OpenLIME

Class: LayerBRDF

LayerBRDF

LayerBRDF implements real-time BRDF (Bidirectional Reflectance Distribution Function) rendering.

The BRDF model describes how light reflects off a surface, taking into account:

  • Diffuse reflection (rough, matte surfaces)
  • Specular reflection (mirror-like reflections)
  • Surface normals (microscopic surface orientation)
  • Glossiness/roughness (surface micro-structure)

Features:

  • Real-time light direction control
  • Multiple material channels support
  • Customizable material properties
  • Interactive lighting model
  • Gamma correction
  • Ambient light component

Technical implementation:

  • Uses normal mapping for surface detail
  • Supports both linear and sRGB color spaces
  • Implements spherical light projection
  • Handles multi-channel textures
  • GPU-accelerated rendering

new LayerBRDF(options)

Creates a new LayerBRDF instance

Parameters:
Name Type Description
options LayerBRDFOptions

Configuration options
Source:
Throws:

  • If required channels (kd, normals) are not provided

    Type
    Error

  • If rasters option is not empty

    Type
    Error
Example
```javascript
// Create BRDF layer with all channels
const brdfLayer = new OpenLIME.LayerBRDF({
  channels: {
    kd: 'diffuse.jpg',
    ks: 'specular.jpg',
    normals: 'normals.jpg',
    gloss: 'gloss.jpg'
  },
  colorspaces: {
    kd: 'srgb',
    ks: 'linear'
  },
  brightness: 1.2,
  gamma: 2.2
});

// Update light direction
brdfLayer.setLight([0.5, 0.5], 500, 'ease-out');
```

Extends

Methods

addControl(name, value)

Adds a shader parameter control

Parameters:
Name Type Description
name string

Control identifier
value *

Initial value
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Throws:

If control already exists

Type
Error

addShaderFilter(filter)

Adds a filter to the current shader

Parameters:
Name Type Description
filter Object

Filter specification
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Throws:

If no shader is set

Type
Error

boundingBox()

Gets layer bounding box in scene coordinates

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Returns:

Bounding box

Type
BoundingBox

clearShaderFilters(name)

Removes all filters from the current shader

Parameters:
Name Type Description
name Object

Filter name
Inherited From:
Overrides:
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Throws:

If no shader is set

Type
Error

getControl(name)

Gets the shader parameter control corresponding to name

Parameters:
Name Type Description
name *

The name of the control. return {*} The control
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getMode()

Gets the current shader visualization mode

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Returns:

Current mode or null if no shader

Type
string | null

getModes()

Gets available shader modes

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Returns:

Array of available modes

Type
Array.<string>

getState( [stateMask])

Gets the current layer state

Parameters:
Name Type Argument Default Description
stateMask Object <optional>
 null

Optional mask to filter returned state properties
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Returns:

Current state object

Type
Object

<async> loadTile(tile, callback)

Loads and processes a single image tile with optimized resource management. Implements request batching, concurrent loading, and proper error handling.

Parameters:
Name Type Description
tile Object

Tile specification object

Properties
Name Type Argument Description
index string

Unique tile identifier
url string

Base URL for tile resource
start number <optional>

Start byte for partial content (for tarzoom)
end number <optional>

End byte for partial content (for tarzoom)
offsets Array.<Object> <optional>

Byte offsets for interleaved formats
callback function

Completion callback(error, size)
Inherited From:
Overrides:
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Throws:

If tile is already in processing queue

Type
Error
Returns:
Type
Promise.<void>

pixelSizePerMM()

Gets pixel size in millimeters

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Returns:

Size of one pixel in mm

Type
number

removeShaderFilter(name)

Removes a filter from the current shader

Parameters:
Name Type Description
name Object

Filter name
Inherited From:
Overrides:
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Throws:

If no shader is set

Type
Error

scale()

Gets layer scale

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Returns:

Current scale value

Type
number

setControl(name, value [, dt] [, easing])

Sets a shader control value with optional animation

Parameters:
Name Type Argument Default Description
name string

Control identifier
value *

New value
dt number <optional>

Animation duration in ms
easing string <optional>
 'linear'

Easing function
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setLight(light [, dt] [, easing])

Sets the light direction with optional animation

Parameters:
Name Type Argument Default Description
light Array.<number>

2D vector [x, y] representing light direction
dt number <optional>

Animation duration in milliseconds
easing string <optional>
 'linear'

Animation easing function
Source:

setMode(mode)

Sets shader visualization mode

Parameters:
Name Type Description
mode string

Mode to set
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setShader(id)

Sets the active shader

Parameters:
Name Type Description
id string

Shader identifier from registered shaders
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Fires:
Throws:

If shader ID is not found

Type
Error

setState(state [, dt] [, easing])

Sets the layer state with optional animation

Parameters:
Name Type Argument Default Description
state Object

State object with controls and mode
dt number <optional>

Animation duration in ms
easing string <optional>
 'linear'

Easing function ('linear'|'ease-out'|'ease-in-out')
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setTransform(tx)

Sets the layer's transform

Parameters:
Name Type Description
tx Transform

New transform
Inherited From:
Overrides:
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Fires:
  • Layer#event:updateSize

setViewport(view)

Sets the layer's viewport

Parameters:
Name Type Description
view Object

Viewport specification

Properties
Name Type Description
x number

X position
y number

Y position
dx number

Width
dy number

Height
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setVisible(visible)

Sets layer visibility

Parameters:
Name Type Description
visible boolean

Whether layer should be visible
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setZindex(zindex)

Sets layer rendering order

Parameters:
Name Type Description
zindex number

Stack order value
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<static> projectToFlattenedSphere(p)

Projects a 2D point onto a flattened sphere using SGI trackball algorithm. This provides more intuitive light control by avoiding acceleration near edges. Based on SIGGRAPH 1988 paper on SGI trackball implementation.

Parameters:
Name Type Description
p Array.<number>

2D point [x, y] in range [-1, 1]
Source:
Returns:

3D normalized vector [x, y, z] on flattened sphere

Type
Array.<number>

<static> projectToSphere(p)

Projects a 2D point onto a sphere surface Used for converting 2D mouse/touch input to 3D light direction

Parameters:
Name Type Description
p Array.<number>

2D point [x, y] in range [-1, 1]
Source:
Returns:

3D normalized vector [x, y, z] on sphere surface

Type
Array.<number>

Events

ready

The event is fired when a layer is initialized.

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update

The event is fired if a redraw is needed.

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