llSetLinkAlpha
Revision as of 12:25, 1 December 2023 by Jenna Huntsman (talk | contribs) (Add Blinn-Phong terminology to page following PBR release.)
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Summary
Function: llSetLinkAlpha( integer link, float alpha, integer face );| 0.0 | Forced Delay |
| 10.0 | Energy |
If a prim exists in the link set at link, set the Blinn-Phong alpha on face of that prim.
| • integer | link | – | Link number (0: unlinked, 1: root prim, >1: child prims and seated avatars) or a LINK_* flag
|
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| • float | alpha | – | from 0.0 (clear) to 1.0 (solid) (0.0 <= alpha <= 1.0) | |
| • integer | face | – | face number or ALL_SIDES |
If face is ALL_SIDES then the function works on all sides.
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Caveats
- The function silently fails if its face value indicates a face that does not exist.
Examples
// Make the entire object disappear for 5 seconds
default
{
touch_start(integer num_detected)
{
// transparent
llSetLinkAlpha(LINK_SET, 0.0, ALL_SIDES);
llSetTimerEvent(5.0);
}
timer()
{
// opaque
llSetLinkAlpha(LINK_SET, 1.0, ALL_SIDES);
llSetTimerEvent(0.0);
}
}
// when the object is touched,
// fade it out and back in again
default
{
touch_start(integer num_detected)
{
// fade out
float alpha = 1.0;
while (alpha >= 0.0)
{
llSetLinkAlpha(LINK_SET, alpha, ALL_SIDES);
alpha -= 0.001;
}
// fade in
while (alpha < 1.0)
{
alpha += 0.001;
llSetLinkAlpha(LINK_SET, alpha, ALL_SIDES);
}
}
}
// Makes selected prims in a linkset become transparent or visible on chat command. Give each prim a unique name.
list PrimList = ["ALL"];
// Start our prim list with a dummy entry, so that the index into this list will correspond directly to the link number
// By making the dummy entry 'ALL' we provide a match for that option too
default
{
changed (integer change)
{
if (change & CHANGED_LINK)
llResetScript();
}
state_entry()
{
integer PrimCount = llGetNumberOfPrims();
llListen(37, "", NULL_KEY, ""); // listen to chat commands from anyone on channel 37
integer i;
for (i = 1; i <= PrimCount; ++i)
PrimList += llToUpper(llGetLinkName(i) ); // Build a list of upper-case link names, where list position equals link number
}
listen(integer channel, string name, key id, string msg)
{
list TempList = llCSV2List( llToUpper(msg) ); // make a list from upper-case version of user command line
integer ListLen = llGetListLength (TempList);
integer alpha = (llList2String(TempList, 0) == "SHOW");
// 'SHOW' sets selected prims visible, otherwise set them transparent
// e.g. HIDE,PLATE,SPOON,NAPKIN <---- makes named prims invisible
// e.g. SHOW,ALL <---- makes all prims visible
integer i;
for (i = 1; i < ListLen; ++i)
{
string ThisPrim = llStringTrim(llList2String(TempList, i), STRING_TRIM);
integer LinkNumber = llListFindList(PrimList, [ThisPrim]);
if (~LinkNumber) // i.e. if LinkNumber != -1
{
if (!LinkNumber)
LinkNumber = LINK_SET; // list position 0 is 'ALL'
llSetLinkAlpha(LinkNumber, alpha, ALL_SIDES);
}
}
}
}
Notes
Link Numbers
Each prim that makes up an object has an address, a link number. To access a specific prim in the object, the prim's link number must be known. In addition to prims having link numbers, avatars seated upon the object do as well.
- If an object consists of only one prim, and there are no avatars seated upon it, the (root) prim's link number is zero.
- However, if the object is made up of multiple prims or there is an avatar seated upon the object, the root prim's link number is one.
When an avatar sits on an object, it is added to the end of the link set and will have the largest link number. In addition to this, while an avatar is seated upon an object, the object is unable to link or unlink prims without unseating all avatars first.
Counting Prims & Avatars
There are two functions of interest when trying to find the number of prims and avatars on an object.
llGetNumberOfPrims()- Returns the number of prims and seated avatars.llGetObjectPrimCount(llGetKey())- Returns only the number of prims in the object but will return zero for attachments.
integer GetPrimCount() { //always returns only the number of prims
if(llGetAttached())//Is it attached?
return llGetNumberOfPrims();//returns avatars and prims but attachments can't be sat on.
return llGetObjectPrimCount(llGetKey());//returns only prims but won't work on attachments.
}
Errata
If a script located in a child prim erroneously attempts to access link 0, it will get or set the property of the linkset's root prim. This bug (BUG-5049) is preserved for broken legacy scripts.
See Also
Events
| • | changed | – | CHANGED_COLOR |
Functions
| • | llGetLinkNumber | – | Returns the link number of the prim the script is in. | |
| • | llGetAlpha | – | Gets the prim's alpha | |
| • | llSetAlpha | – | Sets the prim's alpha | |
| • | llGetColor | – | Gets the prim's color | |
| • | llSetColor | – | Sets the prim's color | |
| • | llSetLinkColor | |||
| • | llSetLinkTexture | |||
| • | llSetLinkPrimitiveParams |
Articles
| • | Translucent Color |