// SPDX-License-Identifier: MIT
// Copyright (c) 2026 Incoprea
// Touch-sampled feathered rectangle mask
// Not compiled or tested in-world
// Setup: Put in a spare ordinary cube you own. Touch different places on one face to sample the procedural pattern at live surface coordinates. Edit the constants to design a pattern.
// Stop / restore: Disable/remove. Only private owner messages are produced; no texture or tint is applied.
// Notes: The feather is a linear transition outside the rectangle; the signed distance combines corner and edge distances. Surface coordinates depend on the viewer and mesh; ordinary prim faces are the clearest test surface.
// License: see LICENSE in this distribution.
// Original Incoprea. MIT. Live surface-coordinate sampler.
vector HALF=<0.6,0.4,0.0>;
float FEATHER=0.15;
default
{
    touch_start(integer detectedCount)
    {
        if(llDetectedKey(0)!=llGetOwner())return;
        vector uv=llDetectedTouchST(0);
        if(llDetectedTouchFace(0)<0||uv==TOUCH_INVALID_TEXCOORD)
        {
            llOwnerSay("Surface coordinates unavailable.");
            return;
        }
        vector p=2.0*uv-<1.0,1.0,0.0>;
        if(HALF.x<=0.0||HALF.y<=0.0||FEATHER<=0.0)
        {
            llOwnerSay("Invalid rectangle.");
            return;
        }
        float x=llFabs(p.x)-HALF.x;
        float y=llFabs(p.y)-HALF.y;
        float ox=x;
        float oy=y;
        if(ox<0.0)ox=0.0;
        if(oy<0.0)oy=0.0;
        float inside=x;
        if(y>inside)inside=y;
        if(inside>0.0)inside=0.0;
        float distance=llSqrt(ox*ox+oy*oy)+inside;
        float mask=1.0-distance/FEATHER;
        if(mask<0.0)mask=0.0;
        if(mask>1.0)mask=1.0;
        llOwnerSay("Soft rectangle mask="+(string)mask);
    }
}