// SPDX-License-Identifier: MIT
// Copyright (c) 2026 Incoprea
// Measure a point’s height above a sampled plane
// Not compiled or tested in-world
// Setup: Put in the root of a spare owned object/linkset. Child touch handlers may consume events. Touch three noncollinear plane points, then the point to compare. Collect 4 owner touches; the next touch starts another measurement.
// Stop / restore: Reset clears collected points; disable/remove to stop. No geometry is changed.
// Notes: Normal direction follows the first triple’s winding. Results use actual touch positions in region coordinates, not hidden mesh dimensions.
// License: see LICENSE in this distribution.
// Original Incoprea. MIT. Live touch measurements only.
list points;
default
{
    touch_start(integer detectedCount)
    {
        if(llDetectedKey(0)!=llGetOwner())return;
        if(llDetectedTouchFace(0)<0)
        {
            llOwnerSay("Touch position unavailable.");
            return;
        }
        if(llGetListLength(points)>=4)points=[];
        points+=[llDetectedTouchPos(0)];
        integer collected=llGetListLength(points);
        if(collected<4)
        {
            llOwnerSay("Recorded point "+(string)collected+" of 4.");
            return;
        }
        vector a=llList2Vector(points,0);
        vector b=llList2Vector(points,1);
        vector c=llList2Vector(points,2);
        vector d=llList2Vector(points,3);
        vector normal=(b-a)%(c-a);
        if(llVecMag(normal)<0.000001)
        {
            llOwnerSay("First three points are collinear.");
            return;
        }
        normal=llVecNorm(normal);
        float height=(d-a)*normal;
        llOwnerSay("Signed height="+(string)height+" projected point="+(string)(d-height*normal));
    }
    changed(integer flags)
    {
        if(flags&CHANGED_OWNER)llResetScript();
    }
}