Visualization and Scriptingd fin Second Life

Sariseelia SoreSenior Lecturer in Mathematics and Computer ScienceSenior Lecturer in Mathematics and Computer Science

Linden Scripting LanguageLSL

BasicsBasics

Behavior of ObjectsBehavior of Objects• Linden Scripting Language (LSL)• Scripts are attached to primitives• Build-in editor• External stand-alone editor (e.g. LSLEditor)

Linden Scripting Language

• Like C or Java• Like C or Java• About 35 ready made event handlers• Hundreds of built-in functions

LSL Portal: • LSL Portal: http://wiki.secondlife.com/wiki/LSL_Portal

Scripts p

• Object 1 Object 2j– Primitive 1:

• Script 1– State 1

Primitive 1:Script 1

State 1Event handler 1State 1

» Event handler 1» Event handler 2» Event handler 3

Event handler 1Event handler 2

Primitive 2:Script 1

– State 2» Event handler 3» Event handler 2

• Script 2

State 1Event handler 1

• Script 2– State 1

» Event handler 2– State 2

» Event handler 4

Events Trigger Event HandlersEvents Trigger Event Handlers

• Object 1• Object 1– Primitive 1:

• Script 1p– State 1

» touch_start()» Event handler 2

St t 2St t 2

triggers

–– State 2State 2»» touch_starttouch_start()()»» Event handler 2Event handler 2

• Script 2Script 2– State 1

» touch_start()» Event handler 2

St t 2– State 2» Event handler 4

Events Trigger Event Handlers

default

Primitive 1: Script1

{state_entry(){

llSay(0, "Hello, Avatar!");}}

touch_start(integer total_number){

llSay(0, " Please, dont touch");}}

…}state melted{

touch_start(integer total_number){

llSay(0, " I’m dying");}

}}

Exercise 1: The First Scriptp

1. Go to a land named IP 2011 and set it to be your 1. Go to a land named IP 2011 and set it to be your

home

2 Create a primitive and add your first script to it:2. Create a primitive and add your first script to it:

Make the primitive to respond to a touch so that

1 th fi t t h ill t t ti 1. the first touch will start a timer

(llSetTimerEvent(float sec) and timer()) showing

the avatar every second an increasing number starting the avatar every second an increasing number starting

from 1, and

2 the second touch will stop the timer2. the second touch will stop the timer

LSL Portal: http://wiki.secondlife.com/wiki/LSL PortalLSL Portal: http://wiki.secondlife.com/wiki/LSL_PortalTimer: http://wiki.secondlife.com/wiki/Timer

Finite State Machines

d l fstate

S1 • A model of behavior

S1default

composed of a finite number of

transitionA1: set color defaultAn: inform about exit

finite number of states, transitionsbetween those

S2between those states, and actions

blueA1: set color blueentry

ti exitAn: inform about exitaction action

Example: Defining StatesExample: Defining States

default {//contents of the default state////goes here

}}

state blue {//contents of state blue goes here

}

States in LSL

• A state is a set of event handlers, that is ,running and waiting for events

• All scripts must have a state named • All scripts must have a state named default, the state SL puts the script in only when it’s only when it s – first compiled and – whenever it’s resetwhenever it s reset

• States cannot have user functions or variables inside their immediate scope variables inside their immediate scope, only event definitions

Several States

• A script may have several states• A script may have several states– The default state must be defined before

all othersall others– Only one state per script can be active at

any one timey• The states are defined with the word

state (except for the default state)state (except for the default state)followed by the name of the state and the contents is enclosed in curly ybrackets

Changing Statesg g

C d f ll d b h • Command state followed by the name of the target state: gstate target_state;

1 Trigger state exit and clear the event 1. Trigger state_exit and clear the event queue

2 Change state to target state2. Change state to target state3. Trigger state_entry in the target state

vector color_default = <1.0, 1.0, 1.0>; // whitevector color_blue = <0.0, 0.0, 1.0>; // blue

default {state_entry() {

llSetColor(color default, ALL SIDES);SetCo o (co o _de au t, _S S);}touch_start(integer total_number) {

state blue; // changes the state to state blue}state_exit() {

llOwnerSay("state_exit() for default state");}}

}state blue {

state entry(){state_entry(){llSetColor(color_blue, ALL_SIDES);

}touch_start(integer total_number){_ _

state default; // changes the state to default state}state_exit() {

llO S (" t t it() f bl t t ")llOwnerSay("state_exit() for blue state");}

}

Data TypesData Types

LSL t b i d t t (i t • LSL supports basic data types (integer, float and string) and the following four:

1. key,2. list,3. vector, and4. rotation

Constants

• Hundreds of predefined • Hundreds of predefined constants: PI, TRUE, , ,ZERO_VECTOR, NULL_KEY, DEG TO RAD etcDEG_TO_RAD, etc.

• Not possible to define own constantsp–Variables can be used as pseudo-

constantsconstants

Some String Functionsg

string message = "add John 1234";llGetSubString(message,4,7) //"John"llStringLength(message) //13llSubStringIndex(message, " ") //3

See more functions: htt // iki dlif / iki/C t LSL F tihttp://wiki.secondlife.com/wiki/Category:LSL_Functions

KeyKey

A i id ifi h ll h i • A unique identifier that all the items in SL have

• Can be used to reference objects and agentsand agents

//Returns the key of the owner of the object//Returns the key of the owner of the objectkey owner = llGetOwner();

//Returns a key for the prim the script is attached to//Returns a key for the prim the script is attached tokey me = llGetKey();

List• Ordered set of values of other data types

(two dimensional lists NOT possible)(two dimensional lists NOT possible)• Created via comma-separated values

l d b b k t ([ ])enclosed by square brackets ([ ])• The values in a list can’t be changed

list lst = []; //Empty list

lst = ["apple", 7];

lst += [6.9, 11]; //lst is now ["apple", 7, 6.9, 11]

integer length llGetListLength(lst); //4integer length = llGetListLength(lst); //4

string s = llList2String(lst, 0); //s is "apple"

lst = llList2List(lst,1,2); //[7, 6.9]lst llList2List(lst,1,2); //[7, 6.9]

integer position = llListFindList(lst,[6.9]); //1

Vector

• Single unit of three floats: <x, y, z>• A vector can represent e.g. position and

colorvector v = ZERO_VECTOR;//Constant ZERO_VECTOR has the value <0.0, 0.0, 0.0>

v = llGetPos(); //Gets the object's position in the sim

v x = 45 6;v.x = 45.6;v.y = v.x + 7.0;//v is now <45.6, 52.6, 0.0>

vector red = <1.0, 0.0, 0.0>; //The components represent red, green, and blue (rgb)

Setting a New Positiong

//Move the object up 1m when someone touches it//Stay there for 2s and return to the origin

vector startPosition;

default {

touch_start(integer total_number) {

startPosition = llGetPos();

ll (ll () 0 0 1 )

+ 1m

llSetPos(llGetPos() + <0,0,1>);

llSleep(2.0);

llSetPos(startPosition);llSetPos(startPosition);}

}

RotationRotation

• Single unit of four floats: <x, y, z, s>Single unit of four floats: <x, y, z, s>– Representation of the mathematical

concept quaternionp q• Represents the orientation of an object

rotation r = ZERO_ROTATION;//Constant ZERO_ROTATION: <0.0, 0.0, 0.0, 1.0>

r = llGetRot();//Gets the object's rotation

r = llEuler2Rot(<0, 45 * DEG TO RAD, 0>);r llEuler2Rot(<0, 45 DEG_TO_RAD, 0>);//45 degrees around the y-axis

Rotation of an Objecti P iin Practice

1 D fi th l f t ti i d ( t )1. Define the angle of rotation in degrees (vector)2. Change it to radians

h3. Convert the vector to rotation4. Set the new orientation (rotation) value for the

objectobject

vector angleInDegrees = <45 0 0>;vector angleInDegrees = <45,0,0>; vector angleInRadians = angleInDegrees * DEG_TO_RAD; rotation rot_x45 = llEuler2Rot(angleInRadians); llSetRot(llGetRot() * rot_x45);

//////// OR ////////

llSetRot(llGetRot()*llEuler2Rot(DEG_TO_RAD*<45,0,0>));

Example: Rotating an Objectp g j//Rotate the object around z-axis when someone touches it//Rotate twice 360 degrees in segments of 15 degrees//Rotate twice 360 degrees in segments of 15 degrees

rotation rot_z15;default {{state_entry() {vector angleInDegrees = <0,0,15>; vector angleInRadians = angleInDegrees * DEG TO RAD;vector angleInRadians angleInDegrees DEG_TO_RAD; rot_z15 = llEuler2Rot(angleInRadians);

}touch start(integer total number){touch_start(integer total_number){integer i;for(i=1; i<49; i++) {llS tR t(llG tR t() * t 15)llSetRot(llGetRot() * rot_z15);

}llSay(0,"Rotation stopped");

}} (48 * 15°)

Creating Opening Doorsg p gThe prims in SL are rotated around their center The around their center. The doors should turn around their side. To achieve the desired result the door may be done

of two linked prims (the • of two linked prims (the actual door and “hinges” on the side, which holds ,the rotation script) or

• one can use the path cut property to cut away half property to cut away half of the prim.

Example: Doordoor(string position) {

if (position == "open") {llSetRot(llEuler2Rot(DEG TO RAD * <0 0 90>));llSetRot(llEuler2Rot(DEG_TO_RAD * <0,0,90>));

}else if (position == "close") {

llSetRot(llEuler2Rot(DEG TO RAD * <0 0 0>));llSetRot(llEuler2Rot(DEG_TO_RAD * <0,0,0>));}

}default {default {

touch_start(integer total_number){door("open");t t t tstate open_state;

}}t t t t {state open_state {

touch_start(integer total_number){door("close");t t d f ltstate default;

}}

Exercise 2: DoorExercise 2: Door

1 Get the house you build from the inventory1. Get the house you build from the inventory

2. Create a door with a doorknob to it

Th d h ll d l h i d k b i – The door shall open and close when its doorknob is

touched

U f diff i i f h d– Use states for different positions of the door

– If the door’s not closed with the touch event for five

d it h ll l t ti llseconds, it shall close automatically

• In this case the door informs the avatar who opened the

door that it’ll be closingdoor that it ll be closing,

e.g.: "Dear Ava Avatar, the door will close!"

Linden Scripting LanguageLSL

Interacting with SurroundingsInteracting with Surroundings

Communicatingg

”I’m a lonely snowman”Channel 0

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐”I’m a lonely snowman”

”Hello”

Channel 50Channel 50‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

”I like rock’n roll”llListen(50,…)

Channel  ‐987 654 321

( , )

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐”Hi”

Talking to Channelsg

A channel may be any valid integerA channel may be any valid integerfrom -2,147,483,648 through 2,147,483,647

• llWhisper(channel, msg) – 10 metersp ( , g)• llSay(channel, msg) – 20 meters• llShout(channel msg) – 100 meters• llShout(channel, msg) – 100 meters• llRegionSay(channel, msg)– current sim

Listening to Channelsg

Enable listeningab e s e g• llListen(channel, name, id, msg)

i t h l h l t li t t– integer channel: channel to listen to

– string name: filter for prim/avatar name

– key id: filter for prim/avatar UUID

– string msg: filter for specific chat messagestring msg: filter for specific chat message

Event handler• listen(channel, name, id, msg)

Example: Talking Cubep g

12

Hello to you, Hello Tor Harbour

12

little cube You said Hello to you, little cubeHello to you tooHello to you too

Example: Talking Cubep g

default {default {

state_entry() {llListen(0,"","","");

}

listen(integer ch, string name, key id, string msg) {

integer i;

llSay(0, "Hello " + name + " You said " + msg);

i llS bSt i I d ( "H ll ")i = llSubStringIndex(msg, "Hello");

//returns -1, if pattern is not found

if (i >= 0){if (i >= 0){

llSay(0, "Hello to you too");}

}}}

Dialog BoxgInstead of typing, just

click one optionclick one option44

Channel x‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐

Friend

OwnerChannel 0

33

Owner ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐Tor Harbour: Hi cube!

Talking Cube:h f d

5511

33Great to have friends!

Talking Cube: Tor Harbour said: Hi cube! 22

Example: Dialog Box…p g

integer channel;integer channel;default {

state_entry() {//C t d h l ithi [500 1000]//Create random channel within range [500,1000]channel =(integer)(llFrand(1000.0-500.0)+501.0);llListen(0,"","","");( , , , )

}listen(integer ch, string name, key id, string msg) {

llOwnerSay(name + " said: " + msg);llOwnerSay(name + " said: " + msg);

//says msg to the owner only

list options = ["Enemy", "Friend", "Nobody"];list options [ Enemy , Friend , Nobody ];

llDialog(id, "You said " + msg, options, channel);

state dialog;g}

}

example continues…example continues

state dialog {state dialog {state_entry() {

llListen(channel,"","","");( , , , );}listen(integer ch, string name, key id, string msg) { {

if (msg == "Friend") llSay(0 "Great to have friends!");llSay(0, Great to have friends! ); state default;

}}

Instant Messaging andOpening URLs

• llInstantMessage(avatar_id, msg); Sends a message to an avatar specified –Sends a message to an avatar specified with the avatar_id

• llLoadURL(avatar_id, msg, url);–Displays a dialog box to the user offering to

load a web page using the default web p g gbrowser

default {

touch_start(integer num_detected){_ g _

key avatarKey = llDetectedKey(0);

llLoadURL(avatarKey, "LUAS Site",

"http://www.lamk.fi/mus/esittely/tarinat/melina.html");}

}}

touchtouch

Using Sensorsg

• Sensors are used to detect objects or avatarsSensors are used to detect objects or avatars• The shape of a sensor is a cone• A script can have only one sensor at a time• A script can have only one sensor at a time• Creating sensors

F i l f ti llS– For a single scan: function llSensor– For repetitive scan: function llSensorRepeat

Needs to be emo ed ith the f nction llS R• Needs to be removed with the function llSensorRemove

• Event handlersWanted found: sensor– Wanted found: sensor

– Wanted not found: no_sensor

Parameters for a Sensor• name: Avatar or object name

id b• id: Avatar or object ID– NULL_KEY is used for searching any key

• type: What to look for• type: What to look for– AGENT: avatars – ACTIVE: objects with active script or moving physical objectsj p g p y j– PASSIVE: objects which are not active– SCRIPTED: objects with active script

Di t h f t ( 96 0 ) • range: Distance how far to sensor (max: 96.0 m)

• arc: The angel (around the x-axis), in radians, to search (range: 0 0 to PI)search (range: 0.0 to PI)

• rate: In seconds, how often to repeat the search

llSensor("Something", NULL_KEY, PASSIVE, 10.0, PI);//Looking for things named Something that are passive//Looking for things named Something that are passive//and within 10 meters and pi radians

llS R t("" llG tO () AGENT 5 0 PI BY TWO 2 0)llSensorRepeat("", llGetOwner(), AGENT, 5.0, PI_BY_TWO, 2.0);//Looking for the owner within 5 meters and pi/2 radians//every two seconds

arc

xllDetectedName(0)

Note

xllDetectedName(0)

llDetectedName(1)

NoteThe angel is arc radians around the forward vector

Example: Sensoring Avatars

default {state entry() {state_entry() {llSensorRepeat("", NULL_KEY, AGENT, 3.0, PI, 8.0);//Range in meters, arc in radians, //repeat time in seconds//repeat time in seconds

}sensor(integer num_detected) {integer i;for (i = 0; i < num_detected; i++) {llInstantMessage(llGetOwner(), "Sensed avatar " +llDetectedName(i) + " at " +(string)llDetectedPos(i));

}}}no_sensor() {llOwnerSay("No avatars in range.");llOwnerSay( No avatars in range. );

}}

Moving Avatarsg

When an avatar sits on a prim, it moves along with the prim.

Elevator

movingdefaultstateenter

targetreached

changed(…)showdialog timer(…) move

elevator

listen(…)

new target set

Some Noticeson the Elevator

• When an avatar sits on an object, the changed(…) event handler is triggered

• To get the key of the avatar sitting on the object, use the function j ,llAvatarOnSitTarget(…)• If the prim lacks a sit target the function If the prim lacks a sit target the function

returns NULL_KEY

• The sit target for a prim is set with the • The sit target for a prim is set with the function llSitTarget(…)

Exercise 3:Getting on the Roof

1. Create a hot-air balloon next to your house

2. When an avatar comes close enough the hot-air 2. When an avatar comes close enough the hot air balloon he/she is shown a dialog box asking whether he/she wants to get up on the roof/ g p

3. If the avatar accepts the invitation she/he is asked to sit on the basket of the hot-air balloon which shall then move up on the roof

4. When the avatar stands up from the basket the 4. When the avatar stands up from the basket the basket will return back to its original place

5. If the owner comes close to the hot-air balloon, 5. If the owner comes close to the hot air balloon, it’ll tell him/her who’s sitting on it

Linden Scripting LanguageLSL

Creating ExperiencesCreating Experiences

Gestures of Avatars

ExampleControlling Gestures of AvatarsControlling Gestures of Avatars

Request permission

R i i i d

Start animation

Runtime permission granted

Start animation

Requesting Permissionsq gllRequestPermissions(key avatar, integer perm);

• Ask an avatar for permissions to run certain classes of functions

• Multiple permissions can be requested simultaneously by oring (using the bit-wise or operator |) the

i i t t t thpermission constants together• PERMISSION_TRIGGER_ANIMATION • PERMISSION_TAKE_CONTROLS• etc.

• If the specified avatar grants the requested permissions the run time permissions( )event permissions, the run_time_permissions(…)event handler will be called

Controlling Gestures of AvatarsControlling Gestures of Avatars

default {

touch_start(integer detected) {

llRequestPermissions(llDetectedKey(0)llRequestPermissions(llDetectedKey(0),

PERMISSION_TRIGGER_ANIMATION);

}}run_time_permissions(integer perm) {

if (perm & PERMISSION_TRIGGER_ANIMATION) {

llStartAnimation("dance5");}

}}

Redirect the Residents Key Commandsy

For example:I t d f ”M th t f d”Instead of: ”Move the avatar forward”

Let the script move the cube upward

ΔKey

pressMove forwardMove forward

ΔpressMove upMove up

The Process of Redirecting the Key Commands

Request permission

Runtime permission granted

Take controls

Runtime permission granted

ΔKey

Move forwardMove forwardlΔpress

Move upMove upA control event occurs

Redirecting Key CommandsRedirecting Key Commands

• Steps to take • Steps to take 1. llRequestPermissions(…) dialog

2. run_time_permissions(…) event

3. if granted llTakeControls(…)g ( )

4. control(…) event

If th t i itti bj t • If the avatar is sitting on an object, permissions are granted implicitly

ith t di lwithout a dialog

Capturing Key InputsCapturing Key Inputs

llTakeControls(integer controls,llTakeControls(integer controls, integer accept, integer pass_on);

• controls: which controls to take

• accept: determines whether input is passed to object i.e. control events are generated (boolean)

• pass on: determines whether input is p _ ppassed to avatar itself (boolean)

Example: Redirecting Key Commands …

vector startPosition;

default{default{

state_entry() {startPosition = llGetPos();

}

touch_start(integer detected) {llRequestPermissions(llDetectedKey(0)llRequestPermissions(llDetectedKey(0),

PERMISSION_TAKE_CONTROLS);}

ti i i (i t ) {run_time_permissions(integer perm) {// Triggered when the avatar responds to the dialogif (perm & PERMISSION_TAKE_CONTROLS) {llTakeControls(CONTROL_FWD|CONTROL_BACK,

TRUE, FALSE);}

}…

… example continuesp…// control: Triggered when change happens in user input// control: Triggered when change happens in user input// levels: controls that are currently pressed// edge: controls that have changed state

control(key avatar, integer levels, integer edges) {

vector position = llGetPos();

if (levels & edges & CONTROL_FWD) {// "move forward" control has been activated

if(position z < (startPosition z + 10 0)) {if(position.z < (startPosition.z + 10.0)) {llSetPos(llGetPos() + <0, 0, 1.0>);

}lelsellSetPos(startPosition);

}}

} // End of state default

Exercise 4:Steering the hot-air balloon1. Take the move up and down controls

(PgUp and PgDn) as well as the ( g p g )forward, backward, left and right controls (arrow keys) from the avatar controls (arrow keys) from the avatar sitting on the hot-air balloon and use h f h b llthem for moving the balloon

2. Make the avatar dance after standing 2. Make the avatar dance after standing up from the balloon

VehiclesVehicles

Defining a Vehicleg

• Linked set of primsLinked set of prims- The vehicle script resides in the root prim

• Physical object (SL physical rules affect it: • Physical object (SL physical rules affect it: material, weight, weather, …)

• Vehicle type (car boat airplane etc )• Vehicle type (car, boat, airplane, etc.)

default {default {

state_entry() {

llSetStatus(STATUS_PHYSICS, TRUE);_

llSetVehicleType(VEHICLE_TYPE_CAR);

}

}

Making a Vehicle Moveg

• A vehicle needs to have a linear motor. It’s defined with the following parameters:• VEHICLE_LINEAR_MOTOR_DIRECTION

• Velocity the linear motor tries to achieve (a vector)

• VEHICLE_LINEAR_MOTOR_TIMESCALEN b f d it t k th li t t hi • Number of seconds it takes the linear motor to achieve its full velocity (a float)

• VEHICLE LINEAR MOTOR DECAY TIMESCALEVEHICLE_LINEAR_MOTOR_DECAY_TIMESCALE• Number of second it takes the linear motor to become

ineffective (a float)

Driving a Vehicle• An avatar sits on the vehicle• The control keys are redirected to the

root prim

Making a Vehicle TurnMaking a Vehicle Turn

• For turning vehicles have an angular motor • For turning, vehicles have an angular motor. It’s defined with the following parameters:

VEHICLE ANGULAR MOTOR DIRECTION• VEHICLE_ANGULAR_MOTOR_DIRECTION• Velocity the angular motor tries to achieve (a vector)

VEHICLE ANGULAR MOTOR TIMESCALE• VEHICLE_ANGULAR_MOTOR_TIMESCALE• Number of seconds it takes the angular motor to

achieve its full velocity (a float)achieve its full velocity (a float)

• VEHICLE_ANGULAR_MOTOR_DECAY_TIMESCALEN b f d it t k th l t t b • Number of second it takes the angular motor to become ineffective (a float)

Keeping a VehicleUpright

• The following parameters are used to keep the vehicle’s z-axis pointing upp g p• VEHICLE_VERTICAL_ATTRACTION_TIMESCALE

• Number of seconds it takes the vehicle to align its z-axis Number of seconds it takes the vehicle to align its z axis to the world z-axis (vertical)

• VEHICLE VERTICAL ATTRACTION EFFICIENCY_ _ _• Slider for stability of the vehicle to keep itself upright

• Values between 0.0 (wobbly) and 1.0 (firm as possible) ( y) ( p )

Setting up a Vehicleg p// setting the vehicle parameterssetupVehicle() {p () {

llSetStatus(STATUS_PHYSICS, TRUE);llSetVehicleType(VEHICLE_TYPE_CAR);

// The vehicle will get up to full speed in 1 second and decay after 2llSetVehicleFloatParam(VEHICLE_LINEAR_MOTOR_TIMESCALE, 1.0);llSetVehicleFloatParam(VEHICLE_LINEAR_MOTOR_DECAY_TIMESCALE, 2.0);

// The angular motor will start almost instantly and decay quicklyllSetVehicleFloatParam(VEHICLE_ANGULAR_MOTOR_TIMESCALE, 0.1);llSetVehicleFloatParam(VEHICLE_ANGULAR_MOTOR_DECAY_TIMESCALE, 0.5);

// Very strong quick vertical attractorllS t hi l l t ( C C C O C C 0 95)llSetVehicleFloatParam(VEHICLE_VERTICAL_ATTRACTION_EFFICIENCY, 0.95);llSetVehicleFloatParam(VEHICLE_VERTICAL_ATTRACTION_TIMESCALE, 0.75);

}

• There are a number of other parameters for vehicles to make them simulate the real life

• See:See:– http://wiki.secondlife.com/wiki/LlSetVehicleVectorParam – http://wiki.secondlife.com/wiki/LlSetVehicleFloatParam

Visual EffectsVisual Effects

ParticlesParticles• 2D floating images (not objects) emitted

from a primitivefrom a primitive• Can be used to simulate fireworks, smoke,

weather, and other effectsweather, and other effects• Each prim has only one particle emitter• A client-side effect• A primitive becomes a particle emitter,

when passing a list to the llP ti l S t f tillParticleSystem function

• The list is a series of name-value pairsParticles can be turned off by calling the • Particles can be turned off by calling the llParticleSystem with an empty list

System Behaviory

PSYS_PART_FLAGS_ _

• Various flags controlling the behavior of the particle system (may be oring together)

llParticleSystem([PSYS PART FLAGSPSYS_PART_FLAGS,

//Particles are moved by windPSYS_PART_WIND_MASK//P ti l lf lit ( l )//Particles are self-lit (glow)| PSYS_PART_EMISSIVE_MASK//Color and alpha transition from their START //settings to their END settings during the//particle's lifetime| PSYS_PART_INTERP_COLOR_MASK_ _ _ _

, …]);

System PresentationyPSYS_SRC_PATTERN• General emission pattern (only one value)

PSYS_SRC_PATTERN_DROP• Particles start at emitter with no velocity

PSYS_SRC_PATTERN_EXPLODEParticles explode from the emitter• Particles explode from the emitter

PSYS_SRC_PATTERN_ANGLE• Particles in a 2-dimensional circular section defined by Particles in a 2 dimensional circular section defined by PSYS_SRC_ANGLE_BEGIN and SYS_SRC_ANGLE_END

PSYS_SRC_PATTERN_ANGLE_CONE• Particles in a 3-dimensional spherical section defined by PSYS_SRC_ANGLE_BEGIN and SYS_SRC_ANGLE_END

Particle AngleParticle Angle

• The angle for the particles to be emitted is defined with parameters PSYS_SRC_ANGLE_BEGIN and PSYS SRC ANGLE ENDand PSYS_SRC_ANGLE_END

90

llParticleSystem([…PSYS_SRC_PATTERN,

°∏/4

PSYS_SRC_PATTERN_ANGLE,

PSYS_SRC_ANGLE_BEGIN, PI/4.0,

PSYS SRC ANGLE END DEG TO RAD*90PSYS_SRC_ANGLE_END, DEG_TO_RAD*90, …]);

Burst parametersBurst parameters

PSYS SRC BURST RATEPSYS_SRC_BURST_RATE• How often, in seconds, to emit particles

PSYS_SRC_BURST_PART_COUNT_ _ _ _• How many particles are emitted each burst

PSYS_SRC_BURST_SPEED_MIN andPSYS SRC BURST SPEED MAXPSYS_SRC_BURST_SPEED_MAX

• The range of initial speeds for particles (m/s)• Each particle is given an initial random speed in this p g p

rangePSYS_SRC_BURST_RADIUS

Di t f th t f th itt t hi h • Distance from the center of the emitter at which particles will be created

Example:Concentric Expanding Rings

llParticleSystem([

PSYS_SRC_PATTERN, PSYS_SRC_PATTERN_ANGLE,

// Emit particles in a complete circlePSYS_SRC_ANGLE_BEGIN, 0.0,PSYS SRC ANGLE END, PI,PSYS_SRC_ANGLE_END, PI,

// Make all the particles spread out at the same speedPSYS_SRC_BURST_SPEED_MIN, 0.3,PSYS SRC BURST SPEED MAX 0 3PSYS_SRC_BURST_SPEED_MAX, 0.3,

// Start the ring 1 meter from the emitterPSYS SRC BURST RADIUS, 1.0,_ _ _ , ,

// Emit 50 particles every 3 secondsPSYS_SRC_BURST_PART_COUNT, 50,PSYS SRC BURST RATE 3 0PSYS_SRC_BURST_RATE, 3.0

]);

Particle Appearancepp

• The change from start to end values requires the PSYS_PART_INTERP_COLOR_MASKt h b tto have been set

• Initial and end color are set with PSYS_PART_START_COLOR and PSYS PART END COLOR_ _ _

• Initial and end transparency are set with PSYS PART START ALPHA and PSYS_PART_START_ALPHA and PSYS_PART_END_ALPHA

• Any texture can be used as a particle • Any texture can be used as a particle. The value is set with PSYS_SRC_TEXTURE

Example: Color Changing and Fading

llParticleSystem( [

// Turn on color interpolationPSYS PART FLAGS PSYS PART INTERP COLOR MASKPSYS_PART_FLAGS, PSYS_PART_INTERP_COLOR_MASK,

// Set the start color to white and //the end color to blue//the end color to bluePSYS_PART_START_COLOR, <1.0, 1.0, 1.0>,PSYS_PART_END_COLOR, <0.0, 0.0, 1.0>,

// Start at full opacity, fade to full transparencyPSYS_PART_START_ALPHA, 1.0,PSYS PART END ALPHA 0 0PSYS_PART_END_ALPHA, 0.0,

// The value is the UUID of the texturePSYS SRC TEXTURE "6ed3abd3 527a 856d 3771 2a04ea4c16e1"PSYS_SRC_TEXTURE, "6ed3abd3-527a-856d-3771-2a04ea4c16e1"

]);

Particle Size

The change from the start to the end value • The change from the start to the end value requires the PSYS_PART_INTERP_SCALE to have been setbeen set

• Initial and end size are set with PSYS START SCALE and PSYS END SCALEPSYS_START_SCALE and PSYS_END_SCALE

llParticleSystem( [// Turn on size interpolationPSYS_PART_FLAGS, PSYS_PART_INTERP_SCALE_MASK,

// Start out small, growPSYS_PART_START_SCALE, <0.25, 0.25, 0.0>,PSYS PART END SCALE, <2.0, 2.0, 0.0>PSYS_PART_END_SCALE, <2.0, 2.0, 0.0>

]);

Th k f Thank you for your tt ti !attention!

FL: Sariseelia SoreSL: Sasse ForzaneSL: Sasse Forzaneemail: sariseelia.sore@lamk.fi

Exercise 5:Simple Car

1. Create a simple car

See e.g. http://wiki secondlife com/wiki/Linden Vhttp://wiki.secondlife.com/wiki/Linden_Vehicle_Tutorial

2. The car shall emit gas when moving moving