Web/API/EXT texture compression rgtc

The EXT_texture_compression_rgtc extension is part of the WebGL API and exposes 4 RGTC compressed texture formats. RGTC is a block-based texture compression format suited for unsigned and signed red and red-green textures (Red-Green Texture Compression).

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

Availability: Support depends on the system's graphics driver. There is no support on Windows.

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

Constants

The compressed texture formats are exposed by 4 constants and can be used in two functions: compressedTexImage2D() and compressedTexSubImage2D().

ext.COMPRESSED_RED_RGTC1_EXT: Each 4x4 block of texels consists of 64 bits of unsigned red image data. See also BC4 unsigned.
ext.COMPRESSED_SIGNED_RED_RGTC1_EXT: Each 4x4 block of texels consists of 64 bits of signed red image data. See also BC4 signed.
ext.COMPRESSED_RED_GREEN_RGTC2_EXT: Each 4x4 block of texels consists of 64 bits of compressed unsigned red image data followed by 64 bits of compressed unsigned green image data. See also BC5 unsigned.
ext.COMPRESSED_SIGNED_RED_GREEN_RGTC2_EXT: Each 4x4 block of texels consists of 64 bits of compressed signed red image data followed by 64 bits of compressed signed green image data. See also BC5 signed.

Examples

var ext = gl.getExtension('EXT_texture_compression_rgtc');

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

gl.compressedTexImage2D(gl.TEXTURE_2D, 0, ext.COMPRESSED_RED_RGTC1_EXT, 128, 128, 0, textureData);

Specifications

Specification	Status
EXT_texture_compression_rgtc	Community Approved

Browser compatibility

The compatibility table on 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
`EXT_texture_compression_rgtc`	Chrome No support No	Edge No support No	Firefox Partial support 65 Notes' Partial support 65 Notes' Notes' Only supported on macOS.	IE No support No	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android No support No	Firefox Android No support No	Opera Android No support No	Safari iOS No support No	Samsung Internet Android No support No

Legend

Partial support: Partial support
No support: No support
See implementation notes.': See implementation notes.