Important UDK Classes How they fit together Copyright © 2015 – Curt Hill.

Important UDK Classes

How they fit together

Copyright © 2015 – Curt Hill


Introduction• We have created a level• We have seen an introduction to

UnrealScript• We should have also set

several .ini files• We should have also created

several UnrealScript classes descended from:– GameInfo– Pawn– Controller

Classes• There are several classes that are

vital to your play• These include:

– WorldInfo– GameInfo– Actor– Pawn– Controller – Camera

• Understanding how these interrelate is crucial


WorldInfo• This is the master class for the

engine– We will use this to find out or change

the world in our programs

• Source is in:…\Development\Src\Engine\Classes

• It has instance variables that control:– Lighting, physics, sounds among

othersCopyright © 2015 – Curt Hill

Functions• GetWorldInfo will return a WorldInfo

object• Several iterators:

– AllControllers– AllPawns

• Several events– PostBeginPlay– PreBeginPlay

• It is unlikely but possible we will make a descendant of WorldInfo


WorldInfo and GameInfo

• One of the most important objects of WorldInfo is GameInfo

• The instance variable of type GameInfo is named Game– Since UnrealScript is polymorphic it

may be any descendant of GameInfo

• This is actually set in the Editor– Among other possible places


Menu• The descendent of GameInfo that is

actually part of the WorldInfo is set from the editor– Use the View and World menu

• This is connected to an individual level

• The Game Type is the set of values which are known descendants– A drop down

• It is also dependent on the ancestry of the GameInfo item you choose


View/World


GameInfo

• Determines the rules and characteristics of this game

• This will determine several things in the game– Presence or absence of the pawn– First or third person camera– Heads Up Display

• Next are four displays with different GameInfos


GameInfo


CloudGame


UTTeamGame


UTDeathMatch


GameInfo Descendents


More on GameInfo

• There will only be one GameInfo (or descendant) instance

• Chosen before the level starts and persists for the rest of gameplay for that level– If the level is terminated and a new

level entered a different GameInfo is used

• This class does delegate some of its duties to other classes


Continuing

• GameInfo also selects the player classes

• It specifies the default pawn, camera and controller class

• In this and other ways it is the central class for determining what game play will be like


Actors

• Recall that an actor is anything with a representation in the level

• This includes– Static meshes– Lights– Sounds– Pawns


Actor Events

• Destroyed()• Falling ()• RanInto (Actor Other)

– Actor ran into another actor

• TakeDamage and Tick will be considered later


More Events• Bump (Actor Other,

PrimitiveComponent OtherComp, Object.Vector HitNormal)– Somebody bumped me

• HitWall ( Object.Vector HitNormal, Actor Wall, PrimitiveComponent WallComp)


TakeDamage

• When a pawn or actor is damaged this event is called

• It may be used to modify the damage– Such as when armor is present

• It may also be called to inflict damage


TakeDamage• Signature:event TakeDamage ( int Damage, Controller InstigatedBy, Object.Vector HitLocation, Object.Vector Momentum, class<DamageType> DamageType, optional Actor.TraceHitInfo HitInfo, optional Actor DamageCauser)


Tick(float delta)

• An event in any actor• Parameter is time since last call• Called so many times per second• Allows animation and AI• Usually want this to be quick if the

actor is not active– Like: if(somebool) return


Actor Methods

• Destroy()– Makes it die

• Move (Vector)– Moves in this direction– Usually invoked in Tick so motion may

be dependent on timing

• TakeRadiusDamage– Wrapper for TakeDamage


The Player

• Any player uses a set of several classes to function

• These are:– Controller– Pawn– Camera

• We now consider these


Pawn

• Controls the presence of the player in the level

• A player does not need a pawn, but if they lack one they can move around but not be seen

• Pawn is a derivation of Actor• URL:

http://wiki.beyondunreal.com/UE3:Pawn_(UDK)http://wiki.beyondunreal.com/UE3:Pawn_%28UDK%29


Pawn Properties

• Float Alertness in the range -1 to 1• bool bLOSHearing • bool bMuffledHearing• bool bCanCrouch • Controller Controller • SkeletalMeshComponent Mesh• Weapon Weapon


Pawn Events

• BreathTimer()• OutsideWorldBounds()

– Max is 524286 uu

• PostBeginPlay()• PreBeginPlay()• SetWalking(bool iswalking)


Controller

• The interface between the person and the pawn class

• Interprets the keyboard commands and passes on to the pawn

• Say method takes a string and displays it to the pawn


Controller Events

• HearNoise• IsInCombat• Destroyed• SeeMonstrer(Pawn)• SeePlayer(Pawn)• We will look at some of these in

the animation presentation


Camera• Generates the display that the

player sees• A first person display has the

camera aligned with the player’s location and orientation

• In third person it usually follows the person around

• For dramatic effect it may leave the player and follow the action somewhere else


Startup

• When the game starts WorldInfo is initialized

• The first piece of code that you might get to see is the GameInfo init() method

• There are also the Post and Pre Begins of the various actors


Logging• The debugging process is

somewhat hard• One of the tricks we use is logging• Every time the editor (which is an

extension of the game) starts it keeps a log

• It closes that log when done• This log is UDKGame\Logs and is

Launch.log• In this we may write messages


Log Macro

• The command is a macro• Part of the preprocessor• The simplest form is just to take a

string– Make the string say all that you need

• Example:`log(“*** Damage ”$DamageAmount);


Finally

• We have the fundamentals for putting actors into motion and making them active agents

• We now need an example to see it all come together


Important UDK Classes How they fit together Copyright © 2015 – Curt Hill.

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