The WEBGL_compressed_texture_astc extension is part of the WebGL API and exposes Adaptive Scalable Texture Compression (ASTC) compressed texture formats to WebGL.
For more information, see the article Using ASTC Texture Compression for Game Assets by nvidia.
WebGL extensions are available using the WebGLRenderingContext.getExtension() method. For more information, see also Using Extensions in the WebGL tutorial.
Availability: ASTC compression is typically available on Mali ARM GPUs, Intel GPUs, and Nividia Tegra chips.
This extension is available to both, WebGL1 and WebGL2 contexts.
Methods
This extension exposes one new methods.
ext.getSupportedProfiles()-
Returns an array of strings containing the names of the ASTC profiles supported by the implementation.
Constants
The compressed texture formats are exposed by 28 constants and can be used in two functions: compressedTexImage2D() and compressedTexSubImage2D().
| Constants | Blocks | Bits per pixel | ArrayBuffer byteLength |
bytes if height and width are 512 |
ext.COMPRESSED_RGBA_ASTC_4x4_KHR |
4x4 | 8.00 | floor((width + 3) / 4) * floor((height + 3) / 4) * 16 |
262144 |
ext.COMPRESSED_RGBA_ASTC_5x4_KHR |
5x4 | 6.40 | floor((width + 4) / 5) * floor((height + 3) / 4) * 16 |
210944 |
ext.COMPRESSED_RGBA_ASTC_5x5_KHR |
5x5 | 5.12 | floor((width + 4) / 5) * floor((height + 4) / 5) * 16 |
169744 |
ext.COMPRESSED_RGBA_ASTC_6x5_KHR |
6x5 | 4.27 | floor((width + 5) / 6) * floor((height + 4) / 5) * 16 |
141728 |
ext.COMPRESSED_RGBA_ASTC_6x6_KHR |
6x6 | 3.56 | floor((width + 5) / 6) * floor((height + 5) / 6) * 16 |
118336 |
ext.COMPRESSED_RGBA_ASTC_8x5_KHR |
8x5 | 3.20 | floor((width + 7) / 8) * floor((height + 4) / 5) * 16 |
105472 |
ext.COMPRESSED_RGBA_ASTC_8x6_KHR |
8x6 | 2.67 | floor((width + 7) / 8) * floor((height + 5) / 6) * 16 |
88064 |
ext.COMPRESSED_RGBA_ASTC_8x8_KHR |
8x8 | 2.00 | floor((width + 7) / 8) * floor((height + 7) / 8) * 16 |
65536 |
ext.COMPRESSED_RGBA_ASTC_10x5_KHR |
10x5 | 2.56 | floor((width + 9) / 10) * floor((height + 4) / 5) * 16 |
85696 |
ext.COMPRESSED_RGBA_ASTC_10x6_KHR |
10x6 | 2.13 | floor((width + 9) / 10) * floor((height + 5) / 6) * 16 |
71552 |
ext.COMPRESSED_RGBA_ASTC_10x8_KHR |
10x8 | 1.60 | floor((width + 9) / 10) * floor((height + 7) / 8) * 16 |
53248 |
ext.COMPRESSED_RGBA_ASTC_10x10_KHR |
10x10 | 1.28 | floor((width + 9) / 10) * floor((height + 9) / 10) * 16 |
43264 |
ext.COMPRESSED_RGBA_ASTC_12x10_KHR |
12x10 | 1.07 | floor((width + 11) / 12) * floor((height + 9) / 10) * 16 |
35776 |
ext.COMPRESSED_RGBA_ASTC_12x12_KHR |
12x12 | 0.89 | floor((width + 11) / 12) * floor((height + 11) / 12) * 16 |
29584 |
Examples
var ext = gl.getExtension('WEBGL_compressed_texture_astc');
var texture = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, texture);
gl.compressedTexImage2D(gl.TEXTURE_2D, 0, ext.COMPRESSED_RGBA_ASTC_12x12_KHR, 512, 512, 0, textureData);
Specifications
| Specification | Status | Comment |
|---|---|---|
| WEBGL_compressed_texture_astc The definition of 'WEBGL_compressed_texture_astc' in that specification. |
Recommendation | Initial definition. |
Browser compatibility
The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
| Feature | Chrome | Firefox | Edge | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|---|
getSupportedProfiles | 47 | 53.0 | (No) | ? | ? | ? |
| Feature | Android | Chrome for Android | Edge mobile | Firefox for Android | IE mobile | Opera Android | iOS Safari |
|---|---|---|---|---|---|---|---|
getSupportedProfiles | ? | 47 | (No) | 53.0 | ? | ? | ? |