rename upstream-man-pages to upstream-doc

[clinton/guile-figl.git] / upstream-doc / manglsl / gl_SampleID.xml

<?xml version="1.0" encoding="UTF-8"?>\r
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"\r
              "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">\r
<refentry id="gl_SampleID">\r
    <refmeta>\r
        <refmetainfo>\r
            <copyright>\r
                <year>2011</year>\r
                <holder>Khronos Group</holder>\r
            </copyright>\r
        </refmetainfo>\r
        <refentrytitle>gl_SampleID</refentrytitle>\r
        <manvolnum>3G</manvolnum>\r
    </refmeta>\r
    <refnamediv>\r
        <refname>gl_SampleID</refname>\r
        <refpurpose>contains the index of the sample currently being processed</refpurpose>\r
    </refnamediv>\r
    <refsynopsisdiv><title>Declaration</title>\r
        <funcsynopsis>\r
            <function>in int gl_SampleID;</function>\r
        </funcsynopsis>\r
    </refsynopsisdiv>\r
    <refsect1 id="description"><title>Description</title>\r
        <para>\r
            <function>gl_SampleID</function> is a fragment language input variable that contains\r
            the index of the sample currently being processed. This variable is in the range\r
            0 to <citerefentry><refentrytitle>gl_NumSamples</refentrytitle></citerefentry> - 1, where\r
            <citerefentry><refentrytitle>gl_NumSamples</refentrytitle></citerefentry>\r
            is the total number of samples in each fragment for the current framebuffer (and thus 1 if\r
            rendering to a non-multisample buffer). Any static use of this variable in a fragment\r
            shader causes the entire shader to be evaluated per-sample rather than per-fragment.\r
        </para>\r
        <para>\r
            When rendering to a non-multisample buffer, or if multisample rasterization is disabled,\r
            <function>gl_SampleID</function> will always be zero. <citerefentry><refentrytitle>gl_NumSamples</refentrytitle></citerefentry>\r
            is the sample count of the framebuffer regardless of whether multisample rasterization is\r
            enabled or not.\r
        </para>\r
    </refsect1>\r
    <refsect1 id="versions"><title>Version Support</title>\r
        <informaltable frame="topbot">\r
            #VARTABLECOLS#\r
                <thead>\r
                    #VARTABLEHEADER#\r
                    <row>\r
                        <entry>gl_SampleID</entry>#newin40#\r
                    </row>\r
                </thead>\r
            </tgroup>\r
        </informaltable>\r
    </refsect1>\r
    <refsect1 id="seealso"><title>See Also</title>\r
        <para>\r
            <citerefentry><refentrytitle>gl_SamplePosition</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>gl_NumSamples</refentrytitle></citerefentry>\r
        </para>\r
    </refsect1>\r
    <refsect1 id="Copyright"><title>Copyright</title>\r
        <para>\r
            Copyright <trademark class="copyright"></trademark> 2011 Khronos Group. \r
            This material may be distributed subject to the terms and conditions set forth in \r
            the Open Publication License, v 1.0, 8 June 1999.\r
            <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.\r
        </para>\r
    </refsect1>\r
</refentry>\r