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MOTION PLANNING IN REAL AND VIRTUAL ENVIRONMENTS
FALL 2007
Second Life:
Bots and
Motion Planning
Russell Gayle
Comp 790-058 – Robot Motion Planning
Fall 2007
October 1, 2007
5/23/2010 1
Last time
RECAP • SL Overview
INTRO: SL BOTS
» The Grid
LSL BOTS
1. Framework » Simulators / Regions
2. Planning
» Avatars, Primitives
3. Results
4. Other MP Ideas » LSL Crash Course
LIBSECONDLIFE
1. Framework
2. Avatar Control
3. Planning
4. Demo
5. Other Ideas
5/23/2010 2
Aside: Path Tracer
RECAP • Results of the LSL portion (Part 0) should
INTRO: SL BOTS
look something like this:
LSL BOTS
1. Framework
» http://www.youtube.com/watch?v=bcemyUuzC
2. Planning ds&eurl=
3. Results
4. Other MP Ideas
LIBSECONDLIFE • Update:
1. Framework
2. Avatar Control
» As of this morning, the UNC Sandbox has
3. Planning turned into an access restricted area.
4. Demo
5. Other Ideas
» I’ve emailed UNC about a place where I can
put it.
» If I don’t hear back soon, I’ll send it out to
everyone.
5/23/2010 3
Introduction: SL Bots
RECAP • What are bots?
INTRO: SL BOTS
» In Second Life?
LSL BOTS
1. Framework • Two varieties
2. Planning
3. Results
» LSL based (prims)
4. Other MP Ideas • Come in many shapes and sizes
LIBSECONDLIFE • Wide range of functions
1. Framework
2. Avatar Control
• Primarily server side code
3. Planning » LibSL based (avatars)
4. Demo
5. Other Ideas • Function by manipulating avatars
• Mixed computation from client and server
» Network delay becomes an issue
5/23/2010 4
LSL Bots
RECAP • Prims with (motion) control
INTRO: SL BOTS
» Control is defined through LSL
LSL BOTS
1. Framework » Integrated sensing (LSL sensors)
2. Planning
» Can interface with remote resources
3. Results
4. Other MP Ideas
LIBSECONDLIFE
1. Framework
• http://www.youtube.com/watch?v=824TFPer
2. Avatar Control XsQ
3. Planning
4. Demo
5. Other Ideas
• Some of the remaining content for this
section is adapted from:
» Alon Shalita
» Tel-Aviv University
» Motion Planning in Virtual Environments Workshop
5/23/2010 5
LSL Bots: LSL Limitations
RECAP • List limitations
INTRO: SL BOTS
» No native arrays
LSL BOTS
1. Framework
• Lists are sequential access
2. Planning » Limited length
3. Results
• Limited by memory script has available (16KB total)
4. Other MP Ideas
LIBSECONDLIFE
• Compile time lists are limited to 72
1. Framework » No nested lists
2. Avatar Control
3. Planning • Type conversion
4. Demo
» More of an annoyance, automatic conversion
5. Other Ideas
may not work
• Cannot incorporate existing libraries
• SL is moving to Mono (Open Source C#)
» Not sure when this will happen though
5/23/2010 6
LSL Bots: Framework
RECAP • Limitations make it difficult to develop large,
INTRO: SL BOTS
complex applications (like motion planning)
LSL BOTS
1. Framework
» Track open issues at:
2. Planning • https://jira.secondlife.com/browse/SVC/compon
3. Results
ent/10043
4. Other MP Ideas
LIBSECONDLIFE » Though, predefined motion like the roomba
1. Framework example should not be too hard
2. Avatar Control
3. Planning • One solution: Use remote resources
4. Demo
» Hybrid planner
5. Other Ideas
• Motion, physics, controls stay in SL
• Communicate with remote resources to get
planning solutions
5/23/2010 7
LSL Bots: Communications
RECAP • LSL has the ability to send and receive
INTRO: SL BOTS
communications
LSL BOTS
1. Framework
» XML-RPC (inbound)
2. Planning
» HTTP (outbound)
3. Results
4. Other MP Ideas • XML-RPC
LIBSECONDLIFE
» Data limited to about 255 bytes
1. Framework
2. Avatar Control » Long latency (about 3 seconds)
• HTTP
3. Planning
4. Demo
5. Other Ideas
» Data in request limited to script’s free memory
» Data in response limited to 2049 bytes
» Responses is asynchronous
» Do not send more than 1 per second
5/23/2010 8
LSL Bots: Comm. Example
RECAP • HTTP makes the most sense
INTRO: SL BOTS
• Example:
LSL BOTS
Uses HTTP POST request
1. Framework » PHP Number Adder
2. Planning
<?php
3. Results $first=$_POST["first"];
4. Other MP Ideas $second=$_POST["second"];
LIBSECONDLIFE if (!ereg("[0-9]+", $first) or !ereg("[0-9]+", $second))
1. Framework {
die ("first and second must be numbers");
2. Avatar Control }
3. Planning
echo $first+$second;
4. Demo
?>
5. Other Ideas
» HTTP POST allows more data to be sent
» HTTP GET is limited to call length
5/23/2010 9
LSL Bots: Comm. Example
RECAP • HTTP makes the most sense
INTRO: SL BOTS
• Example:
LSL BOTS
1. Framework » Number Adder LSL Script
2. Planning key requestid;
3. Results default
{
4. Other MP Ideas state_entry()
{
LIBSECONDLIFE llSay(0, "Hello, Avatar!"); Initiate HTTP request
}
1. Framework
touch_start(integer total_number)
Process response
2. Avatar Control {
3. Planning llSay(0, "Touched.");
4. Demo requestid = llHTTPRequest("http://www.somehostname.com/add.php",
[HTTP_METHOD, "POST", HTTP_MIMETYPE, "application/x-www-form-urlencoded"],
5. Other Ideas "first=9&second=20");
}
http_response(key request_id, integer status, list metadata, string body)
{
if (request_id == requestid)
{
llSay(0, body);
} else
llSay(0,(string)status+" error");
}
}
5/23/2010 10
LSL Bots: Sensors
RECAP • Functionality for scripts to scan for items
INTRO: SL BOTS
» Scan by name/id, type
LSL BOTS
1. Framework » Within a range and arc radians from viewing
2. Planning direction
3. Results
llSensor( string name, key id, integer
4. Other MP Ideas
type, float range, float arc );
LIBSECONDLIFE
1. Framework » llSensor
2. Avatar Control
• Run a sensor once
3. Planning
4. Demo » llSensorRepeat
5. Other Ideas
• Repeat the same sensor over some interval
» llSensorRemove
• Remove a repeating sensor
5/23/2010 11
LSL Bots: Sensor example
RECAP • Finding the start of a maze (Alon Shalita)
INTRO: SL BOTS
LSL BOTS default
1. Framework {
2. Planning
state_entry() Find maze start
{
llSay(0, "Touch me to scan for the maze");
3. Results }
4. Other MP Ideas Start sensor
touch_start(integer total_number) With any id
LIBSECONDLIFE {
llSay(0, "Touched.");
1. Framework llSensor("Maze Start", NULL_KEY, ACTIVE | PASSIVE, 90, PI);
}
2. Avatar Control
3. Planning sensor(integer total_number)
{
4. Demo if (llDetectedName(0) == "Maze Start") Either moving or not
{
5. Other Ideas llSay(0, "Maze start is at " + (string)llDetectedPos(0));
}
}
Within 90 meters Within a sphere
no_sensor()
{
around the rim
llSay(0, "Error: Sensor failed");
}
}
5/23/2010 12
LSL Bots: Sensor example
RECAP • Finding the start of a maze (Alon Shalita)
INTRO: SL BOTS
LSL BOTS default
1. Framework {
state_entry()
2. Planning {
llSay(0, "Touch me to scan for the maze");
3. Results }
4. Other MP Ideas
touch_start(integer total_number) Sensor returned an item
LIBSECONDLIFE {
llSay(0, "Touched.");
1. Framework llSensor("Maze Start", NULL_KEY, ACTIVE | PASSIVE, 90, PI);
}
2. Avatar Control
3. Planning sensor(integer total_number)
{
4. Demo if (llDetectedName(0) == "Maze Start") Nothing returned
{
5. Other Ideas llSay(0, "Maze start is at " + (string)llDetectedPos(0));
}
}
no_sensor()
{
llSay(0, "Error: Sensor failed");
}
}
5/23/2010 13
LSL Bots: Motion Planning
RECAP • There are several possible solutions
INTRO: SL BOTS
» Using CGAL
LSL BOTS
1. Framework
• Proposed by Danny Halperin and Alon Shalita
2. Planning
3. Results
4. Other MP Ideas
LIBSECONDLIFE
1. Framework
2. Avatar Control
3. Planning
4. Demo
5. Other Ideas
Stop
Start
5/23/2010 Obstacles 14
LSL Bots: Motion Planning
RECAP • There are several possible solutions
INTRO: SL BOTS
» Using CGAL
LSL BOTS
1. Framework
• Proposed by Danny Halperin and Alon Shalita
2. Planning 1. Write a script to “sense” obstacles
3. Results
4. Other MP Ideas
LIBSECONDLIFE
1. Framework
2. Avatar Control
3. Planning
4. Demo
5. Other Ideas
Stop
Start
5/23/2010 Obstacles 15
LSL Bots: Motion Planning
RECAP • There are several possible solutions
INTRO: SL BOTS
» Using CGAL
LSL BOTS
1. Framework
• Proposed by Danny Halperin and Alon Shalita
2. Planning 1. Write a script to “sense” obstacles
3. Results
2. Append robot and obstacles to a file
4. Other MP Ideas
LIBSECONDLIFE
1. Framework
2. Avatar Control
3. Planning
4. Demo
5. Other Ideas
Stop
Start
5/23/2010 Obstacles 16
LSL Bots: Motion Planning
RECAP • There are several possible solutions
INTRO: SL BOTS
» Using CGAL
LSL BOTS
1. Framework
• Proposed by Danny Halperin and Alon Shalita
2. Planning 1. Write a script to “sense” obstacles
3. Results
2. Append robot and obstacles to a file
4. Other MP Ideas
3. Run CGAL on the file and send the response
LIBSECONDLIFE
1. Framework
2. Avatar Control
3. Planning
4. Demo
5. Other Ideas
Stop
Start
5/23/2010 Obstacles 17
LSL Bots: Motion Planning
RECAP • There are several possible solutions
INTRO: SL BOTS
» Using CGAL
LSL BOTS
1. Framework
• Proposed by Danny Halperin and Alon Shalita
2. Planning 1. Write a script to “sense” obstacles
3. Results
2. Append robot and obstacles to a file
4. Other MP Ideas
3. Run CGAL on the file and send the response
LIBSECONDLIFE
1. Framework
4. Process the response and run the path
2. Avatar Control
3. Planning
4. Demo
5. Other Ideas
Stop
Start
5/23/2010 Obstacles 18
LSL Bots: Considerations
RECAP • Identifying obstacles
INTRO: SL BOTS
» Sensors only return nearest 16 objects
LSL BOTS
1. Framework
• This may be fixed soon
2. Planning
» Much easier for self-built environments
3. Results
4. Other MP Ideas • Know exactly which prims to look for
LIBSECONDLIFE • Limited script memory, HTTP response size
1. Framework
2. Avatar Control » Can only send finite amounts at a time
3. Planning
• Send in groups
4. Demo
5. Other Ideas » Process results in groups
• Note: CGAL is not necessary
» Any command-line planner which can return
text information to SL should suffice
5/23/2010 19
LSL Bots: Results Movies
RECAP
INTRO: SL BOTS
LSL BOTS
1. Framework
2. Planning
3. Results
4. Other MP Ideas
LIBSECONDLIFE
1. Framework
2. Avatar Control
3. Planning
4. Demo
5. Other Ideas
5/23/2010 20
LSL Bots: Some other ideas
RECAP • None of these have been implemented (to my
INTRO: SL BOTS
knowledge)
LSL BOTS
1. Framework
» Bug algorithm
2. Planning
» Online mapping
3. Results
4. Other MP Ideas • Have the robot move until it collides, record this
LIBSECONDLIFE information
1. Framework » Use other prims as waypoints
2. Avatar Control
3. Planning • Difficult to maintain
4. Demo • Ordering could be maintained and stored
5. Other Ideas
remotely
» Potential fields
• Keep track of a goal and move in that direction
while moving away from obstacles
5/23/2010 21
LibSecondLife (LibSL)
RECAP • Potential for complete avatar simulation
INTRO: SL BOTS
» Reverse engineering of SL network protocol
LSL BOTS
1. Framework » Framework for using protocol with The Grid
2. Planning
» Theoretically, could implement new SL viewer
3. Results
4. Other MP Ideas • Based on C#
LIBSECONDLIFE
1. Framework
» All C# features are available
2. Avatar Control » Much more flexible programming environment
3. Planning
4. Demo • Avatar control
5. Other Ideas
» Could have an avatar control a prim, in theory
• Client-server interface
• Extend range of SL capabilities
• Actively developed
» Much of this section is just ideas so far
5/23/2010 22
LibSL: Getting Started
RECAP • Prerequisites
INTRO: SL BOTS
» C# compiler
LSL BOTS
1. Framework
• Mono (all platforms except Windows)
2. Planning • Visual Studio .NET 2005 (Windows)
3. Results
4. Other MP Ideas
• Visual Studio Express .NET (Windows, free)
LIBSECONDLIFE » Source code via SubVersion
1. Framework
• svn://openmetaverse.org/libsl/trunk
2. Avatar Control
3. Planning 1. Build code
4. Demo
5. Other Ideas
2. Start a new project
3. Add libsecondlife as a reference
» For more help:
• http://www.libsecondlife.org/wiki/Use_libSL_to_l
ogin_to_the_SL_grid
5/23/2010 23
LibSL: Framework
• LibSL example
RECAP using System;
using System.Collections.Generic;
INTRO: SL BOTS using System.Text;
using libsecondlife; Include libsecondlife libraries
LSL BOTS
namespace MyFirstBot {
1. Framework class MyFirstBot {
public static SecondLife client = new SecondLife();
2. Planning private static string first_name = "First";
3. Results private static string last_name = "Last";
private static string password = "password";
4. Other MP Ideas
public static void Main() {
LIBSECONDLIFE client.Network.OnConnected += new
1. Framework NetworkManager.ConnectedCallback(Network_OnConnected);
2. Avatar Control if (client.Network.Login(first_name, last_name, password,
"My First Bot", "Your name")) {
3. Planning Console.WriteLine("I logged into Second Life!");
} else {
4. Demo Console.WriteLine("I couldn't log in, here is why: "
5. Other Ideas + client.Network.LoginMessage);
}
}
static void Network_OnConnected(object sender) {
Console.WriteLine("I'm connected to the simulator, going to
greet everyone around me");
client.Self.Chat("Hello World!", 0, ChatType.Normal);
Console.WriteLine("Now I am going to
logout of SL.. Goodbye!");
client.Network.Logout();
}
}
5/23/2010
} 24
LibSL: Framework
• LibSL example
RECAP using System;
using System.Collections.Generic;
INTRO: SL BOTS using System.Text;
using libsecondlife; Define SecondLife client(s)
LSL BOTS
namespace MyFirstBot {
1. Framework class MyFirstBot {
public static SecondLife client = new SecondLife();
2. Planning private static string first_name = "First";
3. Results private static string last_name = "Last";
private static string password = "password";
4. Other MP Ideas
public static void Main() {
LIBSECONDLIFE client.Network.OnConnected += new
1. Framework NetworkManager.ConnectedCallback(Network_OnConnected);
2. Avatar Control if (client.Network.Login(first_name, last_name, password,
"My First Bot", "Your name")) {
3. Planning Console.WriteLine("I logged into Second Life!");
} else {
4. Demo Console.WriteLine("I couldn't log in, here is why: "
5. Other Ideas + client.Network.LoginMessage);
}
}
static void Network_OnConnected(object sender) {
Console.WriteLine("I'm connected to the simulator, going to
greet everyone around me");
client.Self.Chat("Hello World!", 0, ChatType.Normal);
Console.WriteLine("Now I am going to
logout of SL.. Goodbye!");
client.Network.Logout();
}
}
5/23/2010
} 25
LibSL: Framework
• LibSL example
RECAP using System;
using System.Collections.Generic;
INTRO: SL BOTS using System.Text;
using libsecondlife; Add your bot’s name
LSL BOTS
namespace MyFirstBot {
1. Framework class MyFirstBot {
public static SecondLife client = new SecondLife();
2. Planning private static string first_name = "First";
3. Results private static string last_name = "Last";
private static string password = "password";
4. Other MP Ideas
public static void Main() {
LIBSECONDLIFE client.Network.OnConnected += new
1. Framework NetworkManager.ConnectedCallback(Network_OnConnected);
2. Avatar Control if (client.Network.Login(first_name, last_name, password,
"My First Bot", "Your name")) {
3. Planning Console.WriteLine("I logged into Second Life!");
} else {
4. Demo Console.WriteLine("I couldn't log in, here is why: "
5. Other Ideas + client.Network.LoginMessage);
}
}
static void Network_OnConnected(object sender) {
Console.WriteLine("I'm connected to the simulator, going to
greet everyone around me");
client.Self.Chat("Hello World!", 0, ChatType.Normal);
Console.WriteLine("Now I am going to
logout of SL.. Goodbye!");
client.Network.Logout();
}
}
5/23/2010
} 26
LibSL: Framework
• LibSL example
RECAP using System;
using System.Collections.Generic;
INTRO: SL BOTS using System.Text;
using libsecondlife; Define a connected event
LSL BOTS
namespace MyFirstBot {
1. Framework class MyFirstBot {
public static SecondLife client = new SecondLife();
2. Planning private static string first_name = "First";
3. Results private static string last_name = "Last";
private static string password = "password";
4. Other MP Ideas
public static void Main() {
LIBSECONDLIFE client.Network.OnConnected += new
1. Framework NetworkManager.ConnectedCallback(Network_OnConnected);
2. Avatar Control if (client.Network.Login(first_name, last_name, password,
"My First Bot", "Your name")) {
3. Planning Console.WriteLine("I logged into Second Life!");
} else {
4. Demo Console.WriteLine("I couldn't log in, here is why: "
5. Other Ideas + client.Network.LoginMessage);
}
}
static void Network_OnConnected(object sender) {
Console.WriteLine("I'm connected to the simulator, going to
greet everyone around me");
client.Self.Chat("Hello World!", 0, ChatType.Normal);
Console.WriteLine("Now I am going to
logout of SL.. Goodbye!");
client.Network.Logout();
}
}
5/23/2010
} 27
LibSL: Framework
• LibSL example
RECAP using System;
using System.Collections.Generic;
INTRO: SL BOTS using System.Text;
using libsecondlife; Try to log in to the Grid
LSL BOTS
namespace MyFirstBot {
1. Framework class MyFirstBot {
public static SecondLife client = new SecondLife();
2. Planning private static string first_name = "First";
3. Results private static string last_name = "Last";
private static string password = "password";
4. Other MP Ideas
public static void Main() {
LIBSECONDLIFE client.Network.OnConnected += new
1. Framework NetworkManager.ConnectedCallback(Network_OnConnected);
2. Avatar Control if (client.Network.Login(first_name, last_name, password,
"My First Bot", "Your name")) {
3. Planning Console.WriteLine("I logged into Second Life!");
} else {
4. Demo Console.WriteLine("I couldn't log in, here is why: "
5. Other Ideas + client.Network.LoginMessage);
}
}
static void Network_OnConnected(object sender) {
Console.WriteLine("I'm connected to the simulator, going to
greet everyone around me");
client.Self.Chat("Hello World!", 0, ChatType.Normal);
Console.WriteLine("Now I am going to
logout of SL.. Goodbye!");
client.Network.Logout();
}
}
5/23/2010
} 28
LibSL: Framework
• LibSL example
RECAP using System;
using System.Collections.Generic;
INTRO: SL BOTS using System.Text;
using libsecondlife; When connected, send a message
LSL BOTS
namespace MyFirstBot {
1. Framework class MyFirstBot {
public static SecondLife client = new SecondLife();
2. Planning private static string first_name = "First";
3. Results private static string last_name = "Last";
private static string password = "password";
4. Other MP Ideas
public static void Main() {
LIBSECONDLIFE client.Network.OnConnected += new
1. Framework NetworkManager.ConnectedCallback(Network_OnConnected);
2. Avatar Control if (client.Network.Login(first_name, last_name, password,
"My First Bot", "Your name")) {
3. Planning Console.WriteLine("I logged into Second Life!");
} else {
4. Demo Console.WriteLine("I couldn't log in, here is why: "
5. Other Ideas + client.Network.LoginMessage);
}
}
static void Network_OnConnected(object sender) {
Console.WriteLine("I'm connected to the simulator, going to
greet everyone around me");
client.Self.Chat("Hello World!", 0, ChatType.Normal);
Console.WriteLine("Now I am going to
logout of SL.. Goodbye!");
client.Network.Logout();
}
}
5/23/2010
} 29
LibSL: Framework
• LibSL example
RECAP using System;
using System.Collections.Generic;
INTRO: SL BOTS using System.Text;
using libsecondlife; After your message, logout
LSL BOTS
namespace MyFirstBot {
1. Framework class MyFirstBot {
public static SecondLife client = new SecondLife();
2. Planning private static string first_name = "First";
3. Results private static string last_name = "Last";
private static string password = "password";
4. Other MP Ideas
public static void Main() {
LIBSECONDLIFE client.Network.OnConnected += new
1. Framework NetworkManager.ConnectedCallback(Network_OnConnected);
2. Avatar Control if (client.Network.Login(first_name, last_name, password,
"My First Bot", "Your name")) {
3. Planning Console.WriteLine("I logged into Second Life!");
} else {
4. Demo Console.WriteLine("I couldn't log in, here is why: "
5. Other Ideas + client.Network.LoginMessage);
}
}
static void Network_OnConnected(object sender) {
Console.WriteLine("I'm connected to the simulator, going to
greet everyone around me");
client.Self.Chat("Hello World!", 0, ChatType.Normal);
Console.WriteLine("Now I am going to
logout of SL.. Goodbye!");
client.Network.Logout();
}
}
5/23/2010
} 30
LibSL: Framework
RECAP • Most actions are defined within callbacks
INTRO: SL BOTS
(events)
LSL BOTS
1. Framework
» Network events
2. Planning • OnConnected / OnDisconnected
3. Results
4. Other MP Ideas
• OnCurrentSimChanged
LIBSECONDLIFE » Client (Avatar) events
1. Framework
• OnInstantMessage
2. Avatar Control
3. Planning • OnChat
4. Demo
• OnTeleport
5. Other Ideas
» Object events
• OnNewAvatar / OnNewPrim
• OnObjectUpdated / OnObjectKilled
5/23/2010 31
LibSL: TestClient
RECAP • Application provided with the SVN code base
INTRO: SL BOTS
» Open source
LSL BOTS
1. Framework » Standard LibSL development framework
2. Planning
3. Results
• Most actions are included as commands
4. Other MP Ideas » Easy to define and use
LIBSECONDLIFE
1. Framework
» Invoked from console or by assigning a
2. Avatar Control “Master” for your bot
3. Planning
» e.g. Wear, GiveAll, Stats, Location, Sit
4. Demo
5. Other Ideas • Supports multiple simultaneous avatar bots
• Organizes most incoming objects as the SL
viewer would see them
5/23/2010 32
LibSL: Avatar Control
RECAP • For planning, we must be able to move the
INTRO: SL BOTS
avatar to a desired location
LSL BOTS
1. Framework
» No built in command for avatars
2. Planning • You may be able to hack something by
3. Results
attaching a prim that can move
4. Other MP Ideas
LIBSECONDLIFE • Use LibSL to build a simple motion controller
1. Framework
» LibSL can send data packets which instruct
2. Avatar Control
3. Planning the avatar to move
4. Demo
5. Other Ideas
• For SL planning purposes (thus far), the
following should suffice
» Move to a position specified by a distance and
direction
» Move to a specified position
5/23/2010 33
LibSL: Avatar Control
RECAP • Homework 1 Hints
INTRO: SL BOTS
» If you use TestClient, make use of existing
LSL BOTS
1. Framework
commands
2. Planning » It will be very valuable to allow your robot to
3. Results
4. Other MP Ideas
move toward either
LIBSECONDLIFE • A sequence of points
1. Framework • A sequence of direction/distance pairs
2. Avatar Control
3. Planning » Make yourself a meter marker to test accuracy
4. Demo
5. Other Ideas
5/23/2010 34
LibSL: Motion Planning
RECAP • Given a basic controller, we need to tell the
INTRO: SL BOTS
avatar where to go
LSL BOTS
1. Framework • Several standard approaches
2. Planning
» Cell Decomposition
3. Results
4. Other MP Ideas » Potential Fields
LIBSECONDLIFE
» Roadmap
1. Framework
2. Avatar Control • For all approaches, “sensing” the
3. Planning
4. Demo
environment is necessary
5. Other Ideas » LibSL comes with an ObjectManager class
» Keeps a Dictionary of all current Prims and
Avatars
• In the same way the SL viewer does, as far as
they understand
5/23/2010 35
LibSL: Local Mapping and
Planning
RECAP • Bug-like approach to planning
INTRO: SL BOTS
1. Move your avatar in a direction toward the
LSL BOTS
1. Framework
goal as far as possible
2. Planning 2. Have it follow the barrier in a given direction
3. Results
4. Other MP Ideas
until you can make progress toward the goal
LIBSECONDLIFE
again
1. Framework
• No need memorize the environment, just
2. Avatar Control
3. Planning when you’re colliding
4. Demo
5. Other Ideas
5/23/2010 36
LibSL: Local Reactions
RECAP • Standard walking motion in SL signaled
INTRO: SL BOTS
through “AutoPilot” packets
LSL BOTS
1. Framework
» This is essentially the straight-line path
2. Planning
» It is cancelled when an event occurs that
3. Results
4. Other MP Ideas
causes the motion to end
LIBSECONDLIFE • Collision
1. Framework • Reached destination
2. Avatar Control
3. Planning • Thus, avatars cannot easily react
4. Demo
5. Other Ideas
» Need a motion model that is modifiable
• A solution
» Move in small increments
» Requires some careful tuning of current
velocity to keep motion smooth
5/23/2010 37
LibSL: Behavior Control
RECAP • Avatars come with default behavior
INTRO: SL BOTS
» However, they are capable of performing other
LSL BOTS
1. Framework
actions / animations
2. Planning
• Solution: Animation Override (AO) to the
3. Results
4. Other MP Ideas rescue
LIBSECONDLIFE » Collect a set of animations you’d like to use
1. Framework
2. Avatar Control
» Get an AO gadget
3. Planning • Francis Chung's Wet Ikon seems to be a free
4. Demo
favorite
5. Other Ideas
» When embedded in a worn prim, it will
override the default
» Depending on the environment, use LibSL to
change the various animations
» Video?
5/23/2010 38
LibSL: Demo
RECAP • Basics of LibSL and TestClient
INTRO: SL BOTS
LSL BOTS
1. Framework
2. Planning
3. Results
4. Other MP Ideas
LIBSECONDLIFE
1. Framework
2. Avatar Control
3. Planning
4. Demo
5. Other Ideas
5/23/2010 39
LibSL: Other Ideas
RECAP • A more kinodynamic approach
INTRO: SL BOTS
» Alter the motion controller to be like that of a
LSL BOTS
1. Framework
car
2. Planning
• Hybrid approach
3. Results
4. Other MP Ideas » What I’m currently playing with
LIBSECONDLIFE » Prims do a great job of finding nearby
1. Framework
2. Avatar Control
obstacles
3. Planning » Prims are easy to move
4. Demo
5. Other Ideas » Use a sequence of prims as a roadmap
• Easy for an avatar to follow
• Difficult to maintain
5/23/2010 40
Fin
RECAP • Motion Planning in SL
INTRO: SL BOTS
» Using LSL
LSL BOTS
1. Framework » Using LibSL
2. Planning
3. Results
4. Other MP Ideas
LIBSECONDLIFE
1. Framework
2. Avatar Control Any questions?
3. Planning
4. Demo
5. Other Ideas
5/23/2010 41
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