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627 lines
25 KiB
XML
627 lines
25 KiB
XML
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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
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"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
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<refentry id="glEvalMesh">
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<refmeta>
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<refmetainfo>
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<copyright>
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<year>1991-2006</year>
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<holder>Silicon Graphics, Inc.</holder>
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</copyright>
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</refmetainfo>
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<refentrytitle>glEvalMesh</refentrytitle>
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<manvolnum>3G</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>glEvalMesh</refname>
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<refpurpose>compute a one- or two-dimensional grid of points or lines</refpurpose>
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</refnamediv>
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<refsynopsisdiv><title>C Specification</title>
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<funcsynopsis>
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<funcprototype>
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<funcdef>void <function>glEvalMesh1</function></funcdef>
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<paramdef>GLenum <parameter>mode</parameter></paramdef>
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<paramdef>GLint <parameter>i1</parameter></paramdef>
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<paramdef>GLint <parameter>i2</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<!-- eqn: ignoring delim $$ -->
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<refsect1 id="parameters"><title>Parameters</title>
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<variablelist>
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<varlistentry>
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<term><parameter>mode</parameter></term>
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<listitem>
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<para>
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In <function>glEvalMesh1</function>, specifies whether to compute a one-dimensional mesh of points or lines.
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Symbolic constants
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<constant>GL_POINT</constant> and
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<constant>GL_LINE</constant> are accepted.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>i1</parameter></term>
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<term><parameter>i2</parameter></term>
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<listitem>
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<para>
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Specify the first and last integer values for grid domain variable
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<inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsynopsisdiv><title>C Specification</title>
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<funcsynopsis>
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<funcprototype>
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<funcdef>void <function>glEvalMesh2</function></funcdef>
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<paramdef>GLenum <parameter>mode</parameter></paramdef>
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<paramdef>GLint <parameter>i1</parameter></paramdef>
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<paramdef>GLint <parameter>i2</parameter></paramdef>
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<paramdef>GLint <parameter>j1</parameter></paramdef>
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<paramdef>GLint <parameter>j2</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1 id="parameters2"><title>Parameters</title>
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<variablelist>
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<varlistentry>
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<term><parameter>mode</parameter></term>
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<listitem>
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<para>
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In <function>glEvalMesh2</function>, specifies whether to compute a two-dimensional mesh of points, lines,
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or polygons.
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Symbolic constants
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<constant>GL_POINT</constant>,
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<constant>GL_LINE</constant>, and
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<constant>GL_FILL</constant> are accepted.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>i1</parameter></term>
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<term><parameter>i2</parameter></term>
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<listitem>
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<para>
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Specify the first and last integer values for grid domain variable
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<inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>j1</parameter></term>
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<term><parameter>j2</parameter></term>
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<listitem>
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<para>
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Specify the first and last integer values for grid domain variable
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<inlineequation><mml:math><mml:mi mathvariant="italic">j</mml:mi></mml:math></inlineequation>.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1 id="description"><title>Description</title>
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<para>
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<citerefentry><refentrytitle>glMapGrid</refentrytitle></citerefentry> and <function>glEvalMesh</function> are used in tandem to efficiently
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generate and evaluate a series of evenly-spaced map domain values.
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<function>glEvalMesh</function> steps through the integer domain of a one- or two-dimensional grid,
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whose range is the domain of the evaluation maps specified by
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<citerefentry><refentrytitle>glMap1</refentrytitle></citerefentry> and <citerefentry><refentrytitle>glMap2</refentrytitle></citerefentry>.
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<parameter>mode</parameter> determines whether the resulting vertices are connected as
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points,
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lines,
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or filled polygons.
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</para>
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<para>
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In the one-dimensional case,
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<function>glEvalMesh1</function>,
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the mesh is generated as if the following code fragment were executed:
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</para>
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<para>
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<programlisting>
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glBegin( <parameter>type</parameter> );
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for ( i = <parameter>i1</parameter>; i <= <parameter>i2</parameter>; i += 1 )
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glEvalCoord1( <mml:math>
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<!-- eqn: i \cdot DELTA u + u sub 1 :-->
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<mml:mrow>
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<mml:mrow>
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<mml:mn>i</mml:mn>
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<mml:mo>·</mml:mo>
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<mml:mo>Δ</mml:mo>
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<mml:mi mathvariant="italic">u</mml:mi>
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</mml:mrow>
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<mml:mo>+</mml:mo>
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<mml:msub>
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<mml:mi mathvariant="italic">u</mml:mi>
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<mml:mn>1</mml:mn>
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</mml:msub>
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</mml:mrow>
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</mml:math> );
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glEnd();
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</programlisting>
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where
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</para>
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<para>
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<informalequation><mml:math>
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<!-- eqn: DELTA u = (u sub 2 - u sub 1 ) / n:-->
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<mml:mrow>
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<mml:mrow>
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<mml:mo>Δ</mml:mo>
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<mml:mi mathvariant="italic">u</mml:mi>
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</mml:mrow>
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<mml:mo>=</mml:mo>
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<mml:mfrac>
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<mml:mfenced open="(" close=")">
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<mml:mrow>
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<mml:msub>
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<mml:mi mathvariant="italic">u</mml:mi>
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<mml:mn>2</mml:mn>
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</mml:msub>
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<mml:mo>-</mml:mo>
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<mml:msub>
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<mml:mi mathvariant="italic">u</mml:mi>
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<mml:mn>1</mml:mn>
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</mml:msub>
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</mml:mrow>
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</mml:mfenced>
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<mml:mi mathvariant="italic">n</mml:mi>
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</mml:mfrac>
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</mml:mrow>
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</mml:math></informalequation>
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</para>
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<para>
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and
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<inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>,
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<inlineequation><mml:math>
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<!-- eqn: u sub 1:-->
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<mml:msub><mml:mi mathvariant="italic">u</mml:mi>
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<mml:mn>1</mml:mn>
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</mml:msub>
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</mml:math></inlineequation>,
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and
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<inlineequation><mml:math>
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<!-- eqn: u sub 2:-->
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<mml:msub><mml:mi mathvariant="italic">u</mml:mi>
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<mml:mn>2</mml:mn>
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</mml:msub>
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</mml:math></inlineequation>
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are the arguments to the most recent
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<citerefentry><refentrytitle>glMapGrid1</refentrytitle></citerefentry> command.
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<emphasis>type</emphasis> is <constant>GL_POINTS</constant> if <parameter>mode</parameter> is <constant>GL_POINT</constant>,
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or <constant>GL_LINES</constant> if <parameter>mode</parameter> is <constant>GL_LINE</constant>.
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</para>
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<para>
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The one absolute numeric requirement is that if
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<inlineequation><mml:math>
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<!-- eqn: i = n:-->
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<mml:mrow>
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<mml:mi mathvariant="italic">i</mml:mi>
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<mml:mo>=</mml:mo>
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<mml:mi mathvariant="italic">n</mml:mi>
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</mml:mrow>
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</mml:math></inlineequation>,
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then the
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value computed from
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<inlineequation><mml:math>
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<!-- eqn: i cdot DELTA u + u sub 1:-->
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<mml:mrow>
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<mml:mrow>
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<mml:mi mathvariant="italic">i</mml:mi>
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<mml:mo>·</mml:mo>
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<mml:mrow>
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<mml:mo>Δ</mml:mo>
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<mml:mi mathvariant="italic">u</mml:mi>
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</mml:mrow>
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</mml:mrow>
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<mml:mo>+</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">u</mml:mi>
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<mml:mn>1</mml:mn>
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</mml:msub>
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</mml:mrow>
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</mml:math></inlineequation>
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is exactly
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<inlineequation><mml:math>
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<!-- eqn: u sub 2:-->
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<mml:msub><mml:mi mathvariant="italic">u</mml:mi>
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<mml:mn>2</mml:mn>
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</mml:msub>
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</mml:math></inlineequation>.
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</para>
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<para>
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In the two-dimensional case, <function>glEvalMesh2</function>, let
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.cp
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<informalequation><mml:math>
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<!-- eqn: DELTA u = ( u sub 2 - u sub 1 ) / n:-->
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<mml:mrow>
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<mml:mrow>
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<mml:mo>Δ</mml:mo>
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<mml:mi mathvariant="italic">u</mml:mi>
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</mml:mrow>
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<mml:mo>=</mml:mo>
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<mml:mfrac>
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<mml:mfenced open="(" close=")">
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<mml:mrow>
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<mml:msub><mml:mi mathvariant="italic">u</mml:mi>
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<mml:mn>2</mml:mn>
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</mml:msub>
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<mml:mo>-</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">u</mml:mi>
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<mml:mn>1</mml:mn>
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</mml:msub>
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</mml:mrow>
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</mml:mfenced>
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<mml:mi mathvariant="italic">n</mml:mi>
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</mml:mfrac>
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</mml:mrow>
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</mml:math></informalequation>
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</para>
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<para>
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<informalequation><mml:math>
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<!-- eqn: DELTA v = ( v sub 2 - v sub 1 ) / m:-->
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<mml:mrow>
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<mml:mrow>
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<mml:mo>Δ</mml:mo>
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<mml:mi mathvariant="italic">v</mml:mi>
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</mml:mrow>
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<mml:mo>=</mml:mo>
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<mml:mfrac>
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<mml:mfenced open="(" close=")">
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<mml:mrow>
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<mml:msub><mml:mi mathvariant="italic">v</mml:mi>
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<mml:mn>2</mml:mn>
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</mml:msub>
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<mml:mo>-</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">v</mml:mi>
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<mml:mn>1</mml:mn>
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</mml:msub>
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</mml:mrow>
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</mml:mfenced>
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<mml:mi mathvariant="italic">m</mml:mi>
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</mml:mfrac>
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</mml:mrow>
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</mml:math></informalequation>
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</para>
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<para>
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where
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<inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>,
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<inlineequation><mml:math>
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<!-- eqn: u sub 1:-->
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<mml:msub><mml:mi mathvariant="italic">u</mml:mi>
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<mml:mn>1</mml:mn>
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</mml:msub>
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</mml:math></inlineequation>,
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<inlineequation><mml:math>
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<!-- eqn: u sub 2:-->
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<mml:msub><mml:mi mathvariant="italic">u</mml:mi>
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<mml:mn>2</mml:mn>
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</mml:msub>
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</mml:math></inlineequation>,
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<inlineequation><mml:math><mml:mi mathvariant="italic">m</mml:mi></mml:math></inlineequation>,
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<inlineequation><mml:math>
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<!-- eqn: v sub 1:-->
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<mml:msub><mml:mi mathvariant="italic">v</mml:mi>
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<mml:mn>1</mml:mn>
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</mml:msub>
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</mml:math></inlineequation>,
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and
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<inlineequation><mml:math>
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<!-- eqn: v sub 2:-->
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<mml:msub><mml:mi mathvariant="italic">v</mml:mi>
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<mml:mn>2</mml:mn>
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</mml:msub>
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</mml:math></inlineequation>
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are the
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arguments to the most recent <citerefentry><refentrytitle>glMapGrid2</refentrytitle></citerefentry> command. Then, if
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<parameter>mode</parameter> is <constant>GL_FILL</constant>, the <function>glEvalMesh2</function> command is equivalent
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||
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to:
|
||
|
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</para>
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||
|
|
<para>
|
||
|
|
<programlisting>
|
||
|
|
for ( j = <parameter>j1</parameter>; j < <parameter>j2</parameter>; j += 1 ) {
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||
|
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glBegin( GL_QUAD_STRIP );
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||
|
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for ( i = <parameter>i1</parameter>; i <= <parameter>i2</parameter>; i += 1 ) {
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glEvalCoord2( <mml:math>
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<!-- i \cdot DELTA u + u sub 1 :-->
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<mml:mrow>
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||
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<mml:mrow>
|
||
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<mml:mn>i</mml:mn>
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<mml:mo>·</mml:mo>
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|
|
<mml:mo>Δ</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">u</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:msub>
|
||
|
|
<mml:mi mathvariant="italic">u</mml:mi>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:mo>,</mml:mo>
|
||
|
|
<!-- j \cdot DELTA v + v sub 1 :-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mn>j</mml:mn>
|
||
|
|
<mml:mo>·</mml:mo>
|
||
|
|
<mml:mo>Δ</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">v</mml:mi>
|
||
|
|
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:msub>
|
||
|
|
<mml:mi mathvariant="italic">v</mml:mi>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math> );
|
||
|
|
glEvalCoord2( <mml:math>
|
||
|
|
<!-- i \cdot DELTA u + u sub 1, :-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mn>i</mml:mn>
|
||
|
|
<mml:mo>·</mml:mo>
|
||
|
|
<mml:mo>Δ</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">u</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:msub>
|
||
|
|
<mml:mi mathvariant="italic">u</mml:mi>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:mo>,</mml:mo>
|
||
|
|
<!-- (j + 1) \cdot DELTA v + v sub 1 :-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mn>j</mml:mn>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mo>·</mml:mo>
|
||
|
|
<mml:mo>Δ</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">v</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:msub>
|
||
|
|
<mml:mi mathvariant="italic">v</mml:mi>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math> );
|
||
|
|
}
|
||
|
|
glEnd();
|
||
|
|
}
|
||
|
|
</programlisting>
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
If <parameter>mode</parameter> is <constant>GL_LINE</constant>, then a call to <function>glEvalMesh2</function> is equivalent to:
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<programlisting>
|
||
|
|
for ( j = <parameter>j1</parameter>; j <= <parameter>j2</parameter>; j += 1 ) {
|
||
|
|
glBegin( GL_LINE_STRIP );
|
||
|
|
for ( i = <parameter>i1</parameter>; i <= <parameter>i2</parameter>; i += 1 )
|
||
|
|
glEvalCoord2( <mml:math>
|
||
|
|
<!-- i \cdot DELTA u + u sub 1 :-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mn>i</mml:mn>
|
||
|
|
<mml:mo>·</mml:mo>
|
||
|
|
<mml:mo>Δ</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">u</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:msub>
|
||
|
|
<mml:mi mathvariant="italic">u</mml:mi>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:mo>,</mml:mo>
|
||
|
|
<!-- i \cdot DELTA v + v sub 1 :-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mn>j</mml:mn>
|
||
|
|
<mml:mo>·</mml:mo>
|
||
|
|
<mml:mo>Δ</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">v</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:msub>
|
||
|
|
<mml:mi mathvariant="italic">v</mml:mi>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math> );
|
||
|
|
glEnd();
|
||
|
|
}
|
||
|
|
|
||
|
|
for ( i = <parameter>i1</parameter>; i <= <parameter>i2</parameter>; i += 1 ) {
|
||
|
|
glBegin( GL_LINE_STRIP );
|
||
|
|
for ( j = <parameter>j1</parameter>; j <= <parameter>j1</parameter>; j += 1 )
|
||
|
|
glEvalCoord2( <mml:math>
|
||
|
|
<!-- i \cdot DELTA u + u sub 1 :-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mn>i</mml:mn>
|
||
|
|
<mml:mo>·</mml:mo>
|
||
|
|
<mml:mo>Δ</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">u</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:msub>
|
||
|
|
<mml:mi mathvariant="italic">u</mml:mi>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:mo>,</mml:mo>
|
||
|
|
<!-- i \cdot DELTA v + v sub 1 :-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mn>j</mml:mn>
|
||
|
|
<mml:mo>·</mml:mo>
|
||
|
|
<mml:mo>Δ</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">v</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:msub>
|
||
|
|
<mml:mi mathvariant="italic">v</mml:mi>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math> );
|
||
|
|
glEnd();
|
||
|
|
}
|
||
|
|
</programlisting>
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
And finally, if <parameter>mode</parameter> is <constant>GL_POINT</constant>, then a call to
|
||
|
|
<function>glEvalMesh2</function> is equivalent to:
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<programlisting>
|
||
|
|
glBegin( GL_POINTS );
|
||
|
|
for ( j = <parameter>j1</parameter>; j <= <parameter>j2</parameter>; j += 1 )
|
||
|
|
for ( i = <parameter>i1</parameter>; i <= <parameter>i2</parameter>; i += 1 )
|
||
|
|
glEvalCoord2( <mml:math>
|
||
|
|
<!-- i \cdot DELTA u + u sub 1 :-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mn>i</mml:mn>
|
||
|
|
<mml:mo>·</mml:mo>
|
||
|
|
<mml:mo>Δ</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">u</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:msub>
|
||
|
|
<mml:mi mathvariant="italic">u</mml:mi>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:msub>
|
||
|
|
<mml:mo>,</mml:mo>
|
||
|
|
<!-- i \cdot DELTA v + v sub 1 :-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mn>j</mml:mn>
|
||
|
|
<mml:mo>·</mml:mo>
|
||
|
|
<mml:mo>Δ</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">v</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:msub>
|
||
|
|
<mml:mi mathvariant="italic">v</mml:mi>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math> );
|
||
|
|
glEnd();
|
||
|
|
</programlisting>
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
In all three cases, the only absolute numeric requirements are that if
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: i = n:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">i</mml:mi>
|
||
|
|
<mml:mo>=</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">n</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></inlineequation>,
|
||
|
|
then the value computed from
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: i cdot DELTA u + u sub 1:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">i</mml:mi>
|
||
|
|
<mml:mo>·</mml:mo>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mo>Δ</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">u</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">u</mml:mi>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></inlineequation>
|
||
|
|
is exactly
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: u sub 2:-->
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">u</mml:mi>
|
||
|
|
<mml:mn>2</mml:mn>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:math></inlineequation>,
|
||
|
|
and if
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: j = m:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">j</mml:mi>
|
||
|
|
<mml:mo>=</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">m</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></inlineequation>,
|
||
|
|
then the value computed from
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: j cdot DELTA v + v sub 1:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">j</mml:mi>
|
||
|
|
<mml:mo>·</mml:mo>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mo>Δ</mml:mo>
|
||
|
|
<mml:mi mathvariant="italic">v</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mrow>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">v</mml:mi>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></inlineequation>
|
||
|
|
is exactly
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: v sub 2:-->
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">v</mml:mi>
|
||
|
|
<mml:mn>2</mml:mn>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:math></inlineequation>.
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="errors"><title>Errors</title>
|
||
|
|
<para>
|
||
|
|
<constant>GL_INVALID_ENUM</constant> is generated if <parameter>mode</parameter> is not an accepted value.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<constant>GL_INVALID_OPERATION</constant> is generated if <function>glEvalMesh</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>glGet</refentrytitle></citerefentry> with argument <constant>GL_MAP1_GRID_DOMAIN</constant>
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_MAP2_GRID_DOMAIN</constant>
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_MAP1_GRID_SEGMENTS</constant>
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_MAP2_GRID_SEGMENTS</constant>
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="seealso"><title>See Also</title>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glEvalCoord</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glEvalPoint</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glMap1</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glMap2</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glMapGrid</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>
|