<div class="refentry" title="glCopyTexImage2D"><a id="glCopyTexImage2D"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glCopyTexImage2D — specify a two-dimensional texture image with pixels from the color buffer</p></div><div class="refsynopsisdiv" title="C Specification"><h2>C Specification</h2><div class="funcsynopsis"><table class="funcprototype-table"><tr><td><code class="funcdef">void <b class="fsfunc">glCopyTexImage2D</b>(</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>GLenum <var class="pdparam">internalformat</var>, </td></tr><tr><td> </td><td>GLint <var class="pdparam">x</var>, </td></tr><tr><td> </td><td>GLint <var class="pdparam">y</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>GLint <var class="pdparam">border</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Parameters"><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">GL_TEXTURE_2D</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 <em class="parameter"><code>n</code></em>

is the <em class="parameter"><code>n</code></em>th mipmap reduction image.</p></dd><dt><span class="term">

<em class="parameter"><code>internalformat</code></em>

</span></dt><dd><p>Specifies the color components of the texture. Must be one

of the following symbolic constants:

<code class="constant">GL_ALPHA</code>,

<code class="constant">GL_LUMINANCE</code>,

<code class="constant">GL_LUMINANCE_ALPHA</code>,

<code class="constant">GL_RGB</code>, or

<code class="constant">GL_RGBA</code>.</p></dd><dt><span class="term">

<em class="parameter"><code>x</code></em>, <em class="parameter"><code>y</code></em>

</span></dt><dd><p>Specify the window coordinates of the lower left

corner of the rectangular region of pixels to be

copied.</p></dd><dt><span class="term">

<em class="parameter"><code>width</code></em>

</span></dt><dd><p>Specifies the width of the texture image. Must be 0 or

<math overflow="scroll">

<msup><mn>2</mn><mi>n</mi></msup>

</math>

for some integer <em class="replaceable"><code>n</code></em>.</p></dd><dt><span class="term">

<em class="parameter"><code>height</code></em>

</span></dt><dd><p>Specifies the height of the texture image. Must be 0 or

<math overflow="scroll">

<msup><mn>2</mn><mi>m</mi></msup>

</math>

for some integer <em class="replaceable"><code>m</code></em>.</p></dd><dt><span class="term">

<em class="parameter"><code>border</code></em>

</span></dt><dd><p>Specifies the width of the border. Must be 0.</p></dd></dl></div></div><div class="refsect1" title="Description"><a id="description"></a><h2>Description</h2><p>

<code class="function">glCopyTexImage2D</code>

defines a two-dimensional texture image with pixels from the

color buffer.</p><p>The screen-aligned pixel rectangle with lower left corner

at (<em class="parameter"><code>x</code></em>, <em class="parameter"><code>y</code></em>)

and with a width of

<math overflow="scroll">

<mi>width</mi>

</math>

and a height of

<math overflow="scroll">

<mi>height</mi>

</math>

defines the texture array at the mipmap level specified by

<em class="parameter"><code>level</code></em>. <em class="parameter"><code>internalformat</code></em>

specifies the color components of the texture.</p><p>

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.</p><p><em class="parameter"><code>internalformat</code></em> 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 <code class="constant">GL_RGB</code> color buffer can be used to create

<code class="constant">GL_LUMINANCE</code> or <code class="constant">GL_RGB</code>

textures, but not <code class="constant">GL_ALPHA</code>,

<code class="constant">GL_LUMINANCE_ALPHA</code> or <code class="constant">GL_RGBA</code>

textures.</p><p>Pixel ordering is such that lower <em class="parameter"><code>x</code></em>

and <em class="parameter"><code>y</code></em> screen coordinates correspond to lower

<em class="parameter"><code>s</code></em> and <em class="parameter"><code>t</code></em> texture

coordinates.</p><p>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.</p></div><div class="refsect1" title="Notes"><a id="notes"></a><h2>Notes</h2><p>An image with height or width of 0 indicates a

null-texture.</p></div><div class="refsect1" title="Errors"><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>.</p><p><code class="constant">GL_INVALID_OPERATION</code> is generated if

<em class="parameter"><code>internalformat</code></em> is not compatible

with the color buffer format.</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

<math overflow="scroll">

<msub><mo>log</mo><mn>2</mn></msub><mi>max</mi>

</math>, where

<em class="replaceable"><code>max</code></em> is the returned value of

<code class="constant">GL_MAX_TEXTURE_SIZE</code>.</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, greater than

<code class="constant">GL_MAX_TEXTURE_SIZE</code>, or if

<em class="parameter"><code>width</code></em> or <em class="parameter"><code>height</code></em>

cannot be represented as

<math overflow="scroll">

<msup><mn>2</mn><mi>k</mi></msup>

</math>

for some integer <em class="replaceable"><code>k</code></em>.</p><p><code class="constant">GL_INVALID_VALUE</code> is generated if

<em class="parameter"><code>border</code></em> is not 0.</p><p>

<code class="constant">GL_INVALID_ENUM</code> is generated if

<em class="parameter"><code>internalformat</code></em>

is not an accepted constant.

</p></div><div class="refsect1" title="Associated Gets"><a id="associatedgets"></a><h2>Associated Gets</h2><p>

<a class="citerefentry" href="glGet"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>

with argument <code class="constant">GL_MAX_TEXTURE_SIZE</code></p></div><div class="refsect1" title="See Also"><a id="seealso"></a><h2>See Also</h2><p>

<a class="citerefentry" href="glCompressedTexImage2D"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage2D</span></span></a>,

<a class="citerefentry" href="glCopyTexSubImage2D"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage2D</span></span></a>,

<a class="citerefentry" href="glGet"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>,

<a class="citerefentry" href="glTexEnv"><span class="citerefentry"><span class="refentrytitle">glTexEnv</span></span></a>,

<a class="citerefentry" href="glTexImage2D"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>,

<a class="citerefentry" href="glTexSubImage2D"><span class="citerefentry"><span class="refentrytitle">glTexSubImage2D</span></span></a>,

<a class="citerefentry" href="glTexParameter"><span class="citerefentry"><span class="refentrytitle">glTexParameter</span></span></a>

</p></div><div class="refsect1" title="Copyright"><a id="copyright"></a><h2>Copyright</h2><p>

Copyright © 2003-2004

Silicon Graphics, Inc. This document is licensed under the SGI

Free Software B License. For details, see

<a class="ulink" href="https://web.archive.org/web/20171022161616/http://oss.sgi.com/projects/FreeB/" target="_top">https://web.archive.org/web/20171022161616/http://oss.sgi.com/projects/FreeB/</a>.

</p></div></div>