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69 lines
2.1 KiB
Markdown
69 lines
2.1 KiB
Markdown
# Attribute (Experimental)
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Wrapper class to be used with the `Model` class' `render` and `setAttributes` methods.
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## Usage
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Create model object by passing shaders, uniforms, geometry and render it by passing updated uniforms.
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```js
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import {_Attribute as Attribute} from 'luma.gl';
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```
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```js
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// construct the model.
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const positions = new Attribute({
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id: 'vertexPositions',
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size: 3,
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value: new Float32Array([0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0])
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});
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// and on each frame update any uniforms (typically matrices) and call render.
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model.setAttributes({positions});
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model.render();
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```
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## Methods
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### constructor
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The constructor for the Attribute class. Use this to create a new Attribute.
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`new Attribute(gl, options);`
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* `gl` - WebGL context.
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* `size` (*number*) - The number of components in each element the buffer (1-4).
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* `id` (*string*, optional) - Identifier of the attribute. Cannot be updated.
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* `type` (*GLenum*, optional) - Type of the attribute. If not supplied will be inferred from `value`. Cannot be updated.
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* `isIndexed` (*bool*, optional) - If the attribute is element index. Default `false`. Cannot be updated.
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* `constant` (*bool*, optional) - If the attribute is a constant. Default `false`.
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* `isInstanced` (*bool*, optional) - Whether buffer contains instance data. Default `false`.
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* `normalized` (*boolean*, optional) - Default `false`
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* `integer` (*boolean*, optional) - Default `false`
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* `offset` (*number*, optional) - where the data starts in the buffer. Default `0`.
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* `stride` (*number*, optional) - an additional offset between each element in the buffer. Default `0`.
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* `value` (*TypedArray*) - value of the attribute.
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- If `constant` is `true`, the length of `value` should match `size`
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- If `constant` is `false`, the length of `value` should be `size` multiplies the number of vertices.
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* `buffer` (*Buffer*) - an external buffer for the attribute.
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### delete
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Free WebGL resources associated with this attribute.
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### update
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```js
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attribute.update({value: newValue});
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```
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Update attribute options. See `constructor` for possible options.
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### getBuffer
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Returns a `Buffer` object associated with this attribute, if any.
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