'\" t
.\"     Title: glGetCompressedTexImage
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
.\"      Date: 05/21/2015
.\"    Manual: [FIXME: manual]
.\"    Source: [FIXME: source]
.\"  Language: English
.\"
.TH "GLGETCOMPRESSEDTEXIM" "3G" "05/21/2015" "[FIXME: source]" "[FIXME: manual]"
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.\" * MAIN CONTENT STARTS HERE *
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.SH "NAME"
glGetCompressedTexImage, glGetnCompressedTexImage, glGetCompressedTextureImage \- return a compressed texture image
.SH "C SPECIFICATION"
.HP \w'void\ glGetCompressedTexImage('u
.BI "void glGetCompressedTexImage(GLenum\ " "target" ", GLint\ " "level" ", GLvoid\ *\ " "pixels" ");"
.HP \w'void\ glGetnCompressedTexImage('u
.BI "void glGetnCompressedTexImage(GLenum\ " "target" ", GLint\ " "level" ", GLsizei\ " "bufSize" ", void\ *" "pixels" ");"
.HP \w'void\ glGetCompressedTextureImage('u
.BI "void glGetCompressedTextureImage(GLuint\ " "texture" ", GLint\ " "level" ", GLsizei\ " "bufSize" ", void\ *" "pixels" ");"
.SH "PARAMETERS"
.PP
\fItarget\fR
.RS 4
Specifies the target to which the texture is bound for
\fBglGetCompressedTexImage\fR
and
\fBglGetnCompressedTexImage\fR
functions\&.
\fBGL_TEXTURE_1D\fR,
\fBGL_TEXTURE_1D_ARRAY\fR,
\fBGL_TEXTURE_2D\fR,
\fBGL_TEXTURE_2D_ARRAY\fR,
\fBGL_TEXTURE_3D\fR,
\fBGL_TEXTURE_CUBE_MAP_ARRAY\fR,
\fBGL_TEXTURE_CUBE_MAP_POSITIVE_X\fR,
\fBGL_TEXTURE_CUBE_MAP_NEGATIVE_X\fR,
\fBGL_TEXTURE_CUBE_MAP_POSITIVE_Y\fR,
\fBGL_TEXTURE_CUBE_MAP_NEGATIVE_Y\fR,
\fBGL_TEXTURE_CUBE_MAP_POSITIVE_Z\fR, and
\fBGL_TEXTURE_CUBE_MAP_NEGATIVE_Z\fR,
\fBGL_TEXTURE_RECTANGLE\fR
are accepted\&.
.RE
.PP
\fItexture\fR
.RS 4
Specifies the texture object name for
\fBglGetCompressedTextureImage\fR
function\&.
.RE
.PP
\fIlevel\fR
.RS 4
Specifies the level\-of\-detail number of the desired image\&. Level 0 is the base image level\&. Level $n$ is the $n$\-th mipmap reduction image\&.
.RE
.PP
\fIbufSize\fR
.RS 4
Specifies the size of the buffer
\fIpixels\fR
for
\fBglGetCompressedTextureImage\fR
and
\fBglGetnCompressedTexImage\fR
functions\&.
.RE
.PP
\fIpixels\fR
.RS 4
Returns the compressed texture image\&.
.RE
.SH "DESCRIPTION"
.PP
\fBglGetCompressedTexImage\fR
and
\fBglGetnCompressedTexImage\fR
return the compressed texture image associated with
\fItarget\fR
and
\fIlod\fR
into
\fIpixels\fR\&.
\fBglGetCompressedTextureImage\fR
serves the same purpose, but instead of taking a texture target, it takes the ID of the texture object\&.
\fIpixels\fR
should be an array of
\fIbufSize\fR
bytes for
\fBglGetnCompresedTexImage\fR
and
\fBglGetCompressedTextureImage\fR
functions, and of
\fBGL_TEXTURE_COMPRESSED_IMAGE_SIZE\fR
bytes in case of
\fBglGetCompressedTexImage\fR\&. If the actual data takes less space than
\fIbufSize\fR, the remaining bytes will not be touched\&.
\fItarget\fR
specifies the texture target, to which the texture the data the function should extract the data from is bound to\&.
\fIlod\fR
specifies the level\-of\-detail number of the desired image\&.
.PP
If a non\-zero named buffer object is bound to the
\fBGL_PIXEL_PACK_BUFFER\fR
target (see
\fBglBindBuffer\fR()) while a texture image is requested,
\fIpixels\fR
is treated as a byte offset into the buffer object\*(Aqs data store\&.
.PP
To minimize errors, first verify that the texture is compressed by calling
\fBglGetTexLevelParameter\fR()
with argument
\fBGL_TEXTURE_COMPRESSED\fR\&. If the texture is compressed, you can determine the amount of memory required to store the compressed texture by calling
\fBglGetTexLevelParameter\fR()
with argument
\fBGL_TEXTURE_COMPRESSED_IMAGE_SIZE\fR\&. Finally, retrieve the internal format of the texture by calling
\fBglGetTexLevelParameter\fR()
with argument
\fBGL_TEXTURE_INTERNAL_FORMAT\fR\&. To store the texture for later use, associate the internal format and size with the retrieved texture image\&. These data can be used by the respective texture or subtexture loading routine used for loading
\fItarget\fR
textures\&.
.SH "ERRORS"
.PP
\fBGL_INVALID_OPERATION\fR
is generated by
\fBglGetCompressedTextureImage\fR
if
\fItexture\fR
is not the name of an existing texture object\&.
.PP
\fBGL_INVALID_VALUE\fR
is generated if
\fIlevel\fR
is less than zero or greater than the maximum number of LODs permitted by the implementation\&.
.PP
\fBGL_INVALID_OPERATION\fR
is generated if
\fBglGetCompressedTexImage\fR,
\fBglGetnCompressedTexImage\fR, and
\fBglGetCompressedTextureImage\fR
is used to retrieve a texture that is in an uncompressed internal format\&.
.PP
\fBGL_INVALID_OPERATION\fR
is generated if a non\-zero buffer object name is bound to the
\fBGL_PIXEL_PACK_BUFFER\fR
target, the buffer storage was not initialized with
\fBglBufferStorage\fR
using
\fBGL_MAP_PERSISTENT_BIT\fR
flag, and the buffer object\*(Aqs data store is currently mapped\&.
.PP
\fBGL_INVALID_OPERATION\fR
is generated if a non\-zero buffer object name is bound to the
\fBGL_PIXEL_PACK_BUFFER\fR
target and the data would be packed to the buffer object such that the memory writes required would exceed the data store size\&.
.SH "ASSOCIATED GETS"
.PP
\fBglGetTexLevelParameter\fR()
with argument
\fBGL_TEXTURE_COMPRESSED\fR
.PP
\fBglGetTexLevelParameter\fR()
with argument
\fBGL_TEXTURE_COMPRESSED_IMAGE_SIZE\fR
.PP
\fBglGetTexLevelParameter\fR()
with argument
\fBGL_TEXTURE_INTERNAL_FORMAT\fR
.PP
\fBglGet\fR()
with argument
\fBGL_PIXEL_PACK_BUFFER_BINDING\fR
.SH "VERSION SUPPORT"
.TS
allbox tab(:);
lB cB s s s s s s s s s s s
lB cB cB cB cB cB cB cB cB cB cB cB cB.
T{

T}:T{
\fBOpenGL Version\fR
T}
T{
\fBFunction / Feature Name\fR
T}:T{
\fB2\&.0\fR
T}:T{
\fB2\&.1\fR
T}:T{
\fB3\&.0\fR
T}:T{
\fB3\&.1\fR
T}:T{
\fB3\&.2\fR
T}:T{
\fB3\&.3\fR
T}:T{
\fB4\&.0\fR
T}:T{
\fB4\&.1\fR
T}:T{
\fB4\&.2\fR
T}:T{
\fB4\&.3\fR
T}:T{
\fB4\&.4\fR
T}:T{
\fB4\&.5\fR
T}
.T&
l c c c c c c c c c c c c
l c c c c c c c c c c c c
l c c c c c c c c c c c c.
T{
\fBglGetCompressedTexImage\fR
T}:T{
✔
T}:T{
✔
T}:T{
✔
T}:T{
✔
T}:T{
✔
T}:T{
✔
T}:T{
✔
T}:T{
✔
T}:T{
✔
T}:T{
✔
T}:T{
✔
T}:T{
✔
T}
T{
\fBglGetCompressedTextureImage\fR
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
✔
T}
T{
\fBglGetnCompressedTexImage\fR
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
\-
T}:T{
✔
T}
.TE
.sp
.SH "SEE ALSO"
.PP
\fBglActiveTexture\fR(),
\fBglCompressedTexImage1D\fR(),
\fBglCompressedTexImage2D\fR(),
\fBglCompressedTexImage3D\fR(),
\fBglCompressedTexSubImage1D\fR(),
\fBglCompressedTexSubImage2D\fR(),
\fBglCompressedTexSubImage3D\fR(),
\fBglReadPixels\fR(),
\fBglTexImage1D\fR(),
\fBglTexImage2D\fR(),
\fBglTexImage3D\fR(),
\fBglTexParameter\fR(),
\fBglTexSubImage1D\fR(),
\fBglTexSubImage2D\fR(),
\fBglTexSubImage3D\fR()
.SH "COPYRIGHT"
.PP
Copyright
\(co
1991\-2006 Silicon Graphics, Inc\&. Copyright
\(co
2010\-2014 Khronos Group\&. This document is licensed under the SGI Free Software B License\&. For details, see
\m[blue]\fBhttp://opencontent\&.org/openpub/\fR\m[]\&.
.SH "COPYRIGHT"
.br
Copyright \(co 1991-2006 Silicon Graphics, Inc.
.br
Copyright \(co 2010-2014 Khronos Group
.br