[clinton/guile-figl.git] / upstream-doc / manglsl / textureGatherOffset.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="textureGatherOffset">\r
    <refmeta>\r
        <refmetainfo>\r
            <copyright>\r
                <year>2011</year>\r
                <holder>Khronos Group</holder>\r
            </copyright>\r
        </refmetainfo>\r
        <refentrytitle>textureGatherOffset</refentrytitle>\r
        <manvolnum>3G</manvolnum>\r
    </refmeta>\r
    <refnamediv>\r
        <refname>textureGatherOffset</refname>\r
        <refpurpose>gathers four texels from a texture with offset</refpurpose>\r
    </refnamediv>\r
    <refsynopsisdiv><title>Declaration</title>\r
        <funcsynopsis>\r
            <funcprototype>\r
                <funcdef>gvec4 <function>textureGatherOffset</function></funcdef>\r
                <paramdef>gsampler2D <parameter>sampler</parameter></paramdef>\r
                <paramdef>vec2 <parameter>P</parameter></paramdef>\r
                <paramdef>ivec2 <parameter>offset</parameter></paramdef>\r
                <paramdef>[int <parameter>comp]</parameter></paramdef>\r
            </funcprototype>\r
            <funcprototype>\r
                <funcdef>gvec4 <function>textureGatherOffset</function></funcdef>\r
                <paramdef>gsampler2DArray <parameter>sampler</parameter></paramdef>\r
                <paramdef>vec3 <parameter>P</parameter></paramdef>\r
                <paramdef>ivec2 <parameter>offset</parameter></paramdef>\r
                <paramdef>[int <parameter>comp]</parameter></paramdef>\r
            </funcprototype>\r
            <funcprototype>\r
                <funcdef>gvec4 <function>textureGatherOffset</function></funcdef>\r
                <paramdef>gsampler2DRect <parameter>sampler</parameter></paramdef>\r
                <paramdef>vec3 <parameter>P</parameter></paramdef>\r
                <paramdef>ivec2 <parameter>offset</parameter></paramdef>\r
                <paramdef>[int <parameter>comp]</parameter></paramdef>\r
            </funcprototype>\r
            <funcprototype>\r
                <funcdef>vec4 <function>textureGatherOffset</function></funcdef>\r
                <paramdef>gsampler2DShadow <parameter>sampler</parameter></paramdef>\r
                <paramdef>vec2 <parameter>P</parameter></paramdef>\r
                <paramdef>float <parameter>refZ</parameter></paramdef>\r
                <paramdef>ivec2 <parameter>offset</parameter></paramdef>\r
            </funcprototype>\r
            <funcprototype>\r
                <funcdef>vec4 <function>textureGatherOffset</function></funcdef>\r
                <paramdef>gsampler2DArrayShadow <parameter>sampler</parameter></paramdef>\r
                <paramdef>vec3 <parameter>P</parameter></paramdef>\r
                <paramdef>float <parameter>refZ</parameter></paramdef>\r
                <paramdef>ivec2 <parameter>offset</parameter></paramdef>\r
            </funcprototype>\r
            <funcprototype>\r
                <funcdef>vec4 <function>textureGatherOffset</function></funcdef>\r
                <paramdef>gsampler2DRectShadow <parameter>sampler</parameter></paramdef>\r
                <paramdef>vec3 <parameter>P</parameter></paramdef>\r
                <paramdef>float <parameter>refZ</parameter></paramdef>\r
                <paramdef>ivec2 <parameter>offset</parameter></paramdef>\r
            </funcprototype>\r
        </funcsynopsis>\r
    </refsynopsisdiv>\r
    <refsect1 id="parameters"><title>Parameters</title>\r
        <variablelist>\r
        <varlistentry>\r
            <term><parameter>sampler</parameter></term>\r
            <listitem>\r
                <para>\r
                    Specifies the sampler to which the texture from which texels will be retrieved is bound.\r
                </para>\r
            </listitem>\r
        </varlistentry>\r
        <varlistentry>\r
            <term><parameter>P</parameter></term>\r
            <listitem>\r
                <para>\r
                    Specifies the texture coordinates at which texture will be sampled.\r
                </para>\r
            </listitem>\r
        </varlistentry>\r
        <varlistentry>\r
            <term><parameter>comp</parameter></term>\r
            <listitem>\r
                <para>\r
                    Specifies the component of the source texture that will be used to generate the resulting vector.\r
                </para>\r
            </listitem>\r
        </varlistentry>\r
        <varlistentry>\r
            <term><parameter>refZ</parameter></term>\r
            <listitem>\r
                <para>\r
                    Specifies the reference Z value used in the comparison for shadow forms.\r
                </para>\r
            </listitem>\r
        </varlistentry>\r
        <varlistentry>\r
            <term><parameter>offset</parameter></term>\r
            <listitem>\r
                <para>\r
                    Specifies the offset from the specified texture coordinate <parameter>P</parameter> from which the texels will be gathered.\r
                </para>\r
            </listitem>\r
        </varlistentry>\r
        </variablelist>\r
    </refsect1>\r
    <refsect1 id="description"><title>Description</title>\r
        <para>\r
            <function>textureGatherOffset</function> returns the value:\r
        </para>\r
        <para>\r
<programlisting><![CDATA[    vec4(Sample_i0_j1(P + offset, base).comp,\r
         Sample_i1_j1(P + offset, base).comp,\r
         Sample_i1_j0(P + offset, base).comp,\r
         Sample_i0_j9(P + offset, base).comp);]]></programlisting>\r
    </para>\r
    <para>\r
        It perfoms as <citerefentry><refentrytitle>textureGather</refentrytitle></citerefentry> but with <parameter>offset</parameter>\r
        applied as described in <citerefentry><refentrytitle>textureOffset</refentrytitle></citerefentry>, except that the\r
        implementation-dependent minimum and maximum offset values are given by <constant>GL_MIN_PROGRRAM_TEXTURE_GATHER_OFFSET</constant>\r
        and <constant>GL_MAX_PROGRAM_TEXTURE_GATHER_OFFSET</constant>, respectively.\r
    </para>\r
    <para>\r
        If specified, the value of <parameter>comp</parameter> must ba constant integer expression with a value\r
        of 0, 1, 2, or 3, identifying the x, y, z or w component of the four-component vector lookup result for each\r
        texel, respectively. If <parameter>comp</parameter> is not specified, it is treated as 0, selecting the x\r
        component of each texel to generate the result.\r
    </para>\r
    </refsect1>\r
    <refsect1 id="versions"><title>Version Support</title>\r
        <informaltable frame="topbot">\r
            #VARTABLECOLS#\r
                <thead>\r
                    #FUNCTABLEHEADER#\r
                    <row>\r
                        <entry>textureGatherOffset</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>texelFetch</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>texelFetchOffset</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>texture</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>textureGather</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>textureGatherOffsets</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>textureGrad</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>textureGradOffset</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>textureLod</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>textureLodOffset</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>textureOffset</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>textureProj</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>textureProjGrad</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>textureProjGradOffset</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>textureProjLod</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>textureProjLodOffset</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>textureProjOffset</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>textureQueryLod</refentrytitle></citerefentry>,\r
            <citerefentry><refentrytitle>textureSize</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
Commit	Line	Data
7faf1d71 AW	1	<?xml version="1.0" encoding="UTF-8"?>\r
	2	<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"\r
	3	"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">\r
	4	<refentry id="textureGatherOffset">\r
	5	<refmeta>\r
	6	<refmetainfo>\r
	7	<copyright>\r
	8	<year>2011</year>\r
	9	<holder>Khronos Group</holder>\r
	10	</copyright>\r
	11	</refmetainfo>\r
	12	<refentrytitle>textureGatherOffset</refentrytitle>\r
	13	<manvolnum>3G</manvolnum>\r
	14	</refmeta>\r
	15	<refnamediv>\r
	16	<refname>textureGatherOffset</refname>\r
	17	<refpurpose>gathers four texels from a texture with offset</refpurpose>\r
	18	</refnamediv>\r
	19	<refsynopsisdiv><title>Declaration</title>\r
	20	<funcsynopsis>\r
	21	<funcprototype>\r
	22	<funcdef>gvec4 <function>textureGatherOffset</function></funcdef>\r
	23	<paramdef>gsampler2D <parameter>sampler</parameter></paramdef>\r
	24	<paramdef>vec2 <parameter>P</parameter></paramdef>\r
	25	<paramdef>ivec2 <parameter>offset</parameter></paramdef>\r
	26	<paramdef>[int <parameter>comp]</parameter></paramdef>\r
	27	</funcprototype>\r
	28	<funcprototype>\r
	29	<funcdef>gvec4 <function>textureGatherOffset</function></funcdef>\r
	30	<paramdef>gsampler2DArray <parameter>sampler</parameter></paramdef>\r
	31	<paramdef>vec3 <parameter>P</parameter></paramdef>\r
	32	<paramdef>ivec2 <parameter>offset</parameter></paramdef>\r
	33	<paramdef>[int <parameter>comp]</parameter></paramdef>\r
	34	</funcprototype>\r
	35	<funcprototype>\r
	36	<funcdef>gvec4 <function>textureGatherOffset</function></funcdef>\r
	37	<paramdef>gsampler2DRect <parameter>sampler</parameter></paramdef>\r
	38	<paramdef>vec3 <parameter>P</parameter></paramdef>\r
	39	<paramdef>ivec2 <parameter>offset</parameter></paramdef>\r
	40	<paramdef>[int <parameter>comp]</parameter></paramdef>\r
	41	</funcprototype>\r
	42	<funcprototype>\r
	43	<funcdef>vec4 <function>textureGatherOffset</function></funcdef>\r
	44	<paramdef>gsampler2DShadow <parameter>sampler</parameter></paramdef>\r
	45	<paramdef>vec2 <parameter>P</parameter></paramdef>\r
	46	<paramdef>float <parameter>refZ</parameter></paramdef>\r
	47	<paramdef>ivec2 <parameter>offset</parameter></paramdef>\r
	48	</funcprototype>\r
	49	<funcprototype>\r
	50	<funcdef>vec4 <function>textureGatherOffset</function></funcdef>\r
	51	<paramdef>gsampler2DArrayShadow <parameter>sampler</parameter></paramdef>\r
	52	<paramdef>vec3 <parameter>P</parameter></paramdef>\r
	53	<paramdef>float <parameter>refZ</parameter></paramdef>\r
	54	<paramdef>ivec2 <parameter>offset</parameter></paramdef>\r
	55	</funcprototype>\r
	56	<funcprototype>\r
	57	<funcdef>vec4 <function>textureGatherOffset</function></funcdef>\r
	58	<paramdef>gsampler2DRectShadow <parameter>sampler</parameter></paramdef>\r
	59	<paramdef>vec3 <parameter>P</parameter></paramdef>\r
	60	<paramdef>float <parameter>refZ</parameter></paramdef>\r
	61	<paramdef>ivec2 <parameter>offset</parameter></paramdef>\r
	62	</funcprototype>\r
	63	</funcsynopsis>\r
	64	</refsynopsisdiv>\r
65	<refsect1 id="parameters"><title>Parameters</title>\r
66	<variablelist>\r
67	<varlistentry>\r
68	<term><parameter>sampler</parameter></term>\r
69	<listitem>\r
70	<para>\r
71	Specifies the sampler to which the texture from which texels will be retrieved is bound.\r
72	</para>\r
73	</listitem>\r
74	</varlistentry>\r
75	<varlistentry>\r
76	<term><parameter>P</parameter></term>\r
77	<listitem>\r
78	<para>\r
79	Specifies the texture coordinates at which texture will be sampled.\r
80	</para>\r
81	</listitem>\r
82	</varlistentry>\r
83	<varlistentry>\r
84	<term><parameter>comp</parameter></term>\r
85	<listitem>\r
86	<para>\r
87	Specifies the component of the source texture that will be used to generate the resulting vector.\r
88	</para>\r
89	</listitem>\r
90	</varlistentry>\r
91	<varlistentry>\r
92	<term><parameter>refZ</parameter></term>\r
93	<listitem>\r
94	<para>\r
95	Specifies the reference Z value used in the comparison for shadow forms.\r
96	</para>\r
97	</listitem>\r
98	</varlistentry>\r
99	<varlistentry>\r
100	<term><parameter>offset</parameter></term>\r
101	<listitem>\r
102	<para>\r
103	Specifies the offset from the specified texture coordinate <parameter>P</parameter> from which the texels will be gathered.\r
104	</para>\r
105	</listitem>\r
106	</varlistentry>\r
107	</variablelist>\r
108	</refsect1>\r
109	<refsect1 id="description"><title>Description</title>\r
110	<para>\r
111	<function>textureGatherOffset</function> returns the value:\r
112	</para>\r
113	<para>\r
114	<programlisting><![CDATA[ vec4(Sample_i0_j1(P + offset, base).comp,\r
115	Sample_i1_j1(P + offset, base).comp,\r
116	Sample_i1_j0(P + offset, base).comp,\r
117	Sample_i0_j9(P + offset, base).comp);]]></programlisting>\r
118	</para>\r
119	<para>\r
120	It perfoms as <citerefentry><refentrytitle>textureGather</refentrytitle></citerefentry> but with <parameter>offset</parameter>\r
121	applied as described in <citerefentry><refentrytitle>textureOffset</refentrytitle></citerefentry>, except that the\r
122	implementation-dependent minimum and maximum offset values are given by <constant>GL_MIN_PROGRRAM_TEXTURE_GATHER_OFFSET</constant>\r
123	and <constant>GL_MAX_PROGRAM_TEXTURE_GATHER_OFFSET</constant>, respectively.\r
124	</para>\r
125	<para>\r
126	If specified, the value of <parameter>comp</parameter> must ba constant integer expression with a value\r
127	of 0, 1, 2, or 3, identifying the x, y, z or w component of the four-component vector lookup result for each\r
128	texel, respectively. If <parameter>comp</parameter> is not specified, it is treated as 0, selecting the x\r
129	component of each texel to generate the result.\r
130	</para>\r
131	</refsect1>\r
132	<refsect1 id="versions"><title>Version Support</title>\r
133	<informaltable frame="topbot">\r
134	#VARTABLECOLS#\r
135	<thead>\r
136	#FUNCTABLEHEADER#\r
137	<row>\r
138	<entry>textureGatherOffset</entry>#newin40#\r
139	</row>\r
140	</thead>\r
141	</tgroup>\r
142	</informaltable>\r
143	</refsect1>\r
144	<refsect1 id="seealso"><title>See Also</title>\r
145	<para>\r
146	<citerefentry><refentrytitle>texelFetch</refentrytitle></citerefentry>,\r
147	<citerefentry><refentrytitle>texelFetchOffset</refentrytitle></citerefentry>,\r
148	<citerefentry><refentrytitle>texture</refentrytitle></citerefentry>,\r
149	<citerefentry><refentrytitle>textureGather</refentrytitle></citerefentry>,\r
150	<citerefentry><refentrytitle>textureGatherOffsets</refentrytitle></citerefentry>,\r
151	<citerefentry><refentrytitle>textureGrad</refentrytitle></citerefentry>,\r
152	<citerefentry><refentrytitle>textureGradOffset</refentrytitle></citerefentry>,\r
153	<citerefentry><refentrytitle>textureLod</refentrytitle></citerefentry>,\r
154	<citerefentry><refentrytitle>textureLodOffset</refentrytitle></citerefentry>,\r
155	<citerefentry><refentrytitle>textureOffset</refentrytitle></citerefentry>,\r
156	<citerefentry><refentrytitle>textureProj</refentrytitle></citerefentry>,\r
157	<citerefentry><refentrytitle>textureProjGrad</refentrytitle></citerefentry>,\r
158	<citerefentry><refentrytitle>textureProjGradOffset</refentrytitle></citerefentry>,\r
159	<citerefentry><refentrytitle>textureProjLod</refentrytitle></citerefentry>,\r
160	<citerefentry><refentrytitle>textureProjLodOffset</refentrytitle></citerefentry>,\r
161	<citerefentry><refentrytitle>textureProjOffset</refentrytitle></citerefentry>,\r
162	<citerefentry><refentrytitle>textureQueryLod</refentrytitle></citerefentry>,\r
163	<citerefentry><refentrytitle>textureSize</refentrytitle></citerefentry>\r
164	</para>\r
165	</refsect1>\r
166	<refsect1 id="Copyright"><title>Copyright</title>\r
167	<para>\r
168	Copyright <trademark class="copyright"></trademark> 2011 Khronos Group. \r
169	This material may be distributed subject to the terms and conditions set forth in \r
170	the Open Publication License, v 1.0, 8 June 1999.\r
171	<ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.\r
172	</para>\r
173	</refsect1>\r
174	</refentry>\r