Find the intersection of a line with a plane: Difference between revisions
Find the intersection of a line with a plane (view source)
Revision as of 14:20, 28 September 2018
, 5 years agoAdded Perl example
SqrtNegInf (talk | contribs) (Added Perl example) |
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ReadChar;
END LinePlane.</lang>
=={{header|Perl}}==
{{trans|Perl 6}}
<lang perl>package Line; sub new { my ($c, $a) = @_; my $self = { P0 => $a->{P0}, u => $a->{u} } } # point / ray
package Plane; sub new { my ($c, $a) = @_; my $self = { V0 => $a->{V0}, n => $a->{n} } } # point / normal
package main;
sub dot { my $p; $p += $_[0][$_] * $_[1][$_] for 0..@{$_[0]}-1; $p } # dot product
sub vd { my @v; $v[$_] = $_[0][$_] - $_[1][$_] for 0..@{$_[0]}-1; @v } # vector difference
sub va { my @v; $v[$_] = $_[0][$_] + $_[1][$_] for 0..@{$_[0]}-1; @v } # vector addition
sub vp { my @v; $v[$_] = $_[0][$_] * $_[1][$_] for 0..@{$_[0]}-1; @v } # vector product
sub line_plane_intersection {
my($L, $P) = @_;
my $cos = dot($L->{u}, $P->{n}); # cosine between normal & ray
return 'Vectors are orthogonol; no intersection or line within plane' if $cos == 0;
my @W = vd($L->{P0},$P->{V0}); # difference between P0 and V0
my $SI = -dot($P->{n}, \@W) / $cos; # line segment where it intersets the plane
my @a = vp($L->{u},[($SI)x3]);
my @b = va($P->{V0},\@a);
va(\@W,\@b);
}
my $L = Line->new({ P0=>[0,0,10], u=>[0,-1,-1]});
my $P = Plane->new({ V0=>[0,0,5 ], n=>[0, 0, 1]});
print 'Intersection at point: ', join(' ', line_plane_intersection($L, $P)) . "\n";
</lang>
{{out}}
<pre>0 -5 5</pre>
=={{header|Perl 6}}==
Line 1,011 ⟶ 1,044:
cos:=dotP(plane.normal,line.ray); # cosine between normal & ray
_assert_((not cos.closeTo(0,1e-6)),
"Vectors are
w:=line.pt.zipWith('-,plane.pt); # difference between P0 and V0
si:=-dotP(plane.normal,w)/cos; # line segment where it intersets the plane
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