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1 | <?xml version="1.0" encoding="UTF-8"?> |
2 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd"> | |
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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>glTransformFeedbackVaryings - 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="glTransformFeedbackVaryings"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glTransformFeedbackVaryings — specify values to record in transform feedback buffers</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">glTransformFeedbackVaryings</b>(</code></td><td>GLuint </td><td><var class="pdparam">program</var>, </td></tr><tr><td> </td><td>GLsizei </td><td><var class="pdparam">count</var>, </td></tr><tr><td> </td><td>const char ** </td><td><var class="pdparam">varyings</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">bufferMode</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>program</code></em></span></dt><dd><p> | |
5 | The name of the target program object. | |
6 | </p></dd><dt><span class="term"><em class="parameter"><code>count</code></em></span></dt><dd><p> | |
7 | The number of varying variables used for transform feedback. | |
8 | </p></dd><dt><span class="term"><em class="parameter"><code>varyings</code></em></span></dt><dd><p> | |
9 | An array of <em class="parameter"><code>count</code></em> zero-terminated strings specifying the | |
10 | names of the varying variables to use for transform feedback. | |
11 | </p></dd><dt><span class="term"><em class="parameter"><code>bufferMode</code></em></span></dt><dd><p> | |
12 | Identifies the mode used to capture the varying variables when transform feedback is active. | |
13 | <em class="parameter"><code>bufferMode</code></em> must be <code class="constant">GL_INTERLEAVED_ATTRIBS</code> or <code class="constant">GL_SEPARATE_ATTRIBS</code>. | |
14 | </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p> | |
15 | The names of the vertex or geometry shader outputs to be recorded in transform feedback mode | |
16 | are specified using <code class="function">glTransformFeedbackVaryings</code>. When a geometry shader | |
17 | is active, transform feedback records the values of selected geometry shader output variables | |
18 | from the emitted vertices. Otherwise, the values of the selected vertex shader outputs are | |
19 | recorded. | |
20 | </p><p> | |
21 | The state set by <code class="function">glTranformFeedbackVaryings</code> is stored and takes effect | |
22 | next time <a href="glLinkProgram.xml"><span class="citerefentry"><span class="refentrytitle">glLinkProgram</span></span></a> is called | |
23 | on <em class="parameter"><code>program</code></em>. When <a href="glLinkProgram.xml"><span class="citerefentry"><span class="refentrytitle">glLinkProgram</span></span></a> | |
24 | is called, <em class="parameter"><code>program</code></em> is linked so that the values of the specified varying variables | |
25 | for the vertices of each primitive generated by the GL are written to a single buffer | |
26 | object if <em class="parameter"><code>bufferMode</code></em> is <code class="constant">GL_INTERLEAVED_ATTRIBS</code> or multiple | |
27 | buffer objects if <em class="parameter"><code>bufferMode</code></em> is <code class="constant">GL_SEPARATE_ATTRIBS</code>. | |
28 | </p><p> | |
29 | In addition to the errors generated by <code class="function">glTransformFeedbackVaryings</code>, the | |
30 | program <em class="parameter"><code>program</code></em> will fail to link if: | |
31 | </p><div class="itemizedlist"><ul type="disc"><li><p> | |
32 | The count specified by <code class="function">glTransformFeedbackVaryings</code> is non-zero, but the | |
33 | program object has no vertex or geometry shader. | |
34 | </p></li><li><p> | |
35 | Any variable name specified in the <em class="parameter"><code>varyings</code></em> array is not declared as an output | |
36 | in the vertex shader (or the geometry shader, if active). | |
37 | </p></li><li><p> | |
38 | Any two entries in the <em class="parameter"><code>varyings</code></em> array specify the same varying variable. | |
39 | </p></li><li><p> | |
40 | The total number of components to capture in any varying variable in <em class="parameter"><code>varyings</code></em> | |
41 | is greater than the constant <code class="constant">GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS</code> | |
42 | and the buffer mode is <code class="constant">GL_SEPARATE_ATTRIBS</code>. | |
43 | </p></li><li><p> | |
44 | The total number of components to capture is greater than the constant | |
45 | <code class="constant">GL_MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS</code> and the buffer | |
46 | mode is <code class="constant">GL_INTERLEAVED_ATTRIBS</code>. | |
47 | </p></li></ul></div><p> | |
48 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p> | |
49 | <code class="function">glGetTransformFeedbackVarying</code> is available only if the GL version is 3.0 or greater. | |
50 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p> | |
51 | <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>program</code></em> is not | |
52 | the name of a program object. | |
53 | </p><p> | |
54 | <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>bufferMode</code></em> is <code class="constant">GL_SEPARATE_ATTRIBS</code> | |
55 | and <em class="parameter"><code>count</code></em> is greater than the implementation-dependent limit <code class="constant">GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_ATTRIBS</code>. | |
56 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p> | |
57 | <a href="glGetTransformFeedbackVarying.xml"><span class="citerefentry"><span class="refentrytitle">glGetTransformFeedbackVarying</span></span></a> | |
58 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p> | |
59 | <a href="glBeginTransformFeedback.xml"><span class="citerefentry"><span class="refentrytitle">glBeginTransformFeedback</span></span></a>, | |
60 | <a href="glEndTransformFeedback.xml"><span class="citerefentry"><span class="refentrytitle">glEndTransformFeedback</span></span></a>, | |
61 | <a href="glGetTransformFeedbackVarying.xml"><span class="citerefentry"><span class="refentrytitle">glGetTransformFeedbackVarying</span></span></a> | |
62 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p> | |
63 | Copyright <span class="trademark"></span>© 2010 Khronos Group. | |
64 | This material may be distributed subject to the terms and conditions set forth in | |
65 | the Open Publication License, v 1.0, 8 June 1999. | |
66 | <a href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>. | |
67 | </p></div></div></body></html> |