// SPDX-License-Identifier: MIT
// Copyright (c) 2026 Incoprea
// Convert vertical and horizontal field of view
// Not compiled or tested in-world
// Setup: Use a spare owned prim. Set vertical degrees and positive ASPECT. Touch for private calculations.
// Stop / restore: Disable/remove. No camera or object settings are changed.
// Notes: Uses a symmetric perspective projection. Diagonal FOV is also reported for planning.
// License: see LICENSE in this distribution.
// Original Incoprea. MIT. Transform planning only.
float VERTICAL_FOV=60.0;
float ASPECT=1.7777778;
default
{
    touch_start(integer detectedCount)
    {
        if(llDetectedKey(0)!=llGetOwner())return;
        if(VERTICAL_FOV<=1.0||VERTICAL_FOV>=170.0||ASPECT<=0.0)
        {
            llOwnerSay("Invalid view parameters.");
            return;
        }
        float t=llTan(VERTICAL_FOV*DEG_TO_RAD*0.5);
        llOwnerSay("Horizontal FOV="+(string)(2.0*llAtan2(t*ASPECT,1.0)*RAD_TO_DEG)+" diagonal FOV="+(string)(2.0*llAtan2(t*llSqrt(1.0+ASPECT*ASPECT),1.0)*RAD_TO_DEG));
    }
}