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Geometry2D

Inherits: Object

Provides methods for some common 2D geometric operations.

Description

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

Methods

Enumerations

enum PolyBooleanOperation:

PolyBooleanOperation OPERATION_UNION = 0

Create regions where either subject or clip polygons (or both) are filled.

PolyBooleanOperation OPERATION_DIFFERENCE = 1

Create regions where subject polygons are filled except where clip polygons are filled.

PolyBooleanOperation OPERATION_INTERSECTION = 2

Create regions where both subject and clip polygons are filled.

PolyBooleanOperation OPERATION_XOR = 3

Create regions where either subject or clip polygons are filled but not where both are filled.

enum PolyJoinType:

PolyJoinType JOIN_SQUARE = 0

Squaring is applied uniformally at all convex edge joins at 1 * delta.

PolyJoinType JOIN_ROUND = 1

While flattened paths can never perfectly trace an arc, they are approximated by a series of arc chords.

PolyJoinType JOIN_MITER = 2

There’s a necessary limit to mitered joins since offsetting edges that join at very acute angles will produce excessively long and narrow “spikes”. For any given edge join, when miter offsetting would exceed that maximum distance, “square” joining is applied.

enum PolyEndType:

PolyEndType END_POLYGON = 0

Endpoints are joined using the PolyJoinType value and the path filled as a polygon.

PolyEndType END_JOINED = 1

Endpoints are joined using the PolyJoinType value and the path filled as a polyline.

PolyEndType END_BUTT = 2

Endpoints are squared off with no extension.

PolyEndType END_SQUARE = 3

Endpoints are squared off and extended by delta units.

PolyEndType END_ROUND = 4

Endpoints are rounded off and extended by delta units.

Method Descriptions

PackedVector2Array[] clip_polygons ( PackedVector2Array polygon_a, PackedVector2Array polygon_b )

Clips polygon_a against polygon_b and returns an array of clipped polygons. This performs 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 is_polygon_clockwise.

PackedVector2Array[] clip_polyline_with_polygon ( PackedVector2Array polyline, PackedVector2Array polygon )

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

PackedVector2Array convex_hull ( PackedVector2Array points )

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[] decompose_polygon_in_convex ( PackedVector2Array polygon )

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

PackedVector2Array[] exclude_polygons ( PackedVector2Array polygon_a, PackedVector2Array polygon_b )

Mutually excludes common area defined by intersection of polygon_a and polygon_b (see intersect_polygons) and returns an array of excluded polygons. This performs 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 is_polygon_clockwise.

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

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_uncapped ( Vector2 point, Vector2 s1, Vector2 s2 )

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.

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

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[] intersect_polygons ( PackedVector2Array polygon_a, PackedVector2Array polygon_b )

Intersects polygon_a with polygon_b and returns an array of intersected polygons. This performs 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 is_polygon_clockwise.

PackedVector2Array[] intersect_polyline_with_polygon ( PackedVector2Array polyline, PackedVector2Array polygon )

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

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

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_polygon ( Vector2 point, PackedVector2Array polygon )

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

bool is_polygon_clockwise ( PackedVector2Array polygon )

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

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

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

Note: The lines are specified using direction vectors, not end points.

Dictionary make_atlas ( PackedVector2Array sizes )

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.

PackedVector2Array[] merge_polygons ( PackedVector2Array polygon_a, PackedVector2Array polygon_b )

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

PackedVector2Array[] offset_polygon ( PackedVector2Array polygon, float delta, PolyJoinType join_type=0 )

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 is_polygon_clockwise.

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

GDScriptC#

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, 50), (150, 50), (150, 150), (50, 150)]

var polygon = new Vector2[] { new Vector2(0, 0), new Vector2(100, 0), new Vector2(100, 100), new Vector2(0, 100) };
var offset = new Vector2(50, 50);
polygon = new Transform2D(0, offset) * polygon;
GD.Print((Variant)polygon); // prints [(50, 50), (150, 50), (150, 150), (50, 150)]

PackedVector2Array[] offset_polyline ( PackedVector2Array polyline, float delta, PolyJoinType join_type=0, PolyEndType end_type=3 )

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 is_polygon_clockwise.

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

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

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

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).

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

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.

PackedInt32Array triangulate_delaunay ( PackedVector2Array points )

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_polygon ( PackedVector2Array polygon )

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.