1. Fundamentals of Game Design, 2 nd Edition by Ernest Adams Chapter 20: Artificial Life and Puzzle Games

2. Chapter 20 Artificial Life and Puzzle Games2 © 2009 by Pearson Education, Inc Objectives Know the different forms of artificial life games and simulations Design basic artificial life systems Know the steps to designing puzzle games Understand the player’s needs for puzzle games

3. Chapter 20 Artificial Life and Puzzle Games3 © 2009 by Pearson Education, Inc Artificial Life Games Artificial life is a branch of computer science research A-life involves modeling biological processes A-life is the study of emergent properties— unanticipated qualities or behaviors that arise out of the interactions of complex systems A-life games typically focus on maintaining and growing a manageable population of organisms

4. Chapter 20 Artificial Life and Puzzle Games4 © 2009 by Pearson Education, Inc Artificial Life Games (Cont.) Artificial pets  They can be simulations or fantasy pets  Almost always cute; seldom reproduce or die  Gameplay concentrates on training, maintenance, and watching the creatures  Pet needs a lot of AI Variety of triggers and behaviors Show the pet's emotions through behavior

5. Chapter 20 Artificial Life and Puzzle Games5 © 2009 by Pearson Education, Inc Artificial Life Games (Cont.) Artificial pets (cont.)  Player influences pet's emotions through interaction  Pet should interact meaningfully with other pets  Pet must be able to learn  Rich AI distinguishes artificial pets from other A- life  Artificial pet is a software toy—no victory condition

6. Chapter 20 Artificial Life and Puzzle Games6 © 2009 by Pearson Education, Inc Artificial Life Games (Cont.) The Sims  Player controls the sims physically and indirectly affects their relationships  Each sim has a personality  Cross between an artificial pet and a CMS—game has an economy

7. Chapter 20 Artificial Life and Puzzle Games7 © 2009 by Pearson Education, Inc Artificial Life Games (Cont.) The Sims (cont.)  Needs Each sim has six needs that must be met Needs drive the sims' behavior Need-based AI is the heart of most simple behavior simulations  Skills Sims (in the first edition) have six skills they can improve Sims teach themselves skills Time management is critical

8. Chapter 20 Artificial Life and Puzzle Games8 © 2009 by Pearson Education, Inc Artificial Life Games (Cont.) The Sims (cont.)  Personalities Game tries to simulate relationships among individuals Variables define each sim's personality and how they react to each other  Success of The Sims is based on the unprecedented scope for creativity it offers and its emphasis on interpersonal relationships

9. Chapter 20 Artificial Life and Puzzle Games9 © 2009 by Pearson Education, Inc Artificial Life Games (Cont.) Defining affinity between two characters:  The “I Can’t Stand” Rule – A character cannot stand another character who has an attribute above a certain threshold  “Birds of a Feather” Rule – Characters with high levels of one attribute are attracted to others with a high level of the same attribute  “Opposite Attract” Rule – Characters with high levels of one attribute are attracted to others with a low value for the same attribute

10. Chapter 20 Artificial Life and Puzzle Games10 © 2009 by Pearson Education, Inc Artificial Life Games (Cont.) God games  Characteristics Player is a god with limited powers who gets more power from simulated worshippers Omnipresent interaction model and an aerial perspective They often share qualities with CMS (indirect control of population) and real-time strategy (compete directly against a rival god) games

11. Chapter 20 Artificial Life and Puzzle Games11 © 2009 by Pearson Education, Inc Artificial Life Games (Cont.) God games (cont.)  The economy of god games Player’s power (mana) grows with the number and prosperity of his worshippers Size of the population influences the maximum amount of mana the player may have and the rate at which mana is restored when it is below maximum Positive feedback can be limited in various ways:  People do not reproduce instantaneously  Making land suitable for population growth costs mana  Mana cost of using higher-level powers rises exponentially

12. Chapter 20 Artificial Life and Puzzle Games12 © 2009 by Pearson Education, Inc Artificial Life Games (Cont.) God games (cont.)  Gameplay in god games Primary challenge is to produce population growth He must also damage the other god’s worshippers and repair the damage the rival god does to the player’s people  To design a god game, start with the question of what powers you would like the god to have  A god game needs a lot of interesting animations for the people

13. Chapter 20 Artificial Life and Puzzle Games13 © 2009 by Pearson Education, Inc Artificial Life Games (Cont.) Genetic A-life games  Characteristics They are about managing a population over time Player tries to achieve goals for the whole population Can’t concentrate too much on individuals  Designing a genome Genome defines the creatures’ inheritable characteristics such as eye color, hair color, height, etc. Alleles are traits inherited from each parent  If parents have different traits, usually one wins—brown eye allele dominates blue eye allele

14. Chapter 20 Artificial Life and Puzzle Games14 © 2009 by Pearson Education, Inc Artificial Life Games (Cont.) Genetic A-life games (cont.)  Mutation Change to the gene caused by an environmental factor Mutations may benefit the population by introducing random new values into the gene pool  Life span, maturity, and natural selection Each creature needs a natural life span To evolve through natural selection, creatures must have a time of immaturity before they can reproduce  Genetic mutations that cause death in children do not get passed on because children do not reproduce

15. Chapter 20 Artificial Life and Puzzle Games15 © 2009 by Pearson Education, Inc Artificial Life Games (Cont.) Genetic A-life games (cont.)  What does the player do? Create new individuals and add them to the population to see how their genes influence the population Add and remove environmental hazards that would weed out certain genes Play with the rate and nature of mutation by adding or modifying mutagenic objects or areas of the environment Mate individuals to select for particular characteristics

16. Chapter 20 Artificial Life and Puzzle Games16 © 2009 by Pearson Education, Inc Puzzle Games Characteristics  In puzzle games, puzzle solving is the primary activity  Puzzle games usually provide related challenges, variations on a theme  The types of puzzles offered include pattern recognition, logic, or understanding a process  The puzzles give the player clues that have to be solved to meet the victory condition

17. Chapter 20 Artificial Life and Puzzle Games17 © 2009 by Pearson Education, Inc Puzzle Games (Cont.)  Find inspiration  Simplify  Create a construction set  Define the rules  Construct the puzzles  Test  Devise a sequence  Pay attention to presentation Scott Kim’s eight steps in puzzle game design

18. Chapter 20 Artificial Life and Puzzle Games18 © 2009 by Pearson Education, Inc Puzzle Games (Cont.) What computers bring to puzzles  Enable nonphysical or awkward moves  Include computation features  Enforce the rules  Record player moves and undo them  Structure the experience  Teach  Use bells and whistles  Enable online play

19. Chapter 20 Artificial Life and Puzzle Games19 © 2009 by Pearson Education, Inc Puzzle Games (Cont.) Checking the victory condition  Path to the solution might be different than you planned  Check the solution, not the way it was reached

20. Chapter 20 Artificial Life and Puzzle Games20 © 2009 by Pearson Education, Inc Summary You should now understand  How to identify an artificial life game and simulation  How to design basic artificial life systems  How to describe the steps to designing puzzle games  How to explain the player’s needs for puzzle games