// SPDX-License-Identifier: MIT
// Copyright (c) 2026 Incoprea
// Check a spherical bound against a virtual view
// Not compiled or tested in-world
// Setup: Use a spare owned prim. Set local camera-space CENTER,+X forward, radius and view parameters. Touch for private calculations.
// Stop / restore: Disable/remove. No camera or object settings are changed.
// Notes: A conservative sphere-frustum test; it does not check occlusion or actual rendering.
// License: see LICENSE in this distribution.
// Original Incoprea. MIT. Transform planning only.
vector CENTER=<10.0,-4.0,2.0>;
float RADIUS=1.0;
float FOV=60.0;
float ASPECT=1.7777778;
float NEAR=0.1;
float FAR=30.0;
default
{
    touch_start(integer detectedCount)
    {
        if(llDetectedKey(0)!=llGetOwner())return;
        if(RADIUS<0.0||FOV<=1.0||FOV>=170.0||ASPECT<=0.0||NEAR<=0.0||FAR<=NEAR)
        {
            llOwnerSay("Invalid view.");
            return;
        }
        float v=llTan(FOV*DEG_TO_RAD*0.5);
        float h=v*ASPECT;
        integer visible=TRUE;
        if(CENTER.x+RADIUS<NEAR||CENTER.x-RADIUS>FAR)visible=FALSE;
        if(CENTER.x*h-llFabs(CENTER.y)< -RADIUS*llSqrt(1.0+h*h))visible=FALSE;
        if(CENTER.x*v-llFabs(CENTER.z)< -RADIUS*llSqrt(1.0+v*v))visible=FALSE;
        llOwnerSay("Potentially visible="+(string)visible);
    }
}