WEBGL_compressed_texture_atc

Deprecated

This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

The WEBGL_compressed_texture_atc extension is part of the WebGL API and exposes 3 ATC compressed texture formats. ATC is a proprietary compression algorithm for compressing textures on handheld devices.

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: ATC compression is typically available on mobile devices with Adreno GPUs, that are currently only built into Qualcomm Snapdragon devices.

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

Constants

The compressed texture formats are exposed by 3 constants and can be used in two functions: compressedTexImage2D() and compressedTexSubImage2D().

ext.COMPRESSED_RGB_ATC_WEBGL
Compresses RGB textures with no alpha channel.
ext.COMPRESSED_RGBA_ATC_EXPLICIT_ALPHA_WEBGL
Compresses RGBA textures using explicit alpha encoding (useful when alpha transitions are sharp).
ext.COMPRESSED_RGBA_ATC_INTERPOLATED_ALPHA_WEBGL
Compresses RGBA textures using interpolated alpha encoding (useful when alpha transitions are gradient).

Examples

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

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

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

Specifications

Specification Status Comment
WEBGL_compressed_texture_atc
The definition of 'WEBGL_compressed_texture_atc' in that specification.
Draft Initial definition.

Browser compatibility

BCD tables only load in the browser

See also