// SPDX-License-Identifier: MIT
// Copyright (c) 2026 Incoprea
// Touch-sampled soft union of two circles
// 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 polynomial smooth minimum rounds the join and slightly expands the combined silhouette. 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.
float RADIUS=0.4;
float SMOOTH_RADIUS=0.2;
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(RADIUS<=0.0||SMOOTH_RADIUS<=0.0)
        {
            llOwnerSay("Positive radius/smoothing required.");
            return;
        }
        float a=llVecDist(p,<-0.3,0.0,0.0>)-RADIUS;
        float b=llVecDist(p,<0.3,0.0,0.0>)-RADIUS;
        float h=0.5+0.5*(b-a)/SMOOTH_RADIUS;
        if(h<0.0)h=0.0;
        if(h>1.0)h=1.0;
        float d=b+(a-b)*h-SMOOTH_RADIUS*h*(1.0-h);
        llOwnerSay("Smooth union distance="+(string)d+" inside="+(string)(d<=0.0));
    }
}