GLCOMPRESSEDTEXSUBIM(3G)

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 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 texture, call glEnable() and glDisable() with argument GL_TEXTURE_CUBE_MAP.

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 an extension-specified compressed-texture format. The format of the compressed texture image is selected by the GL implementation that compressed it (see glTexImage2D()) and should be queried at the time the texture was compressed with 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

glCompressedTexSubImage2D is available only if the GL version is 1.3 or greater.

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

ERRORS

GL_INVALID_ENUM is generated if format is one of these generic compressed internal formats: GL_COMPRESSED_ALPHA, GL_COMPRESSED_LUMINANCE, GL_COMPRESSED_LUMINANCE_ALPHA, GL_COMPRESSED_INTENSITY, GL_COMPRESSED_RGB, GL_COMPRESSED_RGBA, GL_COMPRESSED_SLUMINANCE, GL_COMPRESSED_SLUMINANCE_ALPHA, GL_COMPRESSED_SRGB, GL_COMPRESSED_SRGBA, or GL_COMPRESSED_SRGB_ALPHA.

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 glCompressedTexSubImage2D 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(), glCompressedTexImage2D(), glCompressedTexImage3D(), glCompressedTexSubImage1D(), glCompressedTexSubImage3D(), glConvolutionFilter1D(), glCopyPixels(), glCopyTexImage1D(), glCopyTexImage2D(), 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/.