1991-2006
Silicon Graphics, Inc.
glCompressedTexSubImage2D
3G
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/.