<!DOCTYPE refentry [ <!ENTITY % mathent SYSTEM "math.ent"> %mathent; ]>

<!-- Converted by db4-upgrade version 1.1 -->

<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="glBlitFramebuffer">
    <info>
        <copyright>
            <year>2010-2014</year>
            <holder>Khronos Group</holder>
        </copyright>
    </info>
    <refmeta>
        <refentrytitle>glBlitFramebuffer</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glBlitFramebuffer</refname>
        <refname>glBlitNamedFramebuffer</refname>
        <refpurpose>copy a block of pixels from one framebuffer object to another</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glBlitFramebuffer</function></funcdef>
                <paramdef>GLint <parameter>srcX0</parameter></paramdef>
                <paramdef>GLint <parameter>srcY0</parameter></paramdef>
                <paramdef>GLint <parameter>srcX1</parameter></paramdef>
                <paramdef>GLint <parameter>srcY1</parameter></paramdef>
                <paramdef>GLint <parameter>dstX0</parameter></paramdef>
                <paramdef>GLint <parameter>dstY0</parameter></paramdef>
                <paramdef>GLint <parameter>dstX1</parameter></paramdef>
                <paramdef>GLint <parameter>dstY1</parameter></paramdef>
                <paramdef>GLbitfield <parameter>mask</parameter></paramdef>
                <paramdef>GLenum <parameter>filter</parameter></paramdef>
            </funcprototype>
            <funcprototype>
                <funcdef>void <function>glBlitNamedFramebuffer</function></funcdef>
                <paramdef>GLuint <parameter>readFramebuffer</parameter></paramdef>
                <paramdef>GLuint <parameter>drawFramebuffer</parameter></paramdef>
                <paramdef>GLint <parameter>srcX0</parameter></paramdef>
                <paramdef>GLint <parameter>srcY0</parameter></paramdef>
                <paramdef>GLint <parameter>srcX1</parameter></paramdef>
                <paramdef>GLint <parameter>srcY1</parameter></paramdef>
                <paramdef>GLint <parameter>dstX0</parameter></paramdef>
                <paramdef>GLint <parameter>dstY0</parameter></paramdef>
                <paramdef>GLint <parameter>dstX1</parameter></paramdef>
                <paramdef>GLint <parameter>dstY1</parameter></paramdef>
                <paramdef>GLbitfield <parameter>mask</parameter></paramdef>
                <paramdef>GLenum <parameter>filter</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 xml:id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>readFramebuffer</parameter></term>
            <listitem>
                <para>
                    Specifies the name of the source framebuffer object
                    for <function>glBlitNamedFramebuffer</function>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>drawFramebuffer</parameter></term>
            <listitem>
                <para>
                    Specifies the name of the destination framebuffer object
                    for <function>glBlitNamedFramebuffer</function>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>srcX0</parameter></term>
            <term><parameter>srcY0</parameter></term>
            <term><parameter>srcX1</parameter></term>
            <term><parameter>srcY1</parameter></term>
            <listitem>
                <para>
                    Specify the bounds of the source rectangle within the read buffer of the read framebuffer.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>dstX0</parameter></term>
            <term><parameter>dstY0</parameter></term>
            <term><parameter>dstX1</parameter></term>
            <term><parameter>dstY1</parameter></term>
            <listitem>
                <para>
                    Specify the bounds of the destination rectangle within the write buffer of the write framebuffer.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>mask</parameter></term>
            <listitem>
                <para>
                    The bitwise OR of the flags indicating which buffers are to be copied. The allowed flags are
                    <constant>GL_COLOR_BUFFER_BIT</constant>, <constant>GL_DEPTH_BUFFER_BIT</constant> and <constant>GL_STENCIL_BUFFER_BIT</constant>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>filter</parameter></term>
            <listitem>
                <para>
                    Specifies the interpolation to be applied if the image is stretched. Must be <constant>GL_NEAREST</constant> or <constant>GL_LINEAR</constant>.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 xml:id="description"><title>Description</title>
        <para>
            <function>glBlitFramebuffer</function> and
            <function>glBlitNamedFramebuffer</function> transfer a rectangle
            of pixel values from one region of a read framebuffer to another
            region of a draw framebuffer.
        </para>
        <para>
            For <function>glBlitFramebuffer</function>, the read and draw
            framebuffers are those bound to the
            <constant>GL_READ_FRAMEBUFFER</constant> and
            <constant>GL_DRAW_FRAMEBUFFER</constant> targets respectively.
        </para>
        <para>
            For <function>glBlitNamedFramebuffer</function>,
            <parameter>readFramebuffer</parameter> and
            <parameter>drawFramebuffer</parameter> are the names of the read
            and draw framebuffer objects respectively. If
            <parameter>readFramebuffer</parameter> or
            <parameter>drawFramebuffer</parameter> is zero, then the default
            read or draw framebuffer respectively is used.
        </para>
        <para>
            <parameter>mask</parameter> is the bitwise OR of a number of
            values indicating which buffers are to be copied. The values are
            <constant>GL_COLOR_BUFFER_BIT</constant>,
            <constant>GL_DEPTH_BUFFER_BIT</constant>, and
            <constant>GL_STENCIL_BUFFER_BIT</constant>. The pixels
            corresponding to these buffers are copied from the source
            rectangle bounded by the locations
            (<parameter>srcX0</parameter>, <parameter>srcY0</parameter>) and
            (<parameter>srcX1</parameter>, <parameter>srcY1</parameter>) to
            the destination rectangle bounded by the locations
            (<parameter>dstX0</parameter>, <parameter>dstY0</parameter>) and
            (<parameter>dstX1</parameter>, <parameter>dstY1</parameter>).
            The lower bounds of the rectangle are inclusive, while the upper
            bounds are exclusive.
        </para>
        <para>
            The actual region taken from the read framebuffer is limited to
            the intersection of the source buffers being transferred, which
            may include the color buffer selected by the read buffer, the
            depth buffer, and/or the stencil buffer depending on mask. The
            actual region written to the draw framebuffer is limited to the
            intersection of the destination buffers being written, which may
            include multiple draw buffers, the depth buffer, and/or the
            stencil buffer depending on mask. Whether or not the source or
            destination regions are altered due to these limits, the scaling
            and offset applied to pixels being transferred is performed as
            though no such limits were present.
        </para>
        <para>
            If the sizes of the source and destination rectangles are not
            equal, <parameter>filter</parameter> specifies the interpolation
            method that will be applied to resize the source image , and
            must be <constant>GL_NEAREST</constant> or
            <constant>GL_LINEAR</constant>. <constant>GL_LINEAR</constant>
            is only a valid interpolation method for the color buffer. If
            <parameter>filter</parameter> is not
            <constant>GL_NEAREST</constant> and <parameter>mask</parameter>
            includes <constant>GL_DEPTH_BUFFER_BIT</constant> or
            <constant>GL_STENCIL_BUFFER_BIT</constant>, no data is
            transferred and a <constant>GL_INVALID_OPERATION</constant>
            error is generated.
        </para>
        <para>
            If <parameter>filter</parameter> is
            <constant>GL_LINEAR</constant> and the source rectangle would
            require sampling outside the bounds of the source framebuffer,
            values are read as if the <constant>GL_CLAMP_TO_EDGE</constant>
            texture wrapping mode were applied.
        </para>
        <para>
            When the color buffer is transferred, values are taken from the
            read buffer of the specified read framebuffer and written to
            each of the draw buffers of the specified draw framebuffer.
        </para>
        <para>
            If the source and destination rectangles overlap or are the same, and the read and draw buffers are the same, the result of the operation
            is undefined.
        </para>
    </refsect1>
    <refsect1 xml:id="errors"><title>Errors</title>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated by
            <function>BlitNamedFramebuffer</function> if
            <parameter>readFramebuffer</parameter> or
            <parameter>drawFramebuffer</parameter> is not zero or the name
            of an existing framebuffer object.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if
            <parameter>mask</parameter> contains any of the
            <constant>GL_DEPTH_BUFFER_BIT</constant> or
            <constant>GL_STENCIL_BUFFER_BIT</constant> and
            <parameter>filter</parameter> is not
            <constant>GL_NEAREST</constant>.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if
            <parameter>mask</parameter> contains
            <constant>GL_COLOR_BUFFER_BIT</constant> and any of the
            following conditions hold:

            <itemizedlist>
                <listitem>
                    <para>
                        The read buffer contains fixed-point or
                        floating-point values and any draw buffer contains
                        neither fixed-point nor floating-point values.
                    </para>
                </listitem>
                <listitem>
                    <para>
                        The read buffer contains unsigned integer values and
                        any draw buffer does not contain unsigned integer
                        values.
                    </para>
                </listitem>
                <listitem>
                    <para>
                        The read buffer contains signed integer values and
                        any draw buffer does not contain signed integer
                        values.
                    </para>
                </listitem>
            </itemizedlist>
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if
            <parameter>mask</parameter> contains
            <constant>GL_DEPTH_BUFFER_BIT</constant> or
            <constant>GL_STENCIL_BUFFER_BIT</constant> and the source and
            destination depth and stencil formats do not match.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if
            <parameter>filter</parameter> is <constant>GL_LINEAR</constant>
            and the read buffer contains integer data.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if the
            effective value of <constant>GL_SAMPLES</constant> for the read
            and draw framebuffers is not identical.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if the
            value of <constant>GL_SAMPLE_BUFFERS</constant> for both read
            and draw buffers is greater than zero and the dimensions of the
            source and destination rectangles is not identical.
        </para>
        <para>
            <constant>GL_INVALID_FRAMEBUFFER_OPERATION</constant> is
            generated if the specified read and draw framebuffers are not
            framebuffer complete.
        </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>glBlitFramebuffer</function></entry>
                        <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='30']/*)"/>
                    </row>
                    <row>
                        <entry><function>glBlitNamedFramebuffer</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>glReadPixels</refentrytitle></citerefentry>
            <citerefentry><refentrytitle>glCheckFramebufferStatus</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glGenFramebuffers</refentrytitle></citerefentry>
            <citerefentry><refentrytitle>glBindFramebuffer</refentrytitle></citerefentry>
            <citerefentry><refentrytitle>glDeleteFramebuffers</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>
