rename upstream-man-pages to upstream-doc

[clinton/guile-figl.git] / upstream-doc / man4 / glDepthRange.xml

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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="glDepthRange">
+    <refmeta>
+        <refmetainfo>
+            <copyright>
+                <year>1991-2006</year>
+                <holder>Silicon Graphics, Inc.</holder>
+            </copyright>
+        </refmetainfo>
+        <refentrytitle>glDepthRange</refentrytitle>
+        <manvolnum>3G</manvolnum>
+    </refmeta>
+    <refnamediv>
+        <refname>glDepthRange</refname>
+        <refpurpose>specify mapping of depth values from normalized device coordinates to window coordinates</refpurpose>
+    </refnamediv>
+    <refsynopsisdiv><title>C Specification</title>
+        <funcsynopsis>
+            <funcprototype>
+                <funcdef>void <function>glDepthRange</function></funcdef>
+                <paramdef>GLdouble <parameter>nearVal</parameter></paramdef>
+                <paramdef>GLdouble <parameter>farVal</parameter></paramdef>
+            </funcprototype>
+            <funcprototype>
+                <funcdef>void <function>glDepthRangef</function></funcdef>
+                <paramdef>GLfloat <parameter>nearVal</parameter></paramdef>
+                <paramdef>GLfloat <parameter>farVal</parameter></paramdef>
+            </funcprototype>
+        </funcsynopsis>
+    </refsynopsisdiv>
+    <!-- eqn: ignoring delim $$ -->
+    <refsect1 id="parameters"><title>Parameters</title>
+        <variablelist>
+        <varlistentry>
+            <term><parameter>nearVal</parameter></term>
+            <listitem>
+                <para>
+                    Specifies the mapping of the near clipping plane to window coordinates.
+                    The initial value is 0.
+                </para>
+            </listitem>
+        </varlistentry>
+        <varlistentry>
+            <term><parameter>farVal</parameter></term>
+            <listitem>
+                <para>
+                    Specifies the mapping of the far clipping plane to window coordinates.
+                    The initial value is 1.
+                </para>
+            </listitem>
+        </varlistentry>
+        </variablelist>
+    </refsect1>
+    <refsect1 id="description"><title>Description</title>
+        <para>
+            After clipping and division by <emphasis>w</emphasis>,
+            depth coordinates range from 
+            <inlineequation><mml:math>
+                <!-- eqn: -1: -->
+                <mml:mn>-1</mml:mn>
+            </mml:math></inlineequation>
+            to 1,
+            corresponding to the near and far clipping planes.
+            <function>glDepthRange</function> specifies a linear mapping of the normalized depth coordinates
+            in this range to window depth coordinates.
+            Regardless of the actual depth buffer implementation,
+            window coordinate depth values are treated as though they range
+            from 0 through 1 (like color components).
+            Thus,
+            the values accepted by <function>glDepthRange</function> are both clamped to this range
+            before they are accepted.
+        </para>
+        <para>
+            The setting of (0,1) maps the near plane to 0 and
+            the far plane to 1.
+            With this mapping,
+            the depth buffer range is fully utilized.
+        </para>
+    </refsect1>
+    <refsect1 id="notes"><title>Notes</title>
+        <para>
+            It is not necessary that <parameter>nearVal</parameter> be less than <parameter>farVal</parameter>.
+            Reverse mappings such as 
+            <inlineequation><mml:math>
+                <!-- eqn: nearVal  =  1: -->
+                <mml:mrow>
+                    <mml:mi mathvariant="italic">nearVal</mml:mi>
+                    <mml:mo>=</mml:mo>
+                    <mml:mn>1</mml:mn>
+                </mml:mrow>
+            </mml:math></inlineequation>,
+            and 
+            <inlineequation><mml:math>
+                <!-- eqn: farVal  =  0: -->
+                <mml:mrow>
+                    <mml:mi mathvariant="italic">farVal</mml:mi>
+                    <mml:mo>=</mml:mo>
+                    <mml:mn>0</mml:mn>
+                </mml:mrow>
+            </mml:math></inlineequation>
+            are acceptable.
+        </para>
+        <para>
+            The type of the <parameter>nearVal</parameter> and
+            <parameter>farVal</parameter> parameters was changed from
+            GLclampf to GLfloat for <function>glDepthRangef</function>
+            and from GLclampd to GLdouble for
+            <function>glDepthRange</function>. This change is
+            transparent to user code and is described in detail on the
+            <citerefentry><refentrytitle>removedTypes</refentrytitle></citerefentry>
+            page.
+        </para>
+    </refsect1>
+    <refsect1 id="associatedgets"><title>Associated Gets</title>
+        <para>
+            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_DEPTH_RANGE</constant>
+        </para>
+    </refsect1>
+    <refsect1 id="seealso"><title>See Also</title>
+        <para>
+            <citerefentry><refentrytitle>glDepthFunc</refentrytitle></citerefentry>,
+            <citerefentry><refentrytitle>glPolygonOffset</refentrytitle></citerefentry>,
+            <citerefentry><refentrytitle>glViewport</refentrytitle></citerefentry>,
+            <citerefentry><refentrytitle>removedTypes</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>