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AttributeManager Class

The AttributeManage class provides automated attribute allocations and updates.

Summary:

  • keeps track of valid state for each attribute
  • auto reallocates attributes when needed
  • auto updates attributes with registered updater functions
  • allows overriding with application supplied buffers

Limitations:

  • The AttributeManager always reinitializes the entire typed array. There are currently no provisions for only invalidating a range of indices in an attribute.

Constructor

Parameters:

  • opts (Object) - named parameters
    • opts.id (String, optional) - identifier (for debugging)
new AttributeManager({id: 'attribute-manager'});

Static Methods

setDefaultLogFunctions

Sets log functions to help trace or time attribute updates. Default logging uses the luma.gl logger.

Note that the app may not be in control of when update is called, so hooks are provided for update start and end.

Parameters:

  • opts (Object) - named parameters
    • opts.onLog (Function) - callback, called to print
    • opts.onUpdateStart (Function) - callback, called before update() starts
    • opts.onUpdateEnd (Function) - callback, called after update() ends

Methods

add

Adds attribute descriptions to the AttributeManager that describe the attributes that should be auto-calculated.

Takes a single parameter as a map of attribute descriptor objects:

  • keys are attribute names
  • values are objects with attribute definitions
    • attribute.size (Number) - number of elements per object
    • attribute.accessor (String | Array of strings) - accessor name(s) that will trigger an update of this attribute when changed. Used with updateTriggers.
    • attribute.update (Function) - the function to be called when
    • attribute.instanced (Boolean, optional) - if this is an instanced attribute (a.k.a. divisor). Default to false.
    • attribute.noAlloc (Boolean, optional) - if this attribute should not be automatically allocated. Default to false.
attributeManager.add({
  positions: {
    size: 2,
    accessor: 'getPosition',
    update: calculatePositions
  }
  colors: {
    size: 4,
    type: GL.UNSIGNED_BYTE,
    accessor: 'getColor',
    update: calculateColors
  }
});
addInstanced

Shorthand for add() in which all attributes instanced field are set to true.

invalidate

Mark an attribute as need update.

Parameters:

  • name (String) - Either the name of the attribute, or the name of an accessor. If an name of accessor is provided, all attributes with that accessor are invalidated.
invalidateAll

Mark all attributes as need update.

remove

Removes defined attributes.

Parameters:

  • attributeNames (Array) - Array of attribute names to be removed

Source

src/lib/attribute-manager.js