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glCopyTexSubImage2D.xml
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glCopyTexSubImage2D.xml
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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="glCopyTexSubImage2D">
<info>
<copyright>
<year>2013</year>
<holder>Khronos Group</holder>
</copyright>
</info>
<refmeta>
<refentrytitle>glCopyTexSubImage2D</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>glCopyTexSubImage2D</refname>
<refpurpose>copy a two-dimensional texture subimage</refpurpose>
</refnamediv>
<refsynopsisdiv><title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glCopyTexSubImage2D</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>GLint <parameter>x</parameter></paramdef>
<paramdef>GLint <parameter>y</parameter></paramdef>
<paramdef>GLsizei <parameter>width</parameter></paramdef>
<paramdef>GLsizei <parameter>height</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 xml:id="parameters"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>target</parameter></term>
<listitem>
<para>
Specifies the target texture.
Must be <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>,
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</constant>, or
<constant>GL_TEXTURE_1D_ARRAY</constant>.
</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>x</parameter></term>
<term><parameter>y</parameter></term>
<listitem>
<para>
Specify the window coordinates of the lower left corner
of the rectangular region of pixels to be copied.
</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>
</variablelist>
</refsect1>
<refsect1 xml:id="description"><title>Description</title>
<para>
<function>glCopyTexSubImage2D</function> replaces a rectangular portion of a two-dimensional texture image,
cube-map texture image or a linear portion of a number of slices of a one-dimensional array texture
with pixels from the current <constant>GL_READ_BUFFER</constant>
(rather than from main memory, as is the case for <citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>).
</para>
<para>
The screen-aligned pixel rectangle with lower left corner at
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
<!-- eqn: (x, y): -->
<mml:mfenced open="(" close=")">
<mml:mi mathvariant="italic">x</mml:mi>
<mml:mi mathvariant="italic">y</mml:mi>
</mml:mfenced>
</mml:math></inlineequation>
and with
width <parameter>width</parameter> and height <parameter>height</parameter> replaces the portion of the
texture array with x indices <parameter>xoffset</parameter> through
<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>,
inclusive, and y indices <parameter>yoffset</parameter> through
<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, at the mipmap level specified by <parameter>level</parameter>.
</para>
<para>
The pixels in the rectangle are processed exactly as if
<citerefentry><refentrytitle>glReadPixels</refentrytitle></citerefentry> had been called, but the process stops just before
final conversion.
At this point, all pixel component values are clamped to the range
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
<!-- eqn: [0,1]: -->
<mml:mfenced open="[" close="]">
<mml:mn>0</mml:mn>
<mml:mn>1</mml:mn>
</mml:mfenced>
</mml:math></inlineequation>
and then converted to the texture's internal format for storage in the texel
array.
</para>
<para>
The destination rectangle in the texture array may not include any texels
outside the texture array as it was originally specified.
It is not an error to specify a subtexture with zero width or height, but
such a specification has no effect.
</para>
<para>
When <parameter>target</parameter> is <constant>GL_TEXTURE_1D_ARRAY</constant>
then the y coordinate and height are treated as the start slice and number
of slices to modify.
</para>
<para>
If any of the pixels within the specified rectangle of the current
<constant>GL_READ_BUFFER</constant> are outside the read window associated with the current
rendering context, then the values obtained for those pixels are undefined.
</para>
<para>
No change is made to the <emphasis>internalformat</emphasis>, <emphasis>width</emphasis>, or
<emphasis>height</emphasis>, parameters of the specified texture
array or to texel values outside the specified subregion.
</para>
</refsect1>
<refsect1 xml:id="notes"><title>Notes</title>
<para>
<citerefentry><refentrytitle>glPixelStore</refentrytitle></citerefentry> modes affect texture images.
</para>
</refsect1>
<refsect1 xml:id="errors"><title>Errors</title>
<para>
<constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> is not <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>,
<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</constant>, or
<constant>GL_TEXTURE_1D_ARRAY</constant>.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if the texture array has not been
defined by a previous <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry> or <citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry> operation.
</para>
<para>
<constant>GL_INVALID_VALUE</constant> is generated if <parameter>level</parameter> is less than 0.
</para>
<para>
<constant>GL_INVALID_VALUE</constant> may be generated if
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
<!-- eqn: level > log sub 2(max): -->
<mml:mrow>
<mml:mi mathvariant="italic">level</mml:mi>
<mml:mo>></mml:mo>
<mml:mrow>
<mml:msub><mml:mi mathvariant="italic">log</mml:mi>
<mml:mn>2</mml:mn>
</mml:msub>
<mml:mo>⁡</mml:mo>
<mml:mfenced open="(" close=")">
<mml:mi mathvariant="italic">max</mml:mi>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:math></inlineequation>,
where
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">max</mml:mi></mml:math></inlineequation>
is the returned value of <constant>GL_MAX_TEXTURE_SIZE</constant>.
</para>
<para>
<constant>GL_INVALID_VALUE</constant> is generated if
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
<!-- eqn: xoffset < -b: -->
<mml:mrow>
<mml:mi mathvariant="italic">xoffset</mml:mi>
<mml:mo><</mml:mo>
<mml:mn>0</mml:mn>
</mml:mrow>
</mml:math></inlineequation>,
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
<!-- eqn: (xoffset + width) > (w - b): -->
<mml:mrow>
<mml:mfenced open="(" close=")">
<mml:mrow>
<mml:mi mathvariant="italic">xoffset</mml:mi>
<mml:mo>+</mml:mo>
<mml:mi mathvariant="italic">width</mml:mi>
</mml:mrow>
</mml:mfenced>
<mml:mo>></mml:mo>
<mml:mi mathvariant="italic">w</mml:mi>
</mml:mrow>
</mml:math></inlineequation>,
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
<!-- eqn: yoffset < -b: -->
<mml:mrow>
<mml:mi mathvariant="italic">yoffset</mml:mi>
<mml:mo><</mml:mo>
<mml:mn>0</mml:mn>
</mml:mrow>
</mml:math></inlineequation>,
or
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
<!-- eqn: (yoffset + height) > (h - b): -->
<mml:mrow>
<mml:mfenced open="(" close=")">
<mml:mrow>
<mml:mi mathvariant="italic">yoffset</mml:mi>
<mml:mo>+</mml:mo>
<mml:mi mathvariant="italic">height</mml:mi>
</mml:mrow>
</mml:mfenced>
<mml:mo>></mml:mo>
<mml:mn>0</mml:mn>
</mml:mrow>
</mml:math></inlineequation>,
where
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">w</mml:mi></mml:math></inlineequation>
is the <constant>GL_TEXTURE_WIDTH</constant>,
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">h</mml:mi></mml:math></inlineequation>
is the <constant>GL_TEXTURE_HEIGHT</constant> and
of the texture image being modified.
</para>
</refsect1>
<refsect1 xml:id="associatedgets"><title>Associated Gets</title>
<para>
<citerefentry><refentrytitle>glGetTexImage</refentrytitle></citerefentry>
</para>
</refsect1>
<refsect1 xml:id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCopyTexSubImage1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glCopyTexSubImage3D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glPixelStore</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glReadBuffer</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexSubImage1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexSubImage3D</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"/> 2012-2013 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>