WebGLRenderingContext: compressedTexImage2D() method

Note: This feature is available in Web Workers.

The compressedTexImage2D() method of the WebGLRenderingContext interface of the WebGL API specifies a two-dimensional texture image in a compressed format.

Compressed image formats are only available via the WebGL2RenderingContext or some WebGL extension.

Syntax

js
// WebGL 1:
compressedTexImage2D(target, level, internalformat, width, height, border, srcData)

// Additionally available in WebGL 2:
compressedTexImage2D(target, level, internalformat, width, height, border, srcData, srcOffset)
compressedTexImage2D(target, level, internalformat, width, height, border, srcData, srcOffset, srcLengthOverride)
compressedTexImage2D(target, level, internalformat, width, height, border, imageSize, offset)

Parameters

target

A GLenum specifying the binding point (target) of the active compressed texture. Possible values:

level

A GLint specifying the level of detail. Level 0 is the base image level and level n is the n-th mipmap reduction level.

internalformat

A GLenum specifying the compressed image format. Compressed image formats are only available via the WebGL2RenderingContext or some WebGL extension. Possible values:

width

A GLsizei specifying the width of the texture in texels.

height

A GLsizei specifying the height of the texture in texels.

depth

A GLsizei specifying the depth of the texture/the number of textures in a TEXTURE_2D_ARRAY.

border

A GLint specifying the width of the border. Must be 0.

The texture source can be provided in one of two ways: from an ArrayBuffer (possibly shared) using srcData, srcOffset, and srcLengthOverride; or, in WebGL 2, from gl.PIXEL_UNPACK_BUFFER using imageSize and offset.

srcData

A TypedArray or DataView containing the compressed texture data.

srcOffset Optional

(WebGL 2 only) An integer specifying the index of srcData to start reading from. Defaults to 0.

srcLengthOverride Optional

(WebGL 2 only) An integer specifying the number of elements in srcData to read. Defaults to srcData.length - srcOffset.

imageSize

(WebGL 2 only) A GLsizei specifying the size of the image data in bytes.

offset

(WebGL 2 only) A GLintptr specifying the starting address in the buffer bound to gl.PIXEL_UNPACK_BUFFER.

Return value

None (undefined).

Examples

js
const ext =
  gl.getExtension("WEBGL_compressed_texture_s3tc") ||
  gl.getExtension("MOZ_WEBGL_compressed_texture_s3tc") ||
  gl.getExtension("WEBKIT_WEBGL_compressed_texture_s3tc");

const 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

See also