WEBGL_compressed_texture_astc

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
ext.COMPRESSED_SRGB8_ALPHA8_ASTC_4x4_KHR
4x4 8.00 floor((width + 3) / 4) * floor((height + 3) / 4) * 16 262144
ext.COMPRESSED_RGBA_ASTC_5x4_KHR
ext.COMPRESSED_SRGB8_ALPHA8_ASTC_5x4_KHR
5x4 6.40 floor((width + 4) / 5) * floor((height + 3) / 4) * 16 210944
ext.COMPRESSED_RGBA_ASTC_5x5_KHR
ext.COMPRESSED_SRGB8_ALPHA8_ASTC_5x5_KHR
5x5 5.12 floor((width + 4) / 5) * floor((height + 4) / 5) * 16 169744
ext.COMPRESSED_RGBA_ASTC_6x5_KHR
ext.COMPRESSED_SRGB8_ALPHA8_ASTC_6x5_KHR
6x5 4.27 floor((width + 5) / 6) * floor((height + 4) / 5) * 16 141728
ext.COMPRESSED_RGBA_ASTC_6x6_KHR
ext.COMPRESSED_SRGB8_ALPHA8_ASTC_6x6_KHR
6x6 3.56 floor((width + 5) / 6) * floor((height + 5) / 6) * 16 118336
ext.COMPRESSED_RGBA_ASTC_8x5_KHR
ext.COMPRESSED_SRGB8_ALPHA8_ASTC_8x5_KHR
8x5 3.20 floor((width + 7) / 8) * floor((height + 4) / 5) * 16 105472
ext.COMPRESSED_RGBA_ASTC_8x6_KHR
ext.COMPRESSED_SRGB8_ALPHA8_ASTC_8x6_KHR
8x6 2.67 floor((width + 7) / 8) * floor((height + 5) / 6) * 16 88064
ext.COMPRESSED_RGBA_ASTC_8x8_KHR
ext.COMPRESSED_SRGB8_ALPHA8_ASTC_8x8_KHR
8x8 2.00 floor((width + 7) / 8) * floor((height + 7) / 8) * 16 65536
ext.COMPRESSED_RGBA_ASTC_10x5_KHR
ext.COMPRESSED_SRGB8_ALPHA8_ASTC_10x5_KHR
10x5 2.56 floor((width + 9) / 10) * floor((height + 4) / 5) * 16 85696
ext.COMPRESSED_RGBA_ASTC_10x6_KHR
ext.COMPRESSED_SRGB8_ALPHA8_ASTC_10x6_KHR
10x6 2.13 floor((width + 9) / 10) * floor((height + 5) / 6) * 16 71552
ext.COMPRESSED_RGBA_ASTC_10x8_KHR
ext.COMPRESSED_SRGB8_ALPHA8_ASTC_10x8_KHR
10x8 1.60 floor((width + 9) / 10) * floor((height + 7) / 8) * 16 53248
ext.COMPRESSED_RGBA_ASTC_10x10_KHR
ext.COMPRESSED_SRGB8_ALPHA8_ASTC_10x10_KHR
10x10 1.28 floor((width + 9) / 10) * floor((height + 9) / 10) * 16 43264
ext.COMPRESSED_RGBA_ASTC_12x10_KHR
ext.COMPRESSED_SRGB8_ALPHA8_ASTC_12x10_KHR
12x10 1.07 floor((width + 11) / 12) * floor((height + 9) / 10) * 16 35776
ext.COMPRESSED_RGBA_ASTC_12x12_KHR
ext.COMPRESSED_SRGB8_ALPHA8_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

Feature Chrome Edge Firefox Internet Explorer Opera Safari Servo
Basic Support47?53.0????
Feature Android Chrome for Android Edge Mobile Firefox for Android IE Mobile Opera Mobile Safari Mobile
Basic Support47?53.0???

See also

Document Tags and Contributors

 Contributors to this page: fscholz
 Last updated by: fscholz,