<div class="refentry" title="glTexSubImage2D"><a id="glTexSubImage2D"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glTexSubImage2D — specify a two-dimensional texture subimage</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">glTexSubImage2D</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>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>GLenum <var class="pdparam">type</var>, </td></tr><tr><td> </td><td>const GLvoid * <var class="pdparam">pixels</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>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 of the pixel data. The following

symbolic values are accepted:

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

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

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

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

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

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

</span></dt><dd><p>Specifies the data type of the pixel data. The

following symbolic values are accepted:

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

<code class="constant">GL_UNSIGNED_SHORT_5_6_5</code>,

<code class="constant">GL_UNSIGNED_SHORT_4_4_4_4</code>, and

<code class="constant">GL_UNSIGNED_SHORT_5_5_5_1</code>.</p></dd><dt><span class="term">

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

</span></dt><dd><p>Specifies a pointer to the image data in

memory.</p></dd></dl></div></div><div class="refsect1" title="Description"><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 enabled.

To enable and disable two-dimensional texturing, call

<a class="citerefentry" href="glEnable"><span class="citerefentry"><span class="refentrytitle">glEnable</span></span></a> and

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

with argument <code class="constant">GL_TEXTURE_2D</code>.

Two-dimensional texturing is initially disabled.

</p><p>

<code class="function">glTexSubImage2D</code>

redefines a contiguous subregion of an existing two-dimensional

texture image. The texels referenced by <em class="parameter"><code>pixels</code></em>

replace the portion of the existing texture array with x indices

<em class="parameter"><code>xoffset</code></em> and

<math overflow="scroll">

<mi>xoffset</mi><mo>+</mo><mi>width</mi><mo>-</mo><mn>1</mn>

</math>,

inclusive, and y indices <em class="parameter"><code>yoffset</code></em> and

<math overflow="scroll">

<mi>yoffset</mi><mo>+</mo><mi>height</mi><mo>-</mo><mn>1</mn>

</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 zero width or

height, but such a specification has no effect.</p></div><div class="refsect1" title="Notes"><a id="notes"></a><h2>Notes</h2><p>

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

affects texture images in exactly the way it affects

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

</p><p>

<code class="function">glTexSubImage2D</code>

specifies a two-dimensional sub texture for the currently bound texture,

specified with

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

and current texture

unit, specified with

<a class="citerefentry" href="glActiveTexture"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>.

</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 the texture array has not been defined by a previous

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

<a class="citerefentry" href="glCopyTexImage2D"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage2D</span></span></a>

operation.</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

<math overflow="scroll">

<mi>xoffset</mi><mo>&lt;</mo>0

</math>,

<math overflow="scroll">

<mi>xoffset</mi><mo>+</mo><mi>width</mi><mo>&gt;</mo>

<mi>w</mi>

</math>,

<math overflow="scroll">

<mi>yoffset</mi><mo>&lt;</mo>0

</math>, or

<math overflow="scroll">

<mi>yoffset</mi><mo>+</mo><mi>height</mi><mo>&gt;</mo>

<mi>h</mi>

</math>, where

<em class="replaceable"><code>w</code></em> is the texture width and

<em class="replaceable"><code>h</code></em> is the texture height.</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_ENUM</code> is generated if

<em class="parameter"><code>format</code></em> is not an accepted constant.</p><p><code class="constant">GL_INVALID_ENUM</code> is generated if

<em class="parameter"><code>type</code></em> is not an accepted constant.</p><p><code class="constant">GL_INVALID_OPERATION</code> is generated if

<em class="parameter"><code>type</code></em> is

<code class="constant">GL_UNSIGNED_SHORT_5_6_5</code> and

<em class="parameter"><code>format</code></em> is not

<code class="constant">GL_RGB</code>.</p><p><code class="constant">GL_INVALID_OPERATION</code> is generated if

<em class="parameter"><code>type</code></em> is one of

<code class="constant">GL_UNSIGNED_SHORT_4_4_4_4</code>, or

<code class="constant">GL_UNSIGNED_SHORT_5_5_5_1</code> and

<em class="parameter"><code>format</code></em> is not

<code class="constant">GL_RGBA</code>.</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="glActiveTexture"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>,

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

<a class="citerefentry" href="glCompressedTexSubImage2D"><span class="citerefentry"><span class="refentrytitle">glCompressedTexSubImage2D</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="glPixelStorei"><span class="citerefentry"><span class="refentrytitle">glPixelStorei</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="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>