upstream-man-pages/man4/glDepthRangeArray.xml

   1 <?xml version="1.0" encoding="UTF-8"?>
   2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
   3               "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
   4 <refentry id="glDepthRangeArray">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>2010</year>
   9                 <holder>Khronos Group</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>glDepthRangeArray</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>glDepthRangeArray</refname>
  17         <refpurpose>specify mapping of depth values from normalized device coordinates to window coordinates for a specified set of viewports</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>C Specification</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>void <function>glDepthRangeArrayv</function></funcdef>
  23                 <paramdef>GLuint <parameter>first</parameter></paramdef>
  24                 <paramdef>GLsizei <parameter>count</parameter></paramdef>
  25                 <paramdef>const GLdouble *<parameter>v</parameter></paramdef>
  26             </funcprototype>
  27         </funcsynopsis>
  28     </refsynopsisdiv>
  29     <!-- eqn: ignoring delim $$ -->
  30     <refsect1 id="parameters"><title>Parameters</title>
  31         <variablelist>
  32         <varlistentry>
  33             <term><parameter>first</parameter></term>
  34             <listitem>
  35                 <para>
  36                     Specifies the index of the first viewport whose depth range to update.
  37                 </para>
  38             </listitem>
  39         </varlistentry>
  40         <varlistentry>
  41             <term><parameter>count</parameter></term>
  42             <listitem>
  43                 <para>
  44                     Specifies the number of viewports whose depth range to update.
  45                 </para>
  46             </listitem>
  47         </varlistentry>
  48         <varlistentry>
  49             <term><parameter>v</parameter></term>
  50             <listitem>
  51                 <para>
  52                     Specifies the address of an array containing the near and far values for the
  53                     depth range of each modified viewport.
  54                 </para>
  55             </listitem>
  56         </varlistentry>
  57         </variablelist>
  58     </refsect1>
  59     <refsect1 id="description"><title>Description</title>
  60         <para>
  61             After clipping and division by <emphasis>w</emphasis>,
  62             depth coordinates range from
  63             <inlineequation><mml:math>
  64                 <!-- eqn: -1: -->
  65                 <mml:mn>-1</mml:mn>
  66             </mml:math></inlineequation>
  67             to 1,
  68             corresponding to the near and far clipping planes.
  69             Each viewport has an independent depth range specified as a linear mapping of the normalized
  70             depth coordinates in this range to window depth coordinates.
  71             Regardless of the actual depth buffer implementation,
  72             window coordinate depth values are treated as though they range
  73             from 0 through 1 (like color components).
  74             <function>glDepthRangeArray</function> specifies a linear mapping of the normalized depth coordinates
  75             in this range to window depth coordinates for each viewport in the range [<parameter>first</parameter>,
  76             <parameter>first</parameter> + <parameter>count</parameter>).
  77             Thus,
  78             the values accepted by <function>glDepthRangeArray</function> are both clamped to this range
  79             before they are accepted.
  80         </para>
  81         <para>
  82             The <parameter>first</parameter> parameter specifies the index of the first viewport whose depth
  83             range to modify and must be less than the value of <constant>GL_MAX_VIEWPORTS</constant>.
  84             <parameter>count</parameter> specifies the number of viewports whose depth range to modify.
  85             <parameter>first</parameter> + <parameter>count</parameter> must be less than or equal to
  86             the value of <constant>GL_MAX_VIEWPORTS</constant>. <parameter>v</parameter> specifies the address of an
  87             array of pairs of double precision floating point values representing the near and far values of the
  88             depth range for each viewport, in that order.
  89         </para>
  90         <para>
  91             The setting of (0,1) maps the near plane to 0 and
  92             the far plane to 1.
  93             With this mapping,
  94             the depth buffer range is fully utilized.
  95         </para>
  96     </refsect1>
  97     <refsect1 id="notes"><title>Notes</title>
  98         <para>
  99             It is not necessary that the near plane distance be less than the far plane distance.
 100             Reverse mappings such as
 101             <inlineequation><mml:math>
 102                 <!-- eqn: nearVal  =  1: -->
 103                 <mml:mrow>
 104                     <mml:mi mathvariant="italic">near</mml:mi>
 105                     <mml:mo>=</mml:mo>
 106                     <mml:mn>1</mml:mn>
 107                 </mml:mrow>
 108             </mml:math></inlineequation>,
 109             and
 110             <inlineequation><mml:math>
 111                 <!-- eqn: farVal  =  0: -->
 112                 <mml:mrow>
 113                     <mml:mi mathvariant="italic">far</mml:mi>
 114                     <mml:mo>=</mml:mo>
 115                     <mml:mn>0</mml:mn>
 116                 </mml:mrow>
 117             </mml:math></inlineequation>
 118             are acceptable.
 119         </para>
 120         <para>
 121             The type of the <parameter>v</parameter> parameter was
 122             changed from GLclampd to GLdouble. This change is
 123             transparent to user code and is described in detail on the
 124             <citerefentry><refentrytitle>removedTypes</refentrytitle></citerefentry>
 125             page.
 126         </para>
 127     </refsect1>
 128     <refsect1 id="errors"><title>Errors</title>
 129         <para>
 130             <constant>GL_INVALID_VALUE</constant> is generated if <parameter>first</parameter> is greater than or equal to
 131             the value of <constant>GL_MAX_VIEWPORTS</constant>.
 132         </para>
 133         <para>
 134             <constant>GL_INVALID_VALUE</constant> is generated if <parameter>first</parameter> + <parameter>count</parameter>
 135             is greater than or equal to the value of <constant>GL_MAX_VIEWPORTS</constant>.
 136         </para>
 137     </refsect1>
 138     <refsect1 id="associatedgets"><title>Associated Gets</title>
 139         <para>
 140             <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_DEPTH_RANGE</constant>
 141         </para>
 142     </refsect1>
 143     <refsect1 id="seealso"><title>See Also</title>
 144         <para>
 145             <citerefentry><refentrytitle>glDepthFunc</refentrytitle></citerefentry>,
 146             <citerefentry><refentrytitle>glDepthRange</refentrytitle></citerefentry>,
 147             <citerefentry><refentrytitle>glDepthRangeIndexed</refentrytitle></citerefentry>,
 148             <citerefentry><refentrytitle>glPolygonOffset</refentrytitle></citerefentry>,
 149             <citerefentry><refentrytitle>glViewportArray</refentrytitle></citerefentry>,
 150             <citerefentry><refentrytitle>glViewport</refentrytitle></citerefentry>,
 151             <citerefentry><refentrytitle>removedTypes</refentrytitle></citerefentry>
 152         </para>
 153     </refsect1>
 154     <refsect1 id="Copyright"><title>Copyright</title>
 155         <para>
 156             Copyright <trademark class="copyright"></trademark> 2010 Khronos Group.
 157             This material may be distributed subject to the terms and conditions set forth in
 158             the Open Publication License, v 1.0, 8 June 1999.
 159             <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
 160         </para>
 161     </refsect1>
 162 </refentry>