OpenLIME

Class: ShaderDstretch

ShaderDstretch

ShaderDStretch implements the GPU-accelerated portion of the DStretch algorithm. Handles color space transformation and normalization for image enhancement.

Features:

  • Real-time color space transformation
  • Dynamic range computation
  • Euler angle-based rotation control
  • Automatic statistics computation
  • WebGL 1.0 and 2.0 compatibility

Technical Implementation:

  • Uses 4x4 matrices for color space transformation
  • Implements color normalization based on sample statistics
  • Supports dynamic update of transformation parameters
  • Handles WebGL uniform management

new ShaderDstretch( [options])

Creates a new ShaderDStretch instance

Parameters:
Name Type Argument Description
options Object <optional>

Configuration options (inherited from Shader)
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Extends

Methods

addFilter(filter)

Adds a filter to the shader pipeline.

Parameters:
Name Type Description
filter Object

Filter to add
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allUniforms()

Returns all uniform variables associated with the shader and its filters. Combines uniforms from both the base shader and all active filters into a single object.

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Combined uniform variables

Type
Object.<string, Object>

clearFilters()

Clears all filters from the shader pipeline.

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getUniform(name)

Gets a uniform variable by name. Searches both shader uniforms and filter uniforms.

Parameters:
Name Type Description
name string

Uniform variable name
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Returns:

Uniform object if found

Type
Object | undefined

init(json)

Initializes the shader with configuration data

Parameters:
Name Type Description
json ShaderDStretch~Config

Configuration data
Properties:
Name Type Description
json.samples Array.<Array.<number>>

Color samples for statistics
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removeFilter(name)

Removes a filter from the pipeline by name.

Parameters:
Name Type Description
name string

Name of filter to remove
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setMode(mode)

Sets the current shader mode.

Parameters:
Name Type Description
mode string

Mode identifier (must be in options.modes)
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Throws:

If mode is not recognized

Type
Error

setTileSize(size)

Sets tile dimensions for shader calculations.

Parameters:
Name Type Description
size Array.<number>

[width, height] of tile
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setUniform(name, value)

Sets a uniform variable value.

Parameters:
Name Type Description
name string

Uniform variable name
value number | boolean | Array

Value to set
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If uniform doesn't exist

Type
Error

updateRotationMatrix(eulerRotation)

Updates the color transformation matrix based on Euler angles

Parameters:
Name Type Description
eulerRotation Array.<number>

Rotation angles [x,y,z] in radians
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vertShaderSrc(gl)

Gets vertex shader source code. Default implementation provides basic vertex transformation and texture coordinate passing.

Parameters:
Name Type Description
gl WebGLRenderingContext

WebGL context
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Returns:

Vertex shader source code

Type
string

Events

update

Fired when shader state changes (uniforms, filters, etc).

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