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renderer=
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"text/html; charset=UTF-8" /><title>glGetTexLevelParameter
</title><meta name=
"generator" content=
"DocBook XSL Stylesheets V1.73.2" /></head><body><div class=
"refentry" lang=
"en" xml:
lang=
"en"><a id=
"glGetTexLevelParameter"></a><div class=
"titlepage"></div><div class=
"refnamediv"><h2>Name
</h2><p>glGetTexLevelParameter — return texture parameter values for a specific level of detail
</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">glGetTexLevelParameterfv
</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">pname
</var>,
</td></tr><tr><td> </td><td>GLfloat *
</td><td><var class=
"pdparam">params
</var><code>)
</code>;
</td></tr></table></div><div class=
"funcsynopsis"><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glGetTexLevelParameteriv
</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">pname
</var>,
</td></tr><tr><td> </td><td>GLint *
</td><td><var class=
"pdparam">params
</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>
4 Specifies the symbolic name of the target texture,
5 either
<code class=
"constant">GL_TEXTURE_1D
</code>,
<code class=
"constant">GL_TEXTURE_2D
</code>,
<code class=
"constant">GL_TEXTURE_3D
</code>,
6 <code class=
"constant">GL_PROXY_TEXTURE_1D
</code>,
<code class=
"constant">GL_PROXY_TEXTURE_2D
</code>,
7 <code class=
"constant">GL_PROXY_TEXTURE_3D
</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 of the desired image.
17 Level
0 is the base image level.
19 <mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll"><mml:mi mathvariant=
"italic">n
</mml:mi></mml:math>
21 <mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll"><mml:mi mathvariant=
"italic">n
</mml:mi></mml:math>th
22 mipmap reduction image.
23 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>pname
</code></em></span></dt><dd><p>
24 Specifies the symbolic name of a texture parameter.
25 <code class=
"constant">GL_TEXTURE_WIDTH
</code>,
26 <code class=
"constant">GL_TEXTURE_HEIGHT
</code>,
27 <code class=
"constant">GL_TEXTURE_DEPTH
</code>,
28 <code class=
"constant">GL_TEXTURE_INTERNAL_FORMAT
</code>,
29 <code class=
"constant">GL_TEXTURE_BORDER
</code>,
30 <code class=
"constant">GL_TEXTURE_RED_SIZE
</code>,
31 <code class=
"constant">GL_TEXTURE_GREEN_SIZE
</code>,
32 <code class=
"constant">GL_TEXTURE_BLUE_SIZE
</code>,
33 <code class=
"constant">GL_TEXTURE_ALPHA_SIZE
</code>,
34 <code class=
"constant">GL_TEXTURE_LUMINANCE_SIZE
</code>,
35 <code class=
"constant">GL_TEXTURE_INTENSITY_SIZE
</code>,
36 <code class=
"constant">GL_TEXTURE_DEPTH_SIZE
</code>,
37 <code class=
"constant">GL_TEXTURE_COMPRESSED
</code>, and
38 <code class=
"constant">GL_TEXTURE_COMPRESSED_IMAGE_SIZE
</code>
40 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>params
</code></em></span></dt><dd><p>
41 Returns the requested data.
42 </p></dd></dl></div></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"description"></a><h2>Description
</h2><p>
43 <code class=
"function">glGetTexLevelParameter
</code> returns in
<em class=
"parameter"><code>params
</code></em> texture parameter values for a specific
44 level-of-detail value,
45 specified as
<em class=
"parameter"><code>level
</code></em>.
46 <em class=
"parameter"><code>target
</code></em> defines the target texture,
47 either
<code class=
"constant">GL_TEXTURE_1D
</code>,
<code class=
"constant">GL_TEXTURE_2D
</code>,
<code class=
"constant">GL_TEXTURE_3D
</code>,
48 <code class=
"constant">GL_PROXY_TEXTURE_1D
</code>,
49 <code class=
"constant">GL_PROXY_TEXTURE_2D
</code>,
50 <code class=
"constant">GL_PROXY_TEXTURE_3D
</code>,
51 <code class=
"constant">GL_TEXTURE_CUBE_MAP_POSITIVE_X
</code>,
52 <code class=
"constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_X
</code>,
53 <code class=
"constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Y
</code>,
54 <code class=
"constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Y
</code>,
55 <code class=
"constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Z
</code>,
56 <code class=
"constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Z
</code>, or
57 <code class=
"constant">GL_PROXY_TEXTURE_CUBE_MAP
</code>.
59 <code class=
"constant">GL_MAX_TEXTURE_SIZE
</code>, and
<code class=
"constant">GL_MAX_3D_TEXTURE_SIZE
</code> are not really
61 It has to report the largest square texture image that can be
62 accommodated with mipmaps and borders,
63 but a long skinny texture, or a texture without mipmaps and borders, may
64 easily fit in texture memory.
65 The proxy targets allow the user to more accurately query
66 whether the GL can accommodate a texture of a given configuration.
67 If the texture cannot be accommodated, the texture state variables, which
68 may be queried with
<code class=
"function">glGetTexLevelParameter
</code>, are set to
0. If the texture can be accommodated,
69 the texture state values will be set as they would be set for a
72 <em class=
"parameter"><code>pname
</code></em> specifies the texture parameter whose value or values
75 The accepted parameter names are as follows:
76 </p><div class=
"variablelist"><dl><dt><span class=
"term"><code class=
"constant">GL_TEXTURE_WIDTH
</code></span></dt><dd><p>
78 <em class=
"parameter"><code>params
</code></em> returns a single value,
79 the width of the texture image.
80 This value includes the border of the texture image. The initial value is
82 </p></dd><dt><span class=
"term"><code class=
"constant">GL_TEXTURE_HEIGHT
</code></span></dt><dd><p>
84 <em class=
"parameter"><code>params
</code></em> returns a single value,
85 the height of the texture image.
86 This value includes the border of the texture image. The initial value is
88 </p></dd><dt><span class=
"term"><code class=
"constant">GL_TEXTURE_DEPTH
</code></span></dt><dd><p>
90 <em class=
"parameter"><code>params
</code></em> returns a single value,
91 the depth of the texture image.
92 This value includes the border of the texture image. The initial value is
94 </p></dd><dt><span class=
"term"><code class=
"constant">GL_TEXTURE_INTERNAL_FORMAT
</code></span></dt><dd><p>
96 <em class=
"parameter"><code>params
</code></em> returns a single value,
97 the internal format of the texture image.
98 </p></dd><dt><span class=
"term"><code class=
"constant">GL_TEXTURE_BORDER
</code></span></dt><dd><p>
100 <em class=
"parameter"><code>params
</code></em> returns a single value,
101 the width in pixels of the border of the texture image. The initial value
103 </p></dd><dt><span class=
"term"><code class=
"constant">GL_TEXTURE_RED_SIZE
</code>,
</span></dt><dd></dd><dt><span class=
"term"><code class=
"constant">GL_TEXTURE_GREEN_SIZE
</code>,
</span></dt><dd></dd><dt><span class=
"term"><code class=
"constant">GL_TEXTURE_BLUE_SIZE
</code>,
</span></dt><dd></dd><dt><span class=
"term"><code class=
"constant">GL_TEXTURE_ALPHA_SIZE
</code>,
</span></dt><dd></dd><dt><span class=
"term"><code class=
"constant">GL_TEXTURE_LUMINANCE_SIZE
</code>,
</span></dt><dd></dd><dt><span class=
"term"><code class=
"constant">GL_TEXTURE_INTENSITY_SIZE
</code>,
</span></dt><dd></dd><dt><span class=
"term"><code class=
"constant">GL_TEXTURE_DEPTH_SIZE
</code></span></dt><dd><p>
105 The internal storage resolution of an individual component.
106 The resolution chosen by the GL will be a close match for the resolution
107 requested by the user with the component argument of
<a class=
"citerefentry" href=
"glTexImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage1D
</span></span></a>,
108 <a class=
"citerefentry" href=
"glTexImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage2D
</span></span></a>,
<a class=
"citerefentry" href=
"glTexImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage3D
</span></span></a>,
<a class=
"citerefentry" href=
"glCopyTexImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexImage1D
</span></span></a>, and
109 <a class=
"citerefentry" href=
"glCopyTexImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexImage2D
</span></span></a>. The initial value is
0.
110 </p></dd><dt><span class=
"term"><code class=
"constant">GL_TEXTURE_COMPRESSED
</code></span></dt><dd><p>
112 <em class=
"parameter"><code>params
</code></em> returns a single boolean value indicating if the texture image is
113 stored in a compressed internal format. The initiali value is
<code class=
"constant">GL_FALSE
</code>.
114 </p></dd><dt><span class=
"term"><code class=
"constant">GL_TEXTURE_COMPRESSED_IMAGE_SIZE
</code></span></dt><dd><p>
116 <em class=
"parameter"><code>params
</code></em> returns a single integer value, the number of unsigned bytes of the
117 compressed texture image that would be returned from
118 <a class=
"citerefentry" href=
"glGetCompressedTexImage.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGetCompressedTexImage
</span></span></a>.
119 </p></dd></dl></div></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"notes"></a><h2>Notes
</h2><p>
120 If an error is generated,
121 no change is made to the contents of
<em class=
"parameter"><code>params
</code></em>.
123 <code class=
"constant">GL_TEXTURE_INTERNAL_FORMAT
</code> is available only if the GL version is
124 1.1 or greater. In version
1.0, use
<code class=
"constant">GL_TEXTURE_COMPONENTS
</code>
127 <code class=
"constant">GL_PROXY_TEXTURE_1D
</code> and
<code class=
"constant">GL_PROXY_TEXTURE_2D
</code> are
128 available only if the GL version is
1.1 or greater.
130 <code class=
"constant">GL_TEXTURE_3D
</code>,
<code class=
"constant">GL_PROXY_TEXTURE_3D
</code>, and
<code class=
"constant">GL_TEXTURE_DEPTH
</code>
131 are available only if the GL version is
1.2 or greater.
133 <code class=
"constant">GL_TEXTURE_COMPRESSED
</code>,
134 <code class=
"constant">GL_TEXTURE_COMPRESSED_IMAGE_SIZE
</code>,
135 <code class=
"constant">GL_TEXTURE_CUBE_MAP_POSITIVE_X
</code>,
136 <code class=
"constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_X
</code>,
137 <code class=
"constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Y
</code>,
138 <code class=
"constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Y
</code>,
139 <code class=
"constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Z
</code>,
140 <code class=
"constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Z
</code>, and
141 <code class=
"constant">GL_PROXY_TEXTURE_CUBE_MAP
</code> are available only if the GL version is
1.3
144 For OpenGL versions
1.3 and greater, or when the
<code class=
"code">ARB_multitexture
</code> extension is supported,
<code class=
"function">glGetTexLevelParameter
</code> returns
145 the texture level parameters for the active texture unit.
146 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"errors"></a><h2>Errors
</h2><p>
147 <code class=
"constant">GL_INVALID_ENUM
</code> is generated if
<em class=
"parameter"><code>target
</code></em> or
<em class=
"parameter"><code>pname
</code></em> is not an
150 <code class=
"constant">GL_INVALID_VALUE
</code> is generated if
<em class=
"parameter"><code>level
</code></em> is less than
0.
152 <code class=
"constant">GL_INVALID_VALUE
</code> may be generated if
<em class=
"parameter"><code>level
</code></em> is greater
154 <mml:math xmlns:
mml=
"http://www.w3.org/1998/Math/MathML" overflow=
"scroll">
156 <mml:msub><mml:mi mathvariant=
"italic">log
</mml:mi>
160 <span class=
"emphasis"><em>max
</em></span>,
161 where
<span class=
"emphasis"><em>max
</em></span> is the returned value of
<code class=
"constant">GL_MAX_TEXTURE_SIZE
</code>.
163 <code class=
"constant">GL_INVALID_OPERATION
</code> is generated if
<code class=
"function">glGetTexLevelParameter
</code>
164 is executed between the execution of
<a class=
"citerefentry" href=
"glBegin.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glBegin
</span></span></a>
165 and the corresponding execution of
<a class=
"citerefentry" href=
"glEnd.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glEnd
</span></span></a>.
167 <code class=
"constant">GL_INVALID_OPERATION
</code> is generated if
168 <code class=
"constant">GL_TEXTURE_COMPRESSED_IMAGE_SIZE
</code> is queried on texture images with an
169 uncompressed internal format or on proxy targets.
170 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"seealso"></a><h2>See Also
</h2><p>
171 <a class=
"citerefentry" href=
"glActiveTexture.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glActiveTexture
</span></span></a>,
172 <a class=
"citerefentry" href=
"glGetTexParameter.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGetTexParameter
</span></span></a>,
173 <a class=
"citerefentry" href=
"glCopyTexImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexImage1D
</span></span></a>,
174 <a class=
"citerefentry" href=
"glCopyTexImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexImage2D
</span></span></a>,
175 <a class=
"citerefentry" href=
"glCopyTexSubImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexSubImage1D
</span></span></a>,
176 <a class=
"citerefentry" href=
"glCopyTexSubImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexSubImage2D
</span></span></a>,
177 <a class=
"citerefentry" href=
"glCopyTexSubImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glCopyTexSubImage3D
</span></span></a>,
178 <a class=
"citerefentry" href=
"glTexEnv.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexEnv
</span></span></a>,
179 <a class=
"citerefentry" href=
"glTexGen.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexGen
</span></span></a>,
180 <a class=
"citerefentry" href=
"glTexImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage1D
</span></span></a>,
181 <a class=
"citerefentry" href=
"glTexImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage2D
</span></span></a>,
182 <a class=
"citerefentry" href=
"glTexImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexImage3D
</span></span></a>,
183 <a class=
"citerefentry" href=
"glTexSubImage1D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexSubImage1D
</span></span></a>,
184 <a class=
"citerefentry" href=
"glTexSubImage2D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexSubImage2D
</span></span></a>,
185 <a class=
"citerefentry" href=
"glTexSubImage3D.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexSubImage3D
</span></span></a>,
186 <a class=
"citerefentry" href=
"glTexParameter.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glTexParameter
</span></span></a>
187 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"Copyright"></a><h2>Copyright
</h2><p>
188 Copyright
<span class=
"trademark"></span>©
1991-
2006
189 Silicon Graphics, Inc. This document is licensed under the SGI
190 Free Software B License. For details, see
191 <a class=
"ulink" href=
"http://oss.sgi.com/projects/FreeB/" target=
"_top">http://oss.sgi.com/projects/FreeB/
</a>.
192 </p></div></div></body></html>