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Refactored the can_connect() logic (includes a refactoring of the SVG library)

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This commit is contained in:
Alessandro Ranellucci 2011-10-06 11:55:26 +02:00
parent 5a07137def
commit 5812804d6b
4 changed files with 342 additions and 187 deletions
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104
lib/Slic3r/Fill/Rectilinear.pm
View file

@ -185,7 +185,7 @@ sub find_connectable_points {
my @connectable_points = ();
foreach my $p (@$points) {
if (!$self->can_connect($polygon, $point, [ $c, $p ])) {
if (!Slic3r::Geometry::can_connect_points($point, [ $c, $p ], [ $polygon->get_polygons ])) {
@connectable_points ? last : next;
}
push @connectable_points, $p;
@ -194,108 +194,6 @@ sub find_connectable_points {
return @connectable_points;
}
# this subroutine tries to determine whether two points in a surface
# are connectable without crossing contour or holes
sub can_connect {
my $self = shift;
my ($polygon, $p1, $p2) = @_;
#printf " Checking connectability of point %d\n", $p2->[1];
# there's room for optimization here
# this is not needed since we assume that $p1 and $p2 belong to $polygon
for ($p1, $p2) {
#return 0 unless $polygon->isinside($_);
# TODO: re-enable this one after testing point_in_polygon() which
# doesn't detect well points on the contour of polygon
#return 0 unless Slic3r::Geometry::point_in_polygon($_, $polygon->points);
}
# check whether the $p1-$p2 segment doesn't intersect any segment
# of the contour or of holes
my ($contour_p, @holes_p) = $polygon->get_polygons;
foreach my $points ($contour_p, @holes_p) {
foreach my $line ($self->_lines_from_mgp_points($points)) {
# theoretically speaking, SegmentIntersection() would be the right tool for the
# job; however floating point math often makes it not return any intersection
# point between our hypothetical extrusion segment and any other one, even
# if, of course, the final point of the extrusion segment is taken from
# $point and thus it's a point that belongs for sure to a segment.
# then, let's calculate intersection considering extrusion segment as a ray
# instead of a segment, and then check whether the intersection point
# belongs to the segment
my $point = SegmentRayIntersection([@$line, $p1, $p2]);
#printf " intersecting ray %f,%f - %f,%f and segment %f,%f - %f,%f\n",
# @$p1, @$p2, map @$_, @$line;
if ($point && Slic3r::Geometry::line_point_belongs_to_segment($point, [$p1, $p2])) {
#printf " ...point intersects!\n";
#YYY [ $point, $p1, $p2 ];
# our $p1-$p2 line intersects $line
# if the intersection point is an intermediate point of $p1-$p2
# it means that $p1-$p2 crosses $line, thus we're sure that
# $p1 and $p2 are not connectible (one is inside polygon and one
# is outside), unless $p1-$p2 and $line coincide but we've got
# an intersection due to floating point math
my @points_not_belonging_to_line = grep !Slic3r::Geometry::points_coincide($point, $_), $p1, $p2;
if (@points_not_belonging_to_line == 2) {
# make sure $p1-$p2 and $line are two distinct lines; we do this
# by checking their slopes
if (!Slic3r::Geometry::lines_parallel([$p1, $p2], $line)) {
#printf " ...lines cross!\n";
#Slic3r::SVG::output_lines($main::print, "lines" . $n++ . ".svg", [ @lines, [$p1, $p2] ]);
return 0;
}
}
# defensive programming, this shouldn't happen
if (@points_not_belonging_to_line == 0) {
die "SegmentIntersection is not expected to return an intersection point "
. "if \$line coincides with \$p1-\$p2";
}
# if we're here, then either $p1 or $p2 belong to $line
# so we have to check whether the other point falls inside
# the polygon or not
# we rely on Math::Geometry::Planar returning contour points
# in counter-clockwise order and hole points in clockwise
# order, so that if the point falls on the left of $line
# it's inside the polygon and viceversa
my $C = $points_not_belonging_to_line[0];
my $isInside = (($line->[B][X] - $line->[A][X])*($C->[Y] - $line->[A][Y])
- ($line->[B][Y] - $line->[A][Y])*($C->[X] - $line->[A][X])) > 0;
#printf " \$line is inside polygon: %d\n", $isInside;
# if the line is outside the polygon then points are not connectable
return 0 if !$isInside;
#Slic3r::SVG::output_lines($main::print, "lines" . $n++ . ".svg", [ @lines, [$p1, $p2] ])
# if !$isInside;
}
}
}
# even if no intersection is found, we should check whether both $p1 and $p2 are
# inside a hole; this may happen due to floating point path
#foreach my $hole_p (map $self->_mgp_from_points_ref($_), @holes_p) {
# if ($hole_p->isinside($p1) || $hole_p->isinside($p2)) {
# return 0;
# }
#}
#use Slic3r::SVG;
#Slic3r::SVG::output_lines($main::print, "lines" . $n++ . ".svg", [ @lines, [$p1, $p2] ]);
return 1;
}
sub _lines_from_mgp_points {
my $self = shift;
my ($points) = @_;

197
lib/Slic3r/Geometry.pm
View file

@ -10,7 +10,7 @@ use constant A => 0;
use constant B => 1;
use constant X => 0;
use constant Y => 1;
use constant epsilon => 1E-6;
use constant epsilon => 1E-4;
our $parallel_degrees_limit = abs(deg2rad(3));
sub slope {
@ -120,6 +120,13 @@ sub point_in_segment {
return abs($y3 - $y) < epsilon ? 1 : 0;
}
sub point_is_on_left_of_segment {
my ($point, $line) = @_;
return (($line->[B][X] - $line->[A][X])*($point->[Y] - $line->[A][Y])
- ($line->[B][Y] - $line->[A][Y])*($point->[X] - $line->[A][X])) > 0;
}
sub polygon_lines {
my ($polygon) = @_;
@ -148,6 +155,7 @@ sub nearest_point {
return $nearest_point;
}
# given a segment $p1-$p2, get the point at $distance from $p1 along segment
sub point_along_segment {
my ($p1, $p2, $distance) = @_;
@ -163,6 +171,39 @@ sub point_along_segment {
return $point;
}
# given a $polygon, return the (first) segment having $point
sub polygon_segment_having_point {
my ($polygon, $point) = @_;
foreach my $line (polygon_lines($polygon)) {
return $line if point_in_segment($point, $line);
}
return undef;
}
sub can_connect_points {
my ($p1, $p2, $polygons) = @_;
# check that the two points are visible from each other
return 0 if grep !polygon_points_visibility($_, $p1, $p2), @$polygons;
# get segment where $p1 lies
my $p1_segment;
for (@$polygons) {
$p1_segment = polygon_segment_having_point($_, $p1);
last if $p1_segment;
}
# defensive programming, this shouldn't happen
if (!$p1_segment) {
die sprintf "Point %f,%f wasn't found in polygon contour or holes!", @$p1;
}
# check whether $p2 is internal or external (internal = on the left)
return point_is_on_left_of_segment($p2, $p1_segment)
|| point_in_segment($p2, $p1_segment);
}
sub deg2rad {
my ($degrees) = @_;
return PI() * $degrees / 180;
@ -264,4 +305,158 @@ sub perp {
return $u->[X] * $v->[Y] - $u->[Y] * $v->[X];
}
sub polygon_points_visibility {
my ($polygon, $p1, $p2) = @_;
my $our_line = [ $p1, $p2 ];
foreach my $line (polygon_lines($polygon)) {
my $intersection = line_intersection($our_line, $line, 1) or next;
next if grep points_coincide($intersection, $_), $p1, $p2;
return 0;
}
return 1;
}
my $i = 0;
sub line_intersection {
my ($line1, $line2, $require_crossing) = @_;
$require_crossing ||= 0;
Slic3r::SVG::output(undef, "line_intersection_" . $i++ . ".svg",
lines => [ $line1, $line2 ],
) if 0;
my $intersection = _line_intersection(map @$_, @$line1, @$line2);
return (ref $intersection && $intersection->[1] == $require_crossing)
? $intersection->[0]
: undef;
}
sub _line_intersection {
my ( $x0, $y0, $x1, $y1, $x2, $y2, $x3, $y3 );
if ( @_ == 8 ) {
( $x0, $y0, $x1, $y1, $x2, $y2, $x3, $y3 ) = @_;
# The bounding boxes chop the lines into line segments.
# bounding_box() is defined later in this chapter.
my @box_a = bounding_box([ [$x0, $y0], [$x1, $y1] ]);
my @box_b = bounding_box([ [$x2, $y2], [$x3, $y3] ]);
# Take this test away and the line segments are
# turned into lines going from infinite to another.
# bounding_box_intersect() defined later in this chapter.
return "out of bounding box" unless bounding_box_intersect( 2, @box_a, @box_b );
}
elsif ( @_ == 4 ) { # The parametric form.
$x0 = $x2 = 0;
( $y0, $y2 ) = @_[ 1, 3 ];
# Need to multiply by 'enough' to get 'far enough'.
my $abs_y0 = abs $y0;
my $abs_y2 = abs $y2;
my $enough = 10 * ( $abs_y0 > $abs_y2 ? $abs_y0 : $abs_y2 );
$x1 = $x3 = $enough;
$y1 = $_[0] * $x1 + $y0;
$y3 = $_[2] * $x2 + $y2;
}
my ($x, $y); # The as-yet-undetermined intersection point.
my $dy10 = $y1 - $y0; # dyPQ, dxPQ are the coordinate differences
my $dx10 = $x1 - $x0; # between the points P and Q.
my $dy32 = $y3 - $y2;
my $dx32 = $x3 - $x2;
my $dy10z = abs( $dy10 ) < epsilon; # Is the difference $dy10 "zero"?
my $dx10z = abs( $dx10 ) < epsilon;
my $dy32z = abs( $dy32 ) < epsilon;
my $dx32z = abs( $dx32 ) < epsilon;
my $dyx10; # The slopes.
my $dyx32;
$dyx10 = $dy10 / $dx10 unless $dx10z;
$dyx32 = $dy32 / $dx32 unless $dx32z;
# Now we know all differences and the slopes;
# we can detect horizontal/vertical special cases.
# E.g., slope = 0 means a horizontal line.
unless ( defined $dyx10 or defined $dyx32 ) {
return "parallel vertical";
}
elsif ( $dy10z and not $dy32z ) { # First line horizontal.
$y = $y0;
$x = $x2 + ( $y - $y2 ) * $dx32 / $dy32;
}
elsif ( not $dy10z and $dy32z ) { # Second line horizontal.
$y = $y2;
$x = $x0 + ( $y - $y0 ) * $dx10 / $dy10;
}
elsif ( $dx10z and not $dx32z ) { # First line vertical.
$x = $x0;
$y = $y2 + $dyx32 * ( $x - $x2 );
}
elsif ( not $dx10z and $dx32z ) { # Second line vertical.
$x = $x2;
$y = $y0 + $dyx10 * ( $x - $x0 );
}
elsif ( abs( $dyx10 - $dyx32 ) < epsilon ) {
# The slopes are suspiciously close to each other.
# Either we have parallel collinear or just parallel lines.
# The bounding box checks have already weeded the cases
# "parallel horizontal" and "parallel vertical" away.
my $ya = $y0 - $dyx10 * $x0;
my $yb = $y2 - $dyx32 * $x2;
return "parallel collinear" if abs( $ya - $yb ) < epsilon;
return "parallel";
}
else {
# None of the special cases matched.
# We have a "honest" line intersection.
$x = ($y2 - $y0 + $dyx10*$x0 - $dyx32*$x2)/($dyx10 - $dyx32);
$y = $y0 + $dyx10 * ($x - $x0);
}
my $h10 = $dx10 ? ($x - $x0) / $dx10 : ($dy10 ? ($y - $y0) / $dy10 : 1);
my $h32 = $dx32 ? ($x - $x2) / $dx32 : ($dy32 ? ($y - $y2) / $dy32 : 1);
return [[$x, $y], $h10 >= 0 && $h10 <= 1 && $h32 >= 0 && $h32 <= 1];
}
# 2D
sub bounding_box {
my ($points) = @_;
my @x = sort { $a <=> $b } map $_->[X], @$points;
my @y = sort { $a <=> $b } map $_->[Y], @$points;
return ($x[0], $y[0], $x[-1], $y[-1]);
}
# bounding_box_intersect($d, @a, @b)
# Return true if the given bounding boxes @a and @b intersect
# in $d dimensions. Used by line_intersection().
sub bounding_box_intersect {
my ( $d, @bb ) = @_; # Number of dimensions and box coordinates.
my @aa = splice( @bb, 0, 2 * $d ); # The first box.
# (@bb is the second one.)
# Must intersect in all dimensions.
for ( my $i_min = 0; $i_min < $d; $i_min++ ) {
my $i_max = $i_min + $d; # The index for the maximum.
return 0 if ( $aa[ $i_max ] + epsilon ) < $bb[ $i_min ];
return 0 if ( $bb[ $i_max ] + epsilon ) < $aa[ $i_min ];
}
return 1;
}
1;

157
lib/Slic3r/SVG.pm
View file

@ -17,106 +17,97 @@ sub svg {
return SVG->new(width => $print->max_length * factor(), height => $print->max_length * factor());
}
sub output_points {
my ($print, $filename, $points, $red_points) = @_;
$red_points ||= [];
sub output {
my ($print, $filename, %things) = @_;
my $svg = svg($print);
my $g = $svg->group(
style => {
'stroke-width' => 2,
'stroke' => 'black',
'fill' => 'black',
},
);
foreach my $point (@$points) {
$g->circle(
cx => $point->[X] * factor(),
cy => $point->[Y] * factor(),
r => 2,
);
foreach my $type (qw(polygons polylines)) {
if ($things{$type}) {
my $method = $type eq 'polygons' ? 'polygon' : 'polyline';
my $g = $svg->group(
style => {
'stroke-width' => 2,
'stroke' => 'black',
'fill' => 'none',
},
);
foreach my $polygon (@{$things{$type}}) {
my $path = $svg->get_path(
'x' => [ map($_->[X] * factor(), @$polygon) ],
'y' => [ map($_->[Y] * factor(), @$polygon) ],
-type => 'polygon',
);
$g->$method(
%$path,
);
}
}
}
my $g2 = $svg->group(
style => {
'stroke-width' => 2,
'stroke' => 'red',
'fill' => 'red',
},
);
foreach my $point (@$red_points) {
$g2->circle(
cx => $point->[X] * factor(),
cy => $point->[Y] * factor(),
r => 3,
);
foreach my $type (qw(points red_points)) {
if ($things{$type}) {
my ($colour, $r) = $type eq 'points' ? ('black', 2) : ('red', 3);
my $g = $svg->group(
style => {
'stroke-width' => 2,
'stroke' => 'black',
'fill' => $colour,
},
);
foreach my $point (@{$things{$type}}) {
$g->circle(
cx => $point->[X] * factor(),
cy => $point->[Y] * factor(),
r => $r,
);
}
}
}
foreach my $type (qw(lines red_lines)) {
if ($things{$type}) {
my ($colour) = $type eq 'lines' ? ('black') : ('red');
my $g = $svg->group(
style => {
'stroke-width' => 2,
},
);
foreach my $line (@{$things{$type}}) {
$g->line(
x1 => $line->[0][X] * factor(),
y1 => $line->[0][Y] * factor(),
x2 => $line->[1][X] * factor(),
y2 => $line->[1][Y] * factor(),
style => {
'stroke' => $colour,
},
);
}
}
}
write_svg($svg, $filename);
}
sub output_points {
my ($print, $filename, $points, $red_points) = @_;
return output($print, $filename, points => $points, red_points => $red_points);
}
sub output_polygons {
my ($print, $filename, $polygons, $type) = @_;
$type ||= 'polygon';
my $svg = svg($print);
my $g = $svg->group(
style => {
'stroke-width' => 2,
'stroke' => 'black',
'fill' => 'none',
},
);
foreach my $polygon (@$polygons) {
my $path = $svg->get_path(
'x' => [ map($_->[X] * factor(), @$polygon) ],
'y' => [ map($_->[Y] * factor(), @$polygon) ],
-type => 'polygon',
);
$g->$type(
%$path,
);
}
write_svg($svg, $filename);
my ($print, $filename, $polygons) = @_;
return output($print, $filename, polygons => $polygons);
}
sub output_polylines {
return output_polygons(@_, 'polyline');
my ($print, $filename, $polylines) = @_;
return output($print, $filename, polylines => $polylines);
}
sub output_lines {
my ($print, $filename, $lines) = @_;
my $svg = svg($print);
my $g = $svg->group(
style => {
'stroke-width' => 2,
},
);
my $color = 'red';
my $draw_line = sub {
my ($line) = @_;
$g->line(
x1 => $line->[0][X] * factor(),
y1 => $line->[0][Y] * factor(),
x2 => $line->[1][X] * factor(),
y2 => $line->[1][Y] * factor(),
style => {
'stroke' => $color,
},
);
};
my $last = pop @$lines;
foreach my $line (@$lines) {
$draw_line->($line);
}
$color = 'black';
$draw_line->($last);
write_svg($svg, $filename);
return output($print, $filename, lines => $lines);
}
sub write_svg {

71
t/geometry.t Normal file
View file

@ -0,0 +1,71 @@
use Test::More;
use strict;
use warnings;
plan tests => 4;
BEGIN {
use FindBin;
use lib "$FindBin::Bin/../lib";
}
use Slic3r;
#==========================================================
my $line1 = [ [73.6310778185108/0.0000001, 371.74239268924/0.0000001], [73.6310778185108/0.0000001, 501.74239268924/0.0000001] ];
my $line2 = [ [75/0.0000001, 437.9853/0.0000001], [62.7484/0.0000001, 440.4223/0.0000001] ];
isnt Slic3r::Geometry::line_intersection($line1, $line2, 1), undef, 'line_intersection';
#==========================================================
my $polyline = [
[459190000, 5152739000], [147261000, 4612464000], [147261000, 3487535000], [339887000, 3153898000],
[437497000, 3438430000], [454223000, 3522515000], [523621000, 3626378000], [627484000, 3695776000],
[750000000, 3720147000], [872515000, 3695776000], [976378000, 3626378000], [1045776000, 3522515000],
[1070147000, 3400000000], [1045776000, 3277484000], [976378000, 3173621000], [872515000, 3104223000],
[827892000, 3095347000], [698461000, 2947261000], [2540810000, 2947261000], [2852739000, 3487535000],
[2852739000, 4612464000], [2540810000, 5152739000],
];
# this points belongs to $polyline
my $point = [2797980957.103410,3392691792.513960];
is_deeply Slic3r::Geometry::polygon_segment_having_point($polyline, $point),
[ [2540810000, 2947261000], [2852739000, 3487535000] ],
'polygon_segment_having_point';
#==========================================================
$point = [ 736310778.185108, 5017423926.8924 ];
my $line = [ [627484000, 3695776000], [750000000, 3720147000] ];
is Slic3r::Geometry::point_in_segment($point, $line), 0, 'point_in_segment';
#==========================================================
my $polygons = [
[ # contour, ccw
[459190000, 5152739000], [147261000, 4612464000], [147261000, 3487535000], [339887000, 3153898000],
[437497000, 3438430000], [454223000, 3522515000], [523621000, 3626378000], [627484000, 3695776000],
[750000000, 3720147000], [872515000, 3695776000], [976378000, 3626378000], [1045776000, 3522515000],
[1070147000, 3400000000], [1045776000, 3277484000], [976378000, 3173621000], [872515000, 3104223000],
[827892000, 3095347000], [698461000, 2947261000], [2540810000, 2947261000], [2852739000, 3487535000],
[2852739000, 4612464000], [2540810000, 5152739000],
],
[ # hole, cw
[750000000, 5020147000], [872515000, 4995776000], [976378000, 4926378000], [1045776000, 4822515000],
[1070147000, 4700000000], [1045776000, 4577484000], [976378000, 4473621000], [872515000, 4404223000],
[750000000, 4379853000], [627484000, 4404223000], [523621000, 4473621000], [454223000, 4577484000],
[429853000, 4700000000], [454223000, 4822515000], [523621000, 4926378000], [627484000, 4995776000],
],
];
my $points = [
[ 736310778.185108, 3717423926.892399788 ],
[ 736310778.185108, 5017423926.8924 ],
];
is Slic3r::Geometry::can_connect_points(@$points, $polygons), 0, 'can_connect_points';
#==========================================================