HCoop / clinton / guile-figl.git / blame
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1 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd"> |
| 2 | <!-- saved from url=(0013)about:internet --> | |
| 3 | <?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" /><title>glGetUniform</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glGetUniform"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glGetUniform — Returns the value 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" style="padding-bottom: 1em"><tr><td><code class="funcdef">void <b class="fsfunc">glGetUniformfv</b>(</code></td><td>GLuint </td><td><var class="pdparam">program</var>, </td></tr><tr><td> </td><td>GLint </td><td><var class="pdparam">location</var>, </td></tr><tr><td> </td><td>GLfloat * </td><td><var class="pdparam">params</var><code>)</code>;</td></tr></table><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glGetUniformiv</b>(</code></td><td>GLuint </td><td><var class="pdparam">program</var>, </td></tr><tr><td> </td><td>GLint </td><td><var class="pdparam">location</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>program</code></em></span></dt><dd><p>Specifies the program object to be | |
| 4 | queried.</p></dd><dt><span class="term"><em class="parameter"><code>location</code></em></span></dt><dd><p>Specifies the location of the uniform variable | |
| 5 | to be queried.</p></dd><dt><span class="term"><em class="parameter"><code>params</code></em></span></dt><dd><p>Returns the value of the specified uniform | |
| 6 | variable.</p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p><code class="function">glGetUniform</code> returns in | |
| 7 | <em class="parameter"><code>params</code></em> the value(s) of the specified | |
| 8 | uniform variable. The type of the uniform variable specified by | |
| 9 | <em class="parameter"><code>location</code></em> determines the number of values | |
| 10 | returned. If the uniform variable is defined in the shader as a | |
| 11 | boolean, int, or float, a single value will be returned. If it | |
| 12 | is defined as a vec2, ivec2, or bvec2, two values will be | |
| 13 | returned. If it is defined as a vec3, ivec3, or bvec3, three | |
| 14 | values will be returned, and so on. To query values stored in | |
| 15 | uniform variables declared as arrays, call | |
| 16 | <code class="function">glGetUniform</code> for each element of the array. | |
| 17 | To query values stored in uniform variables declared as | |
| 18 | structures, call <code class="function">glGetUniform</code> for each | |
| 19 | field in the structure. The values for uniform variables | |
| 20 | declared as a matrix will be returned in column major | |
| 21 | order.</p><p>The locations assigned to uniform variables are not known | |
| 22 | until the program object is linked. After linking has occurred, | |
| 23 | the command | |
| 24 | <a class="citerefentry" href="glGetUniformLocation.xml"><span class="citerefentry"><span class="refentrytitle">glGetUniformLocation</span></span></a> | |
| 25 | can be used to obtain the location of a uniform variable. This | |
| 26 | location value can then be passed to | |
| 27 | <code class="function">glGetUniform</code> in order to query the current | |
| 28 | value of the uniform variable. After a program object has been | |
| 29 | linked successfully, the index values for uniform variables | |
| 30 | remain fixed until the next link command occurs. The uniform | |
| 31 | variable values can only be queried after a link if the link was | |
| 32 | successful.</p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p><code class="function">glGetUniform</code> is available only if the | |
| 33 | GL version is 2.0 or greater.</p><p>If an error is generated, no change is made to the | |
| 34 | contents of <em class="parameter"><code>params</code></em>.</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 | |
| 35 | <em class="parameter"><code>program</code></em> is not a value generated by | |
| 36 | OpenGL.</p><p><code class="constant">GL_INVALID_OPERATION</code> is generated if | |
| 37 | <em class="parameter"><code>program</code></em> is not a program object.</p><p><code class="constant">GL_INVALID_OPERATION</code> is generated if | |
| 38 | <em class="parameter"><code>program</code></em> has not been successfully | |
| 39 | linked.</p><p><code class="constant">GL_INVALID_OPERATION</code> is generated if | |
| 40 | <em class="parameter"><code>location</code></em> does not correspond to a valid | |
| 41 | uniform variable location for the specified program object.</p><p><code class="constant">GL_INVALID_OPERATION</code> is generated if | |
| 42 | <code class="function">glGetUniform</code> is executed between the | |
| 43 | execution of | |
| 44 | <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a> | |
| 45 | and the corresponding execution of | |
| 46 | <a class="citerefentry" href="glEnd.xml"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>.</p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p><a class="citerefentry" href="glGetActiveUniform.xml"><span class="citerefentry"><span class="refentrytitle">glGetActiveUniform</span></span></a> | |
| 47 | with arguments <em class="parameter"><code>program</code></em> and the index of an active | |
| 48 | uniform variable</p><p><a class="citerefentry" href="glGetProgram.xml"><span class="citerefentry"><span class="refentrytitle">glGetProgram</span></span></a> | |
| 49 | with arguments <em class="parameter"><code>program</code></em> and | |
| 50 | <code class="constant">GL_ACTIVE_UNIFORMS</code> or | |
| 51 | <code class="constant">GL_ACTIVE_UNIFORM_MAX_LENGTH</code></p><p><a class="citerefentry" href="glGetUniformLocation.xml"><span class="citerefentry"><span class="refentrytitle">glGetUniformLocation</span></span></a> | |
| 52 | with arguments <em class="parameter"><code>program</code></em> and the name of a | |
| 53 | uniform variable</p><p><a class="citerefentry" 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 class="citerefentry" href="glCreateProgram.xml"><span class="citerefentry"><span class="refentrytitle">glCreateProgram</span></span></a>, | |
| 54 | <a class="citerefentry" href="glLinkProgram.xml"><span class="citerefentry"><span class="refentrytitle">glLinkProgram</span></span></a>, | |
| 55 | <a class="citerefentry" 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> | |
| 56 | Copyright <span class="trademark"></span>© 2003-2005 3Dlabs Inc. Ltd. | |
| 57 | This material may be distributed subject to the terms and conditions set forth in | |
| 58 | the Open Publication License, v 1.0, 8 June 1999. | |
| 59 | <a class="ulink" href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>. | |
| 60 | </p></div></div></body></html> |