component sphereprobe "Probe a pretend hemisphere";
author "Jeff Epler";
license "GPL";

pin in signed px;
pin in signed py;
pin in signed pz "\\fBrawcounts\\fR position from software encoder";

pin in signed cx;
pin in signed cy;
pin in signed cz "Center of sphere in counts";
pin in signed r "Radius of hemisphere in counts";

pin out bit probe-out;

function _ nofp "update probe-out based on inputs";
;;
#undef abs
int abs(int x) { if(x < 0) return -x; else return x; }

FUNCTION(_) {
    __u64 dx = abs(px-cx), dy=abs(py-cy), dz=abs(pz-cz);
    __u64 d2 = dx*dx + dy*dy;
    __u64 r2 = (__s64)r*(__s64)r;
    if(d2 > r2) {
        probe_out = pz < cz;
    } else {
        d2 += dz*dz;
        probe_out = d2 <= r2;
    }
}