glCompressedTexSubImage2D - OpenGL ES 3 Reference Pages

## Name

glCompressedTexSubImage2D — specify a two-dimensional texture subimage in a compressed format

## C Specification

`void glCompressedTexSubImage2D(` | GLenum target,
| GLint level,
| GLint xoffset,
| GLint yoffset,
| GLsizei width,
| GLsizei height,
| GLenum format,
| GLsizei imageSize,
| const GLvoid * data`)`;

## Parameters

`target`

  Specifies the target texture. Must be `GL_TEXTURE_2D`, `GL_TEXTURE_CUBE_MAP_POSITIVE_X`, `GL_TEXTURE_CUBE_MAP_NEGATIVE_X`, `GL_TEXTURE_CUBE_MAP_POSITIVE_Y`, `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y`, `GL_TEXTURE_CUBE_MAP_POSITIVE_Z`, or `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z`.

`level`

  Specifies the level-of-detail number. Level 0 is the base image level. Level n is the nth mipmap reduction image.

`xoffset`

  Specifies a texel offset in the x direction within the texture array.

`yoffset`

  Specifies a texel offset in the y direction within the texture array.

`width`

  Specifies the width of the texture subimage.

`height`

  Specifies the height of the texture subimage.

`format`

  Specifies the format of the compressed image data stored at address `data`.

`imageSize`

  Specifies the number of unsigned bytes of image data starting at the address specified by `data`.

`data`

  Specifies a pointer to the compressed image data in memory.

## Description

Texturing allows elements of an image array to be read by shaders.

`glCompressedTexSubImage2D` redefines a contiguous subregion of an existing two-dimensional texture image. The texels referenced by `data` replace the portion of the existing texture array with x indices `xoffset` and xoffset + width - 1 , and the y indices `yoffset` and yoffset + height - 1 , inclusive. This region may not include any texels outside the range of the texture array as it was originally specified. It is not an error to specify a subtexture with width of 0, but such a specification has no effect.

`format` must be a known compressed image format (such as `GL_COMPRESSED_R11_EAC`) or an extension-specified compressed-texture format.

If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER` target (see glBindBuffer) while a texture image is specified, `data` is treated as a byte offset into the buffer object's data store.

## Errors

`GL_INVALID_ENUM` is generated if `format` is not one of the specific compressed internal formats: `GL_COMPRESSED_R11_EAC`, `GL_COMPRESSED_SIGNED_R11_EAC`, `GL_COMPRESSED_RG11_EAC`, `GL_COMPRESSED_SIGNED_RG11_EAC`, `GL_COMPRESSED_RGB8_ETC2`, `GL_COMPRESSED_SRGB8_ETC2`, `GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2`, `GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2`, `GL_COMPRESSED_RGBA8_ETC2_EAC`, or `GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC`.

`GL_INVALID_VALUE` is generated if `imageSize` is not consistent with the format, dimensions, and contents of the specified compressed image data.

`GL_INVALID_OPERATION` is generated if parameter combinations are not supported by the specific compressed internal format as specified in the specific texture compression extension.

For ETC2/EAC images `GL_INVALID_OPERATION` is generated if `width` is not a multiple of four, and `width` + `xoffset` is not equal to the width of the texture level; if `height` is not a multiple of four, and `height` + `yoffset` is not equal to the height of the texture level; or if `xoffset` or `yoffset` is not a multiple of four.

`GL_INVALID_OPERATION` is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER` target and the buffer object's data store is currently mapped.

`GL_INVALID_OPERATION` is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER` target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size.

Undefined results, including abnormal program termination, are generated if `data` is not encoded in a manner consistent with the extension specification defining the internal compression format.

## Associated Gets

glGet with argument `GL_PIXEL_UNPACK_BUFFER_BINDING`

## API Version Support

| OpenGL ES API Version
--- | ---
Function Name | 2.0 | 3.0
glCompressedTexSubImage2D | ✔ | ✔

## See Also

glActiveTexture, glCompressedTexImage2D, glCompressedTexImage3D, glCompressedTexSubImage3D, glCopyTexImage2D, glCopyTexSubImage2D, glCopyTexSubImage3D, glPixelStorei, glTexImage2D, glTexImage3D, glTexSubImage2D, glTexSubImage3D, glTexParameter

## Copyright

Copyright © 1991-2006 Silicon Graphics, Inc. Copyright © 2010-2014 Khronos Group. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.