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<!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="glTextureView">
<info>
<copyright>
<year>2013-2014</year>
<holder>Khronos Group</holder>
</copyright>
</info>
<refmeta>
<refentrytitle>glTextureView</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>glTextureView</refname>
<refpurpose>initialize a texture as a data alias of another texture's data store</refpurpose>
</refnamediv>
<refsynopsisdiv><title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glTextureView</function></funcdef>
<paramdef>GLuint <parameter>texture</parameter></paramdef>
<paramdef>GLenum <parameter>target</parameter></paramdef>
<paramdef>GLuint <parameter>origtexture</parameter></paramdef>
<paramdef>GLenum <parameter>internalformat</parameter></paramdef>
<paramdef>GLuint <parameter>minlevel</parameter></paramdef>
<paramdef>GLuint <parameter>numlevels</parameter></paramdef>
<paramdef>GLuint <parameter>minlayer</parameter></paramdef>
<paramdef>GLuint <parameter>numlayers</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 xml:id="parameters"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>texture</parameter></term>
<listitem>
<para>
Specifies the texture object to be initialized as a view.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>target</parameter></term>
<listitem>
<para>
Specifies the target to be used for the newly initialized texture.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>origtexture</parameter></term>
<listitem>
<para>
Specifies the name of a texture object of which to make a view.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>internalFormat</parameter></term>
<listitem>
<para>
Specifies the internal format for the newly created view.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>minlevel</parameter></term>
<listitem>
<para>
Specifies lowest level of detail of the view.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>numlevels</parameter></term>
<listitem>
<para>
Specifies the number of levels of detail to include in the view.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>minlayer</parameter></term>
<listitem>
<para>
Specifies the index of the first layer to include in the view.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>numlayers</parameter></term>
<listitem>
<para>
Specifies the number of layers to include in the view.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 xml:id="description"><title>Description</title>
<para>
<function>glTextureView</function> initializes a texture object as an
alias, or view of another texture object, sharing some or all of the
parent texture's data store with the initialized texture. <parameter>texture</parameter>
specifies a name previously reserved by a successful call to <citerefentry><refentrytitle>glGenTextures</refentrytitle></citerefentry>
but that has not yet been bound or given a target. <parameter>target</parameter>
specifies the target for the newly initialized texture and must be compatible
with the target of the parent texture, given in <parameter>origtexture</parameter>
as specified in the following table:
</para>
<informaltable>
<tgroup cols="2" align="left">
<colspec colnum="1" colname="col1" colwidth="1*"/>
<colspec colnum="2" colname="col2" colwidth="2*"/>
<thead>
<row>
<entry>Original Target</entry>
<entry>Compatible New Targets</entry>
</row>
</thead>
<tbody>
<row>
<entry><constant>GL_TEXTURE_1D</constant></entry>
<entry><constant>GL_TEXTURE_1D</constant>, <constant>GL_TEXTURE_1D_ARRAY</constant></entry>
</row>
<row>
<entry><constant>GL_TEXTURE_2D</constant></entry>
<entry><constant>GL_TEXTURE_2D</constant>, <constant>GL_TEXTURE_2D_ARRAY</constant></entry>
</row>
<row>
<entry><constant>GL_TEXTURE_3D</constant></entry>
<entry><constant>GL_TEXTURE_3D</constant></entry>
</row>
<row>
<entry><constant>GL_TEXTURE_CUBE_MAP</constant></entry>
<entry><constant>GL_TEXTURE_CUBE_MAP</constant>, <constant>GL_TEXTURE_2D</constant>, <constant>GL_TEXTURE_2D_ARRAY</constant>, <constant>GL_TEXTUER_CUBE_MAP_ARRAY</constant></entry>
</row>
<row>
<entry><constant>GL_TEXTURE_RECTANGLE</constant></entry>
<entry><constant>GL_TEXTURE_RECTANGLE</constant></entry>
</row>
<row>
<entry><constant>GL_TEXTURE_BUFFER</constant></entry>
<entry><emphasis>none</emphasis></entry>
</row>
<row>
<entry><constant>GL_TEXTURE_1D_ARRAY</constant></entry>
<entry><constant>GL_TEXTURE_1D</constant>, <constant>GL_TEXTURE_1D_ARRAY</constant></entry>
</row>
<row>
<entry><constant>GL_TEXTURE_2D_ARRAY</constant></entry>
<entry><constant>GL_TEXTURE_2D</constant>, <constant>GL_TEXTURE_2D_ARRAY</constant></entry>
</row>
<row>
<entry><constant>GL_TEXTURE_CUBE_MAP_ARRAY</constant></entry>
<entry><constant>GL_TEXTURE_CUBE_MAP</constant>, <constant>GL_TEXTURE_2D</constant>, <constant>GL_TEXTURE_2D_ARRAY</constant>, <constant>GL_TEXTUER_CUBE_MAP_ARRAY</constant></entry>
</row>
<row>
<entry><constant>GL_TEXTURE_2D_MULTISAMPLE</constant></entry>
<entry><constant>GL_TEXTURE_2D_MULTISAMPLE</constant>, <constant>GL_TEXTURE_MULTISAMPLE_ARRAY</constant></entry>
</row>
<row>
<entry><constant>GL_TEXTURE_2D_MULTISAMPLE_ARRAY</constant></entry>
<entry><constant>GL_TEXTURE_2D_MULTISAMPLE</constant>, <constant>GL_TEXTURE_MULTISAMPLE_ARRAY</constant></entry>
</row>
</tbody>
</tgroup>
</informaltable>
<para>
The value of <constant>GL_TEXTURE_IMMUTABLE_FORMAT</constant> for <parameter>origtexture</parameter>
must be <constant>GL_TRUE</constant>.
After initialization, <parameter>texture</parameter> inherits the data store of
the parent texture, <parameter>origtexture</parameter> and is usable as a normal
texture object with target <parameter>target</parameter>. Data in the shared store
is reinterpreted with the new internal format specified by <parameter>internalformat</parameter>.
<parameter>internalformat</parameter> must be compatible with the internal format
of the parent texture as specified in the following table:
</para>
<informaltable>
<tgroup cols="2" align="left">
<colspec colnum="1" colname="col1" colwidth="1*"/>
<colspec colnum="2" colname="col2" colwidth="2*"/>
<thead>
<row>
<entry>Class</entry>
<entry>Internal Formats</entry>
</row>
</thead>
<tbody>
<row>
<entry>128-bit</entry>
<entry><constant>GL_RGBA32F</constant>, <constant>GL_RGBA32UI</constant>, <constant>GL_RGBA32I</constant></entry>
</row>
<row>
<entry>96-bit</entry>
<entry><constant>GL_RGB32F</constant>, <constant>GL_RGB32UI</constant>, <constant>GL_RGB32I</constant></entry>
</row>
<row>
<entry>64-bit</entry>
<entry><constant>GL_RGBA16F</constant>, <constant>GL_RG32F</constant>, <constant>GL_RGBA16UI</constant>,
<constant>GL_RG32UI</constant>, <constant>GL_RGBA16I</constant>, <constant>GL_RG32I</constant>, <constant>GL_RGBA16</constant>, <constant>GL_RGBA16_SNORM</constant></entry>
</row>
<row>
<entry>48-bit</entry>
<entry><constant>GL_RGB16</constant>, <constant>GL_RGB16_SNORM</constant>, <constant>GL_RGB16F</constant>, <constant>GL_RGB16UI</constant>, <constant>GL_RGB16I</constant></entry>
</row>
<row>
<entry>32-bit</entry>
<entry><constant>GL_RG16F</constant>, <constant>GL_R11F_G11F_B10F</constant>, <constant>GL_R32F</constant>, <constant>GL_RGB10_A2UI</constant>,
<constant>GL_RGBA8UI</constant>, <constant>GL_RG16UI</constant>, <constant>GL_R32UI</constant>, <constant>GL_RGBA8I</constant>,
<constant>GL_RG16I</constant>, <constant>GL_R32I</constant>, <constant>GL_RGB10_A2</constant>, <constant>GL_RGBA8</constant>,
<constant>GL_RG16</constant>, <constant>GL_RGBA8_SNORM</constant>, <constant>GL_RG16_SNORM</constant>, <constant>GL_SRGB8_ALPHA8</constant>,
<constant>GL_RGB9_E5</constant></entry>
</row>
<row>
<entry>24-bit</entry>
<entry><constant>GL_RGB8</constant>, <constant>GL_RGB8_SNORM</constant>, <constant>GL_SRGB8</constant>,
<constant>GL_RGB8UI</constant>, <constant>GL_RGB8I</constant></entry>
</row>
<row>
<entry>16-bit</entry>
<entry><constant>GL_R16F</constant>, <constant>GL_RG8UI</constant>, <constant>GL_R16UI</constant>, <constant>GL_RG8I</constant>,
<constant>GL_R16I</constant>, <constant>GL_RG8</constant>, <constant>GL_R16</constant>, <constant>GL_RG8_SNORM</constant>, <constant>GL_R16_SNORM</constant></entry>
</row>
<row>
<entry>8-bit</entry>
<entry><constant>GL_R8UI</constant>, <constant>GL_R8I</constant>, <constant>GL_R8</constant>, <constant>GL_R8_SNORM</constant></entry>
</row>
<row>
<entry><constant>GL_RGTC1_RED</constant></entry>
<entry><constant>GL_COMPRESSED_RED_RGTC1</constant>, <constant>GL_COMPRESSED_SIGNED_RED_RGTC1</constant></entry>
</row>
<row>
<entry><constant>GL_RGTC2_RG</constant></entry>
<entry><constant>GL_COMPRESSED_RG_RGTC2</constant>, <constant>GL_COMPRESSED_SIGNED_RG_RGTC2</constant></entry>
</row>
<row>
<entry><constant>GL_BPTC_UNORM</constant></entry>
<entry><constant>GL_COMPRESSED_RGBA_BPTC_UNORM</constant>, <constant>GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM</constant></entry>
</row>
<row>
<entry><constant>GL_BPTC_FLOAT</constant></entry>
<entry><constant>GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT</constant>, <constant>GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT</constant></entry>
</row>
</tbody>
</tgroup>
</informaltable>
<para>
If the original texture is an array or has multiple mipmap levels,
the parameters <parameter>minlayer</parameter>, <parameter>numlayers</parameter>, <parameter>minlevel</parameter>, and <parameter>numlevels</parameter>
control which of those slices and levels are considered part of the texture.
The <parameter>minlevel</parameter> and <parameter>minlayer</parameter> parameters are relative to the view of the
original texture. If <parameter>numlayers</parameter> or <parameter>numlevels</parameter> extend beyond the original
texture, they are clamped to the max extent of the original texture.
</para>
<para>
If the new texture's target is <constant>GL_TEXTURE_CUBE_MAP</constant>, the clamped <parameter>numlayers</parameter>
must be equal to 6. If the new texture's target is <constant>GL_TEXTURE_CUBE_MAP_ARRAY</constant>,
then <parameter>numlayers</parameter> counts layer-faces rather than layers, and the clamped
<parameter>numlayers</parameter> must be a multiple of 6. If the new texture's target is <constant>GL_TEXTURE_CUBE_MAP</constant> or
<constant>GL_TEXTURE_CUBE_MAP_ARRAY</constant>, the width and height of the original texture's
levels must be equal.
</para>
<para>
When the original texture's target is <constant>GL_TEXTURE_CUBE_MAP</constant>, the layer
parameters are interpreted in the same order as if it were a
<constant>GL_TEXTURE_CUBE_MAP_ARRAY</constant> with 6 layer-faces.
</para>
<para>
If <parameter>target</parameter> is <constant>GL_TEXTURE_1D</constant>, <constant>GL_TEXTURE_2D</constant>, <constant>GL_TEXTURE_3D</constant>, <constant>GL_TEXTURE_RECTANGLE</constant>, or
<constant>GL_TEXTURE_2D_MULTISAMPLE</constant>, <parameter>numlayers</parameter> must equal 1.
</para>
<para>
The dimensions of the original texture must be less than or equal to the maximum
supported dimensions of the new target. For example, if the original texture has a <constant>GL_TEXTURE_2D_ARRAY</constant>
target and its width is greater than <constant>GL_MAX_CUBE_MAP_TEXTURE_SIZE</constant>, an error
will be generated if <function>glTextureView</function> is called to create a <constant>GL_TEXTURE_CUBE_MAP</constant>
view.
</para>
<para>
Texture commands that take a <parameter>level</parameter> or <parameter>layer</parameter> parameter, such as
<citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>, interpret that parameter to be relative to the view of the
texture. i.e. the mipmap level of the data store that would be updated via
<citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry> would be the sum of <parameter>level</parameter> and the value of
<constant>GL_TEXTURE_VIEW_MIN_LEVEL</constant>.
</para>
</refsect1>
<refsect1 xml:id="errors"><title>Errors</title>
<para>
<constant>GL_INVALID_VALUE</constant> is generated if <parameter>minlayer</parameter> or <parameter>minlevel</parameter>
are larger than the greatest layer or level of <parameter>origtexture</parameter>.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if <parameter>target</parameter> is not compatible
with the target of <parameter>origtexture</parameter>.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if the dimensions of <parameter>origtexture</parameter>
are greater than the maximum supported dimensions for <parameter>target</parameter>.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if <parameter>internalformat</parameter> is not compatible
with the internal format of <parameter>origtexture</parameter>.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if <parameter>texture</parameter> has already been bound
or otherwise given a target.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if the value of <constant>GL_TEXTURE_IMMUTABLE_FORMAT</constant>
for <parameter>origtexture</parameter> is not <constant>GL_TRUE</constant>.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if <parameter>origtexture</parameter> is not the name of an
existing texture object.
</para>
<para>
<constant>GL_INVALID_VALUE</constant> is generaged if <parameter>target</parameter> is <constant>GL_TEXTURE_CUBE_MAP</constant>
and <parameter>numlayers</parameter> is not 6, or if <parameter>target</parameter> is <constant>GL_TEXTURE_CUBE_MAP_ARRAY</constant>
and <parameter>numlayers</parameter> is not an integer multiple of 6.
</para>
<para>
<constant>GL_INVALID_VALUE</constant> is generated if <parameter>target</parameter> is <constant>GL_TEXTURE_1D</constant>,
<constant>GL_TEXTURE_2D</constant>, <constant>GL_TEXTURE_3D</constant>, <constant>GL_TEXTURE_RECTANGLE</constant>, or
<constant>GL_TEXTURE_2D_MULTISAMPLE</constant> and <parameter>numlayers</parameter> does not equal 1.
</para>
<para>
<constant>GL_INVALID_VALUE</constant> is generated if <parameter>texture</parameter> zero or is not the name of a texture previously
returned from a successful call to <citerefentry><refentrytitle>glGenTextures</refentrytitle></citerefentry>.
</para>
</refsect1>
<refsect1 xml:id="associatedgets"><title>Associated Gets</title>
<para>
<citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry> with arguments <constant>GL_TEXTURE_VIEW_MIN_LEVEL</constant>,
<constant>GL_TEXTURE_VIEW_NUM_LEVELS</constant>, <constant>GL_TEXTURE_VIEW_MIN_LAYER</constant>,
<constant>GL_TEXTURE_VIEW_NUM_LAYERS</constant>, or <constant>GL_TEXTURE_IMMUTABLE_LEVELS</constant>.
</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>glTextureView</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='43']/*)"/>
</row>
</tbody>
</tgroup>
</informaltable>
</refsect1>
<refsect1 xml:id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>glTexStorage1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexStorage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexStorage3D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glGetTexParameter</refentrytitle></citerefentry>.
</para>
</refsect1>
<refsect1 xml:id="Copyright"><title>Copyright</title>
<para>
Copyright <trademark class="copyright"/> 2013-2014 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>
|
