ShaderBlockLayout

ShaderBlockLayout is the portable description of how luma.gl packs uniform-style and storage-style shader blocks on the CPU before uploading them to GPU buffers.

Use makeShaderBlockLayout() to build the immutable layout metadata, then pass that layout to ShaderBlockWriter to flatten nested values and serialize binary block data.

Usage

Create layout metadata that matches the block declaration in your shader:

#version 300 es
layout(std140) uniform matrixBlock {
  mat4 mvp;
} matrix;

import {makeShaderBlockLayout, ShaderBlockWriter} from '@luma.gl/core';

const shaderBlockLayout = makeShaderBlockLayout({
  mvp: 'mat4x4<f32>'
});

const shaderBlockWriter = new ShaderBlockWriter(shaderBlockLayout);
const data = shaderBlockWriter.getData({
  mvp: [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1]
});

Allocate a GPU buffer using the computed byte length:

const uniformBuffer = device.createBuffer({
  usage: Buffer.UNIFORM | Buffer.COPY_DST,
  byteLength: shaderBlockLayout.byteLength
});

uniformBuffer.write(data);

`makeShaderBlockLayout(uniformTypes, options?)`

Builds a pure ShaderBlockLayout object.

uniformTypes uses the composite shader-type descriptors documented in Shader Types
options.layout selects the packing rules:
- 'std140'
- 'wgsl-uniform'
- 'wgsl-storage'

The returned layout includes:

layout
byteLength
uniformTypes
fields

Each fields[name] entry describes one flattened leaf field with:

offset
size
components
columns
rows
columnStride
shaderType
type

All offsets and sizes are expressed in 32-bit words.

`ShaderBlockWriter`

ShaderBlockWriter serializes nested JavaScript values using a precomputed ShaderBlockLayout.

`new ShaderBlockWriter(layout)`

Creates a writer for an existing ShaderBlockLayout.

`has(name): boolean`

Returns whether the flattened block contains a field path.

`get(name)`

Returns the offset and size for a flattened field path.

`getFlatUniformValues(uniformValues)`

Flattens nested struct and fixed-size array values into leaf-path uniforms.

`getData(uniformValues): Uint8Array`

Returns serialized block data ready to upload into a GPU buffer.

Remarks

WebGL uniform buffers should use layout(std140) in GLSL to match host-side std140 packing.
ShaderBlockLayout is the portable block-packing API. The separate BufferLayout type still describes vertex buffer attribute layout.
UniformStore uses ShaderBlockLayout and ShaderBlockWriter internally.