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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>glCompressedTexSubImage2D</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1" /></head><body><div class="refentry"><a id="glCompressedTexSubImage2D"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glCompressedTexSubImage2D — specify a two-dimensional texture subimage in a compressed format</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">void <strong class="fsfunc">glCompressedTexSubImage2D</strong>(</code></td><td>GLenum <var class="pdparam">target</var>, </td></tr><tr><td> </td><td>GLint <var class="pdparam">level</var>, </td></tr><tr><td> </td><td>GLint <var class="pdparam">xoffset</var>, </td></tr><tr><td> </td><td>GLint <var class="pdparam">yoffset</var>, </td></tr><tr><td> </td><td>GLsizei <var class="pdparam">width</var>, </td></tr><tr><td> </td><td>GLsizei <var class="pdparam">height</var>, </td></tr><tr><td> </td><td>GLenum <var class="pdparam">format</var>, </td></tr><tr><td> </td><td>GLsizei <var class="pdparam">imageSize</var>, </td></tr><tr><td> </td><td>const GLvoid * <var class="pdparam">data</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>target</code></em></span></dt><dd><p>
                    Specifies the target texture of the active texture unit.
                    Must be <code class="constant">GL_TEXTURE_2D</code>,
                    <code class="constant">GL_TEXTURE_CUBE_MAP_POSITIVE_X</code>,
                    <code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_X</code>,
                    <code class="constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Y</code>,
                    <code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</code>,
                    <code class="constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Z</code>, or
                    <code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</code>.
                </p></dd><dt><span class="term"><em class="parameter"><code>level</code></em></span></dt><dd><p>
                    Specifies the level-of-detail number.
                    Level 0 is the base image level.
                    Level <span class="emphasis"><em>n</em></span> is the <span class="emphasis"><em>n</em></span>th mipmap reduction image.
                </p></dd><dt><span class="term"><em class="parameter"><code>xoffset</code></em></span></dt><dd><p>
                    Specifies a texel offset in the x direction within the texture array.
                </p></dd><dt><span class="term"><em class="parameter"><code>yoffset</code></em></span></dt><dd><p>
                    Specifies a texel offset in the y direction within the texture array.
                </p></dd><dt><span class="term"><em class="parameter"><code>width</code></em></span></dt><dd><p>
                    Specifies the width of the texture subimage.
                </p></dd><dt><span class="term"><em class="parameter"><code>height</code></em></span></dt><dd><p>
                    Specifies the height of the texture subimage.
                </p></dd><dt><span class="term"><em class="parameter"><code>format</code></em></span></dt><dd><p>
                    Specifies the format of the compressed image data stored at address <em class="parameter"><code>data</code></em>.
                </p></dd><dt><span class="term"><em class="parameter"><code>imageSize</code></em></span></dt><dd><p>
                    Specifies the number of unsigned bytes of image data starting at the
                    address specified by <em class="parameter"><code>data</code></em>.
                </p></dd><dt><span class="term"><em class="parameter"><code>data</code></em></span></dt><dd><p>
                    Specifies a pointer to the compressed image data in memory.
                </p></dd></dl></div></div><div class="refsect1"><a id="description"></a><h2>Description</h2><p>
            Texturing maps a portion of a specified texture image 
            onto each graphical primitive for which texturing is
            active.  Texturing is active when the current fragment shader or
            vertex shader makes use of built-in texture lookup 
            functions.
        </p><p>
            <code class="function">glCompressedTexSubImage2D</code> redefines a contiguous subregion of an existing two-dimensional
            texture image.  The texels referenced by <em class="parameter"><code>data</code></em> replace the portion of the
            existing texture array with x indices <em class="parameter"><code>xoffset</code></em> and 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <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>,
            and the y indices <em class="parameter"><code>yoffset</code></em> and 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <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>,
            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.
        </p><p>
            <em class="parameter"><code>format</code></em> must be the same extension-specified
            compressed-texture format previously specified by
            <a class="citerefentry" href="glCompressedTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage2D</span></span></a>.
        </p></div><div class="refsect1"><a id="notes"></a><h2>Notes</h2><p>
            <code class="function">glCompressedTexSubImage2D</code>
            specifies a two-dimensional or cube-map texture for the current texture unit,
            specified with <a class="citerefentry" href="glActiveTexture.xml"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>.
        </p></div><div class="refsect1"><a id="errors"></a><h2>Errors</h2><p>
            <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>target</code></em> is 
            not <code class="constant">GL_TEXTURE_2D</code>,
            <code class="constant">GL_TEXTURE_CUBE_MAP_POSITIVE_X</code>,
            <code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_X</code>,
            <code class="constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Y</code>,
            <code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</code>,
            <code class="constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Z</code>, or
            <code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</code>.
        </p><p>
            <code class="constant">GL_INVALID_ENUM</code> is generated if 
            <em class="parameter"><code>format</code></em> is not a supported format returned in
            <code class="constant">GL_COMPRESSED_TEXTURE_FORMATS</code>.
        </p><p>
            <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>level</code></em> is less than 0.
        </p><p>
            <code class="constant">GL_INVALID_VALUE</code> may be generated if <em class="parameter"><code>level</code></em> is greater
            than 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:mrow>
                    <mml:msub><mml:mi mathvariant="italic">log</mml:mi>
                    <mml:mn>2</mml:mn>
                    </mml:msub>
                    <mml:mo>⁢</mml:mo>
                    <mml:mi mathvariant="italic">max</mml:mi>
                </mml:mrow>
            </mml:math>,
            where 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">max</mml:mi></mml:math>
            is the returned value of <code class="constant">GL_MAX_TEXTURE_SIZE</code> when <em class="parameter"><code>target</code></em>
            is <code class="constant">GL_TEXTURE_2D</code> or <code class="constant">GL_MAX_CUBE_MAP_TEXTURE_SIZE</code> when
            <em class="parameter"><code>target</code></em> is not <code class="constant">GL_TEXTURE_2D</code>.
        </p><p>
            <code class="constant">GL_INVALID_VALUE</code> is generated if 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:mrow>
                    <mml:mi mathvariant="italic">xoffset</mml:mi>
                    <mml:mo>&lt;</mml:mo>
                    0
                </mml:mrow>
            </mml:math>,
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <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>&gt;</mml:mo>
                    <mml:mi mathvariant="italic">w</mml:mi>
                </mml:mrow>
            </mml:math>,
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:mrow>
                    <mml:mi mathvariant="italic">yoffset</mml:mi>
                    <mml:mo>&lt;</mml:mo>
                    0
                </mml:mrow>
            </mml:math>,
            or 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <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>&gt;</mml:mo>
                    <mml:mi mathvariant="italic">h</mml:mi>
                </mml:mrow>
            </mml:math>,
            where 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">w</mml:mi></mml:math>
            is the width and
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">h</mml:mi></mml:math>
            is the height
            of the texture image being modified.
        </p><p>
            <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>width</code></em> or <em class="parameter"><code>height</code></em> is less than 0.
        </p><p>
            <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>imageSize</code></em> is not consistent with
            the format, dimensions, and contents of the specified compressed image
            data.
        </p><p>
            <code class="constant">GL_INVALID_OPERATION</code> is generated if the texture array has not
            been defined by a previous 
            <a class="citerefentry" href="glCompressedTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage2D</span></span></a>
            operation whose <em class="parameter"><code>internalformat</code></em> matches the <em class="parameter"><code>format</code></em>
            of <code class="function">glCompressedTexSubImage2D</code>.
        </p><p>
            <code class="constant">GL_INVALID_OPERATION</code> is generated if parameter combinations are not
            supported by the specific compressed internal format as specified in the
            specific texture compression extension.
        </p><p>
            Undefined results, including abnormal program termination, are generated if
            <em class="parameter"><code>data</code></em> is not encoded in a manner consistent with the extension
            specification defining the internal compression format.
        </p></div><div class="refsect1"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
            <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with arguments 
            <code class="constant">GL_NUM_COMPRESSED_TEXTURE_FORMATS</code> and
            <code class="constant">GL_COMPRESSED_TEXTURE_FORMATS</code>
        </p><p>
            <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>
            with argument <code class="constant">GL_MAX_TEXTURE_SIZE</code> or
            <code class="constant">GL_MAX_CUBE_MAP_TEXTURE_SIZE</code>
        </p></div><div class="refsect1"><a id="seealso"></a><h2>See Also</h2><p>
            <a class="citerefentry" href="glActiveTexture.xml"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>,
            <a class="citerefentry" href="glCompressedTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage2D</span></span></a>,
            <a class="citerefentry" href="glCopyTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage2D</span></span></a>,
            <a class="citerefentry" href="glCopyTexSubImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage2D</span></span></a>,
            <a class="citerefentry" href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>,
            <a class="citerefentry" href="glTexSubImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage2D</span></span></a>,
            <a class="citerefentry" href="glTexParameter.xml"><span class="citerefentry"><span class="refentrytitle">glTexParameter</span></span></a>
        </p></div><div class="refsect1"><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>