HCoop / clinton / guile-figl.git / blame
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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"> | |
| 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>glGetUniformLocation - 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="glGetUniformLocation"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glGetUniformLocation — Returns the location of a uniform variable</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">GLint <b class="fsfunc">glGetUniformLocation</b>(</code></td><td>GLuint </td><td><var class="pdparam">program</var>, </td></tr><tr><td> </td><td>const GLchar * </td><td><var class="pdparam">name</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>Specifies the program object to be | |
| 5 | queried.</p></dd><dt><span class="term"><em class="parameter"><code>name</code></em></span></dt><dd><p>Points to a null terminated string containing | |
| 6 | the name of the uniform variable whose location is | |
| 7 | to be queried.</p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p><code class="function">glGetUniformLocation </code> returns an | |
| 8 | integer that represents the location of a specific uniform | |
| 9 | variable within a program object. <em class="parameter"><code>name</code></em> | |
| 10 | must be a null terminated string that contains no white space. | |
| 11 | <em class="parameter"><code>name</code></em> must be an active uniform variable | |
| 12 | name in <em class="parameter"><code>program</code></em> that is not a structure, | |
| 13 | an array of structures, or a subcomponent of a vector or a | |
| 14 | matrix. This function returns -1 if <em class="parameter"><code>name</code></em> | |
| 15 | does not correspond to an active uniform variable in | |
| 16 | <em class="parameter"><code>program</code></em>, if <em class="parameter"><code>name</code></em> | |
| 17 | starts with the reserved prefix "gl_", or if | |
| 18 | <em class="parameter"><code>name</code></em> is associated with an atomic counter or | |
| 19 | a named uniform block.</p><p>Uniform variables that are structures or arrays of | |
| 20 | structures may be queried by calling | |
| 21 | <code class="function">glGetUniformLocation</code> for each field within | |
| 22 | the structure. The array element operator "[]" and the | |
| 23 | structure field operator "." may be used in | |
| 24 | <em class="parameter"><code>name</code></em> in order to select elements within | |
| 25 | an array or fields within a structure. The result of using these | |
| 26 | operators is not allowed to be another structure, an array of | |
| 27 | structures, or a subcomponent of a vector or a matrix. Except if | |
| 28 | the last part of <em class="parameter"><code>name</code></em> indicates a uniform | |
| 29 | variable array, the location of the first element of an array | |
| 30 | can be retrieved by using the name of the array, or by using the | |
| 31 | name appended by "[0]".</p><p>The actual locations assigned to uniform variables are not | |
| 32 | known until the program object is linked successfully. After | |
| 33 | linking has occurred, the command | |
| 34 | <code class="function">glGetUniformLocation</code> can be used to obtain | |
| 35 | the location of a uniform variable. This location value can then | |
| 36 | be passed to | |
| 37 | <a href="glUniform.xml"><span class="citerefentry"><span class="refentrytitle">glUniform</span></span></a> | |
| 38 | to set the value of the uniform variable or to | |
| 39 | <a href="glGetUniform.xml"><span class="citerefentry"><span class="refentrytitle">glGetUniform</span></span></a> | |
| 40 | in order to query the current value of the uniform variable. | |
| 41 | After a program object has been linked successfully, the index | |
| 42 | values for uniform variables remain fixed until the next link | |
| 43 | command occurs. Uniform variable locations and values can only | |
| 44 | be queried after a link if the link was successful.</p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p><code class="constant">GL_INVALID_VALUE</code> is generated if | |
| 45 | <em class="parameter"><code>program</code></em> is not a value generated by | |
| 46 | OpenGL.</p><p><code class="constant">GL_INVALID_OPERATION</code> is generated if | |
| 47 | <em class="parameter"><code>program</code></em> is not a program object.</p><p><code class="constant">GL_INVALID_OPERATION</code> is generated if | |
| 48 | <em class="parameter"><code>program</code></em> has not been successfully | |
| 49 | linked.</p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p><a href="glGetActiveUniform.xml"><span class="citerefentry"><span class="refentrytitle">glGetActiveUniform</span></span></a> | |
| 50 | with arguments <em class="parameter"><code>program</code></em> and the index of | |
| 51 | an active uniform variable</p><p><a href="glGetProgram.xml"><span class="citerefentry"><span class="refentrytitle">glGetProgram</span></span></a> | |
| 52 | with arguments <em class="parameter"><code>program</code></em> and | |
| 53 | <code class="constant">GL_ACTIVE_UNIFORMS</code> or | |
| 54 | <code class="constant">GL_ACTIVE_UNIFORM_MAX_LENGTH</code></p><p><a href="glGetUniform.xml"><span class="citerefentry"><span class="refentrytitle">glGetUniform</span></span></a> | |
| 55 | with arguments <em class="parameter"><code>program</code></em> and the name of a | |
| 56 | uniform variable</p><p><a href="glIsProgram.xml"><span class="citerefentry"><span class="refentrytitle">glIsProgram</span></span></a></p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p><a href="glLinkProgram.xml"><span class="citerefentry"><span class="refentrytitle">glLinkProgram</span></span></a>, | |
| 57 | <a href="glUniform.xml"><span class="citerefentry"><span class="refentrytitle">glUniform</span></span></a></p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p> | |
| 58 | Copyright <span class="trademark"></span>© 2003-2005 3Dlabs Inc. Ltd. | |
| 59 | <span class="trademark"></span>© 2011 Khronos Group. | |
| 60 | This material may be distributed subject to the terms and conditions set forth in | |
| 61 | the Open Publication License, v 1.0, 8 June 1999. | |
| 62 | <a href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>. | |
| 63 | </p></div></div></body></html> |