
<refentry id="gluBuild1DMipmapLevels">
    <refmeta>
        <refmetainfo>
            <copyright>
                <year>1991-2006</year>
                <holder>Silicon Graphics, Inc.</holder>
            </copyright>
        </refmetainfo>
        <refentrytitle>gluBuild1DMipmapLevels</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>gluBuild1DMipmapLevels</refname>
        <refpurpose>builds a subset of one-dimensional mipmap levels</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>GLint <function>gluBuild1DMipmapLevels</function></funcdef>
                <paramdef>GLenum <parameter>target</parameter></paramdef>
                <paramdef>GLint <parameter>internalFormat</parameter></paramdef>
                <paramdef>GLsizei <parameter>width</parameter></paramdef>
                <paramdef>GLenum <parameter>format</parameter></paramdef>
                <paramdef>GLenum <parameter>type</parameter></paramdef>
                <paramdef>GLint <parameter>level</parameter></paramdef>
                <paramdef>GLint <parameter>base</parameter></paramdef>
                <paramdef>GLint <parameter>max</parameter></paramdef>
                <paramdef>const void * <parameter>data</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <!-- eqn: ignoring delim $$ -->
    <refsect1 id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>target</parameter></term>
            <listitem>
                <para>
                    Specifies the target texture.  Must be <constant>GLU_TEXTURE_1D</constant>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>internalFormat</parameter></term>
            <listitem>
                <para>
                    Requests the internal storage format of the texture image.  The most
                    current version of the SGI implementation of GLU does not check this
                    value for validity before passing it on to the underlying OpenGL
                    implementation.  A value that is not accepted by the OpenGL
                    implementation will lead to an OpenGL error.  The benefit of not
                    checking this value at the GLU level is that OpenGL extensions can add
                    new internal texture formats without requiring a revision of the GLU
                    implementation.  Older implementations of GLU check this value and
                    raise a GLU error if it is not 1, 2, 3, or 4 or one of the following
                    symbolic constants:
                    <constant>GLU_ALPHA</constant>,
                    <constant>GLU_ALPHA4</constant>,
                    <constant>GLU_ALPHA8</constant>,
                    <constant>GLU_ALPHA12</constant>,
                    <constant>GLU_ALPHA16</constant>,
                    <constant>GLU_LUMINANCE</constant>,
                    <constant>GLU_LUMINANCE4</constant>,
                    <constant>GLU_LUMINANCE8</constant>,
                    <constant>GLU_LUMINANCE12</constant>,
                    <constant>GLU_LUMINANCE16</constant>,
                    <constant>GLU_LUMINANCE_ALPHA</constant>,
                    <constant>GLU_LUMINANCE4_ALPHA4</constant>,
                    <constant>GLU_LUMINANCE6_ALPHA2</constant>,
                    <constant>GLU_LUMINANCE8_ALPHA8</constant>,
                    <constant>GLU_LUMINANCE12_ALPHA4</constant>,
                    <constant>GLU_LUMINANCE12_ALPHA12</constant>,
                    <constant>GLU_LUMINANCE16_ALPHA16</constant>,
                    <constant>GLU_INTENSITY</constant>,
                    <constant>GLU_INTENSITY4</constant>,
                    <constant>GLU_INTENSITY8</constant>,
                    <constant>GLU_INTENSITY12</constant>,
                    <constant>GLU_INTENSITY16</constant>,
                    <constant>GLU_RGB</constant>,
                    <constant>GLU_R3_G3_B2</constant>,
                    <constant>GLU_RGB4</constant>,
                    <constant>GLU_RGB5</constant>,
                    <constant>GLU_RGB8</constant>,
                    <constant>GLU_RGB10</constant>,
                    <constant>GLU_RGB12</constant>,
                    <constant>GLU_RGB16</constant>,
                    <constant>GLU_RGBA</constant>,
                    <constant>GLU_RGBA2</constant>,
                    <constant>GLU_RGBA4</constant>,
                    <constant>GLU_RGB5_A1</constant>,
                    <constant>GLU_RGBA8</constant>,
                    <constant>GLU_RGB10_A2</constant>,
                    <constant>GLU_RGBA12</constant>, or
                    <constant>GLU_RGBA16</constant>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>width</parameter></term>
            <listitem>
                <para>
                    Specifies the width in pixels of the texture image. 
                    This should be a power of 2.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>format</parameter></term>
            <listitem>
                <para>
                    Specifies the format of the pixel data.
                    Must be one of:
                    <constant>GLU_COLOR_INDEX</constant>,
                    <constant>GLU_DEPTH_COMPONENT</constant>,
                    <constant>GLU_RED</constant>,
                    <constant>GLU_GREEN</constant>,
                    <constant>GLU_BLUE</constant>,
                    <constant>GLU_ALPHA</constant>,
                    <constant>GLU_RGB</constant>,
                    <constant>GLU_RGBA</constant>,
                    <constant>GLU_BGR</constant>,
                    <constant>GLU_BGRA</constant>,
                    <constant>GLU_LUMINANCE</constant>, or
                    <constant>GLU_LUMINANCE_ALPHA</constant>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>type</parameter></term>
            <listitem>
                <para>
                    Specifies the data type for <parameter>data</parameter>.
                    Must be one of: <constant>GLU_UNSIGNED_BYTE</constant>,
                    <constant>GLU_BYTE</constant>,
                    <constant>GLU_BITMAP</constant>,
                    <constant>GLU_UNSIGNED_SHORT</constant>,
                    <constant>GLU_SHORT</constant>,
                    <constant>GLU_UNSIGNED_INT</constant>,
                    <constant>GLU_INT</constant>, 
                    <constant>GLU_FLOAT</constant>, 
                    <constant>GLU_UNSIGNED_BYTE_3_3_2</constant>,
                    <constant>GLU_UNSIGNED_BYTE_2_3_3_REV</constant>,
                    <constant>GLU_UNSIGNED_SHORT_5_6_5</constant>,
                    <constant>GLU_UNSIGNED_SHORT_5_6_5_REV</constant>,
                    <constant>GLU_UNSIGNED_SHORT_4_4_4_4</constant>,
                    <constant>GLU_UNSIGNED_SHORT_4_4_4_4_REV</constant>,
                    <constant>GLU_UNSIGNED_SHORT_5_5_5_1</constant>,
                    <constant>GLU_UNSIGNED_SHORT_1_5_5_5_REV</constant>,
                    <constant>GLU_UNSIGNED_INT_8_8_8_8</constant>,
                    <constant>GLU_UNSIGNED_INT_8_8_8_8_REV</constant>,
                    <constant>GLU_UNSIGNED_INT_10_10_10_2</constant>, or
                    <constant>GLU_UNSIGNED_INT_2_10_10_10_REV</constant>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>level</parameter></term>
            <listitem>
                <para>
                    Specifies the mipmap level of the image data.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>base</parameter></term>
            <listitem>
                <para>
                    Specifies the minimum mipmap level to pass to <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>max</parameter></term>
            <listitem>
                <para>
                    Specifies the maximum mipmap level to pass to <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>data</parameter></term>
            <listitem>
                <para>
                    Specifies a pointer to the image data in memory.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 id="description"><title>Description</title>
        <para>
            <function>gluBuild1DMipmapLevels</function> builds a subset of prefiltered one-dimensional texture maps of decreasing
            resolutions called a mipmap. This is used for the antialiasing of
            texture mapped primitives.
        </para>
        <para>
            A return value of zero indicates success, otherwise a GLU error code is
            returned (see <citerefentry><refentrytitle>gluErrorString</refentrytitle></citerefentry>).
        </para>
        <para>
            A series of mipmap levels from <parameter>base</parameter> to <parameter>max</parameter> is built by decimating 
            <parameter>data</parameter> in half 
            until size 
            <inlineequation><mml:math>
                <!-- eqn: 1  times  1:-->
                <mml:mrow>
                    <mml:mn>1</mml:mn>
                    <mml:mo>&times;</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math></inlineequation>
            is reached. At each level, each texel in the
            halved mipmap level is an average of the corresponding two texels in the larger
            mipmap level. 
            <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry> is called to load these mipmap levels from <parameter>base</parameter>
            to <parameter>max</parameter>. If <parameter>max</parameter> is larger than the highest mipmap level for the
            texture of the specified size, then a GLU error code is returned (see
            <citerefentry><refentrytitle>gluErrorString</refentrytitle></citerefentry>) and nothing is loaded.
        </para>
        <para>
            For example, if <parameter>level</parameter> is 2 and <parameter>width</parameter> is 16, the
            following levels are possible: 
            <inlineequation><mml:math>
                <!-- eqn: 16  times  1:-->
                <mml:mrow>
                    <mml:mn>16</mml:mn>
                    <mml:mo>&times;</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math></inlineequation>, 
            <inlineequation><mml:math>
                <!-- eqn: 8  times  1:-->
                <mml:mrow>
                    <mml:mn>8</mml:mn>
                    <mml:mo>&times;</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math></inlineequation>, 
            <inlineequation><mml:math>
                <!-- eqn: 4  times  1:-->
                <mml:mrow>
                    <mml:mn>4</mml:mn>
                    <mml:mo>&times;</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math></inlineequation>,
            <inlineequation><mml:math>
                <!-- eqn: 2  times  1:-->
                <mml:mrow>
                    <mml:mn>2</mml:mn>
                    <mml:mo>&times;</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math></inlineequation>, 
            <inlineequation><mml:math>
                <!-- eqn: 1  times  1:-->
                <mml:mrow>
                    <mml:mn>1</mml:mn>
                    <mml:mo>&times;</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math></inlineequation>.
            These correspond
            to levels 2 through 6 respectively.
            If <parameter>base</parameter> is 3 and <parameter>max</parameter> is 5, then only mipmap levels 
            <inlineequation><mml:math>
                <!-- eqn: 8  times  1:-->
                <mml:mrow>
                    <mml:mn>8</mml:mn>
                    <mml:mo>&times;</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math></inlineequation>,
            <inlineequation><mml:math>
                <!-- eqn: 4  times  1:-->
                <mml:mrow>
                    <mml:mn>4</mml:mn>
                    <mml:mo>&times;</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math></inlineequation>
            and 
            <inlineequation><mml:math>
                <!-- eqn: 2  times  1:-->
                <mml:mrow>
                    <mml:mn>2</mml:mn>
                    <mml:mo>&times;</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math></inlineequation>
            are
            loaded. However, if <parameter>max</parameter> is 7, then an error is returned and nothing is
            loaded since <parameter>max</parameter> is larger than the highest mipmap level which is, in 
            this case, 6.
        </para>
        <para>
            The highest mipmap level can be derived from the formula
            <inlineequation><mml:math>
                <!-- eqn: log sub 2 (width * 2 sup level):-->
                <mml:mrow>
                    <mml:msub><mml:mi mathvariant="italic">log</mml:mi>
                    <mml:mn>2</mml:mn>
                    </mml:msub>
                    <mml:mo>&af;</mml:mo>
                    <mml:mfenced open="(" close=")">
                        <mml:mrow>
                            <mml:mi mathvariant="italic">width</mml:mi>
                            <mml:mo>&times;</mml:mo>
                            <mml:msup><mml:mn>2</mml:mn>
                            <mml:mi mathvariant="italic">level</mml:mi>
                            </mml:msup>
                        </mml:mrow>
                    </mml:mfenced>
                </mml:mrow>
            </mml:math></inlineequation>.
        </para>
        <para>
            See the <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry> reference page for a description of the
            acceptable values for <parameter>type</parameter> parameter. See the <citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry> 
            reference page for a description of the acceptable values 
            for <parameter>level</parameter> parameter.
        </para>
    </refsect1>
    <refsect1 id="notes"><title>Notes</title>
        <para>
            <function>gluBuild1DMipmapLevels</function> is only available if the GLU version is 1.3 or greater.
        </para>
        <para>
            Formats <constant>GLU_BGR</constant>, and <constant>GLU_BGRA</constant>, and types 
            <constant>GLU_UNSIGNED_BYTE_3_3_2</constant>,
            <constant>GLU_UNSIGNED_BYTE_2_3_3_REV</constant>,
            <constant>GLU_UNSIGNED_SHORT_5_6_5</constant>,
            <constant>GLU_UNSIGNED_SHORT_5_6_5_REV</constant>,
            <constant>GLU_UNSIGNED_SHORT_4_4_4_4</constant>,
            <constant>GLU_UNSIGNED_SHORT_4_4_4_4_REV</constant>,
            <constant>GLU_UNSIGNED_SHORT_5_5_5_1</constant>,
            <constant>GLU_UNSIGNED_SHORT_1_5_5_5_REV</constant>,
            <constant>GLU_UNSIGNED_INT_8_8_8_8</constant>,
            <constant>GLU_UNSIGNED_INT_8_8_8_8_REV</constant>,
            <constant>GLU_UNSIGNED_INT_10_10_10_2</constant>, and
            <constant>GLU_UNSIGNED_INT_2_10_10_10_REV</constant> are only available if the GL version 
            is 1.2 or greater.
        </para>
    </refsect1>
    <refsect1 id="errors"><title>Errors</title>
        <para>
            <constant>GLU_INVALID_VALUE</constant> is returned if <parameter>level</parameter> &gt; <parameter>base</parameter>, <parameter>base</parameter> &lt; 0,
            <parameter>max</parameter> &lt; <parameter>base</parameter> or <parameter>max</parameter> is &gt; the highest mipmap level for <parameter>data</parameter>.
        </para>
        <para>
            <constant>GLU_INVALID_VALUE</constant> is returned if <parameter>width</parameter> is &lt; 1.
        </para>
        <para>
            <constant>GLU_INVALID_ENUM</constant> is returned if <parameter>internalFormat</parameter>, <parameter>format</parameter>, or <parameter>type</parameter> are not 
            legal.
        </para>
        <para>
            <constant>GLU_INVALID_OPERATION</constant> is returned if <parameter>type</parameter> is <constant>GLU_UNSIGNED_BYTE_3_3_2</constant> or <constant>GLU_UNSIGNED_BYTE_2_3_3_REV</constant>
            and <parameter>format</parameter> is not <constant>GLU_RGB</constant>.
        </para>
        <para>
            <constant>GLU_INVALID_OPERATION</constant> is returned if <parameter>type</parameter> is <constant>GLU_UNSIGNED_SHORT_5_6_5</constant> or <constant>GLU_UNSIGNED_SHORT_5_6_5_REV</constant>
            and <parameter>format</parameter> is not <constant>GLU_RGB</constant>.
        </para>
        <para>
            <constant>GLU_INVALID_OPERATION</constant> is returned if <parameter>type</parameter> is <constant>GLU_UNSIGNED_SHORT_4_4_4_4</constant> or <constant>GLU_UNSIGNED_SHORT_4_4_4_4_REV</constant>
            and <parameter>format</parameter> is neither <constant>GLU_RGBA</constant> nor <constant>GLU_BGRA</constant>.
        </para>
        <para>
            <constant>GLU_INVALID_OPERATION</constant> is returned if <parameter>type</parameter> is <constant>GLU_UNSIGNED_SHORT_5_5_5_1</constant> or <constant>GLU_UNSIGNED_SHORT_1_5_5_5_REV</constant>
            and <parameter>format</parameter> is neither <constant>GLU_RGBA</constant> nor <constant>GLU_BGRA</constant>.
        </para>
        <para>
            <constant>GLU_INVALID_OPERATION</constant> is returned if <parameter>type</parameter> is <constant>GLU_UNSIGNED_INT_8_8_8_8</constant> or <constant>GLU_UNSIGNED_INT_8_8_8_8_REV</constant>
            and <parameter>format</parameter> is neither <constant>GLU_RGBA</constant> nor <constant>GLU_BGRA</constant>.
        </para>
        <para>
            <constant>GLU_INVALID_OPERATION</constant> is returned if <parameter>type</parameter> is <constant>GLU_UNSIGNED_INT_10_10_10_2</constant> or <constant>GLU_UNSIGNED_INT_2_10_10_10_REV</constant>
            and <parameter>format</parameter> is neither <constant>GLU_RGBA</constant> nor <constant>GLU_BGRA</constant>. 
        </para>
    </refsect1>
    <refsect1 id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>gluBuild1DMipmaps</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>gluBuild2DMipmapLevels</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>gluBuild2DMipmaps</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>gluBuild3DMipmapLevels</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>gluBuild3DMipmaps</refentrytitle></citerefentry>, 
            <citerefentry><refentrytitle>gluErrorString</refentrytitle></citerefentry>, 
            <citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glGetTexImage</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glGetTexLevelParameter</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>, 
            <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>
        </para>
    </refsect1>
    <refsect1 id="Copyright"><title>Copyright</title>
        <para>
            Copyright <trademark class="copyright"></trademark> 1991-2006
            Silicon Graphics, Inc. This document is licensed under the SGI
            Free Software B License. For details, see
            <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
        </para>
    </refsect1>
</refentry>
