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3.3 Reference Pages
</title><meta name=
"generator" content=
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"refentry" lang=
"en" xml:
lang=
"en"><a id=
"glCompressedTexImage2D"></a><div class=
"titlepage"></div><div class=
"refnamediv"><h2>Name
</h2><p>glCompressedTexImage2D — specify a two-dimensional texture image 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">glCompressedTexImage2D
</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>GLenum
</td><td><var class=
"pdparam">internalformat
</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>GLint
</td><td><var class=
"pdparam">border
</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>,
<code class=
"constant">GL_PROXY_TEXTURE_2D
</code>,
7 <code class=
"constant">GL_TEXTURE_1D_ARRAY
</code>,
<code class=
"constant">GL_PROXY_TEXTURE_1D_ARRAY
</code>,
8 <code class=
"constant">GL_TEXTURE_CUBE_MAP_POSITIVE_X
</code>,
9 <code class=
"constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_X
</code>,
10 <code class=
"constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Y
</code>,
11 <code class=
"constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Y
</code>,
12 <code class=
"constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Z
</code>,
13 <code class=
"constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Z
</code>, or
14 <code class=
"constant">GL_PROXY_TEXTURE_CUBE_MAP
</code>.
15 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>level
</code></em></span></dt><dd><p>
16 Specifies the level-of-detail number.
17 Level
0 is the base image level.
18 Level
<span class=
"emphasis"><em>n
</em></span> is the
<span class=
"emphasis"><em>n
</em></span>th mipmap reduction image.
19 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>internalformat
</code></em></span></dt><dd><p>
20 Specifies the format of the compressed image data stored at address
<em class=
"parameter"><code>data
</code></em>.
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 image.
23 All implementations support
2D texture images that are at least
64 texels
24 wide and cube-mapped texture images that are at least
16 texels wide.
25 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>height
</code></em></span></dt><dd><p>
26 Specifies the height of the texture image.
27 All implementations support
2D texture images that are at least
64 texels
28 high and cube-mapped texture images that are at least
16 texels high.
29 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>border
</code></em></span></dt><dd><p>
31 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>imageSize
</code></em></span></dt><dd><p>
32 Specifies the number of unsigned bytes of image data starting at the
33 address specified by
<em class=
"parameter"><code>data
</code></em>.
34 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>data
</code></em></span></dt><dd><p>
35 Specifies a pointer to the compressed image data in memory.
36 </p></dd></dl></div></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"description"></a><h2>Description
</h2><p>
37 Texturing allows elements of an image array to be read by shaders.
39 <code class=
"function">glCompressedTexImage2D
</code> loads a previously defined, and retrieved, compressed two-dimensional
40 texture image if
<em class=
"parameter"><code>target
</code></em> is
<code class=
"constant">GL_TEXTURE_2D
</code>, or one of the
41 cube map faces such as
<code class=
"constant">GL_TEXTURE_CUBE_MAP_POSITIVE_X
</code>.
42 (see
<a href=
"glTexImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage2D
</span></span></a>).
44 If
<em class=
"parameter"><code>target
</code></em> is
<code class=
"constant">GL_TEXTURE_1D_ARRAY
</code>,
<em class=
"parameter"><code>data
</code></em>
45 is treated as an array of compressed
1D textures.
47 If
<em class=
"parameter"><code>target
</code></em> is
<code class=
"constant">GL_PROXY_TEXTURE_2D
</code>,
<code class=
"constant">GL_PROXY_TEXTURE_1D_ARRAY
</code>
48 or
<code class=
"constant">GL_PROXY_TEXTURE_CUBE_MAP
</code>, no data is read from
<em class=
"parameter"><code>data
</code></em>, but
49 all of the texture image state is recalculated, checked for consistency,
50 and checked against the implementation's capabilities. If the
51 implementation cannot handle a texture of the requested texture size, it
52 sets all of the image state to
0, but does not generate an error (see
53 <a href=
"glGetError.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGetError
</span></span></a>). To query for an entire mipmap array,
54 use an image array level greater than or equal to
1.
56 <em class=
"parameter"><code>internalformat
</code></em> must be a known compressed image format (such as
<code class=
"constant">GL_RGTC
</code>)
57 or an extension-specified compressed-texture format.
58 When a texture is loaded with
<a href=
"glTexImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage2D
</span></span></a> using a generic compressed
59 texture format (e.g.,
<code class=
"constant">GL_COMPRESSED_RGB
</code>), the GL selects from one of
60 its extensions supporting compressed textures. In order to load the
61 compressed texture image using
<code class=
"function">glCompressedTexImage2D
</code>, query the compressed texture image's
62 size and format using
<a href=
"glGetTexLevelParameter.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGetTexLevelParameter
</span></span></a>.
64 If a non-zero named buffer object is bound to the
<code class=
"constant">GL_PIXEL_UNPACK_BUFFER
</code> target
65 (see
<a href=
"glBindBuffer.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glBindBuffer
</span></span></a>) while a texture image is
66 specified,
<em class=
"parameter"><code>data
</code></em> is treated as a byte offset into the buffer object's data store.
67 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"errors"></a><h2>Errors
</h2><p>
68 <code class=
"constant">GL_INVALID_ENUM
</code> is generated if
<em class=
"parameter"><code>internalformat
</code></em> is not one of the generic
69 compressed internal formats:
70 <code class=
"constant">GL_COMPRESSED_RED
</code>,
71 <code class=
"constant">GL_COMPRESSED_RG
</code>,
72 <code class=
"constant">GL_COMPRESSED_RGB
</code>,
73 <code class=
"constant">GL_COMPRESSED_RGBA
</code>.
74 <code class=
"constant">GL_COMPRESSED_SRGB
</code>, or
75 <code class=
"constant">GL_COMPRESSED_SRGB_ALPHA
</code>.
77 <code class=
"constant">GL_INVALID_VALUE
</code> is generated if
<em class=
"parameter"><code>imageSize
</code></em> is not consistent with
78 the format, dimensions, and contents of the specified compressed image
81 <code class=
"constant">GL_INVALID_VALUE
</code> is generated if
<em class=
"parameter"><code>border
</code></em> is not
0.
83 <code class=
"constant">GL_INVALID_OPERATION
</code> is generated if parameter combinations are not
84 supported by the specific compressed internal format as specified in the
85 specific texture compression extension.
87 <code class=
"constant">GL_INVALID_OPERATION
</code> is generated if a non-zero buffer object name is bound to the
88 <code class=
"constant">GL_PIXEL_UNPACK_BUFFER
</code> target and the buffer object's data store is currently mapped.
90 <code class=
"constant">GL_INVALID_OPERATION
</code> is generated if a non-zero buffer object name is bound to the
91 <code class=
"constant">GL_PIXEL_UNPACK_BUFFER
</code> target and the data would be unpacked from the buffer
92 object such that the memory reads required would exceed the data store size.
94 Undefined results, including abnormal program termination, are generated if
95 <em class=
"parameter"><code>data
</code></em> is not encoded in a manner consistent with the extension
96 specification defining the internal compression format.
97 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"associatedgets"></a><h2>Associated Gets
</h2><p>
98 <a href=
"glGetCompressedTexImage.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGetCompressedTexImage
</span></span></a>
100 <a href=
"glGet.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGet
</span></span></a> with argument
<code class=
"constant">GL_TEXTURE_COMPRESSED
</code>
102 <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>
104 <a href=
"glGetTexLevelParameter.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGetTexLevelParameter
</span></span></a> with arguments
<code class=
"constant">GL_TEXTURE_INTERNAL_FORMAT
</code>
105 and
<code class=
"constant">GL_TEXTURE_COMPRESSED_IMAGE_SIZE
</code>
106 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"seealso"></a><h2>See Also
</h2><p>
107 <a href=
"glActiveTexture.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glActiveTexture
</span></span></a>,
108 <a href=
"glCompressedTexImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCompressedTexImage1D
</span></span></a>,
109 <a href=
"glCompressedTexImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCompressedTexImage3D
</span></span></a>,
110 <a href=
"glCompressedTexSubImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCompressedTexSubImage1D
</span></span></a>,
111 <a href=
"glCompressedTexSubImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCompressedTexSubImage2D
</span></span></a>,
112 <a href=
"glCompressedTexSubImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCompressedTexSubImage3D
</span></span></a>,
113 <a href=
"glCopyTexImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexImage1D
</span></span></a>,
114 <a href=
"glCopyTexSubImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexSubImage1D
</span></span></a>,
115 <a href=
"glCopyTexSubImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexSubImage2D
</span></span></a>,
116 <a href=
"glCopyTexSubImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexSubImage3D
</span></span></a>,
117 <a href=
"glPixelStore.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glPixelStore
</span></span></a>,
118 <a href=
"glTexImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage2D
</span></span></a>,
119 <a href=
"glTexImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage3D
</span></span></a>,
120 <a href=
"glTexSubImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexSubImage1D
</span></span></a>,
121 <a href=
"glTexSubImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexSubImage2D
</span></span></a>,
122 <a href=
"glTexSubImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexSubImage3D
</span></span></a>,
123 <a href=
"glTexParameter.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexParameter
</span></span></a>
124 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"Copyright"></a><h2>Copyright
</h2><p>
125 Copyright
<span class=
"trademark"></span>©
1991-
2006
126 Silicon Graphics, Inc. This document is licensed under the SGI
127 Free Software B License. For details, see
128 <a href=
"http://oss.sgi.com/projects/FreeB/" target=
"_top">http://oss.sgi.com/projects/FreeB/
</a>.
129 </p></div></div></body></html>