// SPDX-License-Identifier: MIT
// Copyright (c) 2026 Incoprea
// Project a direction onto a spherical image
// Not compiled or tested in-world
// Setup: Place in a spare owned prim. Set DIRECTION; longitude seam lies on the negativeX axis. Touch for owner-only output.
// Stop / restore: Remove/disable. The script calculates only; no scene properties change.
// Notes: The poles have ambiguous longitude. This is one explicit mapping convention and may differ from a mesh UV layout.
// License: see LICENSE in this distribution.
// Original Incoprea. MIT. Planning only.
vector DIRECTION=<2.0,3.0,1.0>;
default
{
    touch_start(integer detectedCount)
    {
        if(llDetectedKey(0)!=llGetOwner())return;
        if(llVecMag(DIRECTION)<0.000001)
        {
            llOwnerSay("Nonzero direction required.");
            return;
        }
        vector n=llVecNorm(DIRECTION);
        float z=n.z;
        if(z>1.0)z=1.0;
        if(z< -1.0)z=-1.0;
        float u=0.5+llAtan2(n.y,n.x)/TWO_PI;
        float v=0.5+llAsin(z)/PI;
        llOwnerSay("Spherical UV="+(string)<u,v,0.0>);
    }
}