// Pet Follower, for an animesh (or any non-physical) pet.
// Written by Tessel the AI (Claude), 2026-10-10. Free to use, change and share.
//
// Put it in the pet's root prim, set the pet down on the ground, then touch it:
// touch toggles between following you and staying put. It walks to a spot just behind and beside you,
// turns to face where it's going, and plays an animation from its contents whose name contains
// "walk" while moving and one containing "idle" or "stand" when it stops (if there are any).
//
// If the pet walks sideways or backwards, change FACING (the direction the model's nose points
// when the object's rotation is zero): <1,0,0> = +X (most common), <0,1,0> = +Y, <-1,0,0> = -X.
// Mesh pets: set the root's physics shape type to Convex Hull (Edit > Features), which smooth
// movement (keyframed motion) needs.

vector  FACING   = <1.0, 0.0, 0.0>;
vector  OFFSET   = <-1.6, 0.9, 0.0>;   // where to stand, relative to you: behind (-x) and to your left (+y)
float   SPEED    = 3.0;                 // metres per second when catching up
float   CLOSE    = 0.6;                 // close enough: stop and idle
float   TICK     = 0.4;
float   TOO_FAR  = 24.0;                // further than this: hop straight to you

integer following = FALSE;
integer moving = FALSE;
float   rest_h;                         // height above the ground when set down
string  walk_anim;
string  idle_anim;

string find_anim(list keys)
{
    integer n = llGetInventoryNumber(INVENTORY_ANIMATION);
    integer i;
    for (i = 0; i < n; ++i)
    {
        string name = llGetInventoryName(INVENTORY_ANIMATION, i);
        integer k;
        for (k = 0; k < llGetListLength(keys); ++k)
            if (llSubStringIndex(llToLower(name), llList2String(keys, k)) != -1) return name;
    }
    return "";
}

play(integer walking)
{
    if (walking == moving) return;
    moving = walking;
    if (walk_anim != "") { if (walking) llStartObjectAnimation(walk_anim); else llStopObjectAnimation(walk_anim); }
    if (idle_anim != "") { if (walking) llStopObjectAnimation(idle_anim); else llStartObjectAnimation(idle_anim); }
}

setup()
{
    walk_anim = find_anim(["walk", "run", "trot"]);
    idle_anim = find_anim(["idle", "stand", "sit"]);
    vector p = llGetPos();
    rest_h = p.z - llGround(ZERO_VECTOR);
    if (rest_h < 0.0 || rest_h > 3.0) rest_h = 0.3;
    moving = TRUE;
    play(FALSE);
}

stop()
{
    llSetKeyframedMotion([], [KFM_COMMAND, KFM_CMD_STOP]);
    play(FALSE);
}

step()
{
    list d = llGetObjectDetails(llGetOwner(), [OBJECT_POS, OBJECT_ROT]);
    if (d == []) { stop(); return; }                      // owner left the region
    vector me = llGetPos();
    rotation owner_rot = llList2Rot(d, 1);
    vector fwd = llRot2Fwd(owner_rot);
    fwd.z = 0.0;
    rotation flat = llRotBetween(<1.0, 0.0, 0.0>, llVecNorm(fwd));
    vector goal = llList2Vector(d, 0) + OFFSET * flat;
    goal.z = llGround(goal - me) + rest_h;

    vector to = goal - me;
    float dist = llVecMag(<to.x, to.y, 0.0>);
    if (dist < CLOSE) { stop(); return; }
    if (dist > TOO_FAR)
    {
        stop();
        llSetRegionPos(goal);
        return;
    }
    float len = SPEED * TICK;
    if (len > dist) len = dist;
    vector move = llVecNorm(<to.x, to.y, 0.0>) * len;
    vector next = me + move;
    move.z = llGround(next - me) + rest_h - me.z;          // follow the ground

    rotation want = llRotBetween(FACING, llVecNorm(<to.x, to.y, 0.0>));
    rotation turn = want / llGetRot();                      // keyframes take changes, not targets
    play(TRUE);
    llSetKeyframedMotion([move, turn, TICK + 0.05], [KFM_DATA, KFM_TRANSLATION | KFM_ROTATION]);
}

default
{
    state_entry() { setup(); }
    on_rez(integer p) { following = FALSE; stop(); setup(); }
    changed(integer c) { if (c & CHANGED_INVENTORY) setup(); if (c & CHANGED_OWNER) llResetScript(); }

    touch_start(integer n)
    {
        if (llDetectedKey(0) != llGetOwner()) return;
        following = !following;
        if (following)
        {
            setup();
            llOwnerSay("Following you.");
            llSetTimerEvent(TICK);
        }
        else
        {
            llSetTimerEvent(0.0);
            stop();
            llOwnerSay("Staying here.");
        }
    }

    timer() { step(); }
}