<div class="refentry"><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 class="funcprototype-table" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">void <strong class="fsfunc">glBindFragDataLocation</strong>(</code></td><td>GLuint <var class="pdparam">program</var>, </td></tr><tr><td> </td><td>GLuint <var class="pdparam">colorNumber</var>, </td></tr><tr><td> </td><td>const char * <var class="pdparam">name</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a id="parameters"></a><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 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"><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 class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>

The number of active outputs is greater than the value <code class="constant">GL_MAX_DRAW_BUFFERS</code>.

</p></li><li class="listitem"><p>

More than one varying out variable is bound to the same color number.

</p></li></ul></div><p>

</p></div><div class="refsect1"><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"><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"><a id="associatedgets"></a><h2>Associated Gets</h2><p>

<a class="citerefentry" href="glGetFragDataLocation"><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>

{$pipelinestall}{$examples}

<div class="refsect1"><a id="seealso"></a><h2>See Also</h2><p>

<a class="citerefentry" href="glCreateProgram"><span class="citerefentry"><span class="refentrytitle">glCreateProgram</span></span></a>,

<a class="citerefentry" href="glGetFragDataLocation"><span class="citerefentry"><span class="refentrytitle">glGetFragDataLocation</span></span></a>

</p></div><div class="refsect1"><div id="Copyright"><h2>Copyright</h2><p>

Copyright © 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 class="ulink" href="https://opencontent.org/openpub/" target="_top">https://opencontent.org/openpub/</a>.

</p></div></div></div>