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<?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>gluBuild1DMipmaps</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="gluBuild1DMipmaps"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>gluBuild1DMipmaps — builds a one-dimensional mipmap</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">GLint <b class="fsfunc">gluBuild1DMipmaps</b>(</code></td><td>GLenum  </td><td><var class="pdparam">target</var>, </td></tr><tr><td> </td><td>GLint  </td><td><var class="pdparam">internalFormat</var>, </td></tr><tr><td> </td><td>GLsizei  </td><td><var class="pdparam">width</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">format</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">type</var>, </td></tr><tr><td> </td><td>const void *  </td><td><var class="pdparam">data</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>target</code></em></span></dt><dd><p>
                    Specifies the target texture.  Must be <code class="constant">GLU_TEXTURE_1D</code>.
                </p></dd><dt><span class="term"><em class="parameter"><code>internalFormat</code></em></span></dt><dd><p>
                    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:
                    <code class="constant">GLU_ALPHA</code>,
                    <code class="constant">GLU_ALPHA4</code>,
                    <code class="constant">GLU_ALPHA8</code>,
                    <code class="constant">GLU_ALPHA12</code>,
                    <code class="constant">GLU_ALPHA16</code>,
                    <code class="constant">GLU_LUMINANCE</code>,
                    <code class="constant">GLU_LUMINANCE4</code>,
                    <code class="constant">GLU_LUMINANCE8</code>,
                    <code class="constant">GLU_LUMINANCE12</code>,
                    <code class="constant">GLU_LUMINANCE16</code>,
                    <code class="constant">GLU_LUMINANCE_ALPHA</code>,
                    <code class="constant">GLU_LUMINANCE4_ALPHA4</code>,
                    <code class="constant">GLU_LUMINANCE6_ALPHA2</code>,
                    <code class="constant">GLU_LUMINANCE8_ALPHA8</code>,
                    <code class="constant">GLU_LUMINANCE12_ALPHA4</code>,
                    <code class="constant">GLU_LUMINANCE12_ALPHA12</code>,
                    <code class="constant">GLU_LUMINANCE16_ALPHA16</code>,
                    <code class="constant">GLU_INTENSITY</code>,
                    <code class="constant">GLU_INTENSITY4</code>,
                    <code class="constant">GLU_INTENSITY8</code>,
                    <code class="constant">GLU_INTENSITY12</code>,
                    <code class="constant">GLU_INTENSITY16</code>,
                    <code class="constant">GLU_RGB</code>,
                    <code class="constant">GLU_R3_G3_B2</code>,
                    <code class="constant">GLU_RGB4</code>,
                    <code class="constant">GLU_RGB5</code>,
                    <code class="constant">GLU_RGB8</code>,
                    <code class="constant">GLU_RGB10</code>,
                    <code class="constant">GLU_RGB12</code>,
                    <code class="constant">GLU_RGB16</code>,
                    <code class="constant">GLU_RGBA</code>,
                    <code class="constant">GLU_RGBA2</code>,
                    <code class="constant">GLU_RGBA4</code>,
                    <code class="constant">GLU_RGB5_A1</code>,
                    <code class="constant">GLU_RGBA8</code>,
                    <code class="constant">GLU_RGB10_A2</code>,
                    <code class="constant">GLU_RGBA12</code>, or
                    <code class="constant">GLU_RGBA16</code>.
                </p></dd><dt><span class="term"><em class="parameter"><code>width</code></em></span></dt><dd><p>
                    Specifies the width, in pixels, of the texture image. 
                </p></dd><dt><span class="term"><em class="parameter"><code>format</code></em></span></dt><dd><p>
                    Specifies the format of the pixel data.
                    Must be one of
                    <code class="constant">GLU_COLOR_INDEX</code>,
                    <code class="constant">GLU_DEPTH_COMPONENT</code>,
                    <code class="constant">GLU_RED</code>,
                    <code class="constant">GLU_GREEN</code>,
                    <code class="constant">GLU_BLUE</code>,
                    <code class="constant">GLU_ALPHA</code>,
                    <code class="constant">GLU_RGB</code>,
                    <code class="constant">GLU_RGBA</code>,
                    <code class="constant">GLU_BGR</code>,
                    <code class="constant">GLU_BGRA</code>,
                    <code class="constant">GLU_LUMINANCE</code>, or
                    <code class="constant">GLU_LUMINANCE_ALPHA</code>.
                </p></dd><dt><span class="term"><em class="parameter"><code>type</code></em></span></dt><dd><p>
                    Specifies the data type for <em class="parameter"><code>data</code></em>.
                    Must be one of
                    <code class="constant">GLU_UNSIGNED_BYTE</code>,
                    <code class="constant">GLU_BYTE</code>,
                    <code class="constant">GLU_BITMAP</code>,
                    <code class="constant">GLU_UNSIGNED_SHORT</code>,
                    <code class="constant">GLU_SHORT</code>,
                    <code class="constant">GLU_UNSIGNED_INT</code>,
                    <code class="constant">GLU_INT</code>, 
                    <code class="constant">GLU_FLOAT</code>, 
                    <code class="constant">GLU_UNSIGNED_BYTE_3_3_2</code>,
                    <code class="constant">GLU_UNSIGNED_BYTE_2_3_3_REV</code>,
                    <code class="constant">GLU_UNSIGNED_SHORT_5_6_5</code>,
                    <code class="constant">GLU_UNSIGNED_SHORT_5_6_5_REV</code>,
                    <code class="constant">GLU_UNSIGNED_SHORT_4_4_4_4</code>,
                    <code class="constant">GLU_UNSIGNED_SHORT_4_4_4_4_REV</code>,
                    <code class="constant">GLU_UNSIGNED_SHORT_5_5_5_1</code>,
                    <code class="constant">GLU_UNSIGNED_SHORT_1_5_5_5_REV</code>,
                    <code class="constant">GLU_UNSIGNED_INT_8_8_8_8</code>,
                    <code class="constant">GLU_UNSIGNED_INT_8_8_8_8_REV</code>,
                    <code class="constant">GLU_UNSIGNED_INT_10_10_10_2</code>, or
                    <code class="constant">GLU_UNSIGNED_INT_2_10_10_10_REV</code>.
                </p></dd><dt><span class="term"><em class="parameter"><code>data</code></em></span></dt><dd><p>
                    Specifies a pointer to the image data in memory.
                </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
            <code class="function">gluBuild1DMipmaps</code> builds a series of prefiltered one-dimensional texture maps of decreasing
            resolutions called a mipmap. This is used for the antialiasing of
            texture mapped primitives.
        </p><p>
            A return value of zero indicates success, otherwise a GLU error code is
            returned (see <a class="citerefentry" href="gluErrorString.xml"><span class="citerefentry"><span class="refentrytitle">gluErrorString</span></span></a>).
        </p><p>
            Initially, the <em class="parameter"><code>width</code></em> of <em class="parameter"><code>data</code></em> is checked to see if it is
            a power of 2. If not, a copy of <em class="parameter"><code>data</code></em> is scaled up or down to the
            nearest power of 2. (If <em class="parameter"><code>width</code></em> is exactly between powers of 2, then
            the copy of <em class="parameter"><code>data</code></em> will scale upwards.)  This copy will be used for
            subsequent mipmapping operations described below. 
            For example, if <em class="parameter"><code>width</code></em> is 57, then a copy of <em class="parameter"><code>data</code></em>
            will scale up to 64 before mipmapping
            takes place.
        </p><p>
            Then, proxy textures (see <a class="citerefentry" href="glTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage1D</span></span></a>) are used to determine if
            the implementation can fit the requested texture. If not, <em class="parameter"><code>width</code></em> is
            continually halved until it fits.
        </p><p>
            Next, a series of mipmap levels is built by decimating a copy of
            <em class="parameter"><code>data</code></em> in half
            until size 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:mrow>
                    <mml:mn>1</mml:mn>
                    <mml:mo>×</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math>
            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.
        </p><p>
            <a class="citerefentry" href="glTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage1D</span></span></a> is called to load each of these mipmap levels.
            Level 0 is a copy of <em class="parameter"><code>data</code></em>. 
            The highest level is 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:mrow>
                    <mml:mfenced open="" close="">
                        <mml:msub><mml:mi mathvariant="italic">log</mml:mi>
                        <mml:mn>2</mml:mn>
                        </mml:msub>
                    </mml:mfenced>
                    <mml:mo>⁡</mml:mo>
                    <mml:mfenced open="(" close=")">
                        <mml:mi mathvariant="italic">width</mml:mi>
                    </mml:mfenced>
                </mml:mrow>
            </mml:math>.
            For example, if <em class="parameter"><code>width</code></em> is 64 and the implementation can store a texture of
            this size, the following mipmap levels are
            built: 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:mrow>
                    <mml:mn>64</mml:mn>
                    <mml:mo>×</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math>, 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:mrow>
                    <mml:mn>32</mml:mn>
                    <mml:mo>×</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math>, 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:mrow>
                    <mml:mn>16</mml:mn>
                    <mml:mo>×</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math>, 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:mrow>
                    <mml:mn>8</mml:mn>
                    <mml:mo>×</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math>,
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:mrow>
                    <mml:mn>4</mml:mn>
                    <mml:mo>×</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math>, 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:mrow>
                    <mml:mn>2</mml:mn>
                    <mml:mo>×</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math>,
            and 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:mrow>
                    <mml:mn>1</mml:mn>
                    <mml:mo>×</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math>.
            These correspond to 
            levels 0 through 6, respectively.
        </p><p>
            See the <a class="citerefentry" href="glTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage1D</span></span></a> reference page for a description of the
            acceptable values for the <em class="parameter"><code>type</code></em> parameter. See the <a class="citerefentry" href="glDrawPixels.xml"><span class="citerefentry"><span class="refentrytitle">glDrawPixels</span></span></a> 
            reference page for a description of the acceptable values 
            for the <em class="parameter"><code>data</code></em> parameter.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
            Note that there is no direct way of querying the maximum level. This can
            be derived indirectly via <a class="citerefentry" href="glGetTexLevelParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a>. First, query
            for the
            width actually used at level 0. 
            (The width may not be equal to <em class="parameter"><code>width</code></em> since
            proxy textures might have scaled it to fit the implementation.)
            Then the maximum
            level can be derived from the formula 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:mrow>
                    <mml:mfenced open="" close="">
                        <mml:msub><mml:mi mathvariant="italic">log</mml:mi>
                        <mml:mn>2</mml:mn>
                        </mml:msub>
                    </mml:mfenced>
                    <mml:mo>⁡</mml:mo>
                    <mml:mfenced open="(" close=")">
                        <mml:mi mathvariant="italic">width</mml:mi>
                    </mml:mfenced>
                </mml:mrow>
            </mml:math>.
        </p><p>
            Formats <code class="constant">GLU_BGR</code>, and <code class="constant">GLU_BGRA</code>, and types 
            <code class="constant">GLU_UNSIGNED_BYTE_3_3_2</code>,
            <code class="constant">GLU_UNSIGNED_BYTE_2_3_3_REV</code>,
            <code class="constant">GLU_UNSIGNED_SHORT_5_6_5</code>,
            <code class="constant">GLU_UNSIGNED_SHORT_5_6_5_REV</code>,
            <code class="constant">GLU_UNSIGNED_SHORT_4_4_4_4</code>,
            <code class="constant">GLU_UNSIGNED_SHORT_4_4_4_4_REV</code>,
            <code class="constant">GLU_UNSIGNED_SHORT_5_5_5_1</code>,
            <code class="constant">GLU_UNSIGNED_SHORT_1_5_5_5_REV</code>,
            <code class="constant">GLU_UNSIGNED_INT_8_8_8_8</code>,
            <code class="constant">GLU_UNSIGNED_INT_8_8_8_8_REV</code>,
            <code class="constant">GLU_UNSIGNED_INT_10_10_10_2</code>, and
            <code class="constant">GLU_UNSIGNED_INT_2_10_10_10_REV</code> are only available if the GL version 
            is 1.2 or greater, and if the GLU version is 1.3 or greater.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
            <code class="constant">GLU_INVALID_VALUE</code> is returned if <em class="parameter"><code>width</code></em> is &lt; 1.
        </p><p>
            <code class="constant">GLU_INVALID_ENUM</code> is returned if <em class="parameter"><code>format</code></em> or <em class="parameter"><code>type</code></em> are not legal.
        </p><p>
            <code class="constant">GLU_INVALID_OPERATION</code> is returned if <em class="parameter"><code>type</code></em> is <code class="constant">GLU_UNSIGNED_BYTE_3_3_2</code> or <code class="constant">GLU_UNSIGNED_BYTE_2_3_3_REV</code>
            and <em class="parameter"><code>format</code></em> is not <code class="constant">GLU_RGB</code>.
        </p><p>
            <code class="constant">GLU_INVALID_OPERATION</code> is returned if <em class="parameter"><code>type</code></em> is <code class="constant">GLU_UNSIGNED_SHORT_5_6_5</code> or <code class="constant">GLU_UNSIGNED_SHORT_5_6_5_REV</code>
            and <em class="parameter"><code>format</code></em> is not <code class="constant">GLU_RGB</code>.
        </p><p>
            <code class="constant">GLU_INVALID_OPERATION</code> is returned if <em class="parameter"><code>type</code></em> is <code class="constant">GLU_UNSIGNED_SHORT_4_4_4_4</code> or <code class="constant">GLU_UNSIGNED_SHORT_4_4_4_4_REV</code>
            and <em class="parameter"><code>format</code></em> is neither <code class="constant">GLU_RGBA</code> nor <code class="constant">GLU_BGRA</code>.
        </p><p>
            <code class="constant">GLU_INVALID_OPERATION</code> is returned if <em class="parameter"><code>type</code></em> is <code class="constant">GLU_UNSIGNED_SHORT_5_5_5_1</code> or <code class="constant">GLU_UNSIGNED_SHORT_1_5_5_5_REV</code>
            and <em class="parameter"><code>format</code></em> is neither <code class="constant">GLU_RGBA</code> nor <code class="constant">GLU_BGRA</code>.
        </p><p>
            <code class="constant">GLU_INVALID_OPERATION</code> is returned if <em class="parameter"><code>type</code></em> is <code class="constant">GLU_UNSIGNED_INT_8_8_8_8</code> or <code class="constant">GLU_UNSIGNED_INT_8_8_8_8_REV</code>
            and <em class="parameter"><code>format</code></em> is neither <code class="constant">GLU_RGBA</code> nor <code class="constant">GLU_BGRA</code>.
        </p><p>
            <code class="constant">GLU_INVALID_OPERATION</code> is returned if <em class="parameter"><code>type</code></em> is <code class="constant">GLU_UNSIGNED_INT_10_10_10_2</code> or <code class="constant">GLU_UNSIGNED_INT_2_10_10_10_REV</code>
            and <em class="parameter"><code>format</code></em> is neither <code class="constant">GLU_RGBA</code> nor <code class="constant">GLU_BGRA</code>.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
            <a class="citerefentry" href="gluBuild1DMipmapLevels.xml"><span class="citerefentry"><span class="refentrytitle">gluBuild1DMipmapLevels</span></span></a>,
            <a class="citerefentry" href="gluBuild2DMipmapLevels.xml"><span class="citerefentry"><span class="refentrytitle">gluBuild2DMipmapLevels</span></span></a>, 
            <a class="citerefentry" href="gluBuild2DMipmaps.xml"><span class="citerefentry"><span class="refentrytitle">gluBuild2DMipmaps</span></span></a>,
            <a class="citerefentry" href="gluBuild3DMipmapLevels.xml"><span class="citerefentry"><span class="refentrytitle">gluBuild3DMipmapLevels</span></span></a>,
            <a class="citerefentry" href="gluBuild3DMipmaps.xml"><span class="citerefentry"><span class="refentrytitle">gluBuild3DMipmaps</span></span></a>,
            <a class="citerefentry" href="gluErrorString.xml"><span class="citerefentry"><span class="refentrytitle">gluErrorString</span></span></a>, 
            <a class="citerefentry" href="glDrawPixels.xml"><span class="citerefentry"><span class="refentrytitle">glDrawPixels</span></span></a>,
            <a class="citerefentry" href="glGetTexImage.xml"><span class="citerefentry"><span class="refentrytitle">glGetTexImage</span></span></a>,
            <a class="citerefentry" href="glGetTexLevelParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a>, 
            <a class="citerefentry" href="glTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage1D</span></span></a>,
            <a class="citerefentry" href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>, 
            <a class="citerefentry" href="glTexImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage3D</span></span></a>
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
            Copyright <span class="trademark"></span>© 1991-2006
            Silicon Graphics, Inc. This document is licensed under the SGI
            Free Software B License. For details, see
            <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
        </p></div></div></body></html>
