EXT_texture_compression_bptc extension

Limited availability

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

The EXT_texture_compression_bptc extension is part of the WebGL API and exposes 4 BPTC compressed texture formats. These compression formats are called BC7 and BC6H in Microsoft's DirectX API.

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

Note: 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_RGBA_BPTC_UNORM_EXT

Compresses 8-bit fixed-point data. Each 4x4 block of texels consists of 128 bits of RGBA or image data. See also BC7 format.

ext.COMPRESSED_SRGB_ALPHA_BPTC_UNORM_EXT

Compresses 8-bit fixed-point data. Each 4x4 block of texels consists of 128 bits of SRGB_ALPHA or image data. See also BC7 format.

ext.COMPRESSED_RGB_BPTC_SIGNED_FLOAT_EXT

Compresses high dynamic range signed floating point values. Each 4x4 block of texels consists of 128 bits of RGB data. It only contains RGB data, so the returned alpha value is 1.0. See also BC6H format.

ext.COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT_EXT

Compresses high dynamic range unsigned floating point values. Each 4x4 block of texels consists of 128 bits of RGB data. It only contains RGB data, so the returned alpha value is 1.0. See also BC6H format.

Examples

js
const ext = gl.getExtension("EXT_texture_compression_bptc");

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

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

Specifications

Specification
WebGL EXT_texture_compression_bptc Extension Specification

Browser compatibility

BCD tables only load in the browser

See also