WEBGL compressed texture atc

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.

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

See also

• WebGLRenderingContext.getExtension()
• WebGLRenderingContext.compressedTexImage2D()
• WebGLRenderingContext.compressedTexSubImage2D()
• WebGLRenderingContext.getParameter()