Table of Contents

Class Curve2D

Describes a Bézier curve in 2D space.

Inheritance
Curve2D

Remarks

This class describes a Bézier curve in 2D space. It is mainly used to give a shape to a Path2D, but can be manually sampled for other purposes.

It keeps a cache of precalculated points along the curve, to speed up further calculations.

Properties

bake_interval

The distance in pixels between two adjacent cached points. Changing it forces the cache to be recomputed the next time the get_baked_points or get_baked_length function is called. The smaller the distance, the more points in the cache and the more memory it will consume, so use with care.

var bake_interval : float = 5.0

Property Value

float

Remarks

  • void set_bake_interval(float value)
  • float get_bake_interval

point_count

The number of points describing the curve.

var point_count : int = 0

Property Value

int

Remarks

  • void set_point_count(int value)
  • int get_point_count

Methods

add_point(Vector2, Vector2, Vector2, int)

Adds a point with the specified position relative to the curve's own position, with control points in and out. Appends the new point at the end of the point list.

If index is given, the new point is inserted before the existing point identified by index index. Every existing point starting from index is shifted further down the list of points. The index must be greater than or equal to 0 and must not exceed the number of existing points in the line. See point_count.

void add_point(Vector2 position, Vector2 in, Vector2 out, int index)

Parameters

position Vector2
in Vector2
out Vector2
index int

clear_points

Removes all points from the curve.

void clear_points

get_baked_length

Qualifiers: const

Returns the total length of the curve, based on the cached points. Given enough density (see bake_interval), it should be approximate enough.

float get_baked_length

get_baked_points

Qualifiers: const

Returns the cache of points as a PackedVector2Array.

PackedVector2Array get_baked_points

get_closest_offset(Vector2)

Qualifiers: const

Returns the closest offset to to_point. This offset is meant to be used in Curve2D.sample_baked.

to_point must be in this curve's local space.

float get_closest_offset(Vector2 to_point)

Parameters

to_point Vector2

get_closest_point(Vector2)

Qualifiers: const

Returns the closest point on baked segments (in curve's local space) to to_point.

to_point must be in this curve's local space.

Vector2 get_closest_point(Vector2 to_point)

Parameters

to_point Vector2

get_point_in(int)

Qualifiers: const

Returns the position of the control point leading to the vertex idx. The returned position is relative to the vertex idx. If the index is out of bounds, the function sends an error to the console, and returns (0, 0).

Vector2 get_point_in(int idx)

Parameters

idx int

get_point_out(int)

Qualifiers: const

Returns the position of the control point leading out of the vertex idx. The returned position is relative to the vertex idx. If the index is out of bounds, the function sends an error to the console, and returns (0, 0).

Vector2 get_point_out(int idx)

Parameters

idx int

get_point_position(int)

Qualifiers: const

Returns the position of the vertex idx. If the index is out of bounds, the function sends an error to the console, and returns (0, 0).

Vector2 get_point_position(int idx)

Parameters

idx int

remove_point(int)

Deletes the point idx from the curve. Sends an error to the console if idx is out of bounds.

void remove_point(int idx)

Parameters

idx int

sample(int, float)

Qualifiers: const

Returns the position between the vertex idx and the vertex idx + 1, where t controls if the point is the first vertex (t = 0.0), the last vertex (t = 1.0), or in between. Values of t outside the range (0.0 <= t <= 1.0) give strange, but predictable results.

If idx is out of bounds it is truncated to the first or last vertex, and t is ignored. If the curve has no points, the function sends an error to the console, and returns (0, 0).

Vector2 sample(int idx, float t)

Parameters

idx int
t float

sample_baked(float, bool)

Qualifiers: const

Returns a point within the curve at position offset, where offset is measured as a pixel distance along the curve.

To do that, it finds the two cached points where the offset lies between, then interpolates the values. This interpolation is cubic if cubic is set to true, or linear if set to false.

Cubic interpolation tends to follow the curves better, but linear is faster (and often, precise enough).

Vector2 sample_baked(float offset, bool cubic)

Parameters

offset float
cubic bool

sample_baked_with_rotation(float, bool)

Qualifiers: const

Similar to Curve2D.sample_baked, but returns Transform2D that includes a rotation along the curve, with origin as the point position and the x vector pointing in the direction of the path at that point. Returns an empty transform if the length of the curve is 0.

var baked = curve.sample_baked_with_rotation(offset)
# The returned Transform2D can be set directly.
transform = baked
# You can also read the origin and rotation separately from the returned Transform2D.
position = baked.get_origin()
rotation = baked.get_rotation()


Transform2D sample_baked_with_rotation(float offset, bool cubic)

Parameters

offset float
cubic bool

samplef(float)

Qualifiers: const

Returns the position at the vertex fofs. It calls Curve2D.sample using the integer part of fofs as idx, and its fractional part as t.

Vector2 samplef(float fofs)

Parameters

fofs float

set_point_in(int, Vector2)

Sets the position of the control point leading to the vertex idx. If the index is out of bounds, the function sends an error to the console. The position is relative to the vertex.

void set_point_in(int idx, Vector2 position)

Parameters

idx int
position Vector2

set_point_out(int, Vector2)

Sets the position of the control point leading out of the vertex idx. If the index is out of bounds, the function sends an error to the console. The position is relative to the vertex.

void set_point_out(int idx, Vector2 position)

Parameters

idx int
position Vector2

set_point_position(int, Vector2)

Sets the position for the vertex idx. If the index is out of bounds, the function sends an error to the console.

void set_point_position(int idx, Vector2 position)

Parameters

idx int
position Vector2

tessellate(int, float)

Qualifiers: const

Returns a list of points along the curve, with a curvature controlled point density. That is, the curvier parts will have more points than the straighter parts.

This approximation makes straight segments between each point, then subdivides those segments until the resulting shape is similar enough.

max_stages controls how many subdivisions a curve segment may face before it is considered approximate enough. Each subdivision splits the segment in half, so the default 5 stages may mean up to 32 subdivisions per curve segment. Increase with care!

tolerance_degrees controls how many degrees the midpoint of a segment may deviate from the real curve, before the segment has to be subdivided.

PackedVector2Array tessellate(int max_stages, float tolerance_degrees)

Parameters

max_stages int
tolerance_degrees float

tessellate_even_length(int, float)

Qualifiers: const

Returns a list of points along the curve, with almost uniform density. max_stages controls how many subdivisions a curve segment may face before it is considered approximate enough. Each subdivision splits the segment in half, so the default 5 stages may mean up to 32 subdivisions per curve segment. Increase with care!

tolerance_length controls the maximal distance between two neighboring points, before the segment has to be subdivided.

PackedVector2Array tessellate_even_length(int max_stages, float tolerance_length)

Parameters

max_stages int
tolerance_length float