// SPDX-License-Identifier: MIT
// Copyright (c) 2026 Incoprea
// Tangent points from an outside anchor
// Not compiled or tested in-world
// Setup: Place in a spare prim. Set circle CENTER, RADIUS, and exterior POINT in the same XY plane. Owner touch prints results without altering the scene.
// Stop / restore: Disable or remove. No prim properties are changed.
// Notes: The point must lie strictly outside the circle. Useful for straight paths meeting a circular border smoothly.
// License: see LICENSE in this distribution.
// Original Incoprea. MIT. Owner-only calculation.
vector CENTER=<0.0,0.0,0.0>;
vector POINT=<8.0,3.0,0.0>;
float RADIUS=3.0;
default
{
    touch_start(integer detectedCount)
    {
        if (llDetectedKey(0)!=llGetOwner()) return;
        vector delta=POINT-CENTER;
        delta.z=0.0;
        float d2=delta*delta;
        if(RADIUS<=0.0||d2<=RADIUS*RADIUS)
        {
            llOwnerSay("Point must be outside a positive-radius circle.");
            return;
        }
        float a=RADIUS*RADIUS/d2;
        float b=RADIUS*llSqrt(d2-RADIUS*RADIUS)/d2;
        vector perpendicular=<-delta.y,delta.x,0.0>;
        llOwnerSay("Tangent points: "+(string)(CENTER+a*delta+b*perpendicular)+" and "+(string)(CENTER+a*delta-b*perpendicular));
    }
}