Table of Contents

Class Geometry2D

Provides methods for some common 2D geometric operations.

Inheritance
Geometry2D

Remarks

Provides a set of helper functions to create geometric shapes, compute intersections between shapes, and process various other geometric operations in 2D.

Methods

bresenham_line(Vector2i, Vector2i)

Returns the Bresenham line between the from and to points. A Bresenham line is a series of pixels that draws a line and is always 1-pixel thick on every row and column of the drawing (never more, never less).

Example code to draw a line between two Marker2D nodes using a series of CanvasItem.draw_rect calls:

func _draw():
    for pixel in Geometry2D.bresenham_line($MarkerA.position, $MarkerB.position):
        draw_rect(Rect2(pixel, Vector2.ONE), Color.WHITE)


Vector2i[] bresenham_line(Vector2i from, Vector2i to)

Parameters

from Vector2i
to Vector2i

clip_polygons(PackedVector2Array, PackedVector2Array)

Clips polygon_a against polygon_b and returns an array of clipped polygons. This performs Geometry2D.OPERATION_DIFFERENCE between polygons. Returns an empty array if polygon_b completely overlaps polygon_a.

If polygon_b is enclosed by polygon_a, returns an outer polygon (boundary) and inner polygon (hole) which could be distinguished by calling Geometry2D.is_polygon_clockwise.

PackedVector2Array[] clip_polygons(PackedVector2Array polygon_a, PackedVector2Array polygon_b)

Parameters

polygon_a PackedVector2Array
polygon_b PackedVector2Array

clip_polyline_with_polygon(PackedVector2Array, PackedVector2Array)

Clips polyline against polygon and returns an array of clipped polylines. This performs Geometry2D.OPERATION_DIFFERENCE between the polyline and the polygon. This operation can be thought of as cutting a line with a closed shape.

PackedVector2Array[] clip_polyline_with_polygon(PackedVector2Array polyline, PackedVector2Array polygon)

Parameters

polyline PackedVector2Array
polygon PackedVector2Array

convex_hull(PackedVector2Array)

Given an array of Vector2s, returns the convex hull as a list of points in counterclockwise order. The last point is the same as the first one.

PackedVector2Array convex_hull(PackedVector2Array points)

Parameters

points PackedVector2Array

decompose_polygon_in_convex(PackedVector2Array)

Decomposes the polygon into multiple convex hulls and returns an array of PackedVector2Array.

PackedVector2Array[] decompose_polygon_in_convex(PackedVector2Array polygon)

Parameters

polygon PackedVector2Array

exclude_polygons(PackedVector2Array, PackedVector2Array)

Mutually excludes common area defined by intersection of polygon_a and polygon_b (see Geometry2D.intersect_polygons) and returns an array of excluded polygons. This performs Geometry2D.OPERATION_XOR between polygons. In other words, returns all but common area between polygons.

The operation may result in an outer polygon (boundary) and inner polygon (hole) produced which could be distinguished by calling Geometry2D.is_polygon_clockwise.

PackedVector2Array[] exclude_polygons(PackedVector2Array polygon_a, PackedVector2Array polygon_b)

Parameters

polygon_a PackedVector2Array
polygon_b PackedVector2Array

get_closest_point_to_segment(Vector2, Vector2, Vector2)

Returns the 2D point on the 2D segment (s1, s2) that is closest to point. The returned point will always be inside the specified segment.

Vector2 get_closest_point_to_segment(Vector2 point, Vector2 s1, Vector2 s2)

Parameters

point Vector2
s1 Vector2
s2 Vector2

get_closest_point_to_segment_uncapped(Vector2, Vector2, Vector2)

Returns the 2D point on the 2D line defined by (s1, s2) that is closest to point. The returned point can be inside the segment (s1, s2) or outside of it, i.e. somewhere on the line extending from the segment.

Vector2 get_closest_point_to_segment_uncapped(Vector2 point, Vector2 s1, Vector2 s2)

Parameters

point Vector2
s1 Vector2
s2 Vector2

get_closest_points_between_segments(Vector2, Vector2, Vector2, Vector2)

Given the two 2D segments (p1, q1) and (p2, q2), finds those two points on the two segments that are closest to each other. Returns a PackedVector2Array that contains this point on (p1, q1) as well the accompanying point on (p2, q2).

PackedVector2Array get_closest_points_between_segments(Vector2 p1, Vector2 q1, Vector2 p2, Vector2 q2)

Parameters

p1 Vector2
q1 Vector2
p2 Vector2
q2 Vector2

intersect_polygons(PackedVector2Array, PackedVector2Array)

Intersects polygon_a with polygon_b and returns an array of intersected polygons. This performs Geometry2D.OPERATION_INTERSECTION between polygons. In other words, returns common area shared by polygons. Returns an empty array if no intersection occurs.

The operation may result in an outer polygon (boundary) and inner polygon (hole) produced which could be distinguished by calling Geometry2D.is_polygon_clockwise.

PackedVector2Array[] intersect_polygons(PackedVector2Array polygon_a, PackedVector2Array polygon_b)

Parameters

polygon_a PackedVector2Array
polygon_b PackedVector2Array

intersect_polyline_with_polygon(PackedVector2Array, PackedVector2Array)

Intersects polyline with polygon and returns an array of intersected polylines. This performs Geometry2D.OPERATION_INTERSECTION between the polyline and the polygon. This operation can be thought of as chopping a line with a closed shape.

PackedVector2Array[] intersect_polyline_with_polygon(PackedVector2Array polyline, PackedVector2Array polygon)

Parameters

polyline PackedVector2Array
polygon PackedVector2Array

is_point_in_circle(Vector2, Vector2, float)

Returns true if point is inside the circle or if it's located exactly on the circle's boundary, otherwise returns false.

bool is_point_in_circle(Vector2 point, Vector2 circle_position, float circle_radius)

Parameters

point Vector2
circle_position Vector2
circle_radius float

is_point_in_polygon(Vector2, PackedVector2Array)

Returns true if point is inside polygon or if it's located exactly on polygon's boundary, otherwise returns false.

bool is_point_in_polygon(Vector2 point, PackedVector2Array polygon)

Parameters

point Vector2
polygon PackedVector2Array

is_polygon_clockwise(PackedVector2Array)

Returns true if polygon's vertices are ordered in clockwise order, otherwise returns false.

Note: Assumes a Cartesian coordinate system where +x is right and +y is up. If using screen coordinates (+y is down), the result will need to be flipped (i.e. a true result will indicate counter-clockwise).

bool is_polygon_clockwise(PackedVector2Array polygon)

Parameters

polygon PackedVector2Array

line_intersects_line(Vector2, Vector2, Vector2, Vector2)

Returns the point of intersection between the two lines (from_a, dir_a) and (from_b, dir_b). Returns a Vector2, or null if the lines are parallel.

from and dir are not endpoints of a line segment or ray but the slope (dir) and a known point (from) on that line.

var from_a = Vector2.ZERO
var dir_a = Vector2.RIGHT
var from_b = Vector2.DOWN

# Returns Vector2(1, 0)
Geometry2D.line_intersects_line(from_a, dir_a, from_b, Vector2(1, -1))
# Returns Vector2(-1, 0)
Geometry2D.line_intersects_line(from_a, dir_a, from_b, Vector2(-1, -1))
# Returns null
Geometry2D.line_intersects_line(from_a, dir_a, from_b, Vector2.RIGHT)


Variant line_intersects_line(Vector2 from_a, Vector2 dir_a, Vector2 from_b, Vector2 dir_b)

Parameters

from_a Vector2
dir_a Vector2
from_b Vector2
dir_b Vector2

make_atlas(PackedVector2Array)

Given an array of Vector2s representing tiles, builds an atlas. The returned dictionary has two keys: points is a PackedVector2Array that specifies the positions of each tile, size contains the overall size of the whole atlas as Vector2i.

Dictionary make_atlas(PackedVector2Array sizes)

Parameters

sizes PackedVector2Array

merge_polygons(PackedVector2Array, PackedVector2Array)

Merges (combines) polygon_a and polygon_b and returns an array of merged polygons. This performs Geometry2D.OPERATION_UNION between polygons.

The operation may result in an outer polygon (boundary) and multiple inner polygons (holes) produced which could be distinguished by calling Geometry2D.is_polygon_clockwise.

PackedVector2Array[] merge_polygons(PackedVector2Array polygon_a, PackedVector2Array polygon_b)

Parameters

polygon_a PackedVector2Array
polygon_b PackedVector2Array

offset_polygon(PackedVector2Array, float, int)

Inflates or deflates polygon by delta units (pixels). If delta is positive, makes the polygon grow outward. If delta is negative, shrinks the polygon inward. Returns an array of polygons because inflating/deflating may result in multiple discrete polygons. Returns an empty array if delta is negative and the absolute value of it approximately exceeds the minimum bounding rectangle dimensions of the polygon.

Each polygon's vertices will be rounded as determined by join_type, see PolyJoinType.

The operation may result in an outer polygon (boundary) and inner polygon (hole) produced which could be distinguished by calling Geometry2D.is_polygon_clockwise.

Note: To translate the polygon's vertices specifically, multiply them to a Transform2D:

var polygon = PackedVector2Array([Vector2(0, 0), Vector2(100, 0), Vector2(100, 100), Vector2(0, 100)])
var offset = Vector2(50, 50)
polygon = Transform2D(0, offset) * polygon
print(polygon) # Prints [(50.0, 50.0), (150.0, 50.0), (150.0, 150.0), (50.0, 150.0)]


PackedVector2Array[] offset_polygon(PackedVector2Array polygon, float delta, int join_type)

Parameters

polygon PackedVector2Array
delta float
join_type int

offset_polyline(PackedVector2Array, float, int, int)

Inflates or deflates polyline by delta units (pixels), producing polygons. If delta is positive, makes the polyline grow outward. Returns an array of polygons because inflating/deflating may result in multiple discrete polygons. If delta is negative, returns an empty array.

Each polygon's vertices will be rounded as determined by join_type, see PolyJoinType.

Each polygon's endpoints will be rounded as determined by end_type, see PolyEndType.

The operation may result in an outer polygon (boundary) and inner polygon (hole) produced which could be distinguished by calling Geometry2D.is_polygon_clockwise.

PackedVector2Array[] offset_polyline(PackedVector2Array polyline, float delta, int join_type, int end_type)

Parameters

polyline PackedVector2Array
delta float
join_type int
end_type int

point_is_inside_triangle(Vector2, Vector2, Vector2, Vector2)

Qualifiers: const

Returns if point is inside the triangle specified by a, b and c.

bool point_is_inside_triangle(Vector2 point, Vector2 a, Vector2 b, Vector2 c)

Parameters

point Vector2
a Vector2
b Vector2
c Vector2

segment_intersects_circle(Vector2, Vector2, Vector2, float)

Given the 2D segment (segment_from, segment_to), returns the position on the segment (as a number between 0 and 1) at which the segment hits the circle that is located at position circle_position and has radius circle_radius. If the segment does not intersect the circle, -1 is returned (this is also the case if the line extending the segment would intersect the circle, but the segment does not).

float segment_intersects_circle(Vector2 segment_from, Vector2 segment_to, Vector2 circle_position, float circle_radius)

Parameters

segment_from Vector2
segment_to Vector2
circle_position Vector2
circle_radius float

segment_intersects_segment(Vector2, Vector2, Vector2, Vector2)

Checks if the two segments (from_a, to_a) and (from_b, to_b) intersect. If yes, return the point of intersection as Vector2. If no intersection takes place, returns null.

Variant segment_intersects_segment(Vector2 from_a, Vector2 to_a, Vector2 from_b, Vector2 to_b)

Parameters

from_a Vector2
to_a Vector2
from_b Vector2
to_b Vector2

triangulate_delaunay(PackedVector2Array)

Triangulates the area specified by discrete set of points such that no point is inside the circumcircle of any resulting triangle. Returns a PackedInt32Array where each triangle consists of three consecutive point indices into points (i.e. the returned array will have n * 3 elements, with n being the number of found triangles). If the triangulation did not succeed, an empty PackedInt32Array is returned.

PackedInt32Array triangulate_delaunay(PackedVector2Array points)

Parameters

points PackedVector2Array

triangulate_polygon(PackedVector2Array)

Triangulates the polygon specified by the points in polygon. Returns a PackedInt32Array where each triangle consists of three consecutive point indices into polygon (i.e. the returned array will have n * 3 elements, with n being the number of found triangles). Output triangles will always be counter clockwise, and the contour will be flipped if it's clockwise. If the triangulation did not succeed, an empty PackedInt32Array is returned.

PackedInt32Array triangulate_polygon(PackedVector2Array polygon)

Parameters

polygon PackedVector2Array