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<!DOCTYPE refentry [ <!ENTITY % mathent SYSTEM "math.ent"> %mathent; ]>
<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="glClearBuffer">
<info>
<copyright>
<year>2010-2014</year>
<holder>Khronos Group</holder>
</copyright>
</info>
<refmeta>
<refentrytitle>glClearBuffer</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>glClearBuffer</refname>
<refpurpose>clear individual buffers of a framebuffer</refpurpose>
</refnamediv>
<refsynopsisdiv><title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glClearBufferiv</function></funcdef>
<paramdef>GLenum <parameter>buffer</parameter></paramdef>
<paramdef>GLint <parameter>drawbuffer</parameter></paramdef>
<paramdef>const GLint * <parameter>value</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>void <function>glClearBufferuiv</function></funcdef>
<paramdef>GLenum <parameter>buffer</parameter></paramdef>
<paramdef>GLint <parameter>drawbuffer</parameter></paramdef>
<paramdef>const GLuint * <parameter>value</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>void <function>glClearBufferfv</function></funcdef>
<paramdef>GLenum <parameter>buffer</parameter></paramdef>
<paramdef>GLint <parameter>drawbuffer</parameter></paramdef>
<paramdef>const GLfloat * <parameter>value</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>void <function>glClearBufferfi</function></funcdef>
<paramdef>GLenum <parameter>buffer</parameter></paramdef>
<paramdef>GLint <parameter>drawbuffer</parameter></paramdef>
<paramdef>GLfloat <parameter>depth</parameter></paramdef>
<paramdef>GLint <parameter>stencil</parameter></paramdef>
</funcprototype>
<!-- DSA commands -->
<funcprototype>
<funcdef>void <function>glClearNamedFramebufferiv</function></funcdef>
<paramdef>GLuint <parameter>framebuffer</parameter></paramdef>
<paramdef>GLenum <parameter>buffer</parameter></paramdef>
<paramdef>GLint <parameter>drawbuffer</parameter></paramdef>
<paramdef>const GLint *<parameter>value</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>void <function>glClearNamedFramebufferuiv</function></funcdef>
<paramdef>GLuint <parameter>framebuffer</parameter></paramdef>
<paramdef>GLenum <parameter>buffer</parameter></paramdef>
<paramdef>GLint <parameter>drawbuffer</parameter></paramdef>
<paramdef>const GLuint *<parameter>value</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>void <function>glClearNamedFramebufferfv</function></funcdef>
<paramdef>GLuint <parameter>framebuffer</parameter></paramdef>
<paramdef>GLenum <parameter>buffer</parameter></paramdef>
<paramdef>GLint <parameter>drawbuffer</parameter></paramdef>
<paramdef>const GLfloat *<parameter>value</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>void <function>glClearNamedFramebufferfi</function></funcdef>
<paramdef>GLuint <parameter>framebuffer</parameter></paramdef>
<paramdef>GLenum <parameter>buffer</parameter></paramdef>
<paramdef>GLint <parameter>drawbuffer</parameter></paramdef>
<paramdef>GLfloat <parameter>depth</parameter></paramdef>
<paramdef>GLint <parameter>stencil</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 xml:id="parameters"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>framebuffer</parameter></term>
<listitem>
<para>
Specifies the name of the framebuffer object for
<function>glClearNamedFramebuffer*</function>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>buffer</parameter></term>
<listitem>
<para>
Specify the buffer to clear.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>drawbuffer</parameter></term>
<listitem>
<para>
Specify a particular draw buffer to clear.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>value</parameter></term>
<listitem>
<para>
A pointer to the value or values to clear the buffer to.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>depth</parameter></term>
<listitem>
<para>
The value to clear the depth buffer to.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>stencil</parameter></term>
<listitem>
<para>
The value to clear the stencil buffer to.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 xml:id="description"><title>Description</title>
<para>
These commands clear a specified buffer of a framebuffer to
specified value(s). For <function>glClearBuffer*</function>, the
framebuffer is the currently bound draw framebuffer object. For
<function>glClearNamedFramebuffer*</function>,
<parameter>framebuffer</parameter> is zero, indicating the
default draw framebuffer, or the name of a framebuffer object.
</para>
<para>
<parameter>buffer</parameter> and
<parameter>drawbuffer</parameter> identify the buffer to clear.
</para>
<para>
If <parameter>buffer</parameter> is
<constant>GL_COLOR</constant>, a particular draw buffer
<constant>GL_DRAW_BUFFER</constant><parameter>i</parameter> is
specified by passing <parameter>i</parameter> as
<parameter>drawbuffer</parameter>, and
<parameter>value</parameter> points to a four-element vector
specifying the R, G, B and A color to clear that draw buffer to.
If the value of
<constant>GL_DRAW_BUFFER</constant><parameter>i</parameter> is
<constant>GL_NONE</constant>, the command has no effect.
Otherwise, the value of
<constant>GL_DRAW_BUFFER</constant><parameter>i</parameter>
identifies one or more color buffers, each of which is cleared
to the same value. Clamping and type conversion for fixed-point
color buffers are performed in the same fashion as for
<citerefentry><refentrytitle>glClearColor</refentrytitle></citerefentry>.
The <function>*fv</function>, <function>*iv</function> and
<function>*uiv</function> forms of these commands should be used
to clear fixed- and floating-point, signed integer, and unsigned
integer color buffers respectively.
</para>
<para>
If <parameter>buffer</parameter> is
<constant>GL_DEPTH</constant>, <parameter>drawbuffer</parameter>
must be zero, and <parameter>value</parameter> points to a
single value to clear the depth buffer to. Clamping and type
conversion for fixed-point depth buffers are performed in the
same fashion as for
<citerefentry><refentrytitle>glClearDepth</refentrytitle></citerefentry>.
Only the <function>*fv</function> forms of these commands should
be used to clear depth buffers; other forms do not accept a
<parameter>buffer</parameter> of <constant>GL_DEPTH</constant>.
</para>
<para>
If <parameter>buffer</parameter> is
<constant>GL_STENCIL</constant>,
<parameter>drawbuffer</parameter> must be zero, and
<parameter>value</parameter> points to a single value to clear
the stencil buffer to. Masking is performed in the same fashion
as for
<citerefentry><refentrytitle>glClearStencil</refentrytitle></citerefentry>.
Only the <function>*iv</function> forms of these commands should
be used to clear stencil buffers; be used to clear stencil
buffers; other forms do not accept a
<parameter>buffer</parameter> of
<constant>GL_STENCIL</constant>.
</para>
<para>
<function>glClearBufferfi</function> and
<function>glClearNamedFramebufferfi</function> are used to clear
the depth and stencil buffers simultaneously.
<parameter>buffer</parameter> must be
<constant>GL_DEPTH_STENCIL</constant> and
<parameter>drawbuffer</parameter> must be zero.
<parameter>depth</parameter> and <parameter>stencil</parameter>
are the values to clear the depth and stencil buffers to,
respectively. Clamping and type conversion of
<parameter>depth</parameter> for fixed-point depth buffers are
performed in the same fashion as for
<citerefentry><refentrytitle>glClearDepth</refentrytitle></citerefentry>.
Masking of <parameter>stencil</parameter> for stencil buffers is
performed in the same fashion as for
<citerefentry><refentrytitle>glClearStencil</refentrytitle></citerefentry>.
These commands are equivalent to clearing the depth and stencil
buffers separately, but may be faster when a buffer of internal
format <constant>GL_DEPTH_STENCIL</constant> is being cleared.
The same per-fragment and masking operations defined for
<function>glClear</function> are applied.
</para>
<para>
The result of these commands is undefined if no conversion
between the type of the specified <parameter>value</parameter>
and the type of the buffer being cleared is defined (for
example, if <function>glClearBufferiv</function> is called for a
fixed- or floating-point buffer, or if
<function>glClearBufferfv</function> is called for a signed or
unsigned integer buffer). This is not an error.
</para>
</refsect1>
<refsect1 xml:id="errors"><title>Errors</title>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated by
<function>glClearNamedFramebuffer*</function> if
<parameter>framebuffer</parameter> is not zero or the name of an
existing framebuffer object.
</para>
<para>
<constant>GL_INVALID_ENUM</constant> is generated by
<function>glClearBufferiv</function> and
<function>glClearNamedFramebufferiv</function>
<parameter>buffer</parameter> is not
<constant>GL_COLOR</constant> or
<constant>GL_STENCIL</constant>.
</para>
<para>
<constant>GL_INVALID_ENUM</constant> is generated by
<function>glClearBufferuiv</function> and
<function>glClearNamedFramebufferuiv</function>
<parameter>buffer</parameter> is not
<constant>GL_COLOR</constant>.
</para>
<para>
<constant>GL_INVALID_ENUM</constant> is generated by
<function>glClearBufferfv</function> and
<function>glClearNamedFramebufferfv</function>
<parameter>buffer</parameter> is not
<constant>GL_COLOR</constant> or
<constant>GL_DEPTH</constant>.
</para>
<para>
<constant>GL_INVALID_ENUM</constant> is generated by
<function>glClearBufferfi</function> and
<function>glClearNamedFramebufferfi</function>
<parameter>buffer</parameter> is not
<constant>GL_DEPTH_STENCIL</constant>.
</para>
<para>
<constant>GL_INVALID_VALUE</constant> is generated if
<parameter>buffer</parameter> is <constant>GL_COLOR</constant>
<parameter>drawbuffer</parameter> is negative, or greater than
the value of <constant>GL_MAX_DRAW_BUFFERS</constant> minus one.
</para>
<para>
<constant>GL_INVALID_VALUE</constant> is generated if
<parameter>buffer</parameter> is <constant>GL_DEPTH</constant>,
<constant>GL_STENCIL</constant> or
<constant>GL_DEPTH_STENCIL</constant> and
<parameter>drawbuffer</parameter> is not zero.
</para>
</refsect1>
<refsect1 xml:id="versions"><title>Version Support</title>
<informaltable>
<tgroup cols="13" align="left">
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apifunchead.xml" xpointer="xpointer(/*/*)"/>
<tbody>
<row>
<entry><function>glClearBufferfi</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='30']/*)"/>
</row>
<row>
<entry><function>glClearBufferfv</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='30']/*)"/>
</row>
<row>
<entry><function>glClearBufferiv</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='30']/*)"/>
</row>
<row>
<entry><function>glClearBufferuiv</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='30']/*)"/>
</row>
<row>
<entry><function>glClearNamedFramebufferfi</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='45']/*)"/>
</row>
<row>
<entry><function>glClearNamedFramebufferfv</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='45']/*)"/>
</row>
<row>
<entry><function>glClearNamedFramebufferiv</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='45']/*)"/>
</row>
<row>
<entry><function>glClearNamedFramebufferuiv</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='45']/*)"/>
</row>
</tbody>
</tgroup>
</informaltable>
</refsect1>
<refsect1 xml:id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>glClearColor</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glClearDepth</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glClearStencil</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glClear</refentrytitle></citerefentry>
</para>
</refsect1>
<refsect1 xml:id="Copyright"><title>Copyright</title>
<para>
Copyright <trademark class="copyright"/> 2010-2014 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.
<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://opencontent.org/openpub/">http://opencontent.org/openpub/</link>.
</para>
</refsect1>
</refentry>
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