https://github.com/stackgl/gl-texture2d-read-float

Read out the contents of a floating-point gl-texture2d
https://github.com/stackgl/gl-texture2d-read-float

Last synced: about 1 year ago
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Read out the contents of a floating-point gl-texture2d

• Host: GitHub
• URL: https://github.com/stackgl/gl-texture2d-read-float
• Owner: stackgl
• License: other
• Created: 2015-06-12T20:47:51.000Z (about 11 years ago)
• Default Branch: master
• Last Pushed: 2016-02-13T23:16:20.000Z (over 10 years ago)
• Last Synced: 2024-04-27T00:07:44.236Z (about 2 years ago)
• Language: JavaScript
• Homepage:
• Size: 4.88 KB
• Stars: 11
• Watchers: 18
• Forks: 1
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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README

          
# gl-texture2d-read-float

[![experimental](http://badges.github.io/stability-badges/dist/experimental.svg)](http://github.com/badges/stability-badges)

Read out the contents of a floating-point

[gl-texture2d](http://github.com/stackgl/gl-texture2d).

This will *eventually* be supported natively in WebGL

[(it's listed in the OpenGL ES 3 spec)](https://www.khronos.org/opengles/sdk/docs/man31/html/glReadPixels.xhtml),

but this fills that need until then!

## Usage

[![NPM](https://nodei.co/npm/gl-texture2d-read-float.png)](https://nodei.co/npm/gl-texture2d-read-float/)

### `read(glTex2d, done(err, data))`

Reads out the contents of `glTex2d`, which should be an instance of

`gl-texture2d`. When complete, `done(err, data)` will be called where `data` is

a `Float32Array` containing the resulting floats in the texture.

``` javascript

const canvas    = document.createElement('canvas')

const gl        = require('gl-context')(canvas)

const read      = require('gl-texture2d-read-float')

const Texture2d = require('gl-texture2d')

const baboon    = require('baboon-image')

const assert    = require('assert')

const texture  = Texture2d(gl, baboon)

read(texture, function(err, data) {

  if (err) throw err

  assert.deepEqual(data, baboon.data)

})

```

A few things to note:

* Right now, this is slow as it requires reading data back from the GPU.

  There's not much that can be done about this for the time being unfortunately.

* The data is retrieved synchronously under the hood, but the API has been made

  asynchronous in preparation for WebGL's eventual async `readPixels` equivalent.

* Only `gl.RGBA`/`gl.FLOAT` textures are currently supported. Pull requests are,

  however, very welcome! :)

## Contributing

See [stackgl/contributing](https://github.com/stackgl/contributing) for details.

## License

MIT. See [LICENSE.md](http://github.com/stackgl/gl-texture2d-read-float/blob/master/LICENSE.md) for details.