// SPDX-License-Identifier: MIT
// Copyright (c) 2026 Incoprea
// Choose a look-ahead steering point
// Not compiled or tested in-world
// Setup: Put in a spare owned prim. Set POINTS, SEGMENT, FRACTION0..1 and nonnegative LOOKAHEAD. Owner touch prints calculations only.
// Stop / restore: Disable/remove. No prim motion or appearance is changed.
// Notes: Assumes the caller already knows its current path segment; does not locate an object in the scene.
// License: see LICENSE in this distribution.
// Original Incoprea. MIT. Motion planning only.
list POINTS=[<0.0,0.0,0.0>,<4.0,0.0,0.0>,<4.0,5.0,0.0>];
integer SEGMENT=0;
float FRACTION=0.5;
float LOOKAHEAD=3.0;
default
{
    touch_start(integer detectedCount)
    {
        if(llDetectedKey(0)!=llGetOwner())return;
        integer n=llGetListLength(POINTS);
        if(SEGMENT<0||SEGMENT>=n-1||FRACTION<0.0||FRACTION>1.0||LOOKAHEAD<0.0)
        {
            llOwnerSay("Invalid route location.");
            return;
        }
        vector a=llList2Vector(POINTS,SEGMENT);
        vector b=llList2Vector(POINTS,SEGMENT+1);
        vector current=a+(b-a)*FRACTION;
        float remaining=LOOKAHEAD;
        integer i;
        for(i=SEGMENT+1;i<n;++i)
        {
            vector target=llList2Vector(POINTS,i);
            float length=llVecDist(current,target);
            if(length>0.0&&remaining<=length)
            {
                llOwnerSay("Lookahead="+(string)(current+(target-current)*(remaining/length)));
                return;
            }
            remaining-=length;
            current=target;
        }
        llOwnerSay("Lookahead clamped="+(string)current);
    }
}