Customs duty are charges levied on goods when they cross international borders. It is a tax that is imposed on imported goods. These duties are charged by special authorities and bodies created by local governments and are meant to protect local industries, economies, and businesses.

Do I have to pay customs charges for the print book order? Chevron down icon Chevron up icon

The orders shipped to the countries that are listed under EU27 will not bear custom charges. They are paid by Packt as part of the order.

List of EU27 countries: www.gov.uk/eu-eea:

A custom duty or localized taxes may be applicable on the shipment and would be charged by the recipient country outside of the EU27 which should be paid by the customer and these duties are not included in the shipping charges been charged on the order.

How do I know my custom duty charges? Chevron down icon Chevron up icon

The amount of duty payable varies greatly depending on the imported goods, the country of origin and several other factors like the total invoice amount or dimensions like weight, and other such criteria applicable in your country.

For example:

  • If you live in Mexico, and the declared value of your ordered items is over $ 50, for you to receive a package, you will have to pay additional import tax of 19% which will be $ 9.50 to the courier service.
  • Whereas if you live in Turkey, and the declared value of your ordered items is over € 22, for you to receive a package, you will have to pay additional import tax of 18% which will be € 3.96 to the courier service.
How can I cancel my order? Chevron down icon Chevron up icon

Cancellation Policy for Published Printed Books:

You can cancel any order within 1 hour of placing the order. Simply contact customercare@packt.com with your order details or payment transaction id. If your order has already started the shipment process, we will do our best to stop it. However, if it is already on the way to you then when you receive it, you can contact us at customercare@packt.com using the returns and refund process.

Please understand that Packt Publishing cannot provide refunds or cancel any order except for the cases described in our Return Policy (i.e. Packt Publishing agrees to replace your printed book because it arrives damaged or material defect in book), Packt Publishing will not accept returns.

What is your returns and refunds policy? Chevron down icon Chevron up icon

Return Policy:

We want you to be happy with your purchase from Packtpub.com. We will not hassle you with returning print books to us. If the print book you receive from us is incorrect, damaged, doesn't work or is unacceptably late, please contact Customer Relations Team on customercare@packt.com with the order number and issue details as explained below:

  1. If you ordered (eBook, Video or Print Book) incorrectly or accidentally, please contact Customer Relations Team on customercare@packt.com within one hour of placing the order and we will replace/refund you the item cost.
  2. Sadly, if your eBook or Video file is faulty or a fault occurs during the eBook or Video being made available to you, i.e. during download then you should contact Customer Relations Team within 14 days of purchase on customercare@packt.com who will be able to resolve this issue for you.
  3. You will have a choice of replacement or refund of the problem items.(damaged, defective or incorrect)
  4. Once Customer Care Team confirms that you will be refunded, you should receive the refund within 10 to 12 working days.
  5. If you are only requesting a refund of one book from a multiple order, then we will refund you the appropriate single item.
  6. Where the items were shipped under a free shipping offer, there will be no shipping costs to refund.

On the off chance your printed book arrives damaged, with book material defect, contact our Customer Relation Team on customercare@packt.com within 14 days of receipt of the book with appropriate evidence of damage and we will work with you to secure a replacement copy, if necessary. Please note that each printed book you order from us is individually made by Packt's professional book-printing partner which is on a print-on-demand basis.

What tax is charged? Chevron down icon Chevron up icon

Currently, no tax is charged on the purchase of any print book (subject to change based on the laws and regulations). A localized VAT fee is charged only to our European and UK customers on eBooks, Video and subscriptions that they buy. GST is charged to Indian customers for eBooks and video purchases.

What payment methods can I use? Chevron down icon Chevron up icon

You can pay with the following card types:

  1. Visa Debit
  2. Visa Credit
  3. MasterCard
  4. PayPal
What is the delivery time and cost of print books? Chevron down icon Chevron up icon

Shipping Details

USA:

'

Economy: Delivery to most addresses in the US within 10-15 business days

Premium: Trackable Delivery to most addresses in the US within 3-8 business days

UK:

Economy: Delivery to most addresses in the U.K. within 7-9 business days.
Shipments are not trackable

Premium: Trackable delivery to most addresses in the U.K. within 3-4 business days!
Add one extra business day for deliveries to Northern Ireland and Scottish Highlands and islands

EU:

Premium: Trackable delivery to most EU destinations within 4-9 business days.

Australia:

Economy: Can deliver to P. O. Boxes and private residences.
Trackable service with delivery to addresses in Australia only.
Delivery time ranges from 7-9 business days for VIC and 8-10 business days for Interstate metro
Delivery time is up to 15 business days for remote areas of WA, NT & QLD.

Premium: Delivery to addresses in Australia only
Trackable delivery to most P. O. Boxes and private residences in Australia within 4-5 days based on the distance to a destination following dispatch.

India:

Premium: Delivery to most Indian addresses within 5-6 business days

Rest of the World:

Premium: Countries in the American continent: Trackable delivery to most countries within 4-7 business days

Asia:

Premium: Delivery to most Asian addresses within 5-9 business days

Disclaimer:
All orders received before 5 PM U.K time would start printing from the next business day. So the estimated delivery times start from the next day as well. Orders received after 5 PM U.K time (in our internal systems) on a business day or anytime on the weekend will begin printing the second to next business day. For example, an order placed at 11 AM today will begin printing tomorrow, whereas an order placed at 9 PM tonight will begin printing the day after tomorrow.


Unfortunately, due to several restrictions, we are unable to ship to the following countries:

  1. Afghanistan
  2. American Samoa
  3. Belarus
  4. Brunei Darussalam
  5. Central African Republic
  6. The Democratic Republic of Congo
  7. Eritrea
  8. Guinea-bissau
  9. Iran
  10. Lebanon
  11. Libiya Arab Jamahriya
  12. Somalia
  13. Sudan
  14. Russian Federation
  15. Syrian Arab Republic
  16. Ukraine
  17. Venezuela