Curve2D

Inherits: Resource < RefCounted < Object

Describes a Bézier curve in 2D space.

Description

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

float

bake_interval

5.0

int

point_count

0

Methods

void

add_point ( Vector2 position, Vector2 in=Vector2(0, 0), Vector2 out=Vector2(0, 0), int index=-1 )

void

clear_points ( )

float

get_baked_length ( ) const

PackedVector2Array

get_baked_points ( ) const

float

get_closest_offset ( Vector2 to_point ) const

Vector2

get_closest_point ( Vector2 to_point ) const

Vector2

get_point_in ( int idx ) const

Vector2

get_point_out ( int idx ) const

Vector2

get_point_position ( int idx ) const

void

remove_point ( int idx )

Vector2

sample ( int idx, float t ) const

Vector2

sample_baked ( float offset=0.0, bool cubic=false ) const

Transform2D

sample_baked_with_rotation ( float offset=0.0, bool cubic=false ) const

Vector2

samplef ( float fofs ) const

void

set_point_in ( int idx, Vector2 position )

void

set_point_out ( int idx, Vector2 position )

void

set_point_position ( int idx, Vector2 position )

PackedVector2Array

tessellate ( int max_stages=5, float tolerance_degrees=4 ) const

PackedVector2Array

tessellate_even_length ( int max_stages=5, float tolerance_length=20.0 ) const


Property Descriptions

float bake_interval = 5.0

  • void set_bake_interval ( float value )

  • float get_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.


int point_count = 0

  • void set_point_count ( int value )

  • int get_point_count ( )

The number of points describing the curve.


Method Descriptions

void add_point ( Vector2 position, Vector2 in=Vector2(0, 0), Vector2 out=Vector2(0, 0), int index=-1 )

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 clear_points ( )

Removes all points from the curve.


float get_baked_length ( ) const

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


PackedVector2Array get_baked_points ( ) const

Returns the cache of points as a PackedVector2Array.


float get_closest_offset ( Vector2 to_point ) const

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

to_point must be in this curve's local space.


Vector2 get_closest_point ( Vector2 to_point ) 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_point_in ( int idx ) 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_out ( int idx ) 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_position ( int idx ) 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).


void remove_point ( int idx )

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


Vector2 sample ( int idx, float t ) 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) 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_baked ( float offset=0.0, bool cubic=false ) 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).


Transform2D sample_baked_with_rotation ( float offset=0.0, bool cubic=false ) const

Similar to sample_baked, but returns Transform2D that includes a rotation along the curve. Returns empty transform if length of the curve is 0.

var transform = curve.sample_baked_with_rotation(offset)
position = transform.get_origin()
rotation = transform.get_rotation()

Vector2 samplef ( float fofs ) const

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


void set_point_in ( int idx, Vector2 position )

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_out ( int idx, Vector2 position )

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_position ( int idx, Vector2 position )

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


PackedVector2Array tessellate ( int max_stages=5, float tolerance_degrees=4 ) 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_even_length ( int max_stages=5, float tolerance_length=20.0 ) 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.