Версия для печати темы

fn sphere_segment_intersect c r o t=
(
    roots_a=#(); sp_dir=normalize(t-o)
    det=(dot sp_dir (o-c))*(dot sp_dir (o-c))- dot (o-c) (o-c)+r*r
    if(det>=0)then
    (
        d1=-(dot sp_dir (o-c))+pow det 0.5; d2=-(dot sp_dir (o-c))-pow det 0.5
        p1=o+d1*sp_dir; p2=o+d2*sp_dir
        if(dot sp_dir (p1-o)>0 and length (p1-o) < length (t-o))then append roots_a p1
        if(dot sp_dir (p2-o)>0 and length (p2-o) < length (t-o))then append roots_a p2
    )--if(det>=0)then
    roots_a
)--fn sphere_segment_intersect c r o t=

point_need=undefined;
with animate off
(
    igorznag_spline_path=$spline
    len=curveLength igorznag_spline_path 1
    if(len>0)then
    (
        seg_points=#();n=numSegments igorznag_spline_path 1
        for i=1 to n do for j=0 to igorznag_spline_path.steps do
        (
            p0=getKnotPoint igorznag_spline_path 1 i; p1=getOutVec igorznag_spline_path 1 i;p2=undefined;p3=undefined
            if i==n then (p2=getInVec igorznag_spline_path 1 1;p3=getKnotPoint igorznag_spline_path 1 1)
            else (p2=getInVec igorznag_spline_path 1 (i+1);p3=getKnotPoint igorznag_spline_path 1 (i+1))
            t=1.0*j/(igorznag_spline_path.steps+1)
            p=(1-t)*(1-t)*(1-t)*p0+3*t*(t-1)*(t-1)*p1+3*t*t*(1-t)*p2+t*t*t*p3; append seg_points p
        )--for i=1 to n do for j=0 to igorznag_spline_path.steps do
        n=seg_points.count; points_intersect=#()
        for i=1 to n do
        (
            c=$Point1.pos; r=length($Point2.pos-$Point1.pos)
            o=seg_points[i]; t=undefined; if i<n then t=seg_points[i+1] else t=seg_points[1]
            roots=sphere_segment_intersect  c r o t
            if roots.count>0 do
            (
                if roots.count==1 do append points_intersect roots[1]
                if roots.count==2 do (append points_intersect roots[1]; append points_intersect roots[2])
            )--if roots.count>0 to
        )--for i=1 to seg_points.count do

        if points_intersect.count>0 do
        (
                if points_intersect.count==1 do
            (
                p1=points_intersect[1]; t1=p1*(inverse $Point1.transform);
                if t1.x>0 then point_need=points_intersect[1] else point_need=$Point2.pos
            )--if points_intersect.count==1 do
            if points_intersect.count==2 do
            (
                p1=points_intersect[1]; p2=points_intersect[2]
                t1=p1*(inverse $Point1.transform); t2=p2*( inverse $Point1.transform)
                if t1.x>0 do point_need=p1; if t2.x>0 do point_need=p2
            )--if points_intersect.count==2 do
        )--if points_intersect.count>0 do
        
        if point_need==undefined do point_need=$Point2.pos
    )--if(len>0)then
)--with animate off
point_need