| 1 | <?xml version="1.0" encoding="UTF-8"?> |
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| 4 | <?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" /><link rel="stylesheet" type="text/css" href="opengl-man.css" /><title>glDrawBuffer - OpenGL 4 Reference Pages</title><meta name="generator" content="DocBook XSL Stylesheets V1.69.1" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glDrawBuffer"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glDrawBuffer — specify which color buffers are to be drawn into</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><p><code class="funcdef">void <b class="fsfunc">glDrawBuffer</b>(</code>GLenum <var class="pdparam">mode</var><code>)</code>;</p></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>mode</code></em></span></dt><dd><p> |
| 5 | Specifies up to four color buffers to be drawn into. |
| 6 | Symbolic constants |
| 7 | <code class="constant">GL_NONE</code>, |
| 8 | <code class="constant">GL_FRONT_LEFT</code>, |
| 9 | <code class="constant">GL_FRONT_RIGHT</code>, |
| 10 | <code class="constant">GL_BACK_LEFT</code>, |
| 11 | <code class="constant">GL_BACK_RIGHT</code>, |
| 12 | <code class="constant">GL_FRONT</code>, |
| 13 | <code class="constant">GL_BACK</code>, |
| 14 | <code class="constant">GL_LEFT</code>, |
| 15 | <code class="constant">GL_RIGHT</code>, and |
| 16 | <code class="constant">GL_FRONT_AND_BACK</code> |
| 17 | are accepted. |
| 18 | The initial value is <code class="constant">GL_FRONT</code> for single-buffered contexts, |
| 19 | and <code class="constant">GL_BACK</code> for double-buffered contexts. |
| 20 | </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p> |
| 21 | When colors are written to the frame buffer, |
| 22 | they are written into the color buffers specified by <code class="function">glDrawBuffer</code>. |
| 23 | The specifications are as follows: |
| 24 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_NONE</code></span></dt><dd><p> |
| 25 | No color buffers are written. |
| 26 | </p></dd><dt><span class="term"><code class="constant">GL_FRONT_LEFT</code></span></dt><dd><p> |
| 27 | Only the front left color buffer is written. |
| 28 | </p></dd><dt><span class="term"><code class="constant">GL_FRONT_RIGHT</code></span></dt><dd><p> |
| 29 | Only the front right color buffer is written. |
| 30 | </p></dd><dt><span class="term"><code class="constant">GL_BACK_LEFT</code></span></dt><dd><p> |
| 31 | Only the back left color buffer is written. |
| 32 | </p></dd><dt><span class="term"><code class="constant">GL_BACK_RIGHT</code></span></dt><dd><p> |
| 33 | Only the back right color buffer is written. |
| 34 | </p></dd><dt><span class="term"><code class="constant">GL_FRONT</code></span></dt><dd><p> |
| 35 | Only the front left and front right color buffers are written. |
| 36 | If there is no front right color buffer, |
| 37 | only the front left color buffer is written. |
| 38 | </p></dd><dt><span class="term"><code class="constant">GL_BACK</code></span></dt><dd><p> |
| 39 | Only the back left and back right color buffers are written. |
| 40 | If there is no back right color buffer, |
| 41 | only the back left color buffer is written. |
| 42 | </p></dd><dt><span class="term"><code class="constant">GL_LEFT</code></span></dt><dd><p> |
| 43 | Only the front left and back left color buffers are written. |
| 44 | If there is no back left color buffer, |
| 45 | only the front left color buffer is written. |
| 46 | </p></dd><dt><span class="term"><code class="constant">GL_RIGHT</code></span></dt><dd><p> |
| 47 | Only the front right and back right color buffers are written. |
| 48 | If there is no back right color buffer, |
| 49 | only the front right color buffer is written. |
| 50 | </p></dd><dt><span class="term"><code class="constant">GL_FRONT_AND_BACK</code></span></dt><dd><p> |
| 51 | All the front and back color buffers |
| 52 | (front left, front right, back left, back right) |
| 53 | are written. |
| 54 | If there are no back color buffers, |
| 55 | only the front left and front right color buffers are written. |
| 56 | If there are no right color buffers, |
| 57 | only the front left and back left color buffers are written. |
| 58 | If there are no right or back color buffers, |
| 59 | only the front left color buffer is written. |
| 60 | </p></dd></dl></div><p> |
| 61 | If more than one color buffer is selected for drawing, |
| 62 | then blending or logical operations are computed and applied independently |
| 63 | for each color buffer and can produce different results in each buffer. |
| 64 | </p><p> |
| 65 | Monoscopic contexts include only |
| 66 | <span class="emphasis"><em>left</em></span> |
| 67 | buffers, and stereoscopic contexts include both |
| 68 | <span class="emphasis"><em>left</em></span> |
| 69 | and |
| 70 | <span class="emphasis"><em>right</em></span> |
| 71 | buffers. |
| 72 | Likewise, single-buffered contexts include only |
| 73 | <span class="emphasis"><em>front</em></span> |
| 74 | buffers, and double-buffered contexts include both |
| 75 | <span class="emphasis"><em>front</em></span> |
| 76 | and |
| 77 | <span class="emphasis"><em>back</em></span> |
| 78 | buffers. |
| 79 | The context is selected at GL initialization. |
| 80 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p> |
| 81 | <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>mode</code></em> is not an accepted value. |
| 82 | </p><p> |
| 83 | <code class="constant">GL_INVALID_OPERATION</code> is generated if none of the buffers indicated |
| 84 | by <em class="parameter"><code>mode</code></em> exists. |
| 85 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p> |
| 86 | <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_DRAW_BUFFER</code> |
| 87 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p> |
| 88 | <a href="glBlendFunc.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFunc</span></span></a>, |
| 89 | <a href="glColorMask.xml"><span class="citerefentry"><span class="refentrytitle">glColorMask</span></span></a>, |
| 90 | <a href="glDrawBuffers.xml"><span class="citerefentry"><span class="refentrytitle">glDrawBuffers</span></span></a>, |
| 91 | <a href="glLogicOp.xml"><span class="citerefentry"><span class="refentrytitle">glLogicOp</span></span></a>, |
| 92 | <a href="glReadBuffer.xml"><span class="citerefentry"><span class="refentrytitle">glReadBuffer</span></span></a> |
| 93 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p> |
| 94 | Copyright <span class="trademark"></span>© 1991-2006 |
| 95 | Silicon Graphics, Inc. This document is licensed under the SGI |
| 96 | Free Software B License. For details, see |
| 97 | <a href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>. |
| 98 | </p></div></div></body></html> |