// SPDX-License-Identifier: MIT
// Copyright (c) 2026 Incoprea
// Clip a finite segment at a plane
// Not compiled or tested in-world
// Setup: Use a spare owned prim. Set A/B and plane point/normal. Touch for owner-only calculation output.
// Stop / restore: Remove/disable. Does not sense, collide with, or modify actual objects.
// Notes: A segment lying in the plane is reported separately from a unique crossing.
// License: see LICENSE in this distribution.
// Original Incoprea. MIT. Ideal geometry only.
vector A=<1.0,2.0,-1.0>;
vector B=<3.0,2.0,4.0>;
vector NORMAL=<0.0,0.0,1.0>;
vector ON_PLANE=ZERO_VECTOR;
default
{
    touch_start(integer detectedCount)
    {
        if(llDetectedKey(0)!=llGetOwner())return;
        if(llVecMag(NORMAL)<0.000001)
        {
            llOwnerSay("Zero normal.");
            return;
        }
        float da=(A-ON_PLANE)*NORMAL;
        float db=(B-ON_PLANE)*NORMAL;
        float denominator=da-db;
        if(llFabs(denominator)<0.000001)
        {
            if(llFabs(da)<0.000001)llOwnerSay("Segment lies in plane.");
            else llOwnerSay("Parallel without crossing.");
            return;
        }
        float t=da/denominator;
        if(t<0.0||t>1.0)
        {
            llOwnerSay("Crossing outside segment.");
            return;
        }
        llOwnerSay("Crossing="+(string)(A+(B-A)*t)+" fraction="+(string)t);
    }
}