Line circle intersection: Difference between revisions

=={{header|Perl 6}}==

Extend solution space to 3D. Reference: this [https://stackoverflow.com/questions/1073336/ SO question and answers]

<lang perl6>#!/usr/bin/env perl6

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";

}</lang>

{{out}}

<pre>For data set: [(-10 11) (10 -9) (3 -5) 3]

Solution(s) is/are: [(3 -2) (6 -5)]

For data set: [(-10 11) (-11 12) (3 -5) 3]

Solution(s) is/are: None

For data set: [(3 -2) (7 -2) (3 -5) 3]

Solution(s) is/are: [(3 -2) (3 -2)]

For data set: [(3 -2) (7 -2) (0 0) 4]

Solution(s) is/are: [(-3.4641016151377544 -2) (3.4641016151377544 -2)]

For data set: [(0 -3) (0 6) (0 0) 4]

Solution(s) is/are: [(0 -4) (0 4)]

For data set: [(6 3) (10 7) (4 2) 5]

Solution(s) is/are: [(1 -2) (8 5)]

For data set: [(7 4) (11 18) (4 2) 5]

Solution(s) is/are: [(5.030680985703315 -2.892616550038399) (7.459885052032535 5.60959768211387)]

For data set: [(5 2 −2.26) (0.77 2 4) (1 4 0) 4]

Solution(s) is/are: [(4.2615520237084015 2 -1.1671668246843006) (1.13386504516801 2 3.461514141193441)]

</pre>