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"opengl-man.css" /><title>glCompressedTexSubImage2D
</title><meta name=
"generator" content=
"DocBook XSL Stylesheets V1.69.1" /></head><body><div class=
"refentry" lang=
"en" xml:
lang=
"en"><a id=
"glCompressedTexSubImage2D"></a><div class=
"titlepage"></div><div class=
"refnamediv"><h2>Name
</h2><p>glCompressedTexSubImage2D — specify a two-dimensional texture subimage in a compressed format
</p></div><div class=
"refsynopsisdiv"><h2>C Specification
</h2><div class=
"funcsynopsis"><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glCompressedTexSubImage2D
</b>(
</code></td><td>GLenum
</td><td><var class=
"pdparam">target
</var>,
</td></tr><tr><td> </td><td>GLint
</td><td><var class=
"pdparam">level
</var>,
</td></tr><tr><td> </td><td>GLint
</td><td><var class=
"pdparam">xoffset
</var>,
</td></tr><tr><td> </td><td>GLint
</td><td><var class=
"pdparam">yoffset
</var>,
</td></tr><tr><td> </td><td>GLsizei
</td><td><var class=
"pdparam">width
</var>,
</td></tr><tr><td> </td><td>GLsizei
</td><td><var class=
"pdparam">height
</var>,
</td></tr><tr><td> </td><td>GLenum
</td><td><var class=
"pdparam">format
</var>,
</td></tr><tr><td> </td><td>GLsizei
</td><td><var class=
"pdparam">imageSize
</var>,
</td></tr><tr><td> </td><td>const GLvoid *
</td><td><var class=
"pdparam">data
</var><code>)
</code>;
</td></tr></table></div></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"parameters"></a><h2>Parameters
</h2><div class=
"variablelist"><dl><dt><span class=
"term"><em class=
"parameter"><code>target
</code></em></span></dt><dd><p>
5 Specifies the target texture.
6 Must be
<code class=
"constant">GL_TEXTURE_2D
</code>,
7 <code class=
"constant">GL_TEXTURE_CUBE_MAP_POSITIVE_X
</code>,
8 <code class=
"constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_X
</code>,
9 <code class=
"constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Y
</code>,
10 <code class=
"constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Y
</code>,
11 <code class=
"constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Z
</code>, or
12 <code class=
"constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Z
</code>.
13 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>level
</code></em></span></dt><dd><p>
14 Specifies the level-of-detail number.
15 Level
0 is the base image level.
16 Level
<span class=
"emphasis"><em>n
</em></span> is the
<span class=
"emphasis"><em>n
</em></span>th mipmap reduction image.
17 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>xoffset
</code></em></span></dt><dd><p>
18 Specifies a texel offset in the x direction within the texture array.
19 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>yoffset
</code></em></span></dt><dd><p>
20 Specifies a texel offset in the y direction within the texture array.
21 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>width
</code></em></span></dt><dd><p>
22 Specifies the width of the texture subimage.
23 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>height
</code></em></span></dt><dd><p>
24 Specifies the height of the texture subimage.
25 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>format
</code></em></span></dt><dd><p>
26 Specifies the format of the compressed image data stored at address
<em class=
"parameter"><code>data
</code></em>.
27 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>imageSize
</code></em></span></dt><dd><p>
28 Specifies the number of unsigned bytes of image data starting at the
29 address specified by
<em class=
"parameter"><code>data
</code></em>.
30 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>data
</code></em></span></dt><dd><p>
31 Specifies a pointer to the compressed image data in memory.
32 </p></dd></dl></div></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"description"></a><h2>Description
</h2><p>
33 Texturing allows elements of an image array to be read by shaders.
35 <code class=
"function">glCompressedTexSubImage2D
</code> redefines a contiguous subregion of an existing two-dimensional
36 texture image. The texels referenced by
<em class=
"parameter"><code>data
</code></em> replace the portion of the
37 existing texture array with x indices
<em class=
"parameter"><code>xoffset
</code></em> and
38 <mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll">
41 <mml:mi mathvariant=
"italic">xoffset
</mml:mi>
43 <mml:mi mathvariant=
"italic">width
</mml:mi>
48 and the y indices
<em class=
"parameter"><code>yoffset
</code></em> and
49 <mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll">
52 <mml:mi mathvariant=
"italic">yoffset
</mml:mi>
54 <mml:mi mathvariant=
"italic">height
</mml:mi>
60 This region may not include any texels
61 outside the range of the texture array as it was originally specified. It
62 is not an error to specify a subtexture with width of
0, but such a
63 specification has no effect.
65 <em class=
"parameter"><code>internalformat
</code></em> must be a known compressed image format (such as
<code class=
"constant">GL_RGTC
</code>)
66 or an extension-specified compressed-texture format.
67 The
<em class=
"parameter"><code>format
</code></em> of the compressed texture
68 image is selected by the GL implementation that compressed it (see
69 <a href=
"glTexImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage2D
</span></span></a>) and should be queried at the time the texture was
70 compressed with
<a href=
"glGetTexLevelParameter.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGetTexLevelParameter
</span></span></a>.
72 If a non-zero named buffer object is bound to the
<code class=
"constant">GL_PIXEL_UNPACK_BUFFER
</code> target
73 (see
<a href=
"glBindBuffer.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glBindBuffer
</span></span></a>) while a texture image is
74 specified,
<em class=
"parameter"><code>data
</code></em> is treated as a byte offset into the buffer object's data store.
75 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"errors"></a><h2>Errors
</h2><p>
76 <code class=
"constant">GL_INVALID_ENUM
</code> is generated if
<em class=
"parameter"><code>internalformat
</code></em> is of the generic compressed internal formats:
77 <code class=
"constant">GL_COMPRESSED_RED
</code>,
78 <code class=
"constant">GL_COMPRESSED_RG
</code>,
79 <code class=
"constant">GL_COMPRESSED_RGB
</code>,
80 <code class=
"constant">GL_COMPRESSED_RGBA
</code>.
81 <code class=
"constant">GL_COMPRESSED_SRGB
</code>, or
82 <code class=
"constant">GL_COMPRESSED_SRGB_ALPHA
</code>.
84 <code class=
"constant">GL_INVALID_VALUE
</code> is generated if
<em class=
"parameter"><code>imageSize
</code></em> is not consistent with
85 the format, dimensions, and contents of the specified compressed image
88 <code class=
"constant">GL_INVALID_OPERATION
</code> is generated if parameter combinations are not
89 supported by the specific compressed internal format as specified in the
90 specific texture compression extension.
92 <code class=
"constant">GL_INVALID_OPERATION
</code> is generated if a non-zero buffer object name is bound to the
93 <code class=
"constant">GL_PIXEL_UNPACK_BUFFER
</code> target and the buffer object's data store is currently mapped.
95 <code class=
"constant">GL_INVALID_OPERATION
</code> is generated if a non-zero buffer object name is bound to the
96 <code class=
"constant">GL_PIXEL_UNPACK_BUFFER
</code> target and the data would be unpacked from the buffer
97 object such that the memory reads required would exceed the data store size.
99 Undefined results, including abnormal program termination, are generated if
100 <em class=
"parameter"><code>data
</code></em> is not encoded in a manner consistent with the extension
101 specification defining the internal compression format.
102 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"associatedgets"></a><h2>Associated Gets
</h2><p>
103 <a href=
"glGetCompressedTexImage.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGetCompressedTexImage
</span></span></a>
105 <a href=
"glGet.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGet
</span></span></a> with argument
<code class=
"constant">GL_TEXTURE_COMPRESSED
</code>
107 <a href=
"glGet.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGet
</span></span></a> with argument
<code class=
"constant">GL_PIXEL_UNPACK_BUFFER_BINDING
</code>
109 <a href=
"glGetTexLevelParameter.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGetTexLevelParameter
</span></span></a> with arguments
<code class=
"constant">GL_TEXTURE_INTERNAL_FORMAT
</code>
110 and
<code class=
"constant">GL_TEXTURE_COMPRESSED_IMAGE_SIZE
</code>
111 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"seealso"></a><h2>See Also
</h2><p>
112 <a href=
"glActiveTexture.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glActiveTexture
</span></span></a>,
113 <a href=
"glCompressedTexImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCompressedTexImage1D
</span></span></a>,
114 <a href=
"glCompressedTexImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCompressedTexImage2D
</span></span></a>,
115 <a href=
"glCompressedTexImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCompressedTexImage3D
</span></span></a>,
116 <a href=
"glCompressedTexSubImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCompressedTexSubImage1D
</span></span></a>,
117 <a href=
"glCompressedTexSubImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCompressedTexSubImage3D
</span></span></a>,
118 <a href=
"glCopyTexImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexImage1D
</span></span></a>,
119 <a href=
"glCopyTexImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexImage2D
</span></span></a>,
120 <a href=
"glCopyTexSubImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexSubImage1D
</span></span></a>,
121 <a href=
"glCopyTexSubImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexSubImage2D
</span></span></a>,
122 <a href=
"glCopyTexSubImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexSubImage3D
</span></span></a>,
123 <a href=
"glPixelStore.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glPixelStore
</span></span></a>,
124 <a href=
"glTexImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage2D
</span></span></a>,
125 <a href=
"glTexImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage3D
</span></span></a>,
126 <a href=
"glTexSubImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexSubImage1D
</span></span></a>,
127 <a href=
"glTexSubImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexSubImage2D
</span></span></a>,
128 <a href=
"glTexSubImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexSubImage3D
</span></span></a>,
129 <a href=
"glTexParameter.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexParameter
</span></span></a>
130 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"Copyright"></a><h2>Copyright
</h2><p>
131 Copyright
<span class=
"trademark"></span>©
1991-
2006
132 Silicon Graphics, Inc. This document is licensed under the SGI
133 Free Software B License. For details, see
134 <a href=
"http://oss.sgi.com/projects/FreeB/" target=
"_top">http://oss.sgi.com/projects/FreeB/
</a>.
135 </p></div></div></body></html>