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
|
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html><html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>glGetTransformFeedbackVarying - OpenGL 4 Reference Pages</title>
<link rel="stylesheet" type="text/css" href="opengl-man.css"/>
<meta name="generator" content="DocBook XSL Stylesheets V1.78.1"/>
<script type="text/x-mathjax-config">
MathJax.Hub.Config({
MathML: {
extensions: ["content-mathml.js"]
},
tex2jax: {
inlineMath: [['$','$'], ['\\(','\\)']]
}
});
</script>
<script type="text/javascript" src="https://c328740.ssl.cf1.rackcdn.com/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML"/>
</head>
<body>
<header/>
<div class="refentry" id="glGetTransformFeedbackVarying">
<div class="titlepage"/>
<div class="refnamediv">
<h2>Name</h2>
<p>glGetTransformFeedbackVarying — retrieve information about varying variables selected for transform feedback</p>
</div>
<div class="refsynopsisdiv">
<h2>C Specification</h2>
<div class="funcsynopsis">
<table style="border: 0; cellspacing: 0; cellpadding: 0;" class="funcprototype-table">
<tr>
<td>
<code class="funcdef">void <strong class="fsfunc">glGetTransformFeedbackVarying</strong>(</code>
</td>
<td>GLuint<var class="pdparam">program</var>, </td>
</tr>
<tr>
<td> </td>
<td>GLuint<var class="pdparam">index</var>, </td>
</tr>
<tr>
<td> </td>
<td>GLsizei<var class="pdparam">bufSize</var>, </td>
</tr>
<tr>
<td> </td>
<td>GLsizei *<var class="pdparam">length</var>, </td>
</tr>
<tr>
<td> </td>
<td>GLsizei *<var class="pdparam">size</var>, </td>
</tr>
<tr>
<td> </td>
<td>GLenum *<var class="pdparam">type</var>, </td>
</tr>
<tr>
<td> </td>
<td>char *<var class="pdparam">name</var><code>)</code>;</td>
</tr>
</table>
<div class="funcprototype-spacer"> </div>
</div>
</div>
<div class="refsect1" id="parameters">
<h2>Parameters</h2>
<div class="variablelist">
<dl class="variablelist">
<dt>
<span class="term">
<em class="parameter">
<code>program</code>
</em>
</span>
</dt>
<dd>
<p>
The name of the target program object.
</p>
</dd>
<dt>
<span class="term">
<em class="parameter">
<code>index</code>
</em>
</span>
</dt>
<dd>
<p>
The index of the varying variable whose information to retrieve.
</p>
</dd>
<dt>
<span class="term">
<em class="parameter">
<code>bufSize</code>
</em>
</span>
</dt>
<dd>
<p>
The maximum number of characters, including the null terminator, that may be written into <em class="parameter"><code>name</code></em>.
</p>
</dd>
<dt>
<span class="term">
<em class="parameter">
<code>length</code>
</em>
</span>
</dt>
<dd>
<p>
The address of a variable which will receive the number of characters written into <em class="parameter"><code>name</code></em>,
excluding the null-terminator. If <em class="parameter"><code>length</code></em> is <code class="constant">NULL</code> no length is returned.
</p>
</dd>
<dt>
<span class="term">
<em class="parameter">
<code>size</code>
</em>
</span>
</dt>
<dd>
<p>
The address of a variable that will receive the size of the varying.
</p>
</dd>
<dt>
<span class="term">
<em class="parameter">
<code>type</code>
</em>
</span>
</dt>
<dd>
<p>
The address of a variable that will recieve the type of the varying.
</p>
</dd>
<dt>
<span class="term">
<em class="parameter">
<code>name</code>
</em>
</span>
</dt>
<dd>
<p>
The address of a buffer into which will be written the name of the varying.
</p>
</dd>
</dl>
</div>
</div>
<div class="refsect1" id="description">
<h2>Description</h2>
<p>
Information about the set of varying variables in a linked program that will be captured
during transform feedback may be retrieved by calling <code class="function">glGetTransformFeedbackVarying</code>.
<code class="function">glGetTransformFeedbackVarying</code> provides information about the varying
variable selected by <em class="parameter"><code>index</code></em>. An <em class="parameter"><code>index</code></em> of 0 selects
the first varying variable specified in the <em class="parameter"><code>varyings</code></em> array passed
to <a class="citerefentry" href="glTransformFeedbackVaryings.xhtml"><span class="citerefentry"><span class="refentrytitle">glTransformFeedbackVaryings</span></span></a>, and
an <em class="parameter"><code>index</code></em> of the value of
<code class="constant">GL_TRANSFORM_FEEDBACK_VARYINGS</code> minus one selects
the last such variable.
</p>
<p>
The name of the selected varying is returned as a null-terminated string in
<em class="parameter"><code>name</code></em>. The actual number of characters written into <em class="parameter"><code>name</code></em>,
excluding the null terminator, is returned in <em class="parameter"><code>length</code></em>. If <em class="parameter"><code>length</code></em>
is NULL, no length is returned. The maximum number of characters that may be written into <em class="parameter"><code>name</code></em>,
including the null terminator, is specified by <em class="parameter"><code>bufSize</code></em>.
</p>
<p>
The length of the longest varying name in program is given by <code class="constant">GL_TRANSFORM_FEEDBACK_VARYING_MAX_LENGTH</code>,
which can be queried with <a class="citerefentry" href="glGetProgram.xhtml"><span class="citerefentry"><span class="refentrytitle">glGetProgram</span></span></a>.
</p>
<p>
For the selected varying variable, its type is returned into <em class="parameter"><code>type</code></em>. The size of
the varying is returned into <em class="parameter"><code>size</code></em>. The value in <em class="parameter"><code>size</code></em> is
in units of the type returned in <em class="parameter"><code>type</code></em>. The type returned can be any of the
scalar, vector, or matrix attribute types returned by <a class="citerefentry" href="glGetActiveAttrib.xhtml"><span class="citerefentry"><span class="refentrytitle">glGetActiveAttrib</span></span></a>.
If an error occurred, the return parameters <em class="parameter"><code>length</code></em>, <em class="parameter"><code>size</code></em>,
<em class="parameter"><code>type</code></em> and <em class="parameter"><code>name</code></em> will be unmodified. This command will return as much
information about the varying variables as possible. If no information is available, <em class="parameter"><code>length</code></em>
will be set to zero and <em class="parameter"><code>name</code></em> will be an empty string. This situation could
arise if <code class="function">glGetTransformFeedbackVarying</code> is called after a failed link.
</p>
</div>
<div class="refsect1" id="errors">
<h2>Errors</h2>
<p>
<code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>program</code></em> is not
the name of a program object.
</p>
<p>
<code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>index</code></em> is greater or equal to
the value of <code class="constant">GL_TRANSFORM_FEEDBACK_VARYINGS</code>.
</p>
<p>
<code class="constant">GL_INVALID_OPERATION</code> is generated <em class="parameter"><code>program</code></em> has not been linked.
</p>
</div>
<div class="refsect1" id="associatedgets">
<h2>Associated Gets</h2>
<p>
<a class="citerefentry" href="glGetProgram.xhtml"><span class="citerefentry"><span class="refentrytitle">glGetProgram</span></span></a> with argument <code class="constant">GL_TRANSFORM_FEEDBACK_VARYING_MAX_LENGTH</code>.
</p>
</div>
<div class="refsect1" id="versions">
<h2>Version Support</h2>
<div class="informaltable">
<table style="border-collapse: collapse; border-top: 2px solid ; border-bottom: 2px solid ; border-left: 2px solid ; border-right: 2px solid ; ">
<colgroup>
<col style="text-align: left; "/>
<col style="text-align: center; " class="firstvers"/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; " class="lastvers"/>
</colgroup>
<thead>
<tr>
<th style="text-align: left; border-right: 2px solid ; ">
</th>
<th style="text-align: center; border-bottom: 2px solid ; " colspan="12">
<span class="bold"><strong>OpenGL Version</strong></span>
</th>
</tr>
<tr>
<th style="text-align: left; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>Function / Feature Name</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>2.0</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>2.1</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>3.0</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>3.1</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>3.2</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>3.3</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>4.0</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>4.1</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>4.2</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>4.3</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>4.4</strong></span>
</th>
<th style="text-align: center; border-bottom: 2px solid ; ">
<span class="bold"><strong>4.5</strong></span>
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left; border-right: 2px solid ; ">
<code class="function">glGetTransformFeedbackVarying</code>
</td>
<td style="text-align: center; border-right: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; ">✔</td>
<td style="text-align: center; ">✔</td>
</tr>
</tbody>
</table>
</div>
</div>
<div class="refsect1" id="seealso">
<h2>See Also</h2>
<p>
<a class="citerefentry" href="glBeginTransformFeedback.xhtml"><span class="citerefentry"><span class="refentrytitle">glBeginTransformFeedback</span></span></a>,
<a class="citerefentry" href="glEndTransformFeedback.xhtml"><span class="citerefentry"><span class="refentrytitle">glEndTransformFeedback</span></span></a>,
<a class="citerefentry" href="glTransformFeedbackVaryings.xhtml"><span class="citerefentry"><span class="refentrytitle">glTransformFeedbackVaryings</span></span></a>,
<a class="citerefentry" href="glGetProgram.xhtml"><span class="citerefentry"><span class="refentrytitle">glGetProgram</span></span></a>
</p>
</div>
<div class="refsect1" id="Copyright">
<h2>Copyright</h2>
<p>
Copyright <span class="trademark"/>© 2010-2014 Khronos Group.
This material may be distributed subject to the terms and conditions set forth in
the Open Publication License, v 1.0, 8 June 1999.
<a class="link" href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>.
</p>
</div>
</div>
<footer/>
</body>
</html>
|
