'\" t
.\"     Title: glGetTextureSubImage
.\"    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 "GLGETTEXTURESUBIMAGE" "3G" "05/21/2015" "[FIXME: source]" "[FIXME: manual]"
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.SH "NAME"
glGetTextureSubImage \- retrieve a sub\-region of a texture image from a texture object
.SH "C SPECIFICATION"
.HP \w'void\ glGetTextureSubImage('u
.BI "void glGetTextureSubImage(GLuint\ " "texture" ", GLint\ " "level" ", GLint\ " "xoffset" ", GLint\ " "yoffset" ", GLint\ " "zoffset" ", GLsizei\ " "width" ", GLsizei\ " "height" ", GLsizei\ " "depth" ", GLenum\ " "format" ", GLenum\ " "type" ", GLsizei\ " "bufSize" ", void\ *" "pixels" ");"
.SH "PARAMETERS"
.PP
\fItexture\fR
.RS 4
Specifies the name of the source texture object\&. Must be
\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\fR,
\fBGL_TEXTURE_CUBE_MAP_ARRAY\fR
or
\fBGL_TEXTURE_RECTANGLE\fR\&. In specific, buffer and multisample textures are not permitted\&.
.RE
.PP
\fIlevel\fR
.RS 4
Specifies the level\-of\-detail number\&. Level 0 is the base image level\&. Level $n$ is the $n$th mipmap reduction image\&.
.RE
.PP
\fIxoffset\fR
.RS 4
Specifies a texel offset in the x direction within the texture array\&.
.RE
.PP
\fIyoffset\fR
.RS 4
Specifies a texel offset in the y direction within the texture array\&.
.RE
.PP
\fIzoffset\fR
.RS 4
Specifies a texel offset in the z direction within the texture array\&.
.RE
.PP
\fIwidth\fR
.RS 4
Specifies the width of the texture subimage\&.
.RE
.PP
\fIheight\fR
.RS 4
Specifies the height of the texture subimage\&.
.RE
.PP
\fIdepth\fR
.RS 4
Specifies the depth of the texture subimage\&.
.RE
.PP
\fIformat\fR
.RS 4
Specifies the format of the pixel data\&. The following symbolic values are accepted:
\fBGL_RED\fR,
\fBGL_RG\fR,
\fBGL_RGB\fR,
\fBGL_BGR\fR,
\fBGL_RGBA\fR,
\fBGL_BGRA\fR,
\fBGL_DEPTH_COMPONENT\fR
and
\fBGL_STENCIL_INDEX\fR\&.
.RE
.PP
\fItype\fR
.RS 4
Specifies the data type of the pixel data\&. The following symbolic values are accepted:
\fBGL_UNSIGNED_BYTE\fR,
\fBGL_BYTE\fR,
\fBGL_UNSIGNED_SHORT\fR,
\fBGL_SHORT\fR,
\fBGL_UNSIGNED_INT\fR,
\fBGL_INT\fR,
\fBGL_FLOAT\fR,
\fBGL_UNSIGNED_BYTE_3_3_2\fR,
\fBGL_UNSIGNED_BYTE_2_3_3_REV\fR,
\fBGL_UNSIGNED_SHORT_5_6_5\fR,
\fBGL_UNSIGNED_SHORT_5_6_5_REV\fR,
\fBGL_UNSIGNED_SHORT_4_4_4_4\fR,
\fBGL_UNSIGNED_SHORT_4_4_4_4_REV\fR,
\fBGL_UNSIGNED_SHORT_5_5_5_1\fR,
\fBGL_UNSIGNED_SHORT_1_5_5_5_REV\fR,
\fBGL_UNSIGNED_INT_8_8_8_8\fR,
\fBGL_UNSIGNED_INT_8_8_8_8_REV\fR,
\fBGL_UNSIGNED_INT_10_10_10_2\fR, and
\fBGL_UNSIGNED_INT_2_10_10_10_REV\fR\&.
.RE
.PP
\fIbufSize\fR
.RS 4
Specifies the size of the buffer to receive the retrieved pixel data\&.
.RE
.PP
\fIpixels\fR
.RS 4
Returns the texture subimage\&. Should be a pointer to an array of the type specified by
\fItype\fR\&.
.RE
.SH "DESCRIPTION"
.PP
\fBglGetTextureSubImage\fR
returns a texture subimage into pixels\&.
.PP
\fItexture\fR
is the name of the source texture object and must not be a buffer or multisample texture\&. The effective
\fItarget\fR
parameter is the value of
\fBGL_TEXTURE_TARGET\fR
for texture\&.
\fILevel\fR,
\fIformat\fR,
\fItype\fR
and
\fIpixels\fR
have the same meaning as for
\fBglGetTexImage\fR\&.
\fIbufSize\fR
is the size of the buffer to receive the retrieved pixel data\&.
.PP
For cube map textures, the behavior is as though
\fBGetTextureImage\fR
were called, but only texels from the requested cube map faces (selected by
\fIzoffset\fR
and
\fIdepth\fR, as described below) were returned\&.
.PP
\fIxoffset\fR,
\fIyoffset\fR
and
\fIzoffset\fR
values indicate the position of the subregion to return\&.
\fIwidth\fR,
\fIheight\fR
and
\fIdepth\fR
indicate the size of the region to return\&. These parameters have the same meaning as for
\fBglTexSubImage3D\fR, though for one\- and two\-dimensional textures there are extra restrictions, described in the errors section below\&.
.PP
For one\-dimensional array textures,
\fIyoffset\fR
is interpreted as the first layer to access and
\fIheight\fR
is the number of layers to access\&.
.PP
For two\-dimensional array textures,
\fIzoffset\fR
is interpreted as the first layer to access and
\fIdepth\fR
is the number of layers to access\&.
.PP
Cube map textures are treated as an array of six slices in the z\-dimension, where the value of
\fIzoffset\fR
is interpreted as specifying the cube map face for the corresponding layer (as presented in the table below) and
\fIdepth\fR
is the number of faces to access:
.PP
.TS
allbox tab(:);
l l
l l
l l
l l
l l
l l
l l.
T{
Layer number
T}:T{
Cube Map Face
T}
T{
0
T}:T{
GL_TEXTURE_CUBE_MAP_POSITIVE_X
T}
T{
1
T}:T{
GL_TEXTURE_CUBE_MAP_NEGATIVE_X
T}
T{
2
T}:T{
GL_TEXTURE_CUBE_MAP_POSITIVE_Y
T}
T{
3
T}:T{
GL_TEXTURE_CUBE_MAP_NEGATIVE_Y
T}
T{
4
T}:T{
GL_TEXTURE_CUBE_MAP_POSITIVE_Z
T}
T{
5
T}:T{
GL_TEXTURE_CUBE_MAP_NEGATIVE_Z
T}
.TE
.PP
For cube map array textures,
\fIzoffset\fR
is the first layer\-face to access, and
\fIdepth\fR
is the number of layer\-faces to access\&. A layer\-face described by $k$ is translated into an array layer and face according to $$ layer = \eleft\elfloor { layer \eover 6 } \eright\erfloor$$ and $$ face = k \ebmod 6\&. $$
.PP
Component groups from the specified sub\-region are packed and placed into memory as described for
\fBglGetTextureImage\fR, starting with the texel at (\fIxoffset\fR,
\fIyoffset\fR,
\fIzoffset\fR)\&.
.SH "ERRORS"
.PP
\fBGL_INVALID_VALUE\fR
error is generated if
\fItexture\fR
is not the name of an existing texture object\&.
.PP
\fBGL_INVALID_OPERATION\fR
error is generated if
\fItexture\fR
is the name of a buffer or multisample texture\&.
.PP
\fBGL_INVALID_VALUE\fR
is generated if
\fIxoffset\fR,
\fIyoffset\fR
or
\fIzoffset\fR
are negative\&.
.PP
\fBGL_INVALID_VALUE\fR
is generated if
\fIxoffset\fR
+
\fIwidth\fR
is greater than the texture\*(Aqs width,
\fIyoffset\fR
+
\fIheight\fR
is greater than the texture\*(Aqs height, or
\fIzoffset\fR
+
\fIdepth\fR
is greater than the texture\*(Aqs depth\&.
.PP
\fBGL_INVALID_VALUE\fR
error is generated if the effective target is
\fBGL_TEXTURE_1D\fR
and either
\fIyoffset\fR
is not zero, or
\fIheight\fR
is not one\&.
.PP
\fBGL_INVALID_VALUE\fR
error is generated if the effective target is
\fBGL_TEXTURE_1D\fR,
\fBGL_TEXTURE_1D_ARRAY\fR,
\fBGL_TEXTURE_2D\fR
or
\fBGL_TEXTURE_RECTANGLE\fR
and either
\fIzoffset\fR
is not zero, or
\fIdepth\fR
is not one\&.
.PP
\fBGL_INVALID_OPERATION\fR
error is generated if the buffer size required to store the requested data is greater than
\fIbufSize\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.
T{
\fBglGetTextureSubImage\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
\fBglGetTexImage\fR(),
\fBglGetTextureImage\fR(),
\fBglReadPixels\fR(),
\fBglTexImage1D\fR(),
\fBglTexImage2D\fR(),
\fBglTexImage3D\fR(),
\fBglTexSubImage1D\fR(),
\fBglTexSubImage2D\fR(),
\fBglTexSubImage3D\fR()
.SH "COPYRIGHT"
.PP
Copyright
\(co
2014 Khronos Group\&. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1\&.0, 8 June 1999\&.
\m[blue]\fBhttp://opencontent\&.org/openpub/\fR\m[]\&.
.SH "COPYRIGHT"
.br
Copyright \(co 2014 Khronos Group
.br