Line circle intersection
Extend solution space to 3D. Reference: this SO question and answers
sub LineCircularOBJintersection(@P1, @P2, @Centre, \Radius) {
my @d = @P2 »-« @P1 ; # d
my @f = @P1 »-« @Centre ; # c
my \a = [+] @d»²; # d dot d
my \b = 2 * ([+] @f »*« @d); # 2 * f dot d
my \c = ([+] @f»²) - Radius²; # f dot f - r²
my \Δ = b²-(4*a*c); # discriminant
if (Δ < 0) {
return [];
} else {
my (\t1,\t2) = (-b - Δ.sqrt)/(2*a), (-b + Δ.sqrt)/(2*a);
if 0 ≤ t1|t2 ≤ 1 {
return @P1 »+« ( @P2 »-« @P1 ) »*» t1, @P1 »+« ( @P2 »-« @P1 ) »*» t2
} else {
return []
}
}
}
my \DATA = [
[ <-10 11>, < 10 -9>, <3 -5>, 3 ],
[ <-10 11>, <-11 12>, <3 -5>, 3 ],
[ < 3 -2>, < 7 -2>, <3 -5>, 3 ],
[ < 3 -2>, < 7 -2>, <0 0>, 4 ],
[ < 0 -3>, < 0 6>, <0 0>, 4 ],
[ < 6 3>, < 10 7>, <4 2>, 5 ],
[ < 7 4>, < 11 18>, <4 2>, 5 ],
[ <5 2 −2.26 >, <0.77 2 4>, <1 4 0>, 4 ]
];
for DATA {
my @solution = LineCircularOBJintersection $_[0] , $_[1] , $_[2], $_[3];
say "For data set: ", $_;
say "Solution(s) is/are: ", @solution.Bool ?? @solution !! "None";
}Output:
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