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 of the active texture unit. 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.

internalformat

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

width

Specifies the width of the texture image. 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. 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 0.

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 active. Texturing is active when the current fragment shader or vertex shader makes use of built-in texture lookup functions.

glCompressedTexImage2D defines a two-dimensional texture image or cube-map texture image using compressed image data from client memory. The texture image is decoded according to the extension specification defining the specified internalformat. OpenGL ES defines no specific compressed texture formats, but does provide a mechanism to obtain symbolic constants for such formats provided by extensions. The number of compressed texture formats supported can be obtained by querying the value of GL_NUM_COMPRESSED_TEXTURE_FORMATS. The list of specific compressed texture formats supported can be obtained by querying the value of GL_COMPRESSED_TEXTURE_FORMATS.

Notes

A GL implementation may choose to store the texture array at any internal resolution it chooses.

glCompressedTexImage2D specifies a two-dimensional or cube-map texture for the current texture unit, specified with glActiveTexture.

Errors

GL_INVALID_ENUM is generated if target is not 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.

GL_INVALID_ENUM is generated if internalformat is not a supported format returned in GL_COMPRESSED_TEXTURE_FORMATS.

GL_INVALID_VALUE is generated if level is less than 0.

GL_INVALID_VALUE may be generated if level is greater than log 2 max , where max is the returned value of GL_MAX_TEXTURE_SIZE when target is GL_TEXTURE_2D or GL_MAX_CUBE_MAP_TEXTURE_SIZE when target is not GL_TEXTURE_2D.

GL_INVALID_VALUE is generated if width or height is less than 0 or greater than GL_MAX_TEXTURE_SIZE when target is GL_TEXTURE_2D or GL_MAX_CUBE_MAP_TEXTURE_SIZE when target is not GL_TEXTURE_2D.

GL_INVALID_VALUE is generated if border is not 0.

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.

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 arguments GL_NUM_COMPRESSED_TEXTURE_FORMATS and GL_COMPRESSED_TEXTURE_FORMATS

glGet with argument GL_MAX_TEXTURE_SIZE or GL_MAX_CUBE_MAP_TEXTURE_SIZE

See Also

glActiveTexture, glCompressedTexSubImage2D, glCopyTexImage2D, glCopyTexSubImage2D, glTexImage2D, glTexSubImage2D, 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/.