// SPDX-License-Identifier: MIT
// Copyright (c) 2026 Incoprea
// Ray meets a plane
// Not compiled or tested in-world
// Setup: Put in a spare prim you own. Edit RAY_START, DIRECTION, PLANE_POINT and NORMAL. Touch for a result.
// Stop / restore: Disable or remove the script. It only reports to its owner and does not change prim properties. Reset clears its temporary state.
// Notes: This is pure geometry, not llCastRay; it does not query real objects or terrain. Direction length controls the reported parameter.
// License: see LICENSE in this distribution.
// Original Incoprea example. MIT. Owner-only calculation; no scene changes.
vector RAY_START = <1.0, 2.0, 8.0>;
vector DIRECTION = <0.5, 0.0, -1.0>;
vector PLANE_POINT = <0.0, 0.0, 0.0>;
vector NORMAL = <0.0, 0.0, 1.0>;
default
{
    touch_start(integer detectedCount)
    {
        if (llDetectedKey(0) != llGetOwner()) return;
        float denominator = DIRECTION * NORMAL;
        if (llFabs(denominator) < 0.000001)
        {
            llOwnerSay("Parallel ray or invalid normal.");
            return;
        }
        float t = ((PLANE_POINT - RAY_START) * NORMAL) / denominator;
        if (t < 0.0)
        {
            llOwnerSay("The plane is behind the ray.");
            return;
        }
        llOwnerSay("Intersection: " + (string)(RAY_START + DIRECTION * t));
    }
    changed(integer change)
    {
        if (change & CHANGED_OWNER) llResetScript();
    }
}