AbstractSpline

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The base concept for a spline: a curve in the scene, used as a drawn path, a motion track, or a distribution of points.

Base class — has no declarative element of its own; subclasses inherit its members.

Remarks

A spline is a smooth curve defined once and reused three ways: draw it (a stroke paint renders it as a ribbon), move along it (an sk-align-to-spline-constraint rides a node down it by arc-length), or sample it (its points seed distributions and fields). It supports arc-length queries (length, point-at-progress, closest-point) that make travel along it uniform.

Where a spline gets its shape. A spline carries no geometry itself — its curve comes from a spline-source. sk-path-spline and sk-points-spline build their source from an attribute (svg path data or control points); sk-spline takes any spline-source as a child, which is how the GPU and morphing sources are used. The spline-source family — sk-svg-spline-source, sk-points-spline-source, sk-morph-spline-source, sk-compute-buffer-spline-source, sk-custom-wgsl-spline-source, and sk-trail-spline-source — each supplies the curve for one input modality.

The example draws a figure-eight laid flat in the ground plane, its geometry coming from an SVG spline-source child, rendered with a stroke paint.

Abstract base class — not instantiated directly. Construct one of its concrete subclasses; this class contributes the members below to them.

Inherited from: RenderableNode, SceneNode, SkenraAnimatable — see those pages for inherited members.

Properties

Config Properties

PropertyTypeDefaultDescriptionDeclared by
overlay boolean false Whether this node renders as an overlay with depth-aware translucency. RenderableNode
overlayOccludedOpacity number 0.3 Alpha multiplier for overlay fragments occluded by scene geometry. RenderableNode
idconfig-only string — Unique identifier for the node, reflected to the host id attribute. SceneNodeConfig
xanimatable number 0 Gets the X position component. SceneNode
yanimatable number 0 Gets the Y position component. SceneNode
zanimatable number 0 Gets the Z position component. SceneNode
hanimatable number 0 Gets the heading (Y-axis) rotation in radians. SceneNode
panimatable number 0 Gets the pitch (X-axis) rotation in radians. SceneNode
banimatable number 0 Gets the bank (Z-axis) rotation in radians. SceneNode
quaternionanimatable Quaternion — Gets the rotation as a quaternion. SceneNode
sxanimatable number 1 Gets the X-axis scale factor. SceneNode
syanimatable number 1 Gets the Y-axis scale factor. SceneNode
szanimatable number 1 Gets the Z-axis scale factor. SceneNode
sconfig-only number — Uniform scale factor for all axes (overrides sx, sy, sz if provided) SceneNodeConfig
classconfig-only string — Standard HTML class applied to the node host at construction SceneNodeConfig
styleconfig-only string — Standard inline style applied to the node host at construction SceneNodeConfig

Other Properties

PropertyTypeDefaultDescriptionDeclared by
castShadow boolean true Whether this spline casts shadows. AbstractSpline
isValidread-only boolean — Indicates whether the spline was successfully initialized and is valid. AbstractSpline
sourceread-only SplineSource — The current segment source providing polyline data. AbstractSpline
pointsSourceread-only PointsSource — The points source for this spline — its SplineSource (which AbstractSpline
pointConstraintsread-only readonly PointConstraint[] [] Read-only view of the attached point constraints. AbstractSpline
hRad number 0 Gets the heading (Y-axis) rotation in radians. SceneNode
pRad number 0 Gets the pitch (X-axis) rotation in radians. SceneNode
bRad number 0 Gets the bank (Z-axis) rotation in radians. SceneNode
hDeg number 0 Gets the heading (Y-axis) rotation in degrees. SceneNode
pDeg number 0 Gets the pitch (X-axis) rotation in degrees. SceneNode
bDeg number 0 Gets the bank (Z-axis) rotation in degrees. SceneNode
xBasebase value number — Gets the base (non-animated) value of X position. SceneNode
yBasebase value number — Gets the base (non-animated) value of Y position. SceneNode
zBasebase value number — Gets the base (non-animated) value of Z position. SceneNode
hBasebase value number 0 Gets the base (non-animated) value of heading (Y-axis rotation). SceneNode
pBasebase value number 0 Gets the base (non-animated) value of pitch (X-axis rotation). SceneNode
bBasebase value number 0 Gets the base (non-animated) value of bank (Z-axis rotation). SceneNode
quaternionBasebase value Quaternion — Gets the base (non-animated) quaternion rotation. SceneNode
sxBasebase value number — Gets the base (non-animated) value of X-axis scale. SceneNode
syBasebase value number — Gets the base (non-animated) value of Y-axis scale. SceneNode
szBasebase value number — Gets the base (non-animated) value of Z-axis scale. SceneNode
draggable boolean false Gets whether this node can be dragged. SceneNode
parentread-only SceneNode | null — The parent node in the scene graph, or null at the root. SceneNode
sceneread-only any — Gets the Scene this node belongs to, if any. SceneNode
posread-only Point3D — Gets the world-space position of this node. SceneNode
matrixread-only Float32Array<ArrayBufferLike> — Gets the computed 4x4 transformation matrix. SceneNode
animationsread-only SkenraAnimation[] — Public getter for the animations affecting this target. SkenraAnimatable

Methods

MethodDescriptionDeclared by
isShadowCaster(): boolean Indicates whether this spline participates in shadow casting. AbstractSpline
getBoundsInSpace(targetSpaceMatrix: Float32Array): { minX: number; maxX: number; minY: number; maxY: number; minZ: number; maxZ: number; } | null Computes the axis-aligned bounding box of this spline in a target AbstractSpline
getPathLength(): number Gets the total length of the processed spline. AbstractSpline
getPointAt(t: number): number[] Gets a 3D point on the spline at a given normalized progression t. AbstractSpline
getClosestPoint(worldPos: [number, number, number]): ClosestPointResult | null Finds the closest point on the spline to a given world-space position. AbstractSpline
getPolyline3D(): readonly Readonly<SplinePoint>[] Gets the internal 3D polyline points. AbstractSpline
getVertices3D(resolution: number = AbstractSpline.DEFAULT_RESOLUTION): Float32Array<ArrayBufferLike> Gets all the 3D vertices of the spline, transformed to world space. AbstractSpline
getVerticesAndWidths3D(resolution: number = AbstractSpline.DEFAULT_RESOLUTION): Float32Array<ArrayBufferLike> Gets all 3D vertices in local space, stride-4 for GPU upload. AbstractSpline
addPointConstraint(constraint: PointConstraint): void Add a PointConstraint to this spline. AbstractSpline
removePointConstraint(constraint: PointConstraint): boolean Remove a PointConstraint from this spline. AbstractSpline
retessellate(currentZoom: number, lookaheadFactor?: number): void Re-tessellates the spline at the given zoom level with adaptive tolerance. AbstractSpline
addMaterialPaint(material: Material, paintTarget: PaintTarget, options?: any): Paint Applies a material to this node for a specific paint target. SceneNode
getPaints(): ReadonlyMap<PaintTarget, Paint> — SceneNode
getOwnPaints(): readonly Paint[] Gets only the paints directly applied to this node (not inherited). SceneNode
removePaint(paint: Paint): void Removes a paint from this node. SceneNode
getWorldPosition(): number[] Returns this node’s origin in world space. SceneNode
getWorldMatrix(): Float32Array<ArrayBufferLike> Returns this node’s world transform — its local transform composed with all ancestor transforms. SceneNode
setViewportPosition(camera: AbstractCamera, x: number, y: number, z: number = 0.5): boolean Sets the node's local translation so that it appears at the specified viewport position. SceneNode
getViewportPosition(camera?: AbstractCamera): [number, number, number] | null Returns the node's current world position projected to viewport CSS pixel coordinates. SceneNode
setNDCPosition(camera: AbstractCamera, ndcX: number, ndcY: number, ndcZ: number = 0.5): boolean Sets the node's local translation so that it appears at the specified NDC position in the viewport. SceneNode
animate(firstArg: TypedKeyframe<this>[] | TypedPropertyIndexedKeyframes<this> | Record<string, any> | globalThis.Keyframe[] | globalThis.PropertyIndexedKeyframes | null, secondArg?: number | KeyframeAnimationOptions | globalThis.KeyframeAnimationOptions): SkenraAnimation & Animation Creates a new SkenraAnimation for this target per Web Animations API. SkenraAnimatable
removeAnimation(animation: SkenraAnimation): boolean Removes a specific animation from this object. SkenraAnimatable
constrain(type: K, config: ConstraintConfigMap[K]): ConstraintReturnMap[K] Creates a constraint on this Animatable using a fluent API. SkenraAnimatable

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