Sega 500

Sega 500

Custom Scripted Actions

Jeff “Ezeikeil” [email protected]://gamestudies.cdis.org/~jgiles

mailto:[email protected]

http://gamestudies.cdis.org/~jgiles

Thus far

We’ve played with both Scripted events and sequences for our pawns and found them to be quite similar.

Not to mention that we had some fun making our bot get squashed and run in circles.

Today

Although the current actions list is quite extensive, without surprise, there is some functionality which is not included.

So we’re going to build our own.

What are we building?

Well, one of the few things thing that I found I could not do in the list was cause the creation of a pawn with AI.

Sure, we could create the pawn, but there was no attachment to a controller.


I’ve found 2 methods that work well to create a pawn at a specific location and both are fairly straight forward.

The first relies almost exclusively on the current functionality for adding bots


The second, has a bit more to it, but if gives more direct control over the pawns creation.

Setup

Both of the classes derive from scriptedaction

class Action_CreateBot extends ScriptedAction;

These will auto-magically appear in the pull down menu of our actions list in the editor.

About Scripted Actions

Actually, setting up a new action is really quite easy.

All the magic happens around one function:

function bool InitActionFor(ScriptedController C)

About Scripted Actions

Although there are a one or two cases where it is not used, it’s fairly safe to say that anything we want to implement will be called from here.

The easy way

Starting by getting the bot into the game at any player start point, we just need to call a few function that already exist in our game type.

The easy way

The trick lies in accessing these functions. The ones we’re after are:

SpawnBot. RestartPlayer.

Both of which are defined in the Deathmatch game type.

The easy way

The nice part is that any gametype we use will have this class as a parent.

The easy way

So how do we get there from here?

As you already know, the game is accessible from just about anywhere in the code.

It just takes some typecasting.

The easy way

I our case, we’re given a controller, which can see the level.

And the level knows about the game, so we can safely cast to our parent class.

DeathMatch(c.Level.game)

The easy way

Cool! So getting our bots in is just a matter of

accessing these functions…

local bot newBot;

newBot = DeathMatch(c.Level.game).SpawnBot();c.Level.game.RestartPlayer(NewBot);

The easy way

And this spawns our dude into the level when this script is hit.

And because we’re using the existing functions, all the initializations are taken care of for us…gota like that!

The easy way

But spawning him at a random start point is not always what we want.

So how to we tell UT where to spawn something?

The easy way

Well UT’s spawn function takes parameters, one of which is location…should be simple no?

Just do an allactors search and match up a tag to an object…simple.

The easy way

But there’s a problem. We don’t have an allactors iterator…can’t see it, can’t access it.

We derive off object, not actor where all our iterators are defined.

…so, does this mean we’re screwed?

The easy way

Well, no…the cost of admission just goes up.

Object has a single iterator for us to use.

AllObjects

<Shudder>

The easy way

So we can get to any object’s tag, we just have to iterate over ALL the objects in the game.

Expensive.

The easy way

It works just like any other iterator

native(197) final iterator function AllObjects

(class baseClass, out Object obj);

The easy way

So how do we us it then…

And inside the InitActionFor function:

var(AIBOT) name loctag; // what we’re looking for

The easy way

foreach AllObjects(class'Actor', A){ if( a.Tag==locTag ) { newBot = DeathMatch(c.Level.game).SpawnBot(); c.Level.game.RestartPlayer(NewBot); NewBot.SetLocation(A.Location); newbot.Pawn.SetLocation(A.Location) }}

The easy way

And TA-DA! It’s in! Spawn anywhere.

But there’s a *small* catch to this method.

The restartplayer call causes a spawn at the player start in the conventional manner

The easy way

An then we set the players location to where we want him.

However, this leaves the spawn effect at the start point.

The easy way

So this works, but we can’t have this effect happening where the player can see it.

On to method number two, which is quite similar. We just change the guts of the InitActionFor function.

A better way

And add a bit more in the set up.

This method also allows us to define which controllers and pawn we want to use.

var(AIBOT) name objecttag; //Where to spawnvar(AIBOT) class<bot> bType; //What Bot typevar(AIBOT) class<Pawn> pType; //What pawn Type

A better way

And in the InitActionFor function, we redefine it as:

function bool InitActionFor(ScriptedController C){ local bot newBot; local Pawn newPawn; local actor A;

local UnrealTeamInfo BotTeam; local RosterEntry Chosen;

A better way

The UnrealTeamInfo and RosterEntry are needed to properly initialize the bot.

Everything else is a handle to an object that we’ll create here.

A better way

We keep the same search method…not much of a choice

foreach AllObjects(class'Actor', A) { if( a.Tag==locTag ) {

A better way

Spawn a pawn and a controller at the desired loaction, based on our search result (Actor a)

newBot = c.Level.Spawn(bType,,,a.Location, a.Rotation);newPawn = c.Level.Spawn(pType,,,a.Location, a.Rotation);

A better way

So they’re both in the game but need to be added to the game roster and initialized

BotTeam=DeathMatch(c.Level.game).GetBotTeam();Chosen =BotTeam.ChooseBotClass();Chosen.Init();

DeathMatch(c.Level.game).InitializeBot(newBot,BotTeam , Chosen);

A better way

And lastly, we need the controller to own the pawn. This is done with the Posses function.

newBot.Possess(newPawn);

A better way

Give it a run, it works nice…

...but there’s something

missing…

A better way

The pawn comes in, with a brain, great!

But where the heck is the gun!

A better way

And, notice that once you frag them, spawn back into the game with all there toys.

So we missed something…

A better way

Actually, just one line…ain’t that always the way?

If you route through the deathmatch class you find this

function AddDefaultInventory( pawn PlayerPawn )

A better way

And it does, just what the name says…

Accessing it is nothing new as well,

DeathMatch(c.Level.game).AddDefaultInventory(newPawn);

A better way

Lastly, in our default properties, we need to set the ActionString to something meaningful.

ActionString="Spawn EzeBot"

A better way

As best I can tell, the action string is used exclusively for debug purposes and this is the text that is thrown to the screen.

This is done from the ScriptedSequence object. Beyond that, I’ve not found any functionality.

That’s all well and good…

But, continually adding bots is only so much fun.

The real fun lies in killing them off

Killing our pawn

So, from our scripted sequence, time to do that.

This part is actually really easy if you controller already has a pawn associated to it…Well go over how to get one in a minute if it doesn’t.

Killing our pawn

So the new action I defined as:

class Action_Gib extends ScriptedAction;

function bool InitActionFor(ScriptedController C){ c.Pawn.ChunkUp(c.Pawn.Rotation, 1.0); c.Pawn.PlaySound(sound'PlayerSounds.Final.Giblets1');

return true; //must return true or UT crashes}

Killing our pawn

Yup, that’s the whole thing.

The actual kill is build into the pawn already, it’s just a matter of accessing it.

Can you guess what it does?

Killing our pawn

Before:

Killing our pawn

After:

SPLAT!

However, I am a bid confused as to how he got 2 skulls though…

Killing our pawn

Yup, it turns our pawn into a bunch of giblets.

The best thing is, you can now just add this to the list of Scripted events for your AIScript.

Killing our pawn

So long as you have a pawn associated with it that is…

Integration into Gameplay

Ok, I believe that it’s great for telling stories to the player and watching things happen.

But can the player interact with it?

In a word, yes.


And this is where the code monkeying starts to take place.

One of the fun levels in the original UT was DM-pressure…


You had to go into a pressure chamber to get the rocket launcher.


However, while in there, you could be sealed in by the push of a button which would cause the player to pop like a ballon.

Tones-o-fun !


You guessed it, we’re going to build something similar.

Just an FYI, something like this is much better suited to a volume or a zone, this is just one possible example.


The first thing I did was set up a level so the we could test this out fairly easily…

Starting with an oddly shaped brush which was built using the deintersect tool.


I’m going to use this so I can box my enemy pawn into a corner…

Then, used a transparent texture so I could see the bot get splattered.


I also left a gap on the edges so I could use a translocator to get out.

But too small for a bot…


Now, over to the code.

The search method we’re going to use here is very similar to the one we just used to find the matching tag.

Using all objects <shudder>


But we have to put some logic in to to a “radius search”.

class Action_FindNewPawn extends ScriptedAction;

var()int radius;

DefaultProperties{ radius=128}


Next up is a simpler iteration over all the objects <shudder> and test to find the closest one.

Integration into Gameplayfunction bool InitActionFor(ScriptedController C){ local pawn p, closest; local float dist, closestDist;

foreach allobjects(class'Pawn', p) { if(closest!=none) { dist=Vsize(p.location-c.Location); if(dist < closestDist) { closest=p; closestDist=dist; } }


else { closest=p; closestDist=Vsize(p.location-c.Location); } }

if( closestDist<radius) c.Pawn=closest;

return true; //must return true or UT crashes}


Nothing overly fancy…

But, now the fun stuff…it’s ready to use.

Jumping back to the editor, we set up our scripted triggers.


I place the scripted trigger in my room and the activation trigger a safe distance away.

Activation trigger

Scriptedtrigger


And then set up my scripts:


Wait for the activation trigger


Spawn some special effects for show…


Find the closed pawn which is within 230 UU’s


And then call my ready-made gib function.


Lastly…do it again


Do an addbots console command and …poof!

Caged like a rat!


Then when you hit the trigger,

ZAP!...no more bot.

That’s all folks

We’ve now customized our own action scripts, hope ya found it fun…

Sega 500

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