Name

glCompressedTexImage2D — specify a two-dimensional texture image in a compressed format

C Specification

void glCompressedTexImage2D(GLenum target,
 GLint level,
 GLenum internalformat,
 GLsizei width,
 GLsizei height,
 GLint border,
 GLsizei imageSize,
 const GLvoid * data);
 

Parameters

target

Specifies the target texture. Must be GL_TEXTURE_2D, GL_PROXY_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, GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, or GL_PROXY_TEXTURE_CUBE_MAP.

level

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

internalformat

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

width

Specifies the width of the texture image including the border if any. If the GL version does not support non-power-of-two sizes, this value must be 2 n + 2 border for some integer n. All implementations support 2D texture images that are at least 64 texels wide and cube-mapped texture images that are at least 16 texels wide.

height

Specifies the height of the texture image including the border if any. If the GL version does not support non-power-of-two sizes, this value must be Must be 2 n + 2 border for some integer n. All implementations support 2D texture images that are at least 64 texels high and cube-mapped texture images that are at least 16 texels high.

border

Specifies the width of the border. Must be either 0 or 1.

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 maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable and disable two-dimensional texturing, call glEnable and glDisable with argument GL_TEXTURE_2D. To enable and disable texturing using cube-mapped textures, call glEnable and glDisable with argument GL_TEXTURE_CUBE_MAP.

glCompressedTexImage2D loads a previously defined, and retrieved, compressed two-dimensional texture image if target is GL_TEXTURE_2D (see glTexImage2D).

If target is GL_PROXY_TEXTURE_2D, no data is read from data, but all of the texture image state is recalculated, checked for consistency, and checked against the implementation's capabilities. If the implementation cannot handle a texture of the requested texture size, it sets all of the image state to 0, but does not generate an error (see glGetError). To query for an entire mipmap array, use an image array level greater than or equal to 1.

internalformat must be an extension-specified compressed-texture format. When a texture is loaded with glTexImage2D using a generic compressed texture format (e.g., GL_COMPRESSED_RGB), the GL selects from one of its extensions supporting compressed textures. In order to load the compressed texture image using glCompressedTexImage2D, query the compressed texture image's size and format using glGetTexLevelParameter.

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.

Notes

glCompressedTexImage2D is available only if the GL version is 1.3 or greater.

Non-power-of-two textures are supported if the GL version is 2.0 or greater, or if the implementation exports the GL_ARB_texture_non_power_of_two extension.

Errors

GL_INVALID_ENUM is generated if internalformat is one of the generic compressed internal formats: GL_COMPRESSED_ALPHA, GL_COMPRESSED_LUMINANCE, GL_COMPRESSED_LUMINANCE_ALPHA, GL_COMPRESSED_INTENSITY, GL_COMPRESSED_RGB, or GL_COMPRESSED_RGBA.

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.

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.

GL_INVALID_OPERATION is generated if glCompressedTexImage2D is executed between the execution of glBegin and the corresponding execution of glEnd.

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

glGetCompressedTexImage

glGet with argument GL_TEXTURE_COMPRESSED

glGet with argument GL_PIXEL_UNPACK_BUFFER_BINDING

glGetTexLevelParameter with arguments GL_TEXTURE_INTERNAL_FORMAT and GL_TEXTURE_COMPRESSED_IMAGE_SIZE

glIsEnabled with argument GL_TEXTURE_2D or GL_TEXTURE_CUBE_MAP

See Also

glActiveTexture, glColorTable, glCompressedTexImage1D, glCompressedTexImage3D, glCompressedTexSubImage1D, glCompressedTexSubImage2D, glCompressedTexSubImage3D, glConvolutionFilter1D, glCopyPixels, glCopyTexImage1D, glCopyTexSubImage1D, glCopyTexSubImage2D, glCopyTexSubImage3D, glDrawPixels, glMatrixMode, glPixelStore, glPixelTransfer, glTexEnv, glTexGen, glTexImage2D, glTexImage3D, glTexSubImage1D, glTexSubImage2D, glTexSubImage3D, glTexParameter

Copyright

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