EdgeDataTexture

Defined in: packages/sigma/src/rendering/edge-data-texture.ts:40

Manages a GPU texture storing edge data.

The texture is a 2D RGBA32F texture where each edge uses 2 texels:

Texel 0 (edgeIndex * 2 + 0):

• R: sourceNodeIndex (index into node data texture)
• G: targetNodeIndex (index into node data texture)
• B: thickness
• A: reserved

Texel 1 (edgeIndex * 2 + 1):

• R: headLengthRatio
• G: tailLengthRatio
• B: pathId (for multi-path programs)
• A: (headId << 4) | tailId (for multi-extremity programs)

Edge index N maps to texel coordinates: texel0: (N * 2) % textureWidth, (N * 2) / textureWidth texel1: (N * 2 + 1) % textureWidth, (N * 2 + 1) / textureWidth

Extends

• DataTexture

Constructors

Constructor

new EdgeDataTexture(gl, initialCapacity?): EdgeDataTexture

Defined in: packages/sigma/src/rendering/edge-data-texture.ts:41

Parameters

gl

WebGL2RenderingContext

initialCapacity?

number

Returns

EdgeDataTexture

Overrides

DataTexture.constructor

Methods

allocate()

allocate(key): number

Defined in: packages/sigma/src/rendering/data-texture.ts:152

Allocates a texture index for an item. Returns existing index if item already allocated.

Parameters

key

string | number

Returns

number

Inherited from

DataTexture.allocate

---

bind()

bind(textureUnit): void

Defined in: packages/sigma/src/rendering/data-texture.ts:271

Binds the texture to a texture unit.

Parameters

textureUnit

number

Returns

void

Inherited from

DataTexture.bind

---

clear()

clear(): void

Defined in: packages/sigma/src/rendering/data-texture.ts:339

Clears all item allocations (but keeps the texture).

Returns

void

Inherited from

DataTexture.clear

---

free()

free(key): void

Defined in: packages/sigma/src/rendering/data-texture.ts:179

Frees an item’s texture index for reuse.

Parameters

key

string | number

Returns

void

Inherited from

DataTexture.free

---

getCapacity()

getCapacity(): number

Defined in: packages/sigma/src/rendering/data-texture.ts:287

Gets the current capacity (max items).

Returns

number

Inherited from

DataTexture.getCapacity

---

getCount()

getCount(): number

Defined in: packages/sigma/src/rendering/data-texture.ts:316

Gets the number of allocated items.

Returns

number

Inherited from

DataTexture.getCount

---

getHighWaterMark()

getHighWaterMark(): number

Defined in: packages/sigma/src/rendering/data-texture.ts:325

Highest index ever allocated + 1. Unlike getCount, this spans freed holes, so it bounds every live item’s row (what a per-row gl_VertexID pass must cover).

Returns

number

Inherited from

DataTexture.getHighWaterMark

---

getIndex()

getIndex(key): number

Defined in: packages/sigma/src/rendering/data-texture.ts:199

Gets the texture index for an item. Returns -1 if item not found.

Parameters

key

string | number

Returns

number

Inherited from

DataTexture.getIndex

---

getTexelsPerItem()

getTexelsPerItem(): number

Defined in: packages/sigma/src/rendering/data-texture.ts:309

Gets the number of texels per item.

Returns

number

Inherited from

DataTexture.getTexelsPerItem

---

getTexture()

getTexture(): WebGLTexture | null

Defined in: packages/sigma/src/rendering/data-texture.ts:280

Gets the WebGL texture object.

Returns

WebGLTexture | null

Inherited from

DataTexture.getTexture

---

getTextureHeight()

getTextureHeight(): number

Defined in: packages/sigma/src/rendering/data-texture.ts:302

Gets the texture height (needed to cover the full texture when rendering into it).

Returns

number

Inherited from

DataTexture.getTextureHeight

---

getTextureWidth()

getTextureWidth(): number

Defined in: packages/sigma/src/rendering/data-texture.ts:294

Gets the texture width (needed for 2D coordinate calculation in shaders).

Returns

number

Inherited from

DataTexture.getTextureWidth

---

has()

has(key): boolean

Defined in: packages/sigma/src/rendering/data-texture.ts:206

Checks if an item has been allocated.

Parameters

key

string | number

Returns

boolean

Inherited from

DataTexture.has

---

isDirty()

isDirty(): boolean

Defined in: packages/sigma/src/rendering/data-texture.ts:332

Checks if there are pending changes to upload.

Returns

boolean

Inherited from

DataTexture.isDirty

---

kill()

kill(): void

Defined in: packages/sigma/src/rendering/data-texture.ts:360

Destroys the texture and clears all data.

Returns

void

Inherited from

DataTexture.kill

---

restore()

restore(): void

Defined in: packages/sigma/src/rendering/data-texture.ts:350

Recreates the GPU texture after a context loss, re-uploading the CPU-side data.

Returns

void

Inherited from

DataTexture.restore

---

updateEdge()

updateEdge(edgeKey, sourceNodeIndex, targetNodeIndex, thickness, headLengthRatio, tailLengthRatio, pathId?, headId?, tailId?): void

Defined in: packages/sigma/src/rendering/edge-data-texture.ts:58

Updates all data for an edge.

Parameters

edgeKey

string

The edge identifier

sourceNodeIndex

number

Index of source node in node data texture

targetNodeIndex

number

Index of target node in node data texture

thickness

number

Edge thickness

headLengthRatio

number

Head extremity length as ratio of thickness

tailLengthRatio

number

Tail extremity length as ratio of thickness

pathId?

number = 0

Path index for multi-path programs (default 0)

headId?

number = 0

Head extremity index for multi-extremity programs (default 0)

tailId?

number = 0

Tail extremity index for multi-extremity programs (default 0)

Returns

void

---

upload()

upload(): void

Defined in: packages/sigma/src/rendering/data-texture.ts:223

Uploads dirty data to the GPU texture. With 2D layout and multiple texels per item, uploads affected rows.

Returns

void

Inherited from

DataTexture.upload