[clinton/guile-figl.git] / upstream-doc / man4 / glSampleCoverage.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
              "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
<refentry id="glSampleCoverage">
    <refmeta>
        <refmetainfo>
            <copyright>
                <year>1991-2006</year>
                <holder>Silicon Graphics, Inc.</holder>
            </copyright>
        </refmetainfo>
        <refentrytitle>glSampleCoverage</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glSampleCoverage</refname>
        <refpurpose>specify multisample coverage parameters</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glSampleCoverage</function></funcdef>
                <paramdef>GLfloat <parameter>value</parameter></paramdef>
                <paramdef>GLboolean <parameter>invert</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <!-- eqn: ignoring delim $$ -->
    <refsect1 id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>value</parameter></term>
            <listitem>
                <para>
                    Specify a single floating-point sample coverage value.  The value is
                    clamped to the range 
                    <inlineequation><mml:math>
                        <!-- eqn: [0 ,1]: -->
                        <mml:mfenced open="[" close="]">
                            <mml:mn>0</mml:mn>
                            <mml:mn>1</mml:mn>
                        </mml:mfenced>
                    </mml:math></inlineequation>.
                    The initial value is 1.0.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>invert</parameter></term>
            <listitem>
                <para>
                    Specify a single boolean value representing if the coverage masks should be
                    inverted.  <constant>GL_TRUE</constant> and <constant>GL_FALSE</constant> are accepted.  The initial value
                    is <constant>GL_FALSE</constant>.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 id="description"><title>Description</title>
        <para>
            Multisampling samples a pixel multiple times at various
            implementation-dependent subpixel locations to generate antialiasing
            effects.  Multisampling transparently antialiases points, lines, polygons,
            and images if it is enabled.
        </para>
        <para>
            <parameter>value</parameter> is used in constructing a temporary mask used in determining which
            samples will be used in resolving the final fragment color.  This mask is
            bitwise-anded with the coverage mask generated from the multisampling
            computation.  If the <parameter>invert</parameter> flag is set, the temporary mask is inverted
            (all bits flipped) and then the bitwise-and is computed.
        </para>
        <para>
            If an implementation does not have any multisample buffers available, or
            multisampling is disabled, rasterization occurs with only a single sample
            computing a pixel's final RGB color.
        </para>
        <para>
            Provided an implementation supports multisample buffers, and multisampling
            is enabled, then a pixel's final color is generated by combining several
            samples per pixel.  Each sample contains color, depth, and stencil
            information, allowing those operations to be performed on each sample.
        </para>
    </refsect1>
    <refsect1 id="notes"><title>Notes</title>
        <para>
            The type of the <parameter>value</parameter> parameter was
            changed from GLclampf to GLfloat. This change is transparent
            to user code and is described in detail on the
            <citerefentry><refentrytitle>removedTypes</refentrytitle></citerefentry>
            page.
        </para>
    </refsect1>
    <refsect1 id="associatedgets"><title>Associated Gets</title>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_SAMPLE_COVERAGE_VALUE</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_SAMPLE_COVERAGE_INVERT</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glIsEnabled</refentrytitle></citerefentry> with argument <constant>GL_MULTISAMPLE</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glIsEnabled</refentrytitle></citerefentry> with argument <constant>GL_SAMPLE_ALPHA_TO_COVERAGE</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glIsEnabled</refentrytitle></citerefentry> with argument <constant>GL_SAMPLE_ALPHA_TO_ONE</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glIsEnabled</refentrytitle></citerefentry> with argument <constant>GL_SAMPLE_COVERAGE</constant>
        </para>
    </refsect1>
    <refsect1 id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glEnable</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>removedTypes</refentrytitle></citerefentry>
        </para>
    </refsect1>
    <refsect1 id="Copyright"><title>Copyright</title>
        <para>
            Copyright <trademark class="copyright"></trademark> 1991-2006
            Silicon Graphics, Inc. This document is licensed under the SGI
            Free Software B License. For details, see
            <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
        </para>
    </refsect1>
</refentry>
Commit	Line	Data
7faf1d71 AW	1	<?xml version="1.0" encoding="UTF-8"?>
	2	<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
	3	"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
	4	<refentry id="glSampleCoverage">
	5	<refmeta>
	6	<refmetainfo>
	7	<copyright>
	8	<year>1991-2006</year>
	9	<holder>Silicon Graphics, Inc.</holder>
	10	</copyright>
	11	</refmetainfo>
	12	<refentrytitle>glSampleCoverage</refentrytitle>
	13	<manvolnum>3G</manvolnum>
	14	</refmeta>
	15	<refnamediv>
	16	<refname>glSampleCoverage</refname>
	17	<refpurpose>specify multisample coverage parameters</refpurpose>
	18	</refnamediv>
	19	<refsynopsisdiv><title>C Specification</title>
	20	<funcsynopsis>
	21	<funcprototype>
	22	<funcdef>void <function>glSampleCoverage</function></funcdef>
	23	<paramdef>GLfloat <parameter>value</parameter></paramdef>
	24	<paramdef>GLboolean <parameter>invert</parameter></paramdef>
	25	</funcprototype>
	26	</funcsynopsis>
	27	</refsynopsisdiv>
	28	<!-- eqn: ignoring delim $$ -->
	29	<refsect1 id="parameters"><title>Parameters</title>
	30	<variablelist>
	31	<varlistentry>
	32	<term><parameter>value</parameter></term>
	33	<listitem>
	34	<para>
	35	Specify a single floating-point sample coverage value. The value is
	36	clamped to the range
	37	<inlineequation><mml:math>
	38	<!-- eqn: [0 ,1]: -->
	39	<mml:mfenced open="[" close="]">
	40	<mml:mn>0</mml:mn>
	41	<mml:mn>1</mml:mn>
	42	</mml:mfenced>
	43	</mml:math></inlineequation>.
	44	The initial value is 1.0.
	45	</para>
	46	</listitem>
	47	</varlistentry>
	48	<varlistentry>
	49	<term><parameter>invert</parameter></term>
	50	<listitem>
	51	<para>
	52	Specify a single boolean value representing if the coverage masks should be
	53	inverted. <constant>GL_TRUE</constant> and <constant>GL_FALSE</constant> are accepted. The initial value
	54	is <constant>GL_FALSE</constant>.
	55	</para>
	56	</listitem>
	57	</varlistentry>
	58	</variablelist>
	59	</refsect1>
	60	<refsect1 id="description"><title>Description</title>
	61	<para>
	62	Multisampling samples a pixel multiple times at various
	63	implementation-dependent subpixel locations to generate antialiasing
	64	effects. Multisampling transparently antialiases points, lines, polygons,
65	and images if it is enabled.
66	</para>
67	<para>
68	<parameter>value</parameter> is used in constructing a temporary mask used in determining which
69	samples will be used in resolving the final fragment color. This mask is
70	bitwise-anded with the coverage mask generated from the multisampling
71	computation. If the <parameter>invert</parameter> flag is set, the temporary mask is inverted
72	(all bits flipped) and then the bitwise-and is computed.
73	</para>
74	<para>
75	If an implementation does not have any multisample buffers available, or
76	multisampling is disabled, rasterization occurs with only a single sample
77	computing a pixel's final RGB color.
78	</para>
79	<para>
80	Provided an implementation supports multisample buffers, and multisampling
81	is enabled, then a pixel's final color is generated by combining several
82	samples per pixel. Each sample contains color, depth, and stencil
83	information, allowing those operations to be performed on each sample.
84	</para>
85	</refsect1>
86	<refsect1 id="notes"><title>Notes</title>
87	<para>
88	The type of the <parameter>value</parameter> parameter was
89	changed from GLclampf to GLfloat. This change is transparent
90	to user code and is described in detail on the
91	<citerefentry><refentrytitle>removedTypes</refentrytitle></citerefentry>
92	page.
93	</para>
94	</refsect1>
95	<refsect1 id="associatedgets"><title>Associated Gets</title>
96	<para>
97	<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_SAMPLE_COVERAGE_VALUE</constant>
98	</para>
99	<para>
100	<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_SAMPLE_COVERAGE_INVERT</constant>
101	</para>
102	<para>
103	<citerefentry><refentrytitle>glIsEnabled</refentrytitle></citerefentry> with argument <constant>GL_MULTISAMPLE</constant>
104	</para>
105	<para>
106	<citerefentry><refentrytitle>glIsEnabled</refentrytitle></citerefentry> with argument <constant>GL_SAMPLE_ALPHA_TO_COVERAGE</constant>
107	</para>
108	<para>
109	<citerefentry><refentrytitle>glIsEnabled</refentrytitle></citerefentry> with argument <constant>GL_SAMPLE_ALPHA_TO_ONE</constant>
110	</para>
111	<para>
112	<citerefentry><refentrytitle>glIsEnabled</refentrytitle></citerefentry> with argument <constant>GL_SAMPLE_COVERAGE</constant>
113	</para>
114	</refsect1>
115	<refsect1 id="seealso"><title>See Also</title>
116	<para>
117	<citerefentry><refentrytitle>glEnable</refentrytitle></citerefentry>,
118	<citerefentry><refentrytitle>removedTypes</refentrytitle></citerefentry>
119	</para>
120	</refsect1>
121	<refsect1 id="Copyright"><title>Copyright</title>
122	<para>
123	Copyright <trademark class="copyright"></trademark> 1991-2006
124	Silicon Graphics, Inc. This document is licensed under the SGI
125	Free Software B License. For details, see
126	<ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
127	</para>
128	</refsect1>
129	</refentry>