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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="glPointParameter">
<refmeta>
<refmetainfo>
<copyright>
<year>1991-2006</year>
<holder>Silicon Graphics, Inc.</holder>
</copyright>
</refmetainfo>
<refentrytitle>glPointParameter</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>glPointParameter</refname>
<refpurpose>specify point parameters</refpurpose>
</refnamediv>
<refsynopsisdiv><title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glPointParameterf</function></funcdef>
<paramdef>GLenum <parameter>pname</parameter></paramdef>
<paramdef>GLfloat <parameter>param</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<para></para>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glPointParameteri</function></funcdef>
<paramdef>GLenum <parameter>pname</parameter></paramdef>
<paramdef>GLint <parameter>param</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<!-- eqn: ignoring delim $$ -->
<refsect1 id="parameters"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>pname</parameter></term>
<listitem>
<para>
Specifies a single-valued point parameter.
<constant>GL_POINT_SIZE_MIN</constant>,
<constant>GL_POINT_SIZE_MAX</constant>,
<constant>GL_POINT_FADE_THRESHOLD_SIZE</constant>, and
<constant>GL_POINT_SPRITE_COORD_ORIGIN</constant>
are accepted.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>param</parameter></term>
<listitem>
<para>
Specifies the value that <parameter>pname</parameter> will be set to.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsynopsisdiv><title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glPointParameterfv</function></funcdef>
<paramdef>GLenum <parameter>pname</parameter></paramdef>
<paramdef>const GLfloat * <parameter>params</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<para></para>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glPointParameteriv</function></funcdef>
<paramdef>GLenum <parameter>pname</parameter></paramdef>
<paramdef>const GLint * <parameter>params</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 id="parameters2"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>pname</parameter></term>
<listitem>
<para>
Specifies a point parameter.
<constant>GL_POINT_SIZE_MIN</constant>,
<constant>GL_POINT_SIZE_MAX</constant>,
<constant>GL_POINT_DISTANCE_ATTENUATION</constant>,
<constant>GL_POINT_FADE_THRESHOLD_SIZE</constant>, and
<constant>GL_POINT_SPRITE_COORD_ORIGIN</constant>
are accepted.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>params</parameter></term>
<listitem>
<para>
Specifies the value or values to be assigned to <parameter>pname</parameter>.
<constant>GL_POINT_DISTANCE_ATTENUATION</constant> requires an array of three values.
All other parameters accept an array containing only a single value.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="description"><title>Description</title>
<para>
The following values are accepted for <parameter>pname</parameter>:
</para>
<variablelist>
<varlistentry>
<term><constant>GL_POINT_SIZE_MIN</constant></term>
<listitem>
<para>
</para>
<para>
<parameter>params</parameter> is a single floating-point value that specifies the minimum point size. The default value is 0.0.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_POINT_SIZE_MAX</constant></term>
<listitem>
<para>
</para>
<para>
<parameter>params</parameter> is a single floating-point value that specifies the maximum point size. The default value is 1.0.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_POINT_FADE_THRESHOLD_SIZE</constant></term>
<listitem>
<para>
</para>
<para>
<parameter>params</parameter> is a single floating-point value that specifies the threshold value
to which point sizes are clamped if they exceed the specified value. The
default value is 1.0.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_POINT_DISTANCE_ATTENUATION</constant></term>
<listitem>
<para>
</para>
<para>
<parameter>params</parameter> is an array of three floating-point values that specify the
coefficients used for scaling the computed point size. The default values
are
<inlineequation><mml:math>
<!-- eqn: (1, 0, 0):-->
<mml:mfenced open="(" close=")">
<mml:mn>1</mml:mn>
<mml:mn>0</mml:mn>
<mml:mn>0</mml:mn>
</mml:mfenced>
</mml:math></inlineequation>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_POINT_SPRITE_COORD_ORIGIN</constant></term>
<listitem>
<para>
</para>
<para>
<parameter>params</parameter> is a single enum specifying the point sprite texture coordinate origin, either <constant>GL_LOWER_LEFT</constant> or <constant>GL_UPPER_LEFT</constant>.
The default value is <constant>GL_UPPER_LEFT</constant>.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="notes"><title>Notes</title>
<para>
<function>glPointParameter</function> is available only if the GL version is 1.4 or greater.
</para>
<para>
<constant>GL_POINT_SPRITE_COORD_ORIGIN</constant> is available only if the GL version is 2.0 or greater.
</para>
</refsect1>
<refsect1 id="errors"><title>Errors</title>
<para>
<constant>GL_INVALID_VALUE</constant> is generated If the value specified for
<constant>GL_POINT_SIZE_MIN</constant>, <constant>GL_POINT_SIZE_MAX</constant>, or
<constant>GL_POINT_FADE_THRESHOLD_SIZE</constant> is less than zero.
</para>
<para>
<constant>GL_INVALID_ENUM</constant> is generated If the value specified for
<constant>GL_POINT_SPRITE_COORD_ORIGIN</constant> is not <constant>GL_LOWER_LEFT</constant> or <constant>GL_UPPER_LEFT</constant>.
</para>
<para>
If the value for <constant>GL_POINT_SIZE_MIN</constant> is greater than
<constant>GL_POINT_SIZE_MAX</constant>, the point size after clamping is undefined, but no
error is generated.
</para>
<para>
</para>
</refsect1>
<refsect1 id="associatedgets"><title>Associated Gets</title>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_POINT_SIZE_MIN</constant>
</para>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_POINT_SIZE_MAX</constant>
</para>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_POINT_FADE_THRESHOLD_SIZE</constant>
</para>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_POINT_DISTANCE_ATTENUATION</constant>
</para>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_POINT_SPRITE_COORD_ORIGIN</constant>
</para>
</refsect1>
<refsect1 id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>glPointSize</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>