1 <?xml version=
"1.0" encoding=
"UTF-8"?>
2 <!DOCTYPE html PUBLIC
"-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd">
3 <!-- saved from url=(0013)about:internet -->
4 <?xml-stylesheet type=
"text/xsl" href=
"mathml.xsl"?><html xmlns=
"http://www.w3.org/1999/xhtml" xmlns:
pref=
"http://www.w3.org/2002/Math/preference" pref:
renderer=
"mathplayer-dl"><head><meta http-equiv=
"Content-Type" content=
"text/html; charset=UTF-8" /><link rel=
"stylesheet" type=
"text/css" href=
"opengl-man.css" /><title>glCompressedTexImage2D - OpenGL
4 Reference Pages
</title><meta name=
"generator" content=
"DocBook XSL Stylesheets V1.69.1" /></head><body><div class=
"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 and cube map texture images that are at least
16384 texels wide.
24 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>height
</code></em></span></dt><dd><p>
25 Specifies the height of the texture image.
26 All implementations support
2D texture and cube map texture images that are at least
16384 texels high.
27 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>border
</code></em></span></dt><dd><p>
29 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>imageSize
</code></em></span></dt><dd><p>
30 Specifies the number of unsigned bytes of image data starting at the
31 address specified by
<em class=
"parameter"><code>data
</code></em>.
32 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>data
</code></em></span></dt><dd><p>
33 Specifies a pointer to the compressed image data in memory.
34 </p></dd></dl></div></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"description"></a><h2>Description
</h2><p>
35 Texturing allows elements of an image array to be read by shaders.
37 <code class=
"function">glCompressedTexImage2D
</code> loads a previously defined, and retrieved, compressed two-dimensional
38 texture image if
<em class=
"parameter"><code>target
</code></em> is
<code class=
"constant">GL_TEXTURE_2D
</code>, or one of the
39 cube map faces such as
<code class=
"constant">GL_TEXTURE_CUBE_MAP_POSITIVE_X
</code>.
40 (see
<a href=
"glTexImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage2D
</span></span></a>).
42 If
<em class=
"parameter"><code>target
</code></em> is
<code class=
"constant">GL_TEXTURE_1D_ARRAY
</code>,
<em class=
"parameter"><code>data
</code></em>
43 is treated as an array of compressed
1D textures.
45 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>
46 or
<code class=
"constant">GL_PROXY_TEXTURE_CUBE_MAP
</code>, no data is read from
<em class=
"parameter"><code>data
</code></em>, but
47 all of the texture image state is recalculated, checked for consistency,
48 and checked against the implementation's capabilities. If the
49 implementation cannot handle a texture of the requested texture size, it
50 sets all of the image state to
0, but does not generate an error (see
51 <a href=
"glGetError.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGetError
</span></span></a>). To query for an entire mipmap array,
52 use an image array level greater than or equal to
1.
54 <em class=
"parameter"><code>internalformat
</code></em> must be a known compressed image format (such as
<code class=
"constant">GL_RGTC
</code>)
55 or an extension-specified compressed-texture format.
56 When a texture is loaded with
<a href=
"glTexImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage2D
</span></span></a> using a generic compressed
57 texture format (e.g.,
<code class=
"constant">GL_COMPRESSED_RGB
</code>), the GL selects from one of
58 its extensions supporting compressed textures. In order to load the
59 compressed texture image using
<code class=
"function">glCompressedTexImage2D
</code>, query the compressed texture image's
60 size and format using
<a href=
"glGetTexLevelParameter.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGetTexLevelParameter
</span></span></a>.
62 If a non-zero named buffer object is bound to the
<code class=
"constant">GL_PIXEL_UNPACK_BUFFER
</code> target
63 (see
<a href=
"glBindBuffer.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glBindBuffer
</span></span></a>) while a texture image is
64 specified,
<em class=
"parameter"><code>data
</code></em> is treated as a byte offset into the buffer object's data store.
66 If the compressed data are arranged into fixed-size blocks of texels, the pixel
67 storage modes can be used to select a sub-rectangle from a larger containing rectangle.
68 These pixel storage modes operate in the same way as they do for
<a href=
"glTexImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage2D
</span></span></a>.
69 In the following description, denote by
<mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll"><mml:mrow><mml:msub><mml:mi>b
</mml:mi><mml:mi>s
</mml:mi></mml:msub></mml:mrow></mml:math>,
70 <mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll"><mml:mrow><mml:msub><mml:mi>b
</mml:mi><mml:mi>w
</mml:mi></mml:msub></mml:mrow></mml:math>,
71 <mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll"><mml:mrow><mml:msub><mml:mi>b
</mml:mi><mml:mi>h
</mml:mi></mml:msub></mml:mrow></mml:math>, and
72 <mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll"><mml:mrow><mml:msub><mml:mi>b
</mml:mi><mml:mi>d
</mml:mi></mml:msub></mml:mrow></mml:math>,
73 the values of pixel storage modes
<code class=
"constant">GL_UNPACK_COMPRESSED_BLOCK_SIZE
</code>,
74 <code class=
"constant">GL_UNPACK_COMPRESSED_BLOCK_WIDTH
</code>,
<code class=
"constant">GL_UNPACK_COMPRESSED_BLOCK_HEIGHT
</code>,
75 and
<code class=
"constant">GL_UNPACK_COMPRESSED_BLOCK_DEPTH
</code>, respectively.
76 <mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll"><mml:mrow><mml:msub><mml:mi>b
</mml:mi><mml:mi>s
</mml:mi></mml:msub></mml:mrow></mml:math> is
77 the compressed block size in bytes;
<mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll"><mml:mrow><mml:msub><mml:mi>b
</mml:mi><mml:mi>w
</mml:mi></mml:msub></mml:mrow></mml:math>,
78 <mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll"><mml:mrow><mml:msub><mml:mi>b
</mml:mi><mml:mi>h
</mml:mi></mml:msub></mml:mrow></mml:math>,
79 and
<mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll"><mml:mrow><mml:msub><mml:mi>b
</mml:mi><mml:mi>d
</mml:mi></mml:msub></mml:mrow></mml:math> are the compressed block width, height, and depth in pixels.
81 By default the pixel storage modes
<code class=
"constant">GL_UNPACK_ROW_LENGTH
</code>,
82 <code class=
"constant">GL_UNPACK_SKIP_ROWS
</code>,
<code class=
"constant">GL_UNPACK_SKIP_PIXELS
</code>,
83 <code class=
"constant">GL_UNPACK_IMAGE_HEIGHT
</code> and
<code class=
"constant">GL_UNPACK_SKIP_IMAGES
</code>
84 are ignored for compressed images. To enable
<code class=
"constant">GL_UNPACK_SKIP_PIXELS
</code>
85 and
<code class=
"constant">GL_UNPACK_ROW_LENGTH
</code>,
<mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll"><mml:mrow><mml:msub><mml:mi>b
</mml:mi><mml:mi>s
</mml:mi></mml:msub></mml:mrow></mml:math>
86 and
<mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll"><mml:mrow><mml:msub><mml:mi>b
</mml:mi><mml:mi>w
</mml:mi></mml:msub></mml:mrow></mml:math> must both be non-zero.
87 To also enable
<code class=
"constant">GL_UNPACK_SKIP_ROWS
</code> and
<code class=
"constant">GL_UNPACK_IMAGE_HEIGHT
</code>,
88 <mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll"><mml:mrow><mml:msub><mml:mi>b
</mml:mi><mml:mi>h
</mml:mi></mml:msub></mml:mrow></mml:math> must be non-zero.
89 To also enable
<code class=
"constant">GL_UNPACK_SKIP_IMAGES
</code>,
<mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll"><mml:mrow><mml:msub><mml:mi>b
</mml:mi><mml:mi>d
</mml:mi></mml:msub></mml:mrow></mml:math>
90 must be non-zero. All parameters must be consistent with the compressed format to produce the desired results.
92 When selecting a sub-rectangle from a compressed image:
93 </p><div class=
"itemizedlist"><ul type=
"disc"><li>the value of
<code class=
"constant">GL_UNPACK_SKIP_PIXELS
</code> must be a multiple of
<mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll"><mml:mrow><mml:msub><mml:mi>b
</mml:mi><mml:mi>w
</mml:mi></mml:msub></mml:mrow></mml:math>;
</li><li>the value of
<code class=
"constant">GL_UNPACK_SKIP_ROWS
</code> must be a multiple of
<mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll"><mml:mrow><mml:msub><mml:mi>b
</mml:mi><mml:mi>w
</mml:mi></mml:msub></mml:mrow></mml:math>.
</li></ul></div><p>
95 <em class=
"parameter"><code>imageSize
</code></em> must be equal to:
97 <mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" display=
"block" overflow=
"scroll">
103 <mml:mo lspace=
"2px" rspace=
"2px">×
</mml:mo>
104 <mml:mfenced open=
"⌈" close=
"⌉">
106 <mml:mi>width
</mml:mi>
113 <mml:mo lspace=
"2px" rspace=
"2px">×
</mml:mo>
114 <mml:mfenced open=
"⌈" close=
"⌉">
116 <mml:mi>height
</mml:mi>
125 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"notes"></a><h2>Notes
</h2><p>
126 The specific compressed internal formats
<code class=
"constant">GL_COMPRESSED_RGB8_ETC2
</code>,
127 <code class=
"constant">GL_COMPRESSED_SRGB8_ETC2
</code>,
128 <code class=
"constant">GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2
</code>,
129 <code class=
"constant">GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2
</code>,
130 <code class=
"constant">GL_COMPRESSED_RGBA8_ETC2_EAC
</code>,
131 <code class=
"constant">GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC
</code>,
132 <code class=
"constant">GL_COMPRESSED_R11_EAC
</code>,
133 <code class=
"constant">GL_COMPRESSED_SIGNED_R11_EAC
</code>,
134 <code class=
"constant">GL_COMPRESSED_RG11_EAC
</code>, and
135 <code class=
"constant">GL_COMPRESSED_SIGNED_RG11_EAC
</code> are available only if the GL version
137 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"errors"></a><h2>Errors
</h2><p>
138 <code class=
"constant">GL_INVALID_ENUM
</code> is generated if
<em class=
"parameter"><code>internalformat
</code></em> is not one of the specific
139 compressed internal formats:
140 <code class=
"constant">GL_COMPRESSED_RED_RGTC1
</code>,
141 <code class=
"constant">GL_COMPRESSED_SIGNED_RED_RGTC1
</code>,
142 <code class=
"constant">GL_COMPRESSED_RG_RGTC2
</code>,
143 <code class=
"constant">GL_COMPRESSED_SIGNED_RG_RGTC2
</code>.
144 <code class=
"constant">GL_COMPRESSED_RGBA_BPTC_UNORM
</code>,
145 <code class=
"constant">GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM
</code>,
146 <code class=
"constant">GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT
</code>,
147 <code class=
"constant">GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT
</code>,
148 <code class=
"constant">GL_COMPRESSED_RGB8_ETC2
</code>,
149 <code class=
"constant">GL_COMPRESSED_SRGB8_ETC2
</code>,
150 <code class=
"constant">GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2
</code>,
151 <code class=
"constant">GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2
</code>,
152 <code class=
"constant">GL_COMPRESSED_RGBA8_ETC2_EAC
</code>,
153 <code class=
"constant">GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC
</code>,
154 <code class=
"constant">GL_COMPRESSED_R11_EAC
</code>,
155 <code class=
"constant">GL_COMPRESSED_SIGNED_R11_EAC
</code>,
156 <code class=
"constant">GL_COMPRESSED_RG11_EAC
</code>, or
157 <code class=
"constant">GL_COMPRESSED_SIGNED_RG11_EAC
</code>.
159 <code class=
"constant">GL_INVALID_VALUE
</code> is generated if
<em class=
"parameter"><code>imageSize
</code></em> is not consistent with
160 the format, dimensions, and contents of the specified compressed image
163 <code class=
"constant">GL_INVALID_VALUE
</code> is generated if
<em class=
"parameter"><code>border
</code></em> is not
0.
165 <code class=
"constant">GL_INVALID_OPERATION
</code> is generated if parameter combinations are not
166 supported by the specific compressed internal format as specified in the
167 specific texture compression extension.
169 <code class=
"constant">GL_INVALID_OPERATION
</code> is generated if a non-zero buffer object name is bound to the
170 <code class=
"constant">GL_PIXEL_UNPACK_BUFFER
</code> target and the buffer object's data store is currently mapped.
172 <code class=
"constant">GL_INVALID_OPERATION
</code> is generated if a non-zero buffer object name is bound to the
173 <code class=
"constant">GL_PIXEL_UNPACK_BUFFER
</code> target and the data would be unpacked from the buffer
174 object such that the memory reads required would exceed the data store size.
176 Undefined results, including abnormal program termination, are generated if
177 <em class=
"parameter"><code>data
</code></em> is not encoded in a manner consistent with the extension
178 specification defining the internal compression format.
179 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"associatedgets"></a><h2>Associated Gets
</h2><p>
180 <a href=
"glGetCompressedTexImage.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGetCompressedTexImage
</span></span></a>
182 <a href=
"glGet.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGet
</span></span></a> with argument
<code class=
"constant">GL_TEXTURE_COMPRESSED
</code>
184 <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>
186 <a href=
"glGetTexLevelParameter.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGetTexLevelParameter
</span></span></a> with arguments
<code class=
"constant">GL_TEXTURE_INTERNAL_FORMAT
</code>
187 and
<code class=
"constant">GL_TEXTURE_COMPRESSED_IMAGE_SIZE
</code>
188 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"seealso"></a><h2>See Also
</h2><p>
189 <a href=
"glActiveTexture.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glActiveTexture
</span></span></a>,
190 <a href=
"glCompressedTexImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCompressedTexImage1D
</span></span></a>,
191 <a href=
"glCompressedTexImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCompressedTexImage3D
</span></span></a>,
192 <a href=
"glCompressedTexSubImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCompressedTexSubImage1D
</span></span></a>,
193 <a href=
"glCompressedTexSubImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCompressedTexSubImage2D
</span></span></a>,
194 <a href=
"glCompressedTexSubImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCompressedTexSubImage3D
</span></span></a>,
195 <a href=
"glCopyTexImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexImage1D
</span></span></a>,
196 <a href=
"glCopyTexSubImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexSubImage1D
</span></span></a>,
197 <a href=
"glCopyTexSubImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexSubImage2D
</span></span></a>,
198 <a href=
"glCopyTexSubImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexSubImage3D
</span></span></a>,
199 <a href=
"glPixelStore.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glPixelStore
</span></span></a>,
200 <a href=
"glTexImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage2D
</span></span></a>,
201 <a href=
"glTexImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage3D
</span></span></a>,
202 <a href=
"glTexSubImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexSubImage1D
</span></span></a>,
203 <a href=
"glTexSubImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexSubImage2D
</span></span></a>,
204 <a href=
"glTexSubImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexSubImage3D
</span></span></a>,
205 <a href=
"glTexParameter.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexParameter
</span></span></a>
206 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"Copyright"></a><h2>Copyright
</h2><p>
207 Copyright
<span class=
"trademark"></span>©
1991-
2006
208 Silicon Graphics, Inc.
<span class=
"trademark"></span>©
2011
209 Khronos Group. This document is licensed under the SGI
210 Free Software B License. For details, see
211 <a href=
"http://oss.sgi.com/projects/FreeB/" target=
"_top">http://oss.sgi.com/projects/FreeB/
</a>.
212 </p></div></div></body></html>