WebGLRenderingContext: compressedTexSubImage2D() method
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
Note: This feature is available in Web Workers.
The compressedTexSubImage2D() method of the WebGLRenderingContext interface of the WebGL API specifies a two-dimensional sub-rectangle for a texture image in a compressed format.
Compressed image formats are only available via the WebGL2RenderingContext or some WebGL extension.
Syntax
// WebGL 1:
compressedTexSubImage2D(target, level, xoffset, yoffset, width, height, format, srcData)
// Additionally available in WebGL 2:
compressedTexSubImage2D(target, level, xoffset, yoffset, width, height, format, srcData, srcOffset)
compressedTexSubImage2D(target, level, xoffset, yoffset, width, height, format, srcData, srcOffset, srcLengthOverride)
compressedTexSubImage2D(target, level, xoffset, yoffset, width, height, format, imageSize, offset)
Parameters
target-
A
GLenumspecifying the binding point (target) of the active compressed texture. Possible values:gl.TEXTURE_2D: A two-dimensional texture.gl.TEXTURE_CUBE_MAP_POSITIVE_X: Positive X face for a cube-mapped texture.gl.TEXTURE_CUBE_MAP_NEGATIVE_X: Negative X face for a cube-mapped texture.gl.TEXTURE_CUBE_MAP_POSITIVE_Y: Positive Y face for a cube-mapped texture.gl.TEXTURE_CUBE_MAP_NEGATIVE_Y: Negative Y face for a cube-mapped texture.gl.TEXTURE_CUBE_MAP_POSITIVE_Z: Positive Z face for a cube-mapped texture.gl.TEXTURE_CUBE_MAP_NEGATIVE_Z: Negative Z face for a cube-mapped texture.
level-
A
GLintspecifying the level of detail. Level 0 is the base image level and level n is the n-th mipmap reduction level. xoffset-
A
GLintspecifying the horizontal offset within the compressed texture image. yoffset-
A
GLintspecifying the vertical offset within the compressed texture image. width-
A
GLsizeispecifying the width of the compressed texture. height-
A
GLsizeispecifying the height of the compressed texture. format-
A
GLenumspecifying the compressed image format. For a list of possible values, seeWebGLRenderingContext.compressedTexImage2D().
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
TypedArrayorDataViewcontaining the compressed texture data. srcOffsetOptional-
(WebGL 2 only) An integer specifying the index of
srcDatato start reading from. Defaults to0. srcLengthOverrideOptional-
(WebGL 2 only) An integer specifying the number of elements in
srcDatato read. Defaults tosrcData.length - srcOffset. imageSize-
(WebGL 2 only) A
GLsizeispecifying the size of the image data in bytes. offset-
(WebGL 2 only) A
GLintptrspecifying the starting address in the buffer bound togl.PIXEL_UNPACK_BUFFER.
Return value
None (undefined).
Examples
const ext =
gl.getExtension("WEBGL_compressed_texture_s3tc") ||
gl.getExtension("MOZ_WEBGL_compressed_texture_s3tc") ||
gl.getExtension("WEBKIT_WEBGL_compressed_texture_s3tc");
gl.compressedTexSubImage2D(
gl.TEXTURE_2D,
0,
256,
256,
512,
512,
ext.COMPRESSED_RGBA_S3TC_DXT5_EXT,
textureData,
);
Specifications
| Specification |
|---|
| WebGL Specification # COMPRESSEDTEXSUBIMAGE2D |
Browser compatibility
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See also
- Using WebGL extensions
WebGLRenderingContext.getExtension()WebGLRenderingContext.compressedTexImage2D()WebGL2RenderingContext.compressedTexSubImage3D()WebGL2RenderingContext.compressedTexImage3D()WEBGL_compressed_texture_s3tcWEBGL_compressed_texture_s3tc_srgbWEBGL_compressed_texture_etcWEBGL_compressed_texture_pvrtcWEBGL_compressed_texture_astcEXT_texture_compression_bptcEXT_texture_compression_rgtc