LSL学习笔记(3)

 

Notecard

Notecard是Second Life里的的其中一种inventory item (通常是a text file), 每个notecard都有一个key，通过下列步骤你可以获得该notecard的key：right-clicking a notecard and selecting "Copy UUID to clipboard".

 

Notecards能够包含any type and number of inventory items embedded into the text (objects, clothes, textures, other notecards, landmarks, etc.).

Notecards are limited in size to 64KiB of text.

Notecards can be read using llGetNotecardLine() unless they contain any inventory items as described above.

 

Notecard涉及到的Functions and Events有：

Functions

Function

Description

llGetNotecardLine

读取所指定的notecard里的某一行的data。当返回data时会trigger dataserver event.

llGetNumberOfNotecardLines

获取所指定的notecard包含的行数。返回行数时会trigger dataserver event.

llGiveInventory

把一个notecard送给a user。执行该方法时，该notecard的内容就会在一个popup notecard window里显示出来，该user可以选择是keep还是discard该notecard。这也是一个常用的显示text的方法。

Events

Event

Description

changed

当1个notecard被添加到object，或从object里删除，或对object里的notecard进行了修改，都会trigger该event。当然其他inventory item发生增删改的情况也会trigger该event，而不仅仅是for notecard。

dataserver

Triggered when calls to llGetNotecardLine or llGetNumberOfNotecardLines returns data. 当然还有其他request data返回时也会trigger该event，我们后面会讲解

 

 

相关Function的详细讲解

string llGetInventoryName(integer type, integer number)

获取某个inventory类型的所指定的index的inventory item。Item index是从0开始的。如果所指定的inventory类型没有任何的item，就返回一个empty string。如果你想要先check该inventory type里是否有item，你需要使用llGetInventoryType

！！请注意: inventory item的排序是根据name的字母大小来排

下面的constants用来指定inventory type:

Constant

Value

Look At

Hex

INVENTORY_ALL

-1

all inventory items

 

INVENTORY_ANIMATION

20

animations

0x14

INVENTORY_BODYPART

13

body parts

0x0D

INVENTORY_CLOTHING

5

clothing

0x05

INVENTORY_GESTURE

21

gestures

0x15

INVENTORY_LANDMARK

3

landmarks

0x03

INVENTORY_NOTECARD

7

notecards

0x07

INVENTORY_OBJECT

6

objects

0x06

INVENTORY_SCRIPT

10

scripts

0x0A

INVENTORY_SOUND

1

sounds

0x01

INVENTORY_TEXTURE

0

textures

0x00

Note: Inventory constants are not bitflags and thus should not be used with Bitwise operators.

 

Example:

//获得该object的第1个inventory notecard

llGetInventoryName(INVENTORY_NOTECARD, 0)

 

相关的函数有：llGetInventoryKey and llGetInventoryNumber

 

 

dataserver(key queryid, string data)

当the requested data返回时就会trigger该 event handler。

 

通过调用函数llGetNotecardLine, llGetNumberOfNotecardLines, llRequestAgentData, llRequestInventoryData, and llRequestSimulatorData就会要求request data，从而trigger该event。

参数queryid是上述函数调用时返回的key。

参数data是requested data。

由于多个函数都能够trigger dataserver event，因此要通过参数queryid来判断是来自哪一个。

Note: Dataserver requests会trigger all dataserver() events in all scripts within the same prim where the request was made，但dataserver() events无法被trigger in other prims in the same linked object.

Remember: 错误的requests会失败，但不会抛出任何error，而且不会触发dataserver() event (例如：如果a notecard line is requested, 但所提供的指向a notecard的key是错误的，那么request data失败).

 

可以通过timer来check在request data后的一段时间内如果no dataserver() event发生，就表明request failed。

！！注意： dataserver很慢，因此慎用该event！！！

 

Example: 在后面有一个结合llGetNotecardLine的例子

 

 

key llGetNotecardLine(string name, integer line)

该函数是获取参数name所指定的notecard里参数line所指定的那一行的data。

当data返回的时候，就会触发dataserver event。Notecard里的line number是从0开始的。如果requested line已经超过the end of the notecard, dataserver event就会返回一个常量EOF ("End Of File") string.

llGetNotecardLine的返回值是一个key，它会作为参数queryid值传递给dataserver event。

参数name可以是a notecard name（该notecard必须在该object的inventory里），也可以是a key pointing to a notecard （该notecard不需要在该object的inventory里). 对于第二种情况，你要注意的是当你edit a notecard时，它的key会变！

如果参数name没有指定a valid notecard, or指定的notecard is empty, 那么就会抛出error："Couldn't find notecard NAME"

注意：

1. 每一行的data不能超过255 characters，超过的部分会被cut
2. Requests from a notecard that contain embedded inventory items总是返回EOF(当然dataserver event会被触发)
3. 调用该函数会delays the script for 0.1 seconds.

 

Example:

integer gLine = 0;         // current line number

key gQueryID;             // id used to identify dataserver queries

default {

    state_entry() {

        gQueryID = llGetNotecardLine(“notecard1”, gLine);    // request first line

    }

    dataserver(key query_id, string data) {

        if (query_id == gQueryID) {

            if (data != EOF) {    // not at the end of the notecard

                llSay(0, (string)gLine+": "+data);    // output the line

                // increase line count

                ++gLine;                

                // request next line

                gQueryID = llGetNotecardLine(“notecard1, gLine);    

            }

        }

    }

}

 

 

key llGetNumberOfNotecardLines(string name)

返回参数name所指定的notecard包含的行数，返回行数时会trigger dataserver event.

该函数的返回值是一个key，它会作为参数queryid值传递给dataserver event。

如果参数name没有指定a valid notecard, or指定的notecard is empty, 那么就会抛出error："Couldn't find notecard NAME"，而且dataserver event也不会被触发（注意：对empty notecard调用函数llGetNotecardLine会触发dataserver event，返回的data为EOF）。

Requests from a notecard that contain embedded inventory items总是返回EOF(当然dataserver event会被触发)

Note: 调用该函数会delays the script for 0.1 seconds.

 

Example:

default {

    state_entry() {

        llGetNumberOfNotecardLines("somenotecard");

    }    

    dataserver(key queryid, string data) {

         // note how the returned value is already a string

        llSay(0, "This notecard has " + data + " lines."); 

        // if you want to use it as a number, you will have to cast it to an integer:

        integer    lines = (integer)data;

    }

}

 

 

changed(integer change)

当the prim/object的properties发生变化时，就会触发changed event。

参数change是a bitfield，它是由一个or多个下列值合并而成的：

Constant

Value

Indicates

 

CHANGED_INVENTORY

0x1

changed object inventory (could include an item being added, removed, or renamed, or a notecard being edited and saved).

Details

CHANGED_COLOR

0x2

changed object color or transparency

 

CHANGED_SHAPE

0x4

changed object shape (box to cylinder, for example), cut, hollow amount/shape, twist, top size, or shear

 

CHANGED_SCALE

0x8

changed object scale.

Details

CHANGED_TEXTURE

0x10

changed object texture: offset, repeats, rotation, and reflection/bump maps (but not transparency -- that's CHANGED_COLOR)

 

CHANGED_LINK

0x20

linking or delinking (also when an avatar sits on or unsits from the object).

Details

CHANGED_ALLOWED_DROP

0x40

An item was dropped (into this object's inventory) that was only allowed by the llAllowInventoryDrop function. This allows the object to identify items dropped by anyone who doesn't have modify permissions on the object.

 

CHANGED_OWNER

0x80

The ownership of the object changed. This value is passed when an object is deeded to a group, when an object is purchased, or when a newly-purchased object is rezzed.

Details

CHANGED_REGION

0x100

The object changed regions/sims.

Details

CHANGED_TELEPORT

0x200

The object has been teleported.

Details

 

 

Details

Constant or Value: changed() is triggered: changed() is not triggered: CHANGED_INVENTORY

• when adding any inventory item to the prim's inventory.
• when deleting any inventory item from the prim's inventory.
• when changing the name or description of an inventory item inside the prim.
• when changing asset permissions of an inventory item within the prim.
• when saving a notecard that already exists within the prim's inventory.
• when recompiling a script that already exists in the prim's inventory.
• when inventory is changed in another prim in the linked object.

• when resetting a script.
• when a no-copy item is removed (but not deleted!) from the prim by manually dragged back to user inventory.
• when inventory is added using llAllowInventoryDrop, and the user dropping the new inventory item is not the owner of the prim.
• when the change is invoked via LSL llRemoveInventory(..). This may be a bug, see: http://jira.secondlife.com/browse/SVC-304

CHANGED_SCALE

• in a prim, linked or not, when resizing that prim.
• in the root prim in a linked object when resizing the entire object.

• in a different prim in a linked object when resizing a separate prim in that object.
• in a child prim in a linked object when resizing the entire object.

CHANGED_LINK

• when linking two (or more) prims together.
• when delinking an object.
• when delinking a prim from an object.
• when an avatar sits on an object.
• when a sitting avatar stands up from the object.
• when duplicating a linked object.
• When changing the prim type/shape of a prim in the object.

• in an attachment when an avatar sits down or stands up.
• in an attachment when it's attached.
• in an attachment when another attachment is attached.
• in an attachment when you sit on an object.
• in an object when the sitting avatar attaches an object.
• when duplicating a single prim.

CHANGED_OWNER

• in the original object when a user buys the object.
• in the original object when a user buys a copy of the object.
• in the original object when a user takes the object or a copy of the object.
• in the newly-rezzed copy when the user rezzes the object for the first time. (on_rez() is still triggered first.) This occurs whether or not the object was copied or purchased.
• when an object is deeded to a group.

• in the original object when the user buys the contents of an object. It is still triggered in the copy when the new owner rezzes it.

CHANGED_REGION

• in the root prim of an attachment when the user teleports to a new sim/region or crosses into a new sim directly.
• in the root prim of an object that moves into a new region.

• in a child prim of an attachment when the user teleports to a new region.
• in a child prim of an object that moves into a new region.

CHANGED_TELEPORT

• in the root prim of an attachment when the user teleports to a new sim, or a location within the current sim. This happens whether they teleport manually, or using one of the teleport functions.

• in a child prim of an attachment when the user teleports to a different location.
• in any prim in an attachment when the user sits on an object that uses the llSitTarget "sit teleport" trick.
• in any prim in an unattached object.
• in an attachment, after teleporting to no-script land, not even being entered into the event queue. This means it will not be triggered after teleporting to a region where scripts are allowed, only the event for that teleport will be triggered.

(As of Second Life 1.16.0 (5) this is not accurate. Teleporting into no-script land will cause the event to trigger once you move onto script-enabled land, as though you had just teleported.)

Aside from the above, the changed() event is also not triggered:

• when an object changes position. (Use moving_start() and moving_end().)
• when an object changes rotation.
• when changing the object's name or description.
• when changing the object's group. (not deeding the object to a group -- that'll trigger CHANGED_OWNER)
• when toggling "Share with group", "Allow anyone to move", "Allow anyone to copy", setting the object "For Sale", changing any of the sale settings, or setting "Next owner can:".
• when toggling "Lock", "Physics", "Temporary" or "Phantom".
• when setting prim material.
• when using llSetText.
• when using llParticleSystem.
• in a worn attachment when the owner attaches or detaches it. (Use attach().)
• in a worn attachment when the wearer sits on something.
• when the object is selected/edited.

 

因此它使用的是”&” or “|”等位操作符。例如：代码总是使用

      if (change & CHANGED_LINK)

而不是使用

      if (change == CHANGED_LINK)

 

Notes:

• The change parameter describes only what type of change happened, not the difference between the original and changed versions of the object. If you need to determine exactly what changed, the script must store the relevant properties and compare the values from before and after the change.
• Prim/object position and rotation are not currently detected when changed but can be via a timer and llGetRot and llGetPos. Position changes can also be detected by using the moving_start and moving_end events.
• When an avatar sits on an object, they seem to become part of the linkset.
• A changed() event is raised with CHANGED_LINK as the parameter when an avatar sits on an object or un-sits. To find out what happened, use llAvatarOnSitTarget which returns the NULL_KEY if no avatar is sitting on the object, or the key of the avatar that is sitting at the sit target.

 

Example 1 当一个avatar坐在object上时，show info “get off” and 强制他stand up:

default {

    state_entry() {

        // needed for llAvatarOnSitTarget to work

        llSitTarget(<0, 0, 0.1>, ZERO_ROTATION); 

    }

    changed(integer change) { // something changed

        if (change & CHANGED_LINK) { // and it was a link change

           // llSleep(0.5); // llUnSit works better with this delay

            key av = llAvatarOnSitTarget();

            if (av) { // somebody is sitting on me

                llSay(0, "Get off!"); // say in chat when person is remove from prim

                llUnSit(av); // unsit him

            }

        }

    }

}

 

Example 2:

changed(integer change)

{

   if((change & CHANGED_OWNER) || (change & CHANGED_INVENTORY))   

   {

       loadNoteCard();

    }

}