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+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
+ "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
+<refentry id="glMinmax">
+ <refmeta>
+ <refmetainfo>
+ <copyright>
+ <year>1991-2006</year>
+ <holder>Silicon Graphics, Inc.</holder>
+ </copyright>
+ </refmetainfo>
+ <refentrytitle>glMinmax</refentrytitle>
+ <manvolnum>3G</manvolnum>
+ </refmeta>
+ <refnamediv>
+ <refname>glMinmax</refname>
+ <refpurpose>define minmax table</refpurpose>
+ </refnamediv>
+ <refsynopsisdiv><title>C Specification</title>
+ <funcsynopsis>
+ <funcprototype>
+ <funcdef>void <function>glMinmax</function></funcdef>
+ <paramdef>GLenum <parameter>target</parameter></paramdef>
+ <paramdef>GLenum <parameter>internalformat</parameter></paramdef>
+ <paramdef>GLboolean <parameter>sink</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+ <refsect1 id="parameters"><title>Parameters</title>
+ <variablelist>
+ <varlistentry>
+ <term><parameter>target</parameter></term>
+ <listitem>
+ <para>
+ The minmax table whose parameters are to be set.
+ Must be
+ <constant>GL_MINMAX</constant>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>internalformat</parameter></term>
+ <listitem>
+ <para>
+ The format of entries in the minmax table.
+ Must be one of
+ <constant>GL_ALPHA</constant>,
+ <constant>GL_ALPHA4</constant>,
+ <constant>GL_ALPHA8</constant>,
+ <constant>GL_ALPHA12</constant>,
+ <constant>GL_ALPHA16</constant>,
+ <constant>GL_LUMINANCE</constant>,
+ <constant>GL_LUMINANCE4</constant>,
+ <constant>GL_LUMINANCE8</constant>,
+ <constant>GL_LUMINANCE12</constant>,
+ <constant>GL_LUMINANCE16</constant>,
+ <constant>GL_LUMINANCE_ALPHA</constant>,
+ <constant>GL_LUMINANCE4_ALPHA4</constant>,
+ <constant>GL_LUMINANCE6_ALPHA2</constant>,
+ <constant>GL_LUMINANCE8_ALPHA8</constant>,
+ <constant>GL_LUMINANCE12_ALPHA4</constant>,
+ <constant>GL_LUMINANCE12_ALPHA12</constant>,
+ <constant>GL_LUMINANCE16_ALPHA16</constant>,
+ <constant>GL_R3_G3_B2</constant>,
+ <constant>GL_RGB</constant>,
+ <constant>GL_RGB4</constant>,
+ <constant>GL_RGB5</constant>,
+ <constant>GL_RGB8</constant>,
+ <constant>GL_RGB10</constant>,
+ <constant>GL_RGB12</constant>,
+ <constant>GL_RGB16</constant>,
+ <constant>GL_RGBA</constant>,
+ <constant>GL_RGBA2</constant>,
+ <constant>GL_RGBA4</constant>,
+ <constant>GL_RGB5_A1</constant>,
+ <constant>GL_RGBA8</constant>,
+ <constant>GL_RGB10_A2</constant>,
+ <constant>GL_RGBA12</constant>, or
+ <constant>GL_RGBA16</constant>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>sink</parameter></term>
+ <listitem>
+ <para>
+ If <constant>GL_TRUE</constant>, pixels will be consumed by the minmax
+ process and no drawing or texture loading will take place.
+ If <constant>GL_FALSE</constant>, pixels will proceed to the final conversion process after
+ minmax.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsect1 id="description"><title>Description</title>
+ <para>
+ When <constant>GL_MINMAX</constant> is enabled, the RGBA components of incoming pixels are
+ compared to the minimum and maximum values for each component, which are
+ stored in the two-element minmax table.
+ (The first element stores the minima, and the second element stores
+ the maxima.)
+ If a pixel component is greater than the corresponding component
+ in the maximum element, then the maximum element is updated with the
+ pixel component value.
+ If a pixel component is less than the corresponding component in
+ the minimum element, then the minimum element is updated with the
+ pixel component value.
+ (In both cases, if the internal format of the minmax table includes
+ luminance, then the R color component of incoming pixels is used
+ for comparison.)
+ The contents of the minmax table may be retrieved at a later time
+ by calling <citerefentry><refentrytitle>glGetMinmax</refentrytitle></citerefentry>.
+ The minmax operation is enabled or disabled by calling <citerefentry><refentrytitle>glEnable</refentrytitle></citerefentry> or
+ <citerefentry><refentrytitle>glDisable</refentrytitle></citerefentry>, respectively, with an argument of <constant>GL_MINMAX</constant>.
+ </para>
+ <para>
+ <function>glMinmax</function> redefines the current minmax table to have entries of the format
+ specified by <parameter>internalformat</parameter>.
+ The maximum element is initialized with the smallest possible component
+ values, and the minimum element is initialized with the largest possible
+ component values.
+ The values in the previous minmax table, if any, are lost.
+ If <parameter>sink</parameter> is <constant>GL_TRUE</constant>, then pixels are discarded after minmax;
+ no further processing of the pixels takes place, and no drawing,
+ texture loading, or pixel readback will result.
+ </para>
+ <para>
+ </para>
+ </refsect1>
+ <refsect1 id="notes"><title>Notes</title>
+ <para>
+ <function>glMinmax</function> is present only if <code>ARB_imaging</code> is returned when <citerefentry><refentrytitle>glGetString</refentrytitle></citerefentry>
+ is called with an argument of <constant>GL_EXTENSIONS</constant>.
+ </para>
+ </refsect1>
+ <refsect1 id="errors"><title>Errors</title>
+ <para>
+ <constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> is not one of the allowable
+ values.
+ </para>
+ <para>
+ <constant>GL_INVALID_ENUM</constant> is generated if <parameter>internalformat</parameter> is not one of the
+ allowable values.
+ </para>
+ <para>
+ <constant>GL_INVALID_OPERATION</constant> is generated if <function>glMinmax</function> is executed
+ between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry> and the corresponding
+ execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
+ </para>
+ </refsect1>
+ <refsect1 id="associatedgets"><title>Associated Gets</title>
+ <para>
+ <citerefentry><refentrytitle>glGetMinmaxParameter</refentrytitle></citerefentry>
+ </para>
+ </refsect1>
+ <refsect1 id="seealso"><title>See Also</title>
+ <para>
+ <citerefentry><refentrytitle>glGetMinmax</refentrytitle></citerefentry>,
+ <citerefentry><refentrytitle>glResetMinmax</refentrytitle></citerefentry>
+ </para>
+ </refsect1>
+ <refsect1 id="Copyright"><title>Copyright</title>
+ <para>
+ Copyright <trademark class="copyright"></trademark> 1991-2006
+ Silicon Graphics, Inc. This document is licensed under the SGI
+ Free Software B License. For details, see
+ <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
+ </para>
+ </refsect1>
+</refentry>
HCoop / clinton / guile-figl.git / blobdiff