BEGINNING SCRIPTING IN SECOND LIFE

Pauli Pinelli

Getting started in scripting in Second Life LSL stands for "Linden Scripting Language" LSL is used to script the objects you will make in

Second Life. This tutorial is intended for those who have

never programmed before in Second Life or elsewhere.

Scripting is harder to learn than basic object manipulation, but is very rewarding once you make progress.

You will begin by running the standard “Hello Avatar " script and eventually move towards making your own.

What is LSL? Linden Scripting Language’s structure is based on Java and C.

Scripts in Second Life can be placed inside any object in the world, or any object worn by an avatar, but not inside an avatar.

They are written with a built-in editor/compiler.

LSL has heavy emphasis on "States" and "Events". Many real life objects have "states" A door can be "open" or "closed" and a light can be "on" or "off". A person can be "hyper", "calm", or "bored". a script will have at least one state, the default state. “event execution model”(unique in this way)

An event can be thought to be a "Trigger". Events are predefined in LSL. Touch_start(), will trigger the code when the object is touched.

Linden Scripting Language

“LSL” makes objects interactive

Allows commerce, serious gaming, interfaces, web connectivity

Linked objects may perform independent actions

WHAT CAN I DO WITH SCRIPTS?

Scripts can make an object:

Move

Listen

Talk

Operate as a car or gun

Change color, size or shape

Talk to you

Talk to another.

WHAT CAN I DO WITH SCRIPTS?

"Prim" or primitive, the basic building block can have a script.

When several prims are linked, they can each contain a script which speaks to the rest of the object via Link Messages.

Here we focus on single scripts in a single prim. If you've built in Second Life, everything you can define

in the edit window can be defined in a script. All interaction you see between objects or between

avatars and objects is via scripts. Learning more about the world and building model is

vital to some aspects of scripting

Running Your First Script

Traditionally one starts by writing the smallest program to print "hello world“.

Since LSL only runs inside objects, you must know how to make an object and put a script inside it.

You must be on land which allows building.

In the edit window you may five tabs marked general, object, featurestexture and content,.

Click "content".

Running Your First Script

Press "new script" to add a new script.

This will open the LSL editor with a default script.

This editor will color code your syntax and provide some info about keywords when you hold your mouse over them. It will also do basic syntax checking.

Hit "save" and close your edit window (not the LSL program window)

You should see the words "Hello Avatar" from "object“

If you touch the object, it will say "Touched.“

(make sure the "edit" window is closed for touching to work. “

GOOD! You have compiled and run your first LSL script!

Write, run, RE-write Most scripts you make won't run the first time you run them.

When you hit "save" on a script, the LSL editor "compiles" the code to form SL can understand. It stops if it finds an error.

Brackets, parenthesis, and semicolons must all be perfectly in place

If you are new to programming this can be frustrating

Part of a programming in ANY language is learning how to precisely define steps and correctly type them into the language you are working in.

Thus you will find yourself writing, running, then RE-writing your code several times.

The script you made runs the instant you hit save. If you take it into inventory, it will "suspend" what it was doing but go right back to it when rezzed again

Each time you re-write your code you must save the script.

A Closer Look

The script:When I am in the default state, and I am touched, say “Touched" on channel zero".

The script:By start say “Hello, Avatar" on channel zero".

STATES

A "State" in LSL is a section that is running, and waiting for events.

Only one state can be active. Every script must have a default state with at

least one event in it. Except for the default state, each state is defined

by the word STATE followed by the name of the state.

The contents of the state are enclosed in two curly brackets.

EVENTS Events are inside of states.

When a state is active, those events wait to be triggered and run the code inside them.

"state entry" which is trigged by the a state being entered

"touch start" which is triggered when you, or anyone, touches an object.

Lets take a look at the default code.

default // state{

touch_start(integer total_number) // this is an event {

// this is the content of the event } // end of event

} // end of state

FUNCTIONS Functions lay inside of events and are either

defined by you or built-in.

Those built in to LSL all start with two lower case L's. ex. llSay()

Functions take "arguments" or values in the parentheses that follow it If you hover over the function in the editor, a popup

will show that tell you what the function is expecting.

In the case of llSay it expects a number and a string. llSay(0, "Touched.");

Putting it all together

After saving your script occurs following: The instant you save your script, it enters

default state, which in turns runs the "state_entry" event which in turn runs the function llSay() which makes the object talk.

After this the program waits idle in the default state until a new event is called.

Touching the box triggers the even "touch_start" which also makes the object speak.

Introducing States and Events

LSL scripts will not run from beginning to end. Instead they will look for a default state and wait for an event. Within those events, there can be a call to go to a new state.

Lets look at a script with two states with two events in each.

A simplification of this would bedefault

{//set color to light and, if touched, enter the "off" state.

}

state off

{//set color to dark and, if touched, enter the "default" state.

}

Note that after "default" all new states begin with the word "state".

A closer look

llOwnerSay( "turning on!"); Object speaks to primitive owner!

A semicolon ends the line.

llSetColor(<1,1,1>, ALL_SIDES);

This turns the prim to it's brightest tint. You see it as bright white . The three 0's stand for the black and the three 1's stand for the white.

Color by Numbers

Program creates a loop

1. Enters default state 2. Runs code in "state entry" 3. Waits to be touched. 4. When touched enters "state off" 5. Enters "state off". 6. Runs code in "state entry" in the "off" state's body 7. Waits to be touched in the "off" state's body 8. When touched enters "default" state.

Where the whole thing starts over.

Objects speaking is a great way to know what a script is doing

As you get into more complex scripts this can get pretty noisy to the surrounding people!

llWhisper( ) is just like llSay( ) but only broadcasts at half the distance.

llWhisper(0,"turnign on!"); //might work a bit to save the sanity of your neighbors.

Using llShout( ) doubles the distance heard, but can cut the amount of friends you have in SL.

llOwnerSay( ) uses no channel and is heard only by you.

Totally silent message via llSetText( )

You can make a totally silent message via llSetText( ) like this.

llSetText("I am on", <1,1,1>,1.0);

<1,1,1>, means "white" and <0,0,0> means "black". Replace the llSay(0,"turnign off!"); with...

The 1.0 is the alpha setting. 1.0 means fully opaque, and 0.0 would be completely transparent (invisible).

http://wiki.secondlife.com/wiki/Category:LSL_Functions

Rotate: llTargetOmega

default

{

state_entry()

{

llTargetOmega( < 0, 0, 1 >, .01, 1.0 );

}

}

URL Loading: llLoadURL

default

{touch_start(integer total_number)

{

llLoadURL(llDetectedKey(0), "Name", “site.com");

}

}

Notecard Giver: llGiveInventory

default

{

touch_start(integer total_number)

{

llGiveInventory(llDetectedKey(0), “Write notecard’s name here");

}

}

Floating text

default{

state_entry(){

llSetText(“Pauli Pinelli", <1,1,1>, 2.0);}

}

http://wiki.secondlife.com/wiki/Category:LSL_Events

Interesting Events

collision(integer total_number)

sensor(integer total_number)

money(key giver, integer amount)

changed(integer changed)

Look at The door script Right click the

mouse on the blue door.

Select take.

The object goes to the inventory (= briefcase box on the right side menu).

• Find the object named:”SL scripting Basics Blue Door”

• Put it on the ground• Right click the mouse and select edit• Select content tab• Double click the program named:

“Door”

paikka = place

Variables what are then?

Variables hold data

They come in flavors (types)

Have meaning to the ENTIRE script or only a portion of it

Using them properly is one of the most important thing in scripting

Variable Types

Float = floating point or real number

Integer = positive whole number

String = a text word or phrase

Vector = a set of three floats

rgb color, xyz pos, xyz vel, xyz accel

Key = uuid - object identity

Rotation = x,y,z,s - hard!

List = rough database

Typecasting a=(string)b

Global vs Local Variables

Declare global variables at top of the script -they are usable throughout

Declare local variables inside the block it will be used in

Loops

for (j = 0; j < count; j++)

{ // do stuff here }

do

{

// do stuff here and increment j

} while (j < count);

while (j < count)

{ // do stuff here and increment j }

Do the scripting!

More infohttp://lslwiki.net/lslwiki/wakka.php?wakka=Home

Page

LSL 101: The Complete Newbie's Guide to Scripting in Second Life

http://wiki.secondlife.com/wiki/SL_Cert_-_Basic_Scripting

Read about programming in SL wiki.