Role Playing Games (RPGs) - PowerPoint Presentation

Slide1

Role Playing Games (RPGs)

Mike Rowan

Anthony

ScimecaSlide2

History Tactics

MMORPG

Large Scale AIReputation SystemSide-Quests

OverviewSlide3

Games which are typically set in a fantasy environment. (Magic, Mythology, etc.)Top Down View

Rich and extensive stories to entertain user.

Strategic element to gameplay.Heavily built on character building.

Use of Hit Points (HP) for health.

OverviewSlide4

RPGs are a hard genre to define and are ultimately descendants from a wide variety of games.

War games, Sports Simulation, etc.

Dungeons & Dragons (1974) – board game that revolutionized the genre and can almost be considered a prototype of later RPGs.

Fantasy based game where users used imaginations to depict a world of possibilities

combination of make-believe, play-acting, and a logical, math-based rule system.

HistorySlide5

DND (1974)– first CRPG (Computer RPG)

Made for PLATO (a computerized learning system at Southern Illinois University)

Game consisted of many novels of RPG genre such as character creation and development of specific statistics, and leveling up with experience points.

Featured a shop to buy equipment.

Story involved killing a dragon and obtaining orb.

HistorySlide6

UNIX based games helped pave the way for common day RPGs.

Rouge (1980) – Featured randomized dungeons for replay ability.

Ultima (1981) – laid many foundations such as tile based graphics, and more complex fights requiring more strategy

Wizardry: Proving Grounds of the Mad

Overworld

(1981) – First RPG that was party-based, offered first-person view of action.

HistorySlide7

Turn basedEach member of party has a turn and can perform an action at this time.

Slower pace to allow for user to think things out

Wizardry video (1:10-2:31)

Real-Time

More realistic, fast-paced.

Can get hectic with needing to keep track of many things at once.

Chinese game

Qingcheng

video

CombatSlide8

Need path finding algorithms for enemy NPCs in today’s games.

Have more difficult AI in later stages of game.

Need smart AI for friendly NPCs and enemy NPCs.Must quickly assess situation and decide what is best tactic to use.

Consider strengths/weaknesses of party members on each side.

Pokemon

(1:45-2:05)

Heroes of Might and Magic (1:40-2:10)

AISlide9

MMORPG

Massively Multiplayer Online Role Playing Game

Popular MMORPG games include EVE Online, World of

Warcraft

,

Aion

, Guild WarsMany are pay to play and do not offer a simple “You Win” or “Game Over” screen, no matter how long you playSlide10

MMORPG Player Interaction

Players can interact with most players usually based upon other player locality

For example, a player can “speak” something that will show up on the chat screen of other players within 25 yards or a player can “yell” something that has a 100 yard radius

Other players follow the same rules as the player, however they interact at their own pace, not controlled by the CPUSlide11

MMORPG Reputation System

The reputation system is one of the biggest drivers of player environment interaction

Some reputations determine who the player fights and who the player can interact friendly towards

The player needs a sense of involvement with the NPC’s in an MMORPG because the player wants to interact with their environment as they do different thingsSlide12

MMORPG NPC Units

The AI is very important in NPC units

Path finding to various players and player set obstacles

Analyzing the reputation of other players

Priority system for determining who to attack or defend, also known as “threat” or “

aggro

”Slide13

Path finding

AI units in MMORPGs need to be able to find the player (or multiple players) from any location and learn how to get there or otherwise compensate for the situation

http://www.youtube.com/watch?v=lw9G-8gL5o0Slide14

Threat / Aggro

There are numerous ways enemies can attack another player when there are multiple players playing the game

Attack at random

Attack first on sight

Attack strategically depending on the players’ roles

There are modifiers that exist to change thisSlide15

Threat / Aggro

For example, a unit may have a specific ability to force the unit to attack it by shielding friendly targets or putting themselves on top of the priority list of potential targets

A good example is in World of

Warcraft

. A “tank” unit is designed to direct all damage to it by using abilities that have high threatSlide16

Threat / Aggro

As threat is generated, the enemy keeps a list of who is generating the most threat. That will determine who they will attackSlide17

With the emergence of MMORPGs and the large sizes that are demanded out of RPG games today, larger maps are needed, meaning more NPCs are interacting at a certain time.

To compensate for this issue, a concept of Level of Detail AI is used.

The following is the implementation used for Neverwinter

Nights (NWN) by

BioWare

.

Level of Detail AISlide18

Concept is borrowed from graphic engines.

Essentially, objects that are further in the distance do not need to be made as complex so they are constructed with less polygons.

Level of Detail AISlide19

To translate this into an AI perspective, NPCs that are out of the viewing distance from the human player do not need to be fully processed and optimized.

Need to split characters into groups according to distance.

Level of Detail AISlide20

Level of Detail AISlide21

Level of Detail AISlide22

Assign a certain % of CPU time to each category. Will determine how much CPU is devoted to specific group every iteration of an update.

Level of Detail AISlide23

Levels 1-3: go through the entire

pathfinding

algorithm, since these characters are shown their movements need to be smooth and natural.Level 4: Characters are out of viewing range, they perform inter-tile method but instead of smooth movement, they jump from tile to tile.

Level 5: Characters are not in vicinity, therefore simply determine time between itself and destination, then have a delay and jump to target location

Level of Detail AI -

PathfindingSlide24

NWN has very complex rule set, the Basic combat rules fill 10 pages of text and there are over 50 pages of exceptions to the base rules.

Therefore need to cut down processing power used in each combat situation, especially when not shown.

Level of Detail AI - CombatSlide25

Level 1&2: Implement full rule system since combat is actively shown to user.

Level 3: Implement full rule system unless many complications occur. If this is the case, skip computations, need to allow character to look like it is performing correct action.

Level 4: Compute each character’s damage capabilities and determine winner through formula. (

Level 5: Perform biased coin flip according to damage capability of each character.

Level of Detail AI - CombatSlide26

Reputation System

Provides a different system of events for players who want an alternative playing experience

Shows the player that the AI controlled factions care about what you do for them, making the player feel involved

Allows the player to strive for things, such as rarities and rewards specific to a particular factionSlide27

Master Event List

So, are all events stored per NPC?

Events are stored in a Master Event List

Conserves memory

Keeps events organized for more timely response

Easy to update

Events are consolidated so that an NPC can reference the list in order to determine how they should react to the player instead of keeping their stance in local memorySlide28

Master Event List

To add an event to the list, you take an event:Slide29

Subject Group

Player

Verb

DidViolenceTo

Object Group

Bandit

Object Individual

Joe

Magnitude

75 (Killed)

Where

50,20,138 (in front of saloon)

When

High Noon

Template

KilledBanditTemplate

Reference Count

Known by 11 NPCs

Reputation Effects

Bandits hate player more

Lawmen like player more

Farmers like player more

Provide a table entry with the details:Slide30

Master Event List

Later on, the NPC can reference that list

NPC’s can share information between themselves if they find it relevant about the player so reputation can trickle down to all NPC’s associated

This gives the programmer the ability to change the

gameplay

for the player based upon previous player choicesSlide31

Faction Knowledge

Now we see how these events can occur, how can an NPC remember?

Assign a hierarchy of reputation

For example, if someone helped or hurt someone from Lehigh, that may affect you. If this someone was also a family member, it would affect you more

The following example from EVE on the trickling down of reputationSlide32

Agent works for Federation Navy

This agent is Level

1

This player’s current standing (reputation) is

6.4

Mission named

Break Their WillSlide33

Upon mission completion, player receives

0.1389%

reputation gain for Federation Navy

This player’s new standing with the agent is

6.5

The player gained some reputationSlide34

Reputation allows for many things:

Access to higher level agents that give better rewards.

Ability to purchase better items

Additional servicesSlide35

Upon completion of a Level 4 mission, there are higher rewards than a Level 1

For example, notice the higher gain in reputation towards the NavySlide36

Optional missions that involve objective based storylines that are separate from main storyline.

Normally used to obtain a useful item, gain extra experience, or learn more about the overall story or background of game.

Allows gamers to make decisions in story, and makes getting a 100% completion rate a more difficult and rewarding task.

Zelda Satire

Side QuestsSlide37

Side QUEst

GEnerator

Tool – software for generating side quests, reduce manual labor in creating them.Programmer can then write dialogue for quest after generating or hook SQUEGE up to a game dependent script generator

Have specific patterns for side quests.

Assassain’s

Creed

SQUEGESlide38

Pattern

Description

Talk Chain

Talk to multiple NPCs

Acquire item

Find location of

item and obtain

Deliver item

Find location

of item and return to an NPC

Kill antagonist

Find location of NPC and kill

Assassinate

antagonist

Find location of NPC and kill then report back to NPC

who assigned mission

One

of many tasks

Must complete one of several tasks

All of many tasks

Must complete all tasks specified

Chain quest

Complete pattern

one after another in specified order

Pattern Catalog

Last 3 are meta-quests, combine simple quests into more complex ones with more options. (Like Recursion)Slide39

Takes input of patterns, NPCs, Containers, Items and Options.Will output a quest outline.

Designer can accept this outline or decline and have SQUEGE generate another.

If accepted, designer adapts quest outline and adds story content and generates a script either manually or automatically.

SQUEGE processSlide40

Examples

Many ways to go about side quests.

Straight forward

Can have a side quest in a side quest.Slide41
Slide42

So while this is all good and well, there are still cases where designers need to adapt or reject SQUEGE generated quests.

For example, do not want to give the user a very powerful item at the beginning of the game through an easy side quest.

SQUEGESlide43

Normal – all other points in the quest are disabledOptional – Is not required to complete the quest

Close – Either close-succeed or close-fail. all points become disabled, quest is considered completed and logged as so if necessary.

SQUEGE - Quest PointsSlide44

Each quest point in a pattern has a set of possible encounters.These encounters have a weight associated with them and are chosen depending on weight of each. (Higher weight has more priority)

Subquests

can also be generated, factor established by user determines how often

subquest

is generated for a quest.

How it worksSlide45

Adding Patterns

Need to specify quest points and possible encounters for each quest point.

Example Code:Slide46

Newer console RPG games have elaborate stories and are evolving into a solo player experience where user can get attached to the main hero.

Computer RPG games are all utilizing trend of MMORPGs.

First and Third person views more popular.

Hybrid versions of RPGs mixed with other genres are being mainstreamed.

Borderlands (FPS+RPG)

Sports Simulators (RPG role of

soley

managing team)

World of

Warcraft (RTS+RPGs)

Currently and Moving ForwardSlide47

Brockington, Mark, “Level-Of-Detail AI for a Large Role-Playing Game” AI Game Programming Wisdom Vol. 1, pp 419-425, 2002

Alt, Greg, “A Dynamic Reputation System Based on Event Knowledge” AI Game Programming Wisdom Vol. 1, pp 426-435, 2002

Onuczko

, Curtis, and

Szafron

, Duane, and Schaeffer, Jonathan, “Stop Getting Side-Tracked by Side-Quests” AI Game Programming Wisdom Vol. 3, pp 513-526, 2002

Barton Matt, “The History of Computer Role-Playing Games Part 1: The Early Years (1980-1983)” http://www.armchairarcade.com/neo/node/1081 2006.

References