Class BufferElement

Used to handle each buffer binding array view and data layout alignment. Compute the exact alignment offsets needed to fill an ArrayBuffer that will be sent to a GPUBuffer, based on an input type and value. Also update the view array at the correct offset.

So all our struct need to be packed into our arrayBuffer using a precise layout. They will be stored in rows, each row made of 4 slots and each slots made of 4 bytes. Depending on the binding element type, its row and slot may vary and we may have to insert empty padded values. All in all it looks like that:

         slot 0    slot 1    slot 2    slot 3
row 0 | _ _ _ _ | _ _ _ _ | _ _ _ _ | _ _ _ _ |
row 1 | _ _ _ _ | _ _ _ _ | _ _ _ _ | _ _ _ _ |
row 2 | _ _ _ _ | _ _ _ _ | _ _ _ _ | _ _ _ _ |

see https://webgpufundamentals.org/webgpu/lessons/resources/wgsl-offset-computer.html

Hierarchy (View Summary)

BufferElement
- BufferArrayElement

Constructors

constructor

new BufferElement(parameters: BufferElementParams): BufferElement
BufferElement constructor
Parameters
- parameters: BufferElementParams
  parameters used to create our BufferElement.
Returns BufferElement
- Defined in src/core/bindings/bufferElements/BufferElement.ts:94

Properties

name

name: string

The name of the BufferElement.

type

type: string

The WGSL variable type of the BufferElement (stripped of array).

baseType

baseType: string

The WGSL base variable type of the BufferElement (stripped of array and atomic).

key

key: string

The key of the BufferElement.

bufferLayout

bufferLayout: BufferLayout

BufferLayout used to fill the BufferBinding arrayBuffer at the right offsets.

alignment

alignment: BufferElementAlignment

Object defining exactly at which place a binding should be inserted into the BufferBinding arrayBuffer.

`Optional`view

view?: TypedArray

Array containing the BufferElement values.

setValue

setValue: (value: InputValue) => void

Function assigned to set the view values.

Accessors

rowCount

get rowCount(): number
Get the total number of rows used by this BufferElement.

Returns number
- Defined in src/core/bindings/bufferElements/BufferElement.ts:142

byteCount

get byteCount(): number
Get the total number of bytes used by this BufferElement based on alignment start and end offsets.

Returns number
- Defined in src/core/bindings/bufferElements/BufferElement.ts:150

paddedByteCount

get paddedByteCount(): number
Get the total number of bytes used by this BufferElement, including final padding.

Returns number
- Defined in src/core/bindings/bufferElements/BufferElement.ts:158

startOffset

get startOffset(): number
Get the offset (i.e. byte index) at which our BufferElement starts.

Returns number
- Defined in src/core/bindings/bufferElements/BufferElement.ts:166

startOffsetToIndex

get startOffsetToIndex(): number
Get the array offset (i.e. array index) at which our BufferElement starts.

Returns number
- Defined in src/core/bindings/bufferElements/BufferElement.ts:174

endOffset

get endOffset(): number
Get the offset (i.e. byte index) at which our BufferElement ends.

Returns number
- Defined in src/core/bindings/bufferElements/BufferElement.ts:182

endOffsetToIndex

get endOffsetToIndex(): number
Get the array offset (i.e. array index) at which our BufferElement ends.

Returns number
- Defined in src/core/bindings/bufferElements/BufferElement.ts:190

Methods

`Static`getType

getType(type: string): string
Get the BufferElement WGSL type.
Parameters
- type: string
  Original type passed.
Returns string
- The BufferElement WGSL type.
- Defined in src/core/bindings/bufferElements/BufferElement.ts:123

`Static`getBaseType

getBaseType(type: string): string
Get the BufferElement WGSL base type.
Parameters
- type: string
  Original type passed.
Returns string
- The BufferElement WGSL base type.
- Defined in src/core/bindings/bufferElements/BufferElement.ts:132

getPositionAtOffset

getPositionAtOffset(offset?: number): BufferElementAlignmentPosition
Get the position at given offset (i.e. byte index).
Parameters
- offset: number = 0
  Byte index to use.
Returns BufferElementAlignmentPosition
- Defined in src/core/bindings/bufferElements/BufferElement.ts:198

getByteCountAtPosition

getByteCountAtPosition(position?: BufferElementAlignmentPosition): number
Get the number of bytes at a given position.
Parameters
- position: BufferElementAlignmentPosition = ...
  Position from which to count.
Returns number
- Byte count at the given position.
- Defined in src/core/bindings/bufferElements/BufferElement.ts:210

applyOverflowToPosition

applyOverflowToPosition(
position?: BufferElementAlignmentPosition,
): BufferElementAlignmentPosition
Check that a byte position does not overflow its max value (16).
Parameters
- position: BufferElementAlignmentPosition = ...
  Position.
Returns BufferElementAlignmentPosition
- Updated position.
- Defined in src/core/bindings/bufferElements/BufferElement.ts:219

getByteCountBetweenPositions

getByteCountBetweenPositions(
p1?: BufferElementAlignmentPosition,
p2?: BufferElementAlignmentPosition,
): number
Get the number of bytes between two positions.
Parameters
- p1: BufferElementAlignmentPosition = ...
  First position.
- p2: BufferElementAlignmentPosition = ...
  Second position.
Returns number
- Number of bytes.
- Defined in src/core/bindings/bufferElements/BufferElement.ts:237

getElementAlignment

getElementAlignment(
nextPositionAvailable?: BufferElementAlignmentPosition,
): BufferElementAlignment
Compute the right alignment (i.e. start and end rows and bytes) given the size and align properties and the next available position.
Parameters
- nextPositionAvailable: BufferElementAlignmentPosition = ...
  next position at which we should insert this element.
Returns BufferElementAlignment
- Computed alignment.
- Defined in src/core/bindings/bufferElements/BufferElement.ts:249

setAlignmentFromPosition

setAlignmentFromPosition(position?: BufferElementAlignmentPosition): void
Set the alignment from a position.
Parameters
- position: BufferElementAlignmentPosition = ...
  position at which to start inserting the values in the BufferBinding arrayBuffer.
Returns void
- Defined in src/core/bindings/bufferElements/BufferElement.ts:296

setAlignment

setAlignment(startOffset?: number, minStride?: number): void
Set the alignment from an offset (byte count).
Parameters
- startOffset: number = 0
  Offset at which to start inserting the values in the parent BufferBinding arrayBuffer.
- minStride: number = 0
  Minimum stride to use for the values in the parent BufferBinding arrayBuffer.
Returns void
- Defined in src/core/bindings/bufferElements/BufferElement.ts:305

setView

setView(arrayBuffer: ArrayBuffer, arrayView: DataView): void
Set this BufferElement view into a parent BufferBinding arrayBuffer.
Parameters
- arrayBuffer: ArrayBuffer
  The parent BufferBinding arrayBuffer.
- arrayView: DataView
  The parent BufferBinding arrayView.
Returns void
- Defined in src/core/bindings/bufferElements/BufferElement.ts:314

setValueFromNumber

setValueFromNumber(value: number): void
Set the view value from a float or an int.
Parameters
- value: number
  Float or int to use.
Returns void
- Defined in src/core/bindings/bufferElements/BufferElement.ts:326

setValueFromVec2

setValueFromVec2(value: number[] | Vec2): void
Set the view value from a Vec2 or an array.
Parameters
- value: number[] | Vec2
  Vec2 or array to use.
Returns void
- Defined in src/core/bindings/bufferElements/BufferElement.ts:334

setValueFromVec3

setValueFromVec3(value: number[] | Vec3): void
Set the view value from a Vec3 or an array.
Parameters
- value: number[] | Vec3
  Vec3 or array to use.
Returns void
- Defined in src/core/bindings/bufferElements/BufferElement.ts:343

setValueFromMat4OrQuat

setValueFromMat4OrQuat(value: Quat | Mat4): void
Set the view value from a Mat4 or Quat.
Parameters
- value: Quat | Mat4
  Mat4 or Quat to use.
Returns void
- Defined in src/core/bindings/bufferElements/BufferElement.ts:353

setValueFromMat3

setValueFromMat3(value: Mat3): void
Set the view value from a Mat3.
Parameters
- value: Mat3
  Mat3 to use.
Returns void
- Defined in src/core/bindings/bufferElements/BufferElement.ts:361

setValueFromArray

setValueFromArray(value: number[] | TypedArray): void
Set the view value from an array.
Parameters
- value: number[] | TypedArray
  Array to use.
Returns void
- Defined in src/core/bindings/bufferElements/BufferElement.ts:370

setValueFromArrayWithPad

setValueFromArrayWithPad(value: number[] | TypedArray): void
Set the view value from an array with pad applied.
Parameters
- value: number[] | TypedArray
  Array to use.
Returns void
- Defined in src/core/bindings/bufferElements/BufferElement.ts:378

update

update(value: InputValue): void
Update the view based on the new value.
Parameters
- value: InputValue
  New value to use.
Returns void
- Defined in src/core/bindings/bufferElements/BufferElement.ts:394

extractDataFromBufferResult

extractDataFromBufferResult(result: Float32Array): Float32Array<ArrayBuffer>
Extract the data corresponding to this specific BufferElement from a Float32Array holding the GPUBuffer data of the parentMesh BufferBinding.
Parameters
- result: Float32Array
  Float32Array holding GPUBuffer data.
Returns Float32Array<ArrayBuffer>
- Extracted data from the Float32Array.
- Defined in src/core/bindings/bufferElements/BufferElement.ts:427

Class BufferElement

Hierarchy (View Summary)

Index

Constructors

Properties

Accessors

Methods

Constructors

constructor

Parameters

Returns BufferElement

Properties

name

type

baseType

key

bufferLayout

alignment

Optionalview

setValue

Accessors

rowCount

Returns number

byteCount

Returns number

paddedByteCount

Returns number

startOffset

Returns number

startOffsetToIndex

Returns number

endOffset

Returns number

endOffsetToIndex

Returns number

Methods

StaticgetType

Parameters

Returns string

StaticgetBaseType

Parameters

Returns string

getPositionAtOffset

Parameters

Returns BufferElementAlignmentPosition

getByteCountAtPosition

Parameters

Returns number

applyOverflowToPosition

Parameters

Returns BufferElementAlignmentPosition

getByteCountBetweenPositions

Parameters

Returns number

getElementAlignment

Parameters

Returns BufferElementAlignment

setAlignmentFromPosition

Parameters

Returns void

setAlignment

Parameters

Returns void

setView

Parameters

Returns void

setValueFromNumber

Parameters

Returns void

setValueFromVec2

Parameters

Returns void

setValueFromVec3

Parameters

Returns void

setValueFromMat4OrQuat

Parameters

Returns void

setValueFromMat3

Parameters

`Optional`view

`Static`getType

`Static`getBaseType