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<?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>glBindFragDataLocation - 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="glBindFragDataLocation"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glBindFragDataLocation — bind a user-defined varying out variable to a fragment shader color number</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">glBindFragDataLocation</b>(</code></td><td>GLuint  </td><td><var class="pdparam">program</var>, </td></tr><tr><td> </td><td>GLuint  </td><td><var class="pdparam">colorNumber</var>, </td></tr><tr><td> </td><td>const char *  </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>
                    The name of the program containing varying out variable whose binding to modify
                </p></dd><dt><span class="term"><em class="parameter"><code>colorNumber</code></em></span></dt><dd><p>
                    The color number to bind the user-defined varying out variable to
                </p></dd><dt><span class="term"><em class="parameter"><code>name</code></em></span></dt><dd><p>
                    The name of the user-defined varying out variable whose binding to modify
                </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
            <code class="function">glBindFragDataLocation</code> explicitly specifies the binding of the user-defined varying out variable
            <em class="parameter"><code>name</code></em> to fragment shader color number <em class="parameter"><code>colorNumber</code></em> for program
            <em class="parameter"><code>program</code></em>. If <em class="parameter"><code>name</code></em> was bound previously, its assigned binding is replaced
            with <em class="parameter"><code>colorNumber</code></em>. <em class="parameter"><code>name</code></em> must be a null-terminated string. <em class="parameter"><code>colorNumber</code></em>
            must be less than <code class="constant">GL_MAX_DRAW_BUFFERS</code>.
        </p><p>
            The bindings specified by <code class="function">glBindFragDataLocation</code> have no effect until <em class="parameter"><code>program</code></em>
            is next linked. Bindings may be specified at any time after <em class="parameter"><code>program</code></em> has been created. Specifically,
            they may be specified before shader objects are attached to the program. Therefore, any name may be specified in <em class="parameter"><code>name</code></em>,
            including a name that is never used as a varying out variable in any fragment shader object. Names beginning with <code class="constant">gl_</code> are
            reserved by the GL.
        </p><p>
            In addition to the errors generated by <code class="function">glBindFragDataLocation</code>, the
            program <em class="parameter"><code>program</code></em> will fail to link if:
            </p><div class="itemizedlist"><ul type="disc"><li><p>
                        The number of active outputs is greater than the value <code class="constant">GL_MAX_DRAW_BUFFERS</code>.
                    </p></li><li><p>
                        More than one varying out variable is bound to the same color number.
                    </p></li></ul></div><p>
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
            Varying out varyings may have indexed locations assigned explicitly in the shader text using a <code class="code">location</code>
            layout qualifier. If a shader statically assigns a location to a varying out variable in the shader text,
            that location is used and any location assigned with <code class="function">glBindFragDataLocation</code> is ignored.
        </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 <em class="parameter"><code>colorNumber</code></em> is greater than or equal to <code class="constant">GL_MAX_DRAW_BUFFERS</code>.
        </p><p>
            <code class="constant">GL_INVALID_OPERATION</code> is generated if <em class="parameter"><code>name</code></em> starts with the reserved <code class="constant">gl_</code> prefix.
        </p><p>
            <code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">program</code> is not the name of a program object.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
            <a href="glGetFragDataLocation.xml"><span class="citerefentry"><span class="refentrytitle">glGetFragDataLocation</span></span></a> with a valid program object
            and the the name of a user-defined varying out variable
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
            <a href="glCreateProgram.xml"><span class="citerefentry"><span class="refentrytitle">glCreateProgram</span></span></a>,
            <a href="glGetFragDataLocation.xml"><span class="citerefentry"><span class="refentrytitle">glGetFragDataLocation</span></span></a>
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
            Copyright <span class="trademark"></span>© 2010 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 href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>.
        </p></div></div></body></html>
