WEBGL_compressed_texture_s3tc extension

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

See full compatibility

The WEBGL_compressed_texture_s3tc extension is part of the WebGL API and exposes four S3TC compressed texture formats.

Compressed textures reduce the amount of memory needed to store a texture on the GPU, allowing for higher resolution textures or more of the same resolution textures.

WebGL extensions are available using the WebGLRenderingContext.getExtension() method. For more information, see also Using Extensions in the WebGL tutorial.

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

Constants

The compressed texture formats are exposed by four constants and can be used in two functions: compressedTexImage2D() and compressedTexSubImage2D().

ext.COMPRESSED_RGB_S3TC_DXT1_EXT: A DXT1-compressed image in an RGB image format.
ext.COMPRESSED_RGBA_S3TC_DXT1_EXT: A DXT1-compressed image in an RGB image format with an on/off alpha value.
ext.COMPRESSED_RGBA_S3TC_DXT3_EXT: A DXT3-compressed image in an RGBA image format. Compared to a 32-bit RGBA texture, it offers 4:1 compression.
ext.COMPRESSED_RGBA_S3TC_DXT5_EXT: A DXT5-compressed image in an RGBA image format. It also provides a 4:1 compression, but differs to the DXT3 compression in how the alpha compression is done.

Examples

const ext =
  gl.getExtension("WEBGL_compressed_texture_s3tc") ||
  gl.getExtension("MOZ_WEBGL_compressed_texture_s3tc") ||
  gl.getExtension("WEBKIT_WEBGL_compressed_texture_s3tc");

const texture = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, texture);

gl.compressedTexImage2D(
  gl.TEXTURE_2D,
  0,
  ext.COMPRESSED_RGBA_S3TC_DXT5_EXT,
  512,
  512,
  0,
  textureData,
);

gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);

Specifications

Specification
WebGL WEBGL_compressed_texture_s3tc Khronos Ratified Extension Specification

Browser compatibility

	desktop					mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on iOS	Samsung Internet	WebView Android	WebView on iOS
`WEBGL_compressed_texture_s3tc`	Chrome – No support Chrome 26 – 55 (Release date: 2013-03-26) prefix footnote Removed in 56 and later prefix Implemented with the vendor prefix: WEBKIT_ Chrome – Full support Chrome 26 (Release date: 2013-03-26) footnote Full support	Edge – Full support Edge 12 (Release date: 2015-07-29) footnote Full support	Firefox – No support Firefox 15 – 57 (Release date: 2012-08-28) prefix footnote Removed in 58 and later prefix Implemented with the vendor prefix: MOZ_ Firefox – Full support Firefox 22 (Release date: 2013-06-25) footnote Full support	Opera – No support Opera 15 – 42 (Release date: 2013-07-02) prefix footnote Removed in 43 and later prefix Implemented with the vendor prefix: WEBKIT_ Opera – Full support Opera 15 (Release date: 2013-07-02) footnote Full support	Safari – Full support Safari 8 (Release date: 2014-10-16) footnote Full support	Chrome Android – No support Chrome Android footnote No support	Firefox for Android – No support Firefox for Android footnote No support	Opera Android – No support Opera Android footnote No support	Safari on iOS – No support Safari on iOS footnote No support	Samsung Internet – No support Samsung Internet footnote No support	WebView Android – No support WebView Android footnote No support	WebView on iOS – No support WebView on iOS footnote No support

Tip: you can click/tap on a cell for more information.

Full support: Full support
No support: No support
: Requires a vendor prefix or different name for use.
: Has more compatibility info.

WEBGL_compressed_texture_s3tc extension

Constants

Examples

Specifications

Browser compatibility

Legend

See also