Documentation
¶
Overview ¶
This class describes a Bézier curve in 2D space. It is mainly used to give a shape to a graphics.gd/classdb/Path2D, but can be manually sampled for other purposes.
It keeps a cache of precalculated points along the curve, to speed up further calculations.
Index ¶
- type Advanced
- type Any
- type Expanded
- func (self Expanded) AddPoint(position Vector2.XY, in Vector2.XY, out Vector2.XY, index int)
- func (self Expanded) SampleBaked(offset Float.X, cubic bool) Vector2.XY
- func (self Expanded) SampleBakedWithRotation(offset Float.X, cubic bool) Transform2D.OriginXY
- func (self Expanded) Tessellate(max_stages int, tolerance_degrees Float.X) []Vector2.XY
- func (self Expanded) TessellateEvenLength(max_stages int, tolerance_length Float.X) []Vector2.XY
- type Extension
- type ID
- type Instance
- func (self Instance) AddPoint(position Vector2.XY)
- func (self Instance) AsCurve2D() Instance
- func (self Instance) AsObject() [1]gd.Object
- func (self Instance) AsRefCounted() [1]gd.RefCounted
- func (self Instance) AsResource() Resource.Instance
- func (self Instance) BakeInterval() Float.X
- func (self Instance) ClearPoints()
- func (self Instance) GetBakedLength() Float.X
- func (self Instance) GetBakedPoints() []Vector2.XY
- func (self Instance) GetClosestOffset(to_point Vector2.XY) Float.X
- func (self Instance) GetClosestPoint(to_point Vector2.XY) Vector2.XY
- func (self Instance) GetPointIn(idx int) Vector2.XY
- func (self Instance) GetPointOut(idx int) Vector2.XY
- func (self Instance) GetPointPosition(idx int) Vector2.XY
- func (self Instance) ID() ID
- func (self Instance) PointCount() int
- func (self Instance) RemovePoint(idx int)
- func (self Instance) Sample(idx int, t Float.X) Vector2.XY
- func (self Instance) SampleBaked() Vector2.XY
- func (self Instance) SampleBakedWithRotation() Transform2D.OriginXY
- func (self Instance) Samplef(fofs Float.X) Vector2.XY
- func (self Instance) SetBakeInterval(value Float.X)
- func (self *Instance) SetObject(obj [1]gd.Object) bool
- func (self Instance) SetPointCount(value int)
- func (self Instance) SetPointIn(idx int, position Vector2.XY)
- func (self Instance) SetPointOut(idx int, position Vector2.XY)
- func (self Instance) SetPointPosition(idx int, position Vector2.XY)
- func (self Instance) Tessellate() []Vector2.XY
- func (self Instance) TessellateEvenLength() []Vector2.XY
- func (self Instance) Virtual(name string) reflect.Value
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Advanced ¶
type Advanced = class
Advanced exposes a 1:1 low-level instance of the class, undocumented, for those who know what they are doing.
type Expanded ¶
func (Expanded) AddPoint ¶
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 Instance.PointCount.
func (Expanded) SampleBaked ¶
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).
func (Expanded) SampleBakedWithRotation ¶
Similar to Instance.SampleBaked, but returns [Transform2D.OriginXY] that includes a rotation along the curve, with graphics.gd/classdb/Transform2D.Instance.Origin as the point position and the graphics.gd/classdb/Transform2D.Instance.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 = curve2d.SampleBakedWithRotation() node2d.SetTransform(baked) // The returned Transform2D can be set directly. // You can also read the origin and rotation separately from the returned Transform2D. node2d.SetPosition(baked.Origin) node2d.SetRotation(Transform2D.Rotation(baked))
func (Expanded) Tessellate ¶
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.
func (Expanded) TessellateEvenLength ¶
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.
type Extension ¶
Extension can be embedded in a new struct to create an extension of this class. T should be the type that is embedding this Extension
func (*Extension[T]) AsRefCounted ¶
func (self *Extension[T]) AsRefCounted() [1]gd.RefCounted
func (*Extension[T]) AsResource ¶
type ID ¶
ID is a typed object ID (reference) to an instance of this class, use it to store references to objects with unknown lifetimes, as an ID will not panic on use if the underlying object has been destroyed.
type Instance ¶
Instance of the class with convieniently typed arguments and results.
var Nil Instance
Nil is a nil/null instance of the class. Equivalent to the zero value.
func (Instance) AddPoint ¶
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 Instance.PointCount.
func (Instance) AsRefCounted ¶
func (self Instance) AsRefCounted() [1]gd.RefCounted
func (Instance) AsResource ¶
func (Instance) BakeInterval ¶
func (Instance) GetBakedLength ¶
Returns the total length of the curve, based on the cached points. Given enough density (see Instance.BakeInterval), it should be approximate enough.
func (Instance) GetBakedPoints ¶
Returns the cache of points as a [][Vector2.XY].
func (Instance) GetClosestOffset ¶
Returns the closest offset to 'to_point'. This offset is meant to be used in Instance.SampleBaked.
'to_point' must be in this curve's local space.
func (Instance) GetClosestPoint ¶
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.
func (Instance) GetPointIn ¶
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).
func (Instance) GetPointOut ¶
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).
func (Instance) GetPointPosition ¶
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).
func (Instance) PointCount ¶
func (Instance) RemovePoint ¶
Deletes the point 'idx' from the curve. Sends an error to the console if 'idx' is out of bounds.
func (Instance) Sample ¶
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).
func (Instance) SampleBaked ¶
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).
func (Instance) SampleBakedWithRotation ¶
func (self Instance) SampleBakedWithRotation() Transform2D.OriginXY
Similar to Instance.SampleBaked, but returns [Transform2D.OriginXY] that includes a rotation along the curve, with graphics.gd/classdb/Transform2D.Instance.Origin as the point position and the graphics.gd/classdb/Transform2D.Instance.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 = curve2d.SampleBakedWithRotation() node2d.SetTransform(baked) // The returned Transform2D can be set directly. // You can also read the origin and rotation separately from the returned Transform2D. node2d.SetPosition(baked.Origin) node2d.SetRotation(Transform2D.Rotation(baked))
func (Instance) Samplef ¶
Returns the position at the vertex 'fofs'. It calls Instance.Sample using the integer part of 'fofs' as idx, and its fractional part as t.
func (Instance) SetBakeInterval ¶
func (Instance) SetPointCount ¶
func (Instance) SetPointIn ¶
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.
func (Instance) SetPointOut ¶
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.
func (Instance) SetPointPosition ¶
Sets the position for the vertex 'idx'. If the index is out of bounds, the function sends an error to the console.
func (Instance) Tessellate ¶
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.
func (Instance) TessellateEvenLength ¶
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.
Source Files