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
Copyright © 2015 – Curt Hill
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 Copyright © 2015 – Curt Hill
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 others
Copyright © 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
Copyright © 2015 – Curt Hill
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
Copyright © 2015 – Curt Hill
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
Copyright © 2015 – Curt Hill
View/World
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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
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GameInfo
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CloudGame
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UTTeamGame
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UTDeathMatch
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GameInfo Descendents
• There are many, some of which also
have descendants
– PlayerCollectorGame
– MobileMenuGame
– FrameWorkGame
• SimpleGame
– UDKGame
• UTGame
• UTDeathMatch
• The one you choose to derive has an
effect on your game
• We will make our own as well
Copyright © 2015 – Curt Hill
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
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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
Copyright © 2015 – Curt Hill
Actors
• Recall that an actor is anything with
a representation in the level
• This includes
–
–
–
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Static meshes
Lights
Sounds
Pawns
Copyright © 2015 – Curt Hill
Actor Events
• Destroyed()
• Falling ()
• RanInto (Actor Other)
– Actor ran into another actor
• TakeDamage and Tick will be
considered later
Copyright © 2015 – Curt Hill
More Events
• Bump (Actor Other,
PrimitiveComponent OtherComp,
Object.Vector HitNormal)
– Somebody bumped me
• HitWall (
Object.Vector HitNormal,
Actor Wall,
PrimitiveComponent WallComp)
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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
Copyright © 2015 – Curt Hill
TakeDamage
• Signature:
event TakeDamage (
int Damage,
Controller InstigatedBy,
Object.Vector HitLocation,
Object.Vector Momentum,
class<DamageType> DamageType,
optional Actor.TraceHitInfo
HitInfo,
optional Actor DamageCauser)
Copyright © 2015 – Curt Hill
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
Copyright © 2015 – Curt Hill
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
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The Player
• Any player uses a set of several
classes to function
• These are:
– Controller
– Pawn
– Camera
• We now consider these
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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_%28UD
K%29
Copyright © 2015 – Curt Hill
Pawn Properties
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•
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•
•
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Float Alertness in the range -1 to 1
bool bLOSHearing
bool bMuffledHearing
bool bCanCrouch
Controller Controller
SkeletalMeshComponent Mesh
Weapon Weapon
Copyright © 2015 – Curt Hill
Pawn Events
• BreathTimer()
• OutsideWorldBounds()
– Max is 524286 uu
• PostBeginPlay()
• PreBeginPlay()
• SetWalking(bool iswalking)
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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
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Controller Events
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•
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HearNoise
IsInCombat
Destroyed
SeeMonstrer(Pawn)
SeePlayer(Pawn)
We will look at some of these in the
animation presentation
Copyright © 2015 – Curt Hill
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
Copyright © 2015 – Curt Hill
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
Copyright © 2015 – Curt Hill
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
Copyright © 2015 – Curt Hill
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);
Copyright © 2015 – Curt Hill
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
Copyright © 2015 – Curt Hill