1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
|
<!DOCTYPE refentry [ <!ENTITY % mathent SYSTEM "math.ent"> %mathent; ]>
<!-- Converted by db4-upgrade version 1.1 -->
<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="glGetTexLevelParameter">
<info>
<copyright>
<year>2014</year>
<holder>Khronos Group</holder>
</copyright>
</info>
<refmeta>
<refentrytitle>glGetTexLevelParameter</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>glGetTexLevelParameter</refname>
<refpurpose>return texture parameter values for a specific level of
detail</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glGetTexLevelParameterfv</function></funcdef>
<paramdef>GLenum <parameter>target</parameter></paramdef>
<paramdef>GLint <parameter>level</parameter></paramdef>
<paramdef>GLenum <parameter>pname</parameter></paramdef>
<paramdef>GLfloat * <parameter>params</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>void <function>glGetTexLevelParameteriv</function></funcdef>
<paramdef>GLenum <parameter>target</parameter></paramdef>
<paramdef>GLint <parameter>level</parameter></paramdef>
<paramdef>GLenum <parameter>pname</parameter></paramdef>
<paramdef>GLint * <parameter>params</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>void <function>glGetTextureLevelParameterfv</function></funcdef>
<paramdef>GLuint <parameter>texture</parameter></paramdef>
<paramdef>GLint <parameter>level</parameter></paramdef>
<paramdef>GLenum <parameter>pname</parameter></paramdef>
<paramdef>GLfloat *<parameter>params</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>void <function>glGetTextureLevelParameteriv</function></funcdef>
<paramdef>GLuint <parameter>texture</parameter></paramdef>
<paramdef>GLint <parameter>level</parameter></paramdef>
<paramdef>GLenum <parameter>pname</parameter></paramdef>
<paramdef>GLint *<parameter>params</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 xml:id="parameters">
<title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>target</parameter></term>
<listitem>
<para>Specifies the target to which the texture is bound for
<function>glGetTexLevelParameterfv</function> and
<function>glGetTexLevelParameteriv</function> functions. Must be one
of the following values: <constant>GL_TEXTURE_1D</constant>,
<constant>GL_TEXTURE_2D</constant>,
<constant>GL_TEXTURE_3D</constant>,
<constant>GL_TEXTURE_1D_ARRAY</constant>,
<constant>GL_TEXTURE_2D_ARRAY</constant>,
<constant>GL_TEXTURE_RECTANGLE</constant>,
<constant>GL_TEXTURE_2D_MULTISAMPLE</constant>,
<constant>GL_TEXTURE_2D_MULTISAMPLE_ARRAY</constant>,
<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_X</constant>,
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_X</constant>,
<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Y</constant>,
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</constant>,
<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Z</constant>,
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</constant>,
<constant>GL_PROXY_TEXTURE_1D</constant>,
<constant>GL_PROXY_TEXTURE_2D</constant>,
<constant>GL_PROXY_TEXTURE_3D</constant>,
<constant>GL_PROXY_TEXTURE_1D_ARRAY</constant>,
<constant>GL_PROXY_TEXTURE_2D_ARRAY</constant>,
<constant>GL_PROXY_TEXTURE_RECTANGLE</constant>,
<constant>GL_PROXY_TEXTURE_2D_MULTISAMPLE</constant>,
<constant>GL_PROXY_TEXTURE_2D_MULTISAMPLE_ARRAY</constant>,
<constant>GL_PROXY_TEXTURE_CUBE_MAP</constant>, or
<constant>GL_TEXTURE_BUFFER</constant>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>texture</parameter></term>
<listitem>
<para>Specifies the texture object name for
<function>glGetTextureLevelParameterfv</function> and
<function>glGetTextureLevelParameteriv</function> functions.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>level</parameter></term>
<listitem>
<para>
Specifies the level-of-detail number of the desired image.
Level 0 is the base image level.
Level
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
is the
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>th
mipmap reduction image.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>pname</parameter></term>
<listitem>
<para>Specifies the symbolic name of a texture parameter.
<constant>GL_TEXTURE_WIDTH</constant>,
<constant>GL_TEXTURE_HEIGHT</constant>,
<constant>GL_TEXTURE_DEPTH</constant>,
<constant>GL_TEXTURE_INTERNAL_FORMAT</constant>,
<constant>GL_TEXTURE_RED_SIZE</constant>,
<constant>GL_TEXTURE_GREEN_SIZE</constant>,
<constant>GL_TEXTURE_BLUE_SIZE</constant>,
<constant>GL_TEXTURE_ALPHA_SIZE</constant>,
<constant>GL_TEXTURE_DEPTH_SIZE</constant>,
<constant>GL_TEXTURE_COMPRESSED</constant>,
<constant>GL_TEXTURE_COMPRESSED_IMAGE_SIZE</constant>, and
<constant>GL_TEXTURE_BUFFER_OFFSET</constant> are accepted.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>params</parameter></term>
<listitem>
<para>Returns the requested data.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 xml:id="description">
<title>Description</title>
<para><function>glGetTexLevelParameterfv</function>,
<function>glGetTexLevelParameteriv</function>,
<function>glGetTextureLevelParameterfv</function> and
<function>glGetTextureLevelParameteriv</function> return in
<parameter>params</parameter> texture parameter values for a specific
level-of-detail value, specified as <parameter>level</parameter>. For the
first two functions, <parameter>target</parameter> defines the target
texture, either <constant>GL_TEXTURE_1D</constant>,
<constant>GL_TEXTURE_2D</constant>, <constant>GL_TEXTURE_3D</constant>,
<constant>GL_PROXY_TEXTURE_1D</constant>,
<constant>GL_PROXY_TEXTURE_2D</constant>,
<constant>GL_PROXY_TEXTURE_3D</constant>,
<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_X</constant>,
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_X</constant>,
<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Y</constant>,
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</constant>,
<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Z</constant>,
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</constant>, or
<constant>GL_PROXY_TEXTURE_CUBE_MAP</constant>. The remaining two take a
<parameter>texture</parameter> argument which specifies the name of the
texture object.</para>
<para><constant>GL_MAX_TEXTURE_SIZE</constant>, and
<constant>GL_MAX_3D_TEXTURE_SIZE</constant> are not really descriptive
enough. It has to report the largest square texture image that can be
accommodated with mipmaps but a long skinny texture, or a texture without
mipmaps may easily fit in texture memory. The proxy targets allow the user
to more accurately query whether the GL can accommodate a texture of a
given configuration. If the texture cannot be accommodated, the texture
state variables, which may be queried with
<function>glGetTexLevelParameter</function> and
<function>glGetTextureLevelParameter</function>, are set to 0. If the
texture can be accommodated, the texture state values will be set as they
would be set for a non-proxy target.</para>
<para><parameter>pname</parameter> specifies the texture parameter whose
value or values will be returned.</para>
<para>The accepted parameter names are as follows:</para>
<variablelist>
<varlistentry>
<term><constant>GL_TEXTURE_WIDTH</constant></term>
<listitem>
<para><parameter>params</parameter> returns a single value, the
width of the texture image. The initial value is 0.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_TEXTURE_HEIGHT</constant></term>
<listitem>
<para><parameter>params</parameter> returns a single value, the
height of the texture image. The initial value is 0.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_TEXTURE_DEPTH</constant></term>
<listitem>
<para><parameter>params</parameter> returns a single value, the
depth of the texture image. The initial value is 0.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_TEXTURE_INTERNAL_FORMAT</constant></term>
<listitem>
<para><parameter>params</parameter> returns a single value, the
internal format of the texture image.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_TEXTURE_RED_TYPE</constant>,
<constant>GL_TEXTURE_GREEN_TYPE</constant>,
<constant>GL_TEXTURE_BLUE_TYPE</constant>,
<constant>GL_TEXTURE_ALPHA_TYPE</constant>,
<constant>GL_TEXTURE_DEPTH_TYPE</constant></term>
<listitem>
<para>The data type used to store the component. The types
<constant>GL_NONE</constant>,
<constant>GL_SIGNED_NORMALIZED</constant>,
<constant>GL_UNSIGNED_NORMALIZED</constant>,
<constant>GL_FLOAT</constant>, <constant>GL_INT</constant>, and
<constant>GL_UNSIGNED_INT</constant> may be returned to indicate
signed normalized fixed-point, unsigned normalized fixed-point,
floating-point, integer unnormalized, and unsigned integer
unnormalized components, respectively.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_TEXTURE_RED_SIZE</constant>,
<constant>GL_TEXTURE_GREEN_SIZE</constant>,
<constant>GL_TEXTURE_BLUE_SIZE</constant>,
<constant>GL_TEXTURE_ALPHA_SIZE</constant>,
<constant>GL_TEXTURE_DEPTH_SIZE</constant></term>
<listitem>
<para/>
<para>The internal storage resolution of an individual component.
The resolution chosen by the GL will be a close match for the
resolution requested by the user with the component argument of
<citerefentry>
<refentrytitle>glTexImage1D</refentrytitle>
</citerefentry>, <citerefentry>
<refentrytitle>glTexImage2D</refentrytitle>
</citerefentry>, <citerefentry>
<refentrytitle>glTexImage3D</refentrytitle>
</citerefentry>, <citerefentry>
<refentrytitle>glCopyTexImage1D</refentrytitle>
</citerefentry>, and <citerefentry>
<refentrytitle>glCopyTexImage2D</refentrytitle>
</citerefentry>. The initial value is 0.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_TEXTURE_COMPRESSED</constant></term>
<listitem>
<para/>
<para><parameter>params</parameter> returns a single boolean value
indicating if the texture image is stored in a compressed internal
format. The initiali value is <constant>GL_FALSE</constant>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_TEXTURE_COMPRESSED_IMAGE_SIZE</constant></term>
<listitem>
<para/>
<para><parameter>params</parameter> returns a single integer value,
the number of unsigned bytes of the compressed texture image that
would be returned from <citerefentry>
<refentrytitle>glGetCompressedTexImage</refentrytitle>
</citerefentry>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_TEXTURE_BUFFER_OFFSET</constant></term>
<listitem>
<para/>
<para><parameter>params</parameter> returns a single integer value,
the offset into the data store of the buffer bound to a buffer
texture. <citerefentry>
<refentrytitle>glTexBufferRange</refentrytitle>
</citerefentry>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_TEXTURE_BUFFER_SIZE</constant></term>
<listitem>
<para/>
<para><parameter>params</parameter> returns a single integer value,
the size of the range of a data store of the buffer bound to a
buffer texture. <citerefentry>
<refentrytitle>glTexBufferRange</refentrytitle>
</citerefentry>.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 xml:id="notes">
<title>Notes</title>
<para>If an error is generated, no change is made to the contents of
<parameter>params</parameter>.</para>
<para><function>glGetTexLevelParameter</function> returns the texture
level parameters for the active texture unit.</para>
<para><constant>GL_TEXTURE_BUFFER_OFFSET</constant> and
<constant>GL_TEXTURE_BUFFER_SIZE</constant> are available only if the GL
version is 4.3 or greater.</para>
</refsect1>
<refsect1 xml:id="errors">
<title>Errors</title>
<para><constant>GL_INVALID_OPERATION</constant> is generated by
<function>glGetTextureLevelParameterfv</function> and
<function>glGetTextureLevelParameteriv</function> functions if
<parameter>texture</parameter> is not the name of an existing texture
object.</para>
<para><constant>GL_INVALID_ENUM</constant> is generated by
<function>glGetTexLevelParameterfv</function> and
<function>glGetTexLevelParameteriv</function> functions if
<parameter>target</parameter> or <parameter>pname</parameter> is not an
accepted value.</para>
<para><constant>GL_INVALID_VALUE</constant> is generated if
<parameter>level</parameter> is less than 0.</para>
<para><constant>GL_INVALID_VALUE</constant> may be generated if
<parameter>level</parameter> is greater than <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
<!-- eqn: log sub 2: -->
<mml:msub>
<mml:mi mathvariant="italic">log</mml:mi>
<mml:mn>2</mml:mn>
</mml:msub>
</mml:math>
</inlineequation> <emphasis>max</emphasis>, where
<emphasis>max</emphasis> is the returned value of
<constant>GL_MAX_TEXTURE_SIZE</constant>.</para>
<para><constant>GL_INVALID_VALUE</constant> is generated if
<parameter>target</parameter> is <constant>GL_TEXTURE_BUFFER</constant>
and <parameter>level</parameter> is not zero.</para>
<para><constant>GL_INVALID_OPERATION</constant> is generated if
<constant>GL_TEXTURE_COMPRESSED_IMAGE_SIZE</constant> is queried on
texture images with an uncompressed internal format or on proxy
targets.</para>
</refsect1>
<refsect1 xml:id="versions"><title>Version Support</title>
<informaltable>
<tgroup cols="13" align="left">
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apifunchead.xml" xpointer="xpointer(/*/*)"/>
<tbody>
<row>
<entry><function>glGetTexLevelParameterfv</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='20']/*)"/>
</row>
<row>
<entry><function>glGetTexLevelParameteriv</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='20']/*)"/>
</row>
<row>
<entry><function>glGetTextureLevelParameterfv</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='45']/*)"/>
</row>
<row>
<entry><function>glGetTextureLevelParameteriv</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='45']/*)"/>
</row>
</tbody>
</tgroup>
</informaltable>
</refsect1>
<refsect1 xml:id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>glActiveTexture</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glGetTexParameter</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCopyTexSubImage1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCopyTexSubImage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCopyTexSubImage3D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexSubImage1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexSubImage3D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>
</para>
</refsect1>
<refsect1 xml:id="Copyright"><title>Copyright</title>
<para>
Copyright <trademark class="copyright"/> 1991-2006
Silicon Graphics, Inc. Copyright <trademark class="copyright"/> 2010-2014
Khronos Group. This document is licensed under the SGI
Free Software B License. For details, see
<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</link>.
</para>
</refsect1>
</refentry>
|
