Scripting Your World: The Official Guide to Second Life® Scripting

CHAPTER 4

THE PRESTO,

ABRACADABRA

OF REZZING

CONTROLLING

MOTION OF

NONPHYSICAL

OBJECTS

SUMMARY

100

THE PRESTO, ABRACADABRA OF REZZING

Rezzing is the creation of a new object in-world. You are already familiar with manual creation of objects;

scripting this process gives you additional flexibility and power in any situation where you have build

privileges. This section presents a few examples of how to automatically rez and control objects—including

how to cheat on your prim budget.

A few caveats do apply. For example, a rezzed object must already exist in the inventory of the rezzing

object. That is, you can rez a basic object that you have in inventory and mutate it, but unlike the build tool

in-world, a script needs to start from something. The rezzing object must have full modify permissions on

the rezzed object. Additionally, LSL does not allow you to create new LSL scripts automatically.

LOOP REZZERS

One thing we all know from firsthand experience is that making large numbers of repetitive objects is a

huge pain. Anyone who has ever made skirts or hair or any other artifacts with large numbers of prims has

certainly experienced the pain. Fortunately, a class of scripts generically known as loop rezzers has evolved

to handle the creation of a large number of similar objects, such as skirts, flower petals, spiral staircases,

and sculptures. You can find some excellent examples of loop rezzers in-world, including a very nice one

offered freely at Vint's primskirtbuilder sandbox, Mindulle <231, 152, 125>.

Loop rezzers can be used as the basis of your own projects. Often, loop rezzers delete themselves

after they have rezzed the more complex object. Other rezzers can play a more active part in the life cycle

of their rezzed items. The next few examples illustrate how to use these automatic loop rezzers.

Making a Flower with a Loop Rezzer

Listing 4.1 illustrates a loop rezzer that creates a flower complete with petals. Put it inside the root prim.

For this flower, that would probably mean the "eye" of the flower head. Note that this script doesn't

actually link the prims together, so you could always delete the "generator" prim after the autogeneration

has completed. This kind of script is extremely useful in place of finicky builds that need prims to line up

exactly: you can do all the math in the script, rather than manually.

Listing 4.1: Flower Loop Rezzer

integer gNumPetals = 8; // how many objects

list gPetals = [];

integer gCmdChannel = 990;

integer gCmdPetalChannel = 991;

makePetals() {

integer petal;

float basicAngle = (360.0 / gNumPetals) * DEG_TO_RAD;

float deltaRot = 0.0;

vector currPos = llGetLocalPos();

rotation rootRot = llGetRootRotation();