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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="glCompressedTexSubImage2D">
<info>
<copyright>
<year>1991-2006</year>
<holder>Silicon Graphics, Inc.</holder>
</copyright>
<copyright>
<year>2010-2014</year>
<holder>Khronos Group</holder>
</copyright>
</info>
<refmeta>
<refentrytitle>glCompressedTexSubImage2D</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>glCompressedTexSubImage2D</refname>
<refname>glCompressedTextureSubImage2D</refname>
<refpurpose>specify a two-dimensional texture subimage in a compressed format</refpurpose>
</refnamediv>
<refsynopsisdiv><title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glCompressedTexSubImage2D</function></funcdef>
<paramdef>GLenum <parameter>target</parameter></paramdef>
<paramdef>GLint <parameter>level</parameter></paramdef>
<paramdef>GLint <parameter>xoffset</parameter></paramdef>
<paramdef>GLint <parameter>yoffset</parameter></paramdef>
<paramdef>GLsizei <parameter>width</parameter></paramdef>
<paramdef>GLsizei <parameter>height</parameter></paramdef>
<paramdef>GLenum <parameter>format</parameter></paramdef>
<paramdef>GLsizei <parameter>imageSize</parameter></paramdef>
<paramdef>const GLvoid * <parameter>data</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>void <function>glCompressedTextureSubImage2D</function></funcdef>
<paramdef>GLuint <parameter>texture</parameter></paramdef>
<paramdef>GLint <parameter>level</parameter></paramdef>
<paramdef>GLint <parameter>xoffset</parameter></paramdef>
<paramdef>GLint <parameter>yoffset</parameter></paramdef>
<paramdef>GLsizei <parameter>width</parameter></paramdef>
<paramdef>GLsizei <parameter>height</parameter></paramdef>
<paramdef>GLenum <parameter>format</parameter></paramdef>
<paramdef>GLsizei <parameter>imageSize</parameter></paramdef>
<paramdef>const void *<parameter>data</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 xml:id="parameters"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>target</parameter></term>
<listitem>
<para>Specifies the target to which the texture is bound for
<function>glCompressedTexSubImage2D</function> function. Must be
<constant>GL_TEXTURE_1D_ARRAY</constant>,
<constant>GL_TEXTURE_2D</constant>,
<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_X</constant>,
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_X</constant>,
<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Y</constant>,
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</constant>,
<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Z</constant>, or
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</constant>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>texture</parameter></term>
<listitem>
<para>Specifies the texture object name for
<function>glCompressedTextureSubImage2D</function> function.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>level</parameter></term>
<listitem>
<para>Specifies the level-of-detail number. Level 0 is the base
image level. Level <emphasis>n</emphasis> is the
<emphasis>n</emphasis>th mipmap reduction image.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>xoffset</parameter></term>
<listitem>
<para>Specifies a texel offset in the x direction within the texture
array.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>yoffset</parameter></term>
<listitem>
<para>Specifies a texel offset in the y direction within the texture
array.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>width</parameter></term>
<listitem>
<para>Specifies the width of the texture subimage.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>height</parameter></term>
<listitem>
<para>Specifies the height of the texture subimage.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>format</parameter></term>
<listitem>
<para>Specifies the format of the compressed image data stored at
address <parameter>data</parameter>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>imageSize</parameter></term>
<listitem>
<para>Specifies the number of unsigned bytes of image data starting
at the address specified by <parameter>data</parameter>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>data</parameter></term>
<listitem>
<para>Specifies a pointer to the compressed image data in
memory.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 xml:id="description">
<title>Description</title>
<para>Texturing allows elements of an image array to be read by
shaders.</para>
<para><function>glCompressedTexSubImage2D</function> and
<function>glCompressedTextureSubImage2D</function> redefine a contiguous
subregion of an existing two-dimensional texture image. The texels
referenced by <parameter>data</parameter> replace the portion of the
existing texture array with x indices <parameter>xoffset</parameter> and
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
<!-- eqn: xoffset + width - 1: -->
<mml:mrow>
<mml:mi mathvariant="italic">xoffset</mml:mi>
<mml:mo>+</mml:mo>
<mml:mi mathvariant="italic">width</mml:mi>
<mml:mo>-</mml:mo>
<mml:mn>1</mml:mn>
</mml:mrow>
</mml:math></inlineequation>,
and the y indices <parameter>yoffset</parameter> and
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
<!-- eqn: yoffset + height - 1: -->
<mml:mrow>
<mml:mi mathvariant="italic">yoffset</mml:mi>
<mml:mo>+</mml:mo>
<mml:mi mathvariant="italic">height</mml:mi>
<mml:mo>-</mml:mo>
<mml:mn>1</mml:mn>
</mml:mrow>
</mml:math></inlineequation>,
inclusive.
This region may not include any texels
outside the range of the texture array as it was originally specified. It
is not an error to specify a subtexture with width of 0, but such a
specification has no effect.</para>
<para><parameter>internalformat</parameter> must be a known compressed
image format (such as <constant>GL_RGTC</constant>) or an
extension-specified compressed-texture format. The
<parameter>format</parameter> of the compressed texture image is selected
by the GL implementation that compressed it (see
<citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>)
and should be queried at the time the texture was
compressed with
<citerefentry><refentrytitle>glGetTexLevelParameter</refentrytitle></citerefentry>.</para>
<para>If a non-zero named buffer object is bound to the
<constant>GL_PIXEL_UNPACK_BUFFER</constant> target (see
<citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>)
while a texture image is specified,
<parameter>data</parameter> is treated as a byte offset into the buffer
object's data store.</para>
</refsect1>
<refsect1 xml:id="errors">
<title>Errors</title>
<para><constant>GL_INVALID_ENUM</constant> is generated if
<parameter>internalformat</parameter> is of the generic compressed
internal formats: <constant>GL_COMPRESSED_RED</constant>,
<constant>GL_COMPRESSED_RG</constant>,
<constant>GL_COMPRESSED_RGB</constant>,
<constant>GL_COMPRESSED_RGBA</constant>.
<constant>GL_COMPRESSED_SRGB</constant>, or
<constant>GL_COMPRESSED_SRGB_ALPHA</constant>.</para>
<para><constant>GL_INVALID_ENUM</constant> is generated by
<function>glCompressedTexSubImage2D</function> if
<parameter>target</parameter> is <constant>GL_TEXTURE_RECTANGLE</constant>
or <constant>GL_PROXY_TEXTURE_RECTANGLE</constant>.</para>
<para><constant>GL_INVALID_VALUE</constant> is generated if
<parameter>imageSize</parameter> is not consistent with the format,
dimensions, and contents of the specified compressed image data.</para>
<para><constant>GL_INVALID_OPERATION</constant> is generated if parameter
combinations are not supported by the specific compressed internal format
as specified in the specific texture compression extension.</para>
<para><constant>GL_INVALID_OPERATION</constant> is generated if a non-zero
buffer object name is bound to the
<constant>GL_PIXEL_UNPACK_BUFFER</constant> target and the buffer object's
data store is currently mapped.</para>
<para><constant>GL_INVALID_OPERATION</constant> is generated if a non-zero
buffer object name is bound to the
<constant>GL_PIXEL_UNPACK_BUFFER</constant> target and the data would be
unpacked from the buffer object such that the memory reads required would
exceed the data store size.</para>
<para><constant>GL_INVALID_OPERATION</constant> is generated by
<function>glCompressedTextureSubImage2D</function> if
<parameter>texture</parameter> is not the name of an existing texture
object.</para>
<para><constant>GL_INVALID_OPERATION</constant> is generated by
<function>glCompressedTextureSubImage2D</function> if the effective target
is <constant>GL_TEXTURE_RECTANGLE</constant>.</para>
<para>Undefined results, including abnormal program termination, are
generated if <parameter>data</parameter> is not encoded in a manner
consistent with the extension specification defining the internal
compression format.</para>
</refsect1>
<refsect1 xml:id="associatedgets"><title>Associated Gets</title>
<para>
<citerefentry><refentrytitle>glGetCompressedTexImage</refentrytitle></citerefentry>
</para>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_TEXTURE_COMPRESSED</constant>
</para>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_PIXEL_UNPACK_BUFFER_BINDING</constant>
</para>
<para>
<citerefentry><refentrytitle>glGetTexLevelParameter</refentrytitle></citerefentry> with arguments <constant>GL_TEXTURE_INTERNAL_FORMAT</constant>
and <constant>GL_TEXTURE_COMPRESSED_IMAGE_SIZE</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>glCompressedTexSubImage2D</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='20']/*)"/>
</row>
<row>
<entry><function>glCompressedTextureSubImage2D</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='45']/*)"/>
</row>
</tbody>
</tgroup>
</informaltable>
</refsect1>
<refsect1 xml:id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>glActiveTexture</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCompressedTexImage1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCompressedTexImage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCompressedTexImage3D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCompressedTexSubImage1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCompressedTexSubImage3D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCopyTexSubImage1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCopyTexSubImage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCopyTexSubImage3D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glPixelStore</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexSubImage1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexSubImage3D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>
</para>
</refsect1>
<refsect1 xml:id="Copyright"><title>Copyright</title>
<para>
Copyright <trademark class="copyright"/> 1991-2006 Silicon Graphics, Inc.
Copyright <trademark class="copyright"/> 2010-2014 Khronos Group.
This document is licensed under the SGI Free Software B License.
For details, see
<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</link>.
</para>
</refsect1>
</refentry>
|
