Web/API/WEBGL compressed texture s3tc

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.

Availability: 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 a simple 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

var ext = (
  gl.getExtension('WEBGL_compressed_texture_s3tc') ||
  gl.getExtension('MOZ_WEBGL_compressed_texture_s3tc') ||
  gl.getExtension('WEBKIT_WEBGL_compressed_texture_s3tc')
);

var 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	Status	Comment
WEBGL_compressed_texture_s3tcThe definition of 'WEBGL_compressed_texture_s3tc' 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.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`WEBGL_compressed_texture_s3tc`	Chrome Full support Yes Full support Yes Full support Yes Prefixed' Prefixed' Implemented with the vendor prefix: WEBKIT_	Edge Full support ≤18	Firefox Full support 22 Full support 22 No support 15 — 58 Prefixed' Prefixed' Implemented with the vendor prefix: MOZ_	IE ?	Opera Full support Yes Full support Yes Full support Yes Prefixed' Prefixed' Implemented with the vendor prefix: WEBKIT_	Safari ?	WebView Android Full support Yes Full support Yes Full support Yes Prefixed' Prefixed' Implemented with the vendor prefix: WEBKIT_	Chrome Android Full support Yes Full support Yes Full support Yes Prefixed' Prefixed' Implemented with the vendor prefix: WEBKIT_	Firefox Android ?	Opera Android Full support Yes Full support Yes Full support Yes Prefixed' Prefixed' Implemented with the vendor prefix: WEBKIT_	Safari iOS ?	Samsung Internet Android Full support Yes Full support Yes Full support Yes Prefixed' Prefixed' Implemented with the vendor prefix: WEBKIT_

Legend

Full support: Full support
Compatibility unknown: Compatibility unknown
Requires a vendor prefix or different name for use.': Requires a vendor prefix or different name for use.