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OpenGL ES 1.0 and EGL 1.0 reference manual and man pages (written by
Claude Knaus, based on OpenGL SI man pages).

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.2//EN" "DTD/docbook/docbookx.dtd">

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<refentry id="glCopyTexImage2D">
  <refmeta>
    <refentrytitle>glCopyTexImage2D</refentrytitle>
    <manvolnum>3G</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>glCopyTexImage2D</refname>
    <refpurpose>specify a two-dimensional texture image with pixels from the color buffer</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <title>C Specification</title>

    <funcsynopsis>
      <funcprototype>
        <funcdef>void <function>glCopyTexImage2D</function></funcdef>
        <paramdef>GLenum <parameter>target</parameter></paramdef>
        <paramdef>GLint <parameter>level</parameter></paramdef>

        <paramdef>GLenum <parameter>internalformat</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>
        <paramdef>GLint <parameter>border</parameter></paramdef>
      </funcprototype>
    </funcsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Parameters</title>

    <variablelist>
      <varlistentry>
        <term>
          <parameter>target</parameter>
        </term>

        <listitem>
          <para>Specifies the target texture. Must be 
          <constant>GL_TEXTURE_2D</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 <parameter>n</parameter> 
          is the <parameter>n</parameter>th mipmap reduction image.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>
          <parameter>internalformat</parameter>
        </term>

        <listitem>
          <para>Specifies the color components of the texture. Must be one
          of the following symbolic constants: 
          <constant>GL_ALPHA</constant>, 
          <constant>GL_LUMINANCE</constant>, 
          <constant>GL_LUMINANCE_ALPHA</constant>, 
          <constant>GL_RGB</constant>, or 
          <constant>GL_RGBA</constant>.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>
        <parameter>x</parameter>, <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 image. Must be 0 or 
          <inlineequation><math>
            <msup><mn>2</mn><mi>n</mi></msup><mo>+</mo><mn>2</mn><mi>border</mi>
          </math></inlineequation>
          for some integer <replaceable>n</replaceable>.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>
          <parameter>height</parameter>
        </term>

        <listitem>
          <para>Specifies the height of the texture image. Must be 0 or 
          <inlineequation><math>
            <msup><mn>2</mn><mi>m</mi></msup><mo>+</mo><mn>2</mn><mi>border</mi>
          </math></inlineequation>
          for some integer <replaceable>m</replaceable>.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>
          <parameter>border</parameter>
        </term>

        <listitem>
          <para>Specifies the width of the border. Must be 0.</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Description</title>

    <para>
    <function>glCopyTexImage2D</function>
    defines a two-dimensional texture image with pixels from the
    color buffer.</para>

    <para>The screen-aligned pixel rectangle with lower left corner
    at (<parameter>x</parameter>, <parameter>y</parameter>)
    and with a width of
    <inlineequation><math>
      <mi>width</mi><mo>+</mo><mn>2</mn><mi>border</mi>
    </math></inlineequation>
    and a height of 
    <inlineequation><math>
      <mi>height</mi><mo>+</mo><mn>2</mn><mi>border</mi>
    </math></inlineequation>
    defines the texture array at the mipmap level specified by 
    <parameter>level</parameter>. <parameter>internalformat</parameter> 
    specifies the color components of the texture.</para>

    <para>
    The red, green, blue, and alpha
    components of each pixel that is read are converted to an
    internal fixed-point or floating-point format with unspecified precision.
    The conversion maps the largest representable component
    value to 1.0, and component value 0 to 0.0.
    The values are then converted to the texture's internal format for
    storage in the texel array.</para>

    <para><parameter>internalformat</parameter> must be chosen such that
    color buffer components can be dropped during conversion to the
    internal format, but new components cannot be added. For example,
    an <constant>RGB</constant> color buffer can be used to create
    <constant>LUMINANCE</constant> or <constant>RGB</constant>
    textures, but not <constant>ALPHA</constant>,
    <constant>LUMINANCE_ALPHA</constant> or <constant>RGBA</constant>
    textures.</para>

    <para>Pixel ordering is such that lower <parameter>x</parameter>
    and <parameter>y</parameter> screen coordinates correspond to lower 
    <parameter>s</parameter> and <parameter>t</parameter> texture
    coordinates.</para>

    <para>If any of the pixels within the specified rectangle of
    the color buffer are outside the window associated with the
    current rendering context, then the values obtained for those
    pixels are undefined.</para>
  </refsect1>

  <refsect1>
    <title>Notes</title>

    <para>An image with height or width of 0 indicates a
    null-texture.</para>
  </refsect1>

  <refsect1>
    <title>Errors</title>

    <para><constant>GL_INVALID_ENUM</constant> is generated if 
    <parameter>target</parameter> is not 
    <constant>GL_TEXTURE_2D</constant>.</para>

    <para><constant>GL_INVALID_OPERATION</constant> is generated if 
    <parameter>internalformat</parameter> is not compatible
    with the color buffer format.</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 
    <parameter>level</parameter> is greater than
    <inlineequation><math>
      <msub><mo>log</mo><mn>2</mn></msub><mi>max</mi>
    </math></inlineequation>, where
    <replaceable>max</replaceable> is the returned value of
    <constant>GL_MAX_TEXTURE_SIZE</constant>.</para>

    <para>
    <constant>GL_INVALID_VALUE</constant> is generated if 
    <parameter>width</parameter> or 
    <parameter>height</parameter> 
    is less than 0, greater than 
    <constant>GL_MAX_TEXTURE_SIZE</constant>, or if 
    <parameter>width</parameter> or <parameter>height</parameter>
    cannot be represented as 
    <inlineequation><math>
      <msup><mn>2</mn><mi>k</mi></msup><mo>+</mo><mn>2</mn><mi>border</mi>
    </math></inlineequation>
    for some integer <replaceable>k</replaceable>.</para>

    <para><constant>GL_INVALID_VALUE</constant> is generated if 
    <parameter>border</parameter> is not 0.</para>

    <para> <constant>GL_INVALID_VALUE</constant> is generated if 
    <parameter>internalformat</parameter> 
    is not an accepted constant.</para>
  </refsect1>

  <refsect1>
    <title>Associated Gets</title>

    <para>
    <citerefentry><refentrytitle>glGetInteger</refentrytitle></citerefentry>
    with argument <constant>GL_MAX_TEXTURE_SIZE</constant></para>
  </refsect1>

  <refsect1>
    <title>See Also</title>

    <para>
    <citerefentry><refentrytitle>glCompressedTexImage2D</refentrytitle></citerefentry>, 
    <citerefentry><refentrytitle>glCopyTexSubImage2D</refentrytitle></citerefentry>, 
    <citerefentry><refentrytitle>glGetInteger</refentrytitle></citerefentry>, 
    <citerefentry><refentrytitle>glTexEnv</refentrytitle></citerefentry>, 
    <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>, 
    <citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>, 
    <citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>
    </para>
  </refsect1>
</refentry>