LlSitTarget - Second Life Wiki

LlSitTarget

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Summary

Function: llSitTarget( vector offset, rotation rot );

Set the sit location for the prim. The sit location is relative to the prim's position and rotation.

• vector offset Additional position for the sit target in local prim coordinates.
• rotation rot Additional rotation for the sit target relative to the prim rotation.

If offset == <0.0, 0.0, 0.0> then the sit target is removed.

Specification

llSitTarget sets the position for the Agent Target (Advanced -> Character -> View Agent Target). The position of the target is based on rot and the offset[1].

Caveats

  • Once a sit target is removed llAvatarOnSitTarget will only return NULL_KEY.
  • Removing or deactivating the script that sets the sit target will not remove the prim's sit target.
    • Sit target is a prim property and not dependent on a script for its continued existence.
  • To remove sit target, use the following:
llSitTarget(ZERO_VECTOR,ZERO_ROTATION);
  • Shift-copying a prim with a sit target, without a script that will set the sit target again, will not keep the sit target on the copy. (The copy is in the original location when shift-copying.)
  • There is no way to remove the Sit option from the pie menu.
    • It will appear to be removed if the llSetSitText is set to a space " " or similar transparent string.
  • Attachments cannot be sat upon (see SVC-6100 to vote for such a feature).
  • rot affects the position of the sit-target in a buggy way way.
    • To correct for the rot bug, simply subtract <0,0,0.4> from the position when rot is zero. See example below.
    • llSetLinkPrimitiveParams is a more difficult work-around.
    • Animations are relative to the Agent Target, but the Agent Target isn't described by the animation.
  • llSitTarget does not update position of an already seated avatar.
  • offset is limited to 300.0 meters on each axis. The x, y and z components must be in the range [-300, 300.0][2].
    • If they are outside the acceptable range they are rounded to the closest limit.
All Issues ~ Search JIRA for related Bugs

Examples

default
{
    state_entry()
    {
        llSitTarget(<0.0, 0.0, 1.0>, ZERO_ROTATION); //The vector's components must not all be set to 0 for effect to take place.
    }
}
default     //example with work-around for llSetTarget rot bug
{           //place in any prim large enough to sit on at any angle
            //click once to choose a place to sit, a second time to sit there
    touch_start(integer num)
    {
        vector pos=llDetectedTouchPos(0);       //use touch to set sit target
        vector lft=llDetectedTouchBinormal(0);  //use normals to rotate avatar to
        vector up=llDetectedTouchNormal(0);     //sit upright
        rotation rot=llAxes2Rot(lft%up,lft,up)/llGetRot();  //rotate avatar to stand there
        vector siz=llGetAgentSize(llDetectedKey(0));
        pos += 0.65*siz.z*up;       //this places MY avatars feet close to the surface
        pos = (pos-llGetPos())/llGetRot();  //llSetTarget expects local co-ordinates
        if (rot!=ZERO_ROTATION) pos -=<0,0,0.4>;  //here is the work around
        llSitTarget(pos,rot);
        llSetClickAction(CLICK_ACTION_SIT);   //switch to sit for second click
    }
    changed(integer change)
    {
        if (llAvatarOnSitTarget()==NULL_KEY)    //if they unsit,
            llSetClickAction(CLICK_ACTION_TOUCH);   //go back to click mode
    }
}

Useful Snippets

UpdateSitTarget

//Sets / Updates the sit target moving the avatar on it if necessary.
UpdateSitTarget(vector pos, rotation rot)
{//Using this while the object is moving may give unpredictable results.
    llSitTarget(pos, rot);//Set the sit target
    key user = llAvatarOnSitTarget();
    if(user)//true if there is a user seated on the sittarget, if so update their position
    {
        vector size = llGetAgentSize(user);
        if(size)//This tests to make sure the user really exists.
        {
            //We need to make the position and rotation local to the current prim
            rotation localrot = ZERO_ROTATION;
            vector localpos = ZERO_VECTOR;
            if(llGetLinkNumber() > 1)//only need the local rot if it's not the root.
            {
                localrot = llGetLocalRot();
                localpos = llGetLocalPos();
            }
            pos.z += 0.4;
            integer linkNum = llGetNumberOfPrims();
            do{
                if(user == llGetLinkKey( linkNum ))//just checking to make sure the index is valid.
                {
                    llSetLinkPrimitiveParams(linkNum,
                                            [PRIM_POSITION, ((pos - (llRot2Up(rot) * size.z * 0.02638)) * localrot) + localpos,
                                             PRIM_ROTATION, rot * localrot / llGetRootRotation()]);
                    jump end;//cheaper but a tad slower then return
                }
            }while( --linkNum );
        }
        else
        {//It is rare that the sit target will bork but it does happen, this can help to fix it.
            llUnSit(user);
        }
    }
    @end;
}//Written by Strife Onizuka, size adjustment provided by Escort DeFarge

GetSitTarget

list GetSitTarget(integer prim, key av)
{//WARNING: llGetObjectDetails can introduce an error that goes as far as the 5th decimal place!
 //This is highly unlikely to be ever noticed unless compounded over time.
 //Do not use while moving (like in a moving vehicle)!!!
    vector tp = llGetAgentSize(av);
    if(tp)
    {
        if(prim == LINK_THIS)//llGetLinkKey doesn't like LINK_THIS
            prim = llGetLinkNumber();
 
        list details = [OBJECT_POS, OBJECT_ROT];
        rotation f = llList2Rot(details = (llGetObjectDetails(llGetLinkKey(prim), details) + llGetObjectDetails(av, details)), 1);
        rotation r = llList2Rot(details, 3) / f;
 
        return [((llList2Vector(details, 2) - llList2Vector(details, 0)) / f) + (llRot2Up(r) * tp.z * 0.02638) - <0.0, 0.0, 0.4>, r];
    }
    return [];
}//Written by Strife Onizuka

See Also

Events

•  changed

Functions

•  llLinkSitTarget
•  llSetSitText
•  llAvatarOnSitTarget
•  llAvatarOnLinkSitTarget
•  llUnSit

Deep Notes

All Issues

~ Search JIRA for related Issues
   llSit() - scriptable ability to force an avatar to sit on an object
   Ability to sit on prims attached to avatars

Footnotes

  1. ^ It is widely considered that the rot should not affect the position, unfortunately the sit target code is a lava-flow. ~ SVC-2277
  2. ^ The ranges in this article are written in Interval Notation.
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