1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
|
<!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="textureGatherOffsets">
<info>
<copyright>
<year>2011-2014</year>
<holder>Khronos Group</holder>
</copyright>
</info>
<refmeta>
<refentrytitle>textureGatherOffsets</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>textureGatherOffsets</refname>
<refpurpose>gathers four texels from a texture with an array of offsets</refpurpose>
</refnamediv>
<refsynopsisdiv><title>Declaration</title>
<funcsynopsis>
<funcprototype>
<funcdef>gvec4 <function>textureGatherOffsets</function></funcdef>
<paramdef>gsampler2D <parameter>sampler</parameter></paramdef>
<paramdef>vec2 <parameter>P</parameter></paramdef>
<paramdef>ivec2 <parameter>offsets[4]</parameter></paramdef>
<paramdef>[int <parameter>comp]</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>gvec4 <function>textureGatherOffsets</function></funcdef>
<paramdef>gsampler2DArray <parameter>sampler</parameter></paramdef>
<paramdef>vec3 <parameter>P</parameter></paramdef>
<paramdef>ivec2 <parameter>offsets[4]</parameter></paramdef>
<paramdef>[int <parameter>comp]</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>gvec4 <function>textureGatherOffsets</function></funcdef>
<paramdef>gsampler2DRect <parameter>sampler</parameter></paramdef>
<paramdef>vec3 <parameter>P</parameter></paramdef>
<paramdef>ivec2 <parameter>offsets[4]</parameter></paramdef>
<paramdef>[int <parameter>comp]</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>vec4 <function>textureGatherOffsets</function></funcdef>
<paramdef>gsampler2DShadow <parameter>sampler</parameter></paramdef>
<paramdef>vec2 <parameter>P</parameter></paramdef>
<paramdef>float <parameter>refZ</parameter></paramdef>
<paramdef>ivec2 <parameter>offsets[4]</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>vec4 <function>textureGatherOffsets</function></funcdef>
<paramdef>gsampler2DArrayShadow <parameter>sampler</parameter></paramdef>
<paramdef>vec3 <parameter>P</parameter></paramdef>
<paramdef>float <parameter>refZ</parameter></paramdef>
<paramdef>ivec2 <parameter>offsets[4]</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>vec4 <function>textureGatherOffsets</function></funcdef>
<paramdef>gsampler2DRectShadow <parameter>sampler</parameter></paramdef>
<paramdef>vec3 <parameter>P</parameter></paramdef>
<paramdef>float <parameter>refZ</parameter></paramdef>
<paramdef>ivec2 <parameter>offsets[4]</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 xml:id="parameters"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>sampler</parameter></term>
<listitem>
<para>
Specifies the sampler to which the texture from which texels will be retrieved is bound.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>P</parameter></term>
<listitem>
<para>
Specifies the texture coordinates at which texture will be sampled.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>comp</parameter></term>
<listitem>
<para>
Specifies the component of the source texture that will be used to generate the resulting vector.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>refZ</parameter></term>
<listitem>
<para>
Specifies the reference Z value used in the comparison for shadow forms.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>offsets</parameter></term>
<listitem>
<para>
Specifies an array of offsets from the specified texture coordinate <parameter>P</parameter> from which the texels will be gathered.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 xml:id="description"><title>Description</title>
<para>
<function>textureGatherOffsets</function> operates identically to <citerefentry><refentrytitle>textureGatherOffset</refentrytitle></citerefentry>,
except that <parameter>offsets</parameter> is used to determine the location of the four texels to sample. Each of the four texels is obtained
by applying the offset in <parameter>offsets</parameter> as a (u, v) coordinate offset to <parameter>P</parameter>, identifying the four-texel
<constant>GL_LINEAR</constant> footprint, and then selecting the texel
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:msub><mml:mi>i</mml:mi><mml:mn>0</mml:mn></mml:msub><mml:msub><mml:mi>i</mml:mi><mml:mn>0</mml:mn></mml:msub></mml:math></inlineequation>
of that footprint. The specified values in <parameter>offsets</parameter> must be set with constant integral expressions.
</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="funchead.xml" xpointer="xpointer(/*/*)"/>
<tbody>
<row>
<entry>textureGatherOffsets</entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="version.xml" xpointer="xpointer(/*/*[@role='40']/*)"/>
</row>
</tbody>
</tgroup>
</informaltable>
</refsect1>
<refsect1 xml:id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>texelFetch</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>texelFetchOffset</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>texture</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>textureGather</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>textureGatherOffset</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>textureGrad</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>textureGradOffset</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>textureLod</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>textureLodOffset</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>textureOffset</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>textureProj</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>textureProjGrad</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>textureProjGradOffset</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>textureProjLod</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>textureProjLodOffset</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>textureProjOffset</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>textureQueryLod</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>textureSize</refentrytitle></citerefentry>
</para>
</refsect1>
<refsect1 xml:id="Copyright"><title>Copyright</title>
<para>
Copyright <trademark class="copyright"/> 2011-2014 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>
|
