WEBGL_compressed_texture_astc extension

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since January 2020.

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.

Note: ASTC compression is typically available on Mali ARM GPUs, Intel GPUs, and NVIDIA Tegra chips.

This extension is available to both, WebGL1 and WebGL2 contexts.

Instance 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

js
const ext = gl.getExtension("WEBGL_compressed_texture_astc");

const 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
WebGL WEBGL_compressed_texture_astc Extension Specification

Browser compatibility

BCD tables only load in the browser

See also