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1265 lines
79 KiB
XML
1265 lines
79 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="glTexParameter">
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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>glTexParameter</refentrytitle>
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<manvolnum>3G</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>glTexParameter</refname>
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<refpurpose>set texture parameters</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>glTexParameterf</function></funcdef>
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<paramdef>GLenum <parameter>target</parameter></paramdef>
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<paramdef>GLenum <parameter>pname</parameter></paramdef>
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<paramdef>GLfloat <parameter>param</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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<funcsynopsis>
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<funcprototype>
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<funcdef>void <function>glTexParameteri</function></funcdef>
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<paramdef>GLenum <parameter>target</parameter></paramdef>
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<paramdef>GLenum <parameter>pname</parameter></paramdef>
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<paramdef>GLint <parameter>param</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>target</parameter></term>
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<listitem>
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<para>
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Specifies the target texture,
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which must be either <constant>GL_TEXTURE_1D</constant>, <constant>GL_TEXTURE_2D</constant>,
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<constant>GL_TEXTURE_3D</constant>, or <constant>GL_TEXTURE_CUBE_MAP</constant>.
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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>pname</parameter></term>
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<listitem>
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<para>
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Specifies the symbolic name of a single-valued texture parameter.
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<parameter>pname</parameter> can be one of the following:
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<constant>GL_TEXTURE_MIN_FILTER</constant>,
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<constant>GL_TEXTURE_MAG_FILTER</constant>,
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<constant>GL_TEXTURE_MIN_LOD</constant>,
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<constant>GL_TEXTURE_MAX_LOD</constant>,
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<constant>GL_TEXTURE_BASE_LEVEL</constant>,
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<constant>GL_TEXTURE_MAX_LEVEL</constant>,
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<constant>GL_TEXTURE_WRAP_S</constant>,
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<constant>GL_TEXTURE_WRAP_T</constant>,
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<constant>GL_TEXTURE_WRAP_R</constant>,
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<constant>GL_TEXTURE_PRIORITY</constant>,
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<constant>GL_TEXTURE_COMPARE_MODE</constant>,
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<constant>GL_TEXTURE_COMPARE_FUNC</constant>,
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<constant>GL_DEPTH_TEXTURE_MODE</constant>, or
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<constant>GL_GENERATE_MIPMAP</constant>.
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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>param</parameter></term>
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<listitem>
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<para>
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Specifies the value of <parameter>pname</parameter>.
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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>glTexParameterfv</function></funcdef>
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<paramdef>GLenum <parameter>target</parameter></paramdef>
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<paramdef>GLenum <parameter>pname</parameter></paramdef>
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<paramdef>const GLfloat * <parameter>params</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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<funcsynopsis>
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<funcprototype>
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<funcdef>void <function>glTexParameteriv</function></funcdef>
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<paramdef>GLenum <parameter>target</parameter></paramdef>
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<paramdef>GLenum <parameter>pname</parameter></paramdef>
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<paramdef>const GLint * <parameter>params</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>target</parameter></term>
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<listitem>
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<para>
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Specifies the target texture,
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which must be either <constant>GL_TEXTURE_1D</constant>, <constant>GL_TEXTURE_2D</constant> or
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<constant>GL_TEXTURE_3D</constant>.
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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>pname</parameter></term>
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<listitem>
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<para>
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Specifies the symbolic name of a texture parameter.
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<parameter>pname</parameter> can be one of the following:
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<constant>GL_TEXTURE_MIN_FILTER</constant>,
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<constant>GL_TEXTURE_MAG_FILTER</constant>,
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<constant>GL_TEXTURE_MIN_LOD</constant>,
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<constant>GL_TEXTURE_MAX_LOD</constant>,
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<constant>GL_TEXTURE_BASE_LEVEL</constant>,
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<constant>GL_TEXTURE_MAX_LEVEL</constant>,
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<constant>GL_TEXTURE_WRAP_S</constant>,
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<constant>GL_TEXTURE_WRAP_T</constant>,
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<constant>GL_TEXTURE_WRAP_R</constant>,
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<constant>GL_TEXTURE_BORDER_COLOR</constant>,
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<constant>GL_TEXTURE_PRIORITY</constant>,
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<constant>GL_TEXTURE_COMPARE_MODE</constant>,
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<constant>GL_TEXTURE_COMPARE_FUNC</constant>,
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<constant>GL_DEPTH_TEXTURE_MODE</constant>, or
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<constant>GL_GENERATE_MIPMAP</constant>.
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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>params</parameter></term>
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<listitem>
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<para>
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Specifies a pointer to an array where the value or values of <parameter>pname</parameter>
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are stored.
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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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Texture mapping is a technique that applies an image onto an object's surface
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as if the image were a decal or cellophane shrink-wrap.
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The image is created in texture space,
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with an
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(<inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>,
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<inlineequation><mml:math><mml:mi mathvariant="italic">t</mml:mi></mml:math></inlineequation>)
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coordinate system.
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A texture is a one- or two-dimensional image and a set of parameters
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that determine how samples are derived from the image.
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</para>
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<para>
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<function>glTexParameter</function> assigns the value or values in <parameter>params</parameter> to the texture parameter
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specified as <parameter>pname</parameter>.
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<parameter>target</parameter> defines the target texture,
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either <constant>GL_TEXTURE_1D</constant>, <constant>GL_TEXTURE_2D</constant>, or <constant>GL_TEXTURE_3D</constant>.
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The following symbols are accepted in <parameter>pname</parameter>:
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</para>
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<variablelist>
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<varlistentry>
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<term><constant>GL_TEXTURE_MIN_FILTER</constant></term>
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<listitem>
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<para>
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The texture minifying function is used whenever the pixel being textured
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maps to an area greater than one texture element.
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There are six defined minifying functions.
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Two of them use the nearest one or nearest four texture elements
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to compute the texture value.
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The other four use mipmaps.
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</para>
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<para>
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A mipmap is an ordered set of arrays representing the same image
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at progressively lower resolutions.
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If the texture has dimensions
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<inlineequation><mml:math>
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<!-- eqn: 2 sup n times 2 sup m:-->
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<mml:mrow>
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<mml:msup><mml:mn>2</mml:mn>
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<mml:mi mathvariant="italic">n</mml:mi>
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</mml:msup>
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<mml:mo>×</mml:mo>
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<mml:msup><mml:mn>2</mml:mn>
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<mml:mi mathvariant="italic">m</mml:mi>
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</mml:msup>
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</mml:mrow>
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</mml:math></inlineequation>,
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there are
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<inlineequation><mml:math>
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<!-- eqn: max ( n, m ) + 1:-->
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<mml:mrow>
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<mml:mrow>
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<mml:mi mathvariant="italic">max</mml:mi>
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<mml:mo>⁡</mml:mo>
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<mml:mfenced open="(" close=")">
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<mml:mi mathvariant="italic">n</mml:mi>
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<mml:mi mathvariant="italic">m</mml:mi>
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</mml:mfenced>
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</mml:mrow>
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<mml:mo>+</mml:mo>
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<mml:mn>1</mml:mn>
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</mml:mrow>
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</mml:math></inlineequation>
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mipmaps.
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The first mipmap is the original texture,
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with dimensions
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<inlineequation><mml:math>
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<!-- eqn: 2 sup n times 2 sup m:-->
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<mml:mrow>
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<mml:msup><mml:mn>2</mml:mn>
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<mml:mi mathvariant="italic">n</mml:mi>
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</mml:msup>
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<mml:mo>×</mml:mo>
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<mml:msup><mml:mn>2</mml:mn>
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<mml:mi mathvariant="italic">m</mml:mi>
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</mml:msup>
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</mml:mrow>
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</mml:math></inlineequation>.
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Each subsequent mipmap has dimensions
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<inlineequation><mml:math>
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<!-- eqn: 2 sup { k - 1 } times 2 sup { l - 1 }:-->
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<mml:mrow>
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<mml:msup><mml:mn>2</mml:mn>
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<mml:mfenced open="" close="">
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<mml:mrow>
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<mml:mi mathvariant="italic">k</mml:mi>
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<mml:mo>-</mml:mo>
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<mml:mn>1</mml:mn>
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</mml:mrow>
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</mml:mfenced>
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</mml:msup>
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<mml:mo>×</mml:mo>
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<mml:msup><mml:mn>2</mml:mn>
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<mml:mfenced open="" close="">
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<mml:mrow>
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<mml:mi mathvariant="italic">l</mml:mi>
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<mml:mo>-</mml:mo>
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<mml:mn>1</mml:mn>
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</mml:mrow>
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</mml:mfenced>
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</mml:msup>
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</mml:mrow>
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</mml:math></inlineequation>,
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where
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<inlineequation><mml:math>
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<!-- eqn: 2 sup k times 2 sup l:-->
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<mml:mrow>
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<mml:msup><mml:mn>2</mml:mn>
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<mml:mi mathvariant="italic">k</mml:mi>
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</mml:msup>
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<mml:mo>×</mml:mo>
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<mml:msup><mml:mn>2</mml:mn>
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<mml:mi mathvariant="italic">l</mml:mi>
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</mml:msup>
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</mml:mrow>
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</mml:math></inlineequation>
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are the dimensions of the previous mipmap,
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until either
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<inlineequation><mml:math>
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<!-- eqn: k = 0:-->
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<mml:mrow>
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<mml:mi mathvariant="italic">k</mml:mi>
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<mml:mo>=</mml:mo>
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<mml:mn>0</mml:mn>
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</mml:mrow>
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</mml:math></inlineequation>
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or
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<inlineequation><mml:math>
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<!-- eqn: l = 0:-->
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<mml:mrow>
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<mml:mi mathvariant="italic">l</mml:mi>
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<mml:mo>=</mml:mo>
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<mml:mn>0</mml:mn>
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</mml:mrow>
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</mml:math></inlineequation>.
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At that point,
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subsequent mipmaps have dimension
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<inlineequation><mml:math>
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|
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<!-- eqn: 1 times 2 sup { l - 1 }:-->
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<mml:mrow>
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||
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<mml:mn>1</mml:mn>
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<mml:mo>×</mml:mo>
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||
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<mml:msup><mml:mn>2</mml:mn>
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||
|
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<mml:mfenced open="" close="">
|
||
|
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<mml:mrow>
|
||
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<mml:mi mathvariant="italic">l</mml:mi>
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||
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<mml:mo>-</mml:mo>
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||
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<mml:mn>1</mml:mn>
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</mml:mrow>
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||
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</mml:mfenced>
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||
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</mml:msup>
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||
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</mml:mrow>
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||
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</mml:math></inlineequation>
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or
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<inlineequation><mml:math>
|
||
|
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<!-- eqn: 2 sup { k - 1} times 1:-->
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||
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<mml:mrow>
|
||
|
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<mml:msup><mml:mn>2</mml:mn>
|
||
|
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<mml:mfenced open="" close="">
|
||
|
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<mml:mrow>
|
||
|
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<mml:mi mathvariant="italic">k</mml:mi>
|
||
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<mml:mo>-</mml:mo>
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||
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<mml:mn>1</mml:mn>
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||
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|
</mml:mrow>
|
||
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|
</mml:mfenced>
|
||
|
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</mml:msup>
|
||
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<mml:mo>×</mml:mo>
|
||
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<mml:mn>1</mml:mn>
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</mml:mrow>
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||
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</mml:math></inlineequation>
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||
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until the final mipmap,
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which has dimension
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||
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<inlineequation><mml:math>
|
||
|
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<!-- eqn: 1 times 1:-->
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||
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<mml:mrow>
|
||
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<mml:mn>1</mml:mn>
|
||
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<mml:mo>×</mml:mo>
|
||
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<mml:mn>1</mml:mn>
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</mml:mrow>
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||
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</mml:math></inlineequation>.
|
||
|
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To define the mipmaps, call <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>, or <citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>
|
||
|
|
with the <emphasis>level</emphasis> argument indicating the order of the mipmaps.
|
||
|
|
Level 0 is the original texture;
|
||
|
|
level
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: max ( n, m ):-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">max</mml:mi>
|
||
|
|
<mml:mo>⁡</mml:mo>
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:mi mathvariant="italic">n</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">m</mml:mi>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></inlineequation>
|
||
|
|
is the final
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: 1 times 1:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
<mml:mo>×</mml:mo>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></inlineequation>
|
||
|
|
mipmap.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<parameter>params</parameter> supplies a function for minifying the texture as one of the
|
||
|
|
following:
|
||
|
|
<variablelist>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_NEAREST</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Returns the value of the texture element that is nearest
|
||
|
|
(in Manhattan distance)
|
||
|
|
to the center of the pixel being textured.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_LINEAR</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Returns the weighted average of the four texture elements
|
||
|
|
that are closest to the center of the pixel being textured.
|
||
|
|
These can include border texture elements,
|
||
|
|
depending on the values of <constant>GL_TEXTURE_WRAP_S</constant> and <constant>GL_TEXTURE_WRAP_T</constant>,
|
||
|
|
and on the exact mapping.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_NEAREST_MIPMAP_NEAREST</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Chooses the mipmap that most closely matches the size of the pixel
|
||
|
|
being textured and uses the <constant>GL_NEAREST</constant> criterion
|
||
|
|
(the texture element nearest to the center of the pixel)
|
||
|
|
to produce a texture value.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_LINEAR_MIPMAP_NEAREST</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Chooses the mipmap that most closely matches the size of the pixel
|
||
|
|
being textured and uses the <constant>GL_LINEAR</constant> criterion
|
||
|
|
(a weighted average of the four texture elements that are closest
|
||
|
|
to the center of the pixel)
|
||
|
|
to produce a texture value.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_NEAREST_MIPMAP_LINEAR</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Chooses the two mipmaps that most closely match the size of the pixel
|
||
|
|
being textured and uses the <constant>GL_NEAREST</constant> criterion
|
||
|
|
(the texture element nearest to the center of the pixel)
|
||
|
|
to produce a texture value from each mipmap.
|
||
|
|
The final texture value is a weighted average of those two values.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_LINEAR_MIPMAP_LINEAR</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Chooses the two mipmaps that most closely match the size of the pixel
|
||
|
|
being textured and uses the <constant>GL_LINEAR</constant> criterion
|
||
|
|
(a weighted average of the four texture elements that are closest
|
||
|
|
to the center of the pixel)
|
||
|
|
to produce a texture value from each mipmap.
|
||
|
|
The final texture value is a weighted average of those two values.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
</variablelist>
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
As more texture elements are sampled in the minification process,
|
||
|
|
fewer aliasing artifacts will be apparent.
|
||
|
|
While the <constant>GL_NEAREST</constant> and <constant>GL_LINEAR</constant> minification functions can be
|
||
|
|
faster than the other four,
|
||
|
|
they sample only one or four texture elements to determine the texture value
|
||
|
|
of the pixel being rendered and can produce moire patterns
|
||
|
|
or ragged transitions.
|
||
|
|
The initial value of <constant>GL_TEXTURE_MIN_FILTER</constant> is
|
||
|
|
<constant>GL_NEAREST_MIPMAP_LINEAR</constant>.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_TEXTURE_MAG_FILTER</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
The texture magnification function is used when the pixel being textured
|
||
|
|
maps to an area less than or equal to one texture element.
|
||
|
|
It sets the texture magnification function to either <constant>GL_NEAREST</constant>
|
||
|
|
or <constant>GL_LINEAR</constant> (see below). <constant>GL_NEAREST</constant> is generally faster
|
||
|
|
than <constant>GL_LINEAR</constant>,
|
||
|
|
but it can produce textured images with sharper edges
|
||
|
|
because the transition between texture elements is not as smooth.
|
||
|
|
The initial value of <constant>GL_TEXTURE_MAG_FILTER</constant> is <constant>GL_LINEAR</constant>.
|
||
|
|
<variablelist>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_NEAREST</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Returns the value of the texture element that is nearest
|
||
|
|
(in Manhattan distance)
|
||
|
|
to the center of the pixel being textured.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_LINEAR</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Returns the weighted average of the four texture elements
|
||
|
|
that are closest to the center of the pixel being textured.
|
||
|
|
These can include border texture elements,
|
||
|
|
depending on the values of <constant>GL_TEXTURE_WRAP_S</constant> and <constant>GL_TEXTURE_WRAP_T</constant>,
|
||
|
|
and on the exact mapping.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
</variablelist>
|
||
|
|
<para>
|
||
|
|
</para>
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
</variablelist>
|
||
|
|
<para>
|
||
|
|
</para>
|
||
|
|
<variablelist>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_TEXTURE_MIN_LOD</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Sets the minimum level-of-detail parameter. This floating-point value
|
||
|
|
limits the selection of highest resolution mipmap (lowest mipmap
|
||
|
|
level). The initial value is -1000.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
</variablelist>
|
||
|
|
<para>
|
||
|
|
</para>
|
||
|
|
<variablelist>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_TEXTURE_MAX_LOD</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Sets the maximum level-of-detail parameter. This floating-point value
|
||
|
|
limits the selection of the lowest resolution mipmap (highest mipmap
|
||
|
|
level). The initial value is 1000.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
</variablelist>
|
||
|
|
<para>
|
||
|
|
</para>
|
||
|
|
<variablelist>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_TEXTURE_BASE_LEVEL</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Specifies the index of the lowest defined mipmap level. This is an
|
||
|
|
integer value. The initial value is 0.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
</variablelist>
|
||
|
|
<para>
|
||
|
|
</para>
|
||
|
|
<variablelist>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_TEXTURE_MAX_LEVEL</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Sets the index of the highest defined mipmap level. This is an integer
|
||
|
|
value. The initial value is 1000.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
</variablelist>
|
||
|
|
<para>
|
||
|
|
</para>
|
||
|
|
<variablelist>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_TEXTURE_WRAP_S</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Sets the wrap parameter for texture coordinate
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
|
||
|
|
to either <constant>GL_CLAMP</constant>,
|
||
|
|
<constant>GL_CLAMP_TO_BORDER</constant>, <constant>GL_CLAMP_TO_EDGE</constant>, <constant>GL_MIRRORED_REPEAT</constant>, or
|
||
|
|
<constant>GL_REPEAT</constant>. <constant>GL_CLAMP</constant> causes
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
|
||
|
|
coordinates to be clamped to the
|
||
|
|
range [0,1] and is useful for preventing wrapping artifacts when mapping a
|
||
|
|
single image onto an object. <constant>GL_CLAMP_TO_BORDER</constant> causes the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
|
||
|
|
coordinate to be clamped to the range
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: left [ {-1 over 2N}, 1 + {1 over 2N} right ]:-->
|
||
|
|
<mml:mfenced open="[" close="]">
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mfrac>
|
||
|
|
<mml:mn>-1</mml:mn>
|
||
|
|
<mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn>
|
||
|
|
</mml:mfrac>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
<mml:mo>+</mml:mo>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mfrac>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
<mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn>
|
||
|
|
</mml:mfrac>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:math></inlineequation>,
|
||
|
|
where
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">N</mml:mi></mml:math></inlineequation>
|
||
|
|
is the size of the texture in the direction of
|
||
|
|
clamping.<constant>GL_CLAMP_TO_EDGE</constant> causes
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
|
||
|
|
coordinates to be clamped to the
|
||
|
|
range
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: left [ {1 over 2N}, 1 - {1 over 2N} right ]:-->
|
||
|
|
<mml:mfenced open="[" close="]">
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mfrac>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
<mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn>
|
||
|
|
</mml:mfrac>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
<mml:mo>-</mml:mo>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mfrac>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
<mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn>
|
||
|
|
</mml:mfrac>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:math></inlineequation>,
|
||
|
|
where
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">N</mml:mi></mml:math></inlineequation>
|
||
|
|
is the size
|
||
|
|
of the texture in the direction of clamping. <constant>GL_REPEAT</constant> causes the
|
||
|
|
integer part of the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
|
||
|
|
coordinate to be ignored; the GL uses only the
|
||
|
|
fractional part, thereby creating a repeating pattern.
|
||
|
|
<constant>GL_MIRRORED_REPEAT</constant> causes the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
|
||
|
|
coordinate to be set to the
|
||
|
|
fractional part of the texture coordinate if the integer part of
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
|
||
|
|
is
|
||
|
|
even; if the integer part of
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
|
||
|
|
is odd, then the
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
|
||
|
|
texture coordinate is
|
||
|
|
set to
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: 1 - frac(s):-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
<mml:mo>-</mml:mo>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">frac</mml:mi>
|
||
|
|
<mml:mo>⁡</mml:mo>
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:mi mathvariant="italic">s</mml:mi>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></inlineequation>,
|
||
|
|
where
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: frac(s):-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">frac</mml:mi>
|
||
|
|
<mml:mo>⁡</mml:mo>
|
||
|
|
<mml:mfenced open="(" close=")">
|
||
|
|
<mml:mi mathvariant="italic">s</mml:mi>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></inlineequation>
|
||
|
|
represents the fractional part of
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>.
|
||
|
|
Border texture
|
||
|
|
elements are accessed only if wrapping is set to <constant>GL_CLAMP</constant> or <constant>GL_CLAMP_TO_BORDER</constant>. Initially,
|
||
|
|
<constant>GL_TEXTURE_WRAP_S</constant> is set to <constant>GL_REPEAT</constant>.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
</variablelist>
|
||
|
|
<para>
|
||
|
|
</para>
|
||
|
|
<variablelist>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_TEXTURE_WRAP_T</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Sets the wrap parameter for texture coordinate
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">t</mml:mi></mml:math></inlineequation>
|
||
|
|
to either <constant>GL_CLAMP</constant>,
|
||
|
|
<constant>GL_CLAMP_TO_BORDER</constant>, <constant>GL_CLAMP_TO_EDGE</constant>, <constant>GL_MIRRORED_REPEAT</constant>, or
|
||
|
|
<constant>GL_REPEAT</constant>. See the discussion under <constant>GL_TEXTURE_WRAP_S</constant>.
|
||
|
|
Initially, <constant>GL_TEXTURE_WRAP_T</constant> is set to <constant>GL_REPEAT</constant>.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_TEXTURE_WRAP_R</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Sets the wrap parameter for texture coordinate
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">r</mml:mi></mml:math></inlineequation>
|
||
|
|
to either <constant>GL_CLAMP</constant>,
|
||
|
|
<constant>GL_CLAMP_TO_BORDER</constant>, <constant>GL_CLAMP_TO_EDGE</constant>, <constant>GL_MIRRORED_REPEAT</constant>, or
|
||
|
|
<constant>GL_REPEAT</constant>. See the discussion under <constant>GL_TEXTURE_WRAP_S</constant>.
|
||
|
|
Initially, <constant>GL_TEXTURE_WRAP_R</constant> is set to <constant>GL_REPEAT</constant>.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_TEXTURE_BORDER_COLOR</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Sets a border color. <parameter>params</parameter> contains four values that comprise the RGBA
|
||
|
|
color of the texture border. Integer color components are interpreted
|
||
|
|
linearly such that the most positive integer maps to 1.0, and the most
|
||
|
|
negative integer maps to -1.0. The values are clamped to the range [0,1]
|
||
|
|
when they are specified. Initially, the border color is (0, 0, 0, 0).
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_TEXTURE_PRIORITY</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Specifies the texture residence priority of the currently bound texture.
|
||
|
|
Permissible values are in the range
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: [0,1]:-->
|
||
|
|
<mml:mfenced open="[" close="]">
|
||
|
|
<mml:mn>0</mml:mn>
|
||
|
|
<mml:mn>1</mml:mn>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:math></inlineequation>.
|
||
|
|
See <citerefentry><refentrytitle>glPrioritizeTextures</refentrytitle></citerefentry> and <citerefentry><refentrytitle>glBindTexture</refentrytitle></citerefentry> for more information.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_TEXTURE_COMPARE_MODE</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Specifies the texture comparison mode for currently bound depth textures.
|
||
|
|
That is, a texture whose internal format is <constant>GL_DEPTH_COMPONENT_*</constant>; see
|
||
|
|
<citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>)
|
||
|
|
Permissible values are:
|
||
|
|
<variablelist>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_COMPARE_R_TO_TEXTURE</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Specifies that the interpolated and clamped
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">r</mml:mi></mml:math></inlineequation>
|
||
|
|
texture coordinate should
|
||
|
|
be compared to the value in the currently bound depth texture. See the
|
||
|
|
discussion of <constant>GL_TEXTURE_COMPARE_FUNC</constant> for details of how the comparison
|
||
|
|
is evaluated. The result of the comparison is assigned to luminance,
|
||
|
|
intensity, or alpha (as specified by <constant>GL_DEPTH_TEXTURE_MODE</constant>).
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_NONE</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Specifies that the luminance, intensity, or alpha (as specified by
|
||
|
|
<constant>GL_DEPTH_TEXTURE_MODE</constant>) should be assigned the
|
||
|
|
appropriate value from the currently bound depth texture.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
</variablelist>
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_TEXTURE_COMPARE_FUNC</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Specifies the comparison operator used when <constant>GL_TEXTURE_COMPARE_MODE</constant> is
|
||
|
|
set to <constant>GL_COMPARE_R_TO_TEXTURE</constant>. Permissible values are:
|
||
|
|
<informaltable frame="topbot">
|
||
|
|
<tgroup cols="2" align="left">
|
||
|
|
<colspec/>
|
||
|
|
<colspec/>
|
||
|
|
<thead>
|
||
|
|
<row>
|
||
|
|
<entry rowsep="1" align="left"><emphasis role="bold">
|
||
|
|
Texture Comparison Function
|
||
|
|
</emphasis></entry>
|
||
|
|
<entry rowsep="1" align="left"><emphasis role="bold">
|
||
|
|
Computed result
|
||
|
|
</emphasis></entry>
|
||
|
|
</row>
|
||
|
|
</thead>
|
||
|
|
<tbody>
|
||
|
|
<row>
|
||
|
|
<entry align="left">
|
||
|
|
<constant>GL_LEQUAL</constant>
|
||
|
|
</entry>
|
||
|
|
<entry align="left">
|
||
|
|
<informalequation><mml:math>
|
||
|
|
<!-- eqn: result = left { cpile {1.0 above 0.0} lpile {r <= {D sub t} above r > {D sub t}}:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">result</mml:mi>
|
||
|
|
<mml:mo>=</mml:mo>
|
||
|
|
<mml:mfenced open="{" close="">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mtable>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mn>1.0</mml:mn>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mn>0.0</mml:mn>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
</mml:mtable>
|
||
|
|
<mml:mo>⁢ </mml:mo>
|
||
|
|
<mml:mtable>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
<mml:mo><=</mml:mo>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">D</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">t</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
<mml:mo>></mml:mo>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">D</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">t</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
</mml:mtable>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></informalequation>
|
||
|
|
</entry>
|
||
|
|
</row>
|
||
|
|
<row>
|
||
|
|
<entry align="left">
|
||
|
|
<constant>GL_GEQUAL</constant>
|
||
|
|
</entry>
|
||
|
|
<entry align="left">
|
||
|
|
<informalequation><mml:math>
|
||
|
|
<!-- eqn: result = left { cpile {1.0 above 0.0} lpile {r <= {D sub t} above r > {D sub t}}:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">result</mml:mi>
|
||
|
|
<mml:mo>=</mml:mo>
|
||
|
|
<mml:mfenced open="{" close="">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mtable>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mn>1.0</mml:mn>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mn>0.0</mml:mn>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
</mml:mtable>
|
||
|
|
<mml:mo>⁢ </mml:mo>
|
||
|
|
<mml:mtable>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
<mml:mo>>=</mml:mo>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">D</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">t</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
<mml:mo><</mml:mo>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">D</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">t</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
</mml:mtable>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></informalequation>
|
||
|
|
</entry>
|
||
|
|
</row>
|
||
|
|
<row>
|
||
|
|
<entry align="left">
|
||
|
|
<constant>GL_LESS</constant>
|
||
|
|
</entry>
|
||
|
|
<entry align="left">
|
||
|
|
<informalequation><mml:math>
|
||
|
|
<!-- eqn: result = left { cpile {1.0 above 0.0} lpile {r <= {D sub t} above r > {D sub t}}:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">result</mml:mi>
|
||
|
|
<mml:mo>=</mml:mo>
|
||
|
|
<mml:mfenced open="{" close="">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mtable>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mn>1.0</mml:mn>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mn>0.0</mml:mn>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
</mml:mtable>
|
||
|
|
<mml:mo>⁢ </mml:mo>
|
||
|
|
<mml:mtable>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
<mml:mo><</mml:mo>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">D</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">t</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
<mml:mo>>=</mml:mo>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">D</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">t</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
</mml:mtable>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></informalequation>
|
||
|
|
</entry>
|
||
|
|
</row>
|
||
|
|
<row>
|
||
|
|
<entry align="left">
|
||
|
|
<constant>GL_GREATER</constant>
|
||
|
|
</entry>
|
||
|
|
<entry align="left">
|
||
|
|
<informalequation><mml:math>
|
||
|
|
<!-- eqn: result = left { cpile {1.0 above 0.0} lpile {r <= {D sub t} above r > {D sub t}}:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">result</mml:mi>
|
||
|
|
<mml:mo>=</mml:mo>
|
||
|
|
<mml:mfenced open="{" close="">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mtable>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mn>1.0</mml:mn>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mn>0.0</mml:mn>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
</mml:mtable>
|
||
|
|
<mml:mo>⁢ </mml:mo>
|
||
|
|
<mml:mtable>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
<mml:mo>></mml:mo>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">D</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">t</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
<mml:mo><=</mml:mo>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">D</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">t</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
</mml:mtable>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></informalequation>
|
||
|
|
</entry>
|
||
|
|
</row>
|
||
|
|
<row>
|
||
|
|
<entry align="left">
|
||
|
|
<constant>GL_EQUAL</constant>
|
||
|
|
</entry>
|
||
|
|
<entry align="left">
|
||
|
|
<informalequation><mml:math>
|
||
|
|
<!-- eqn: result = left { cpile {1.0 above 0.0} lpile {r <= {D sub t} above r > {D sub t}}:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">result</mml:mi>
|
||
|
|
<mml:mo>=</mml:mo>
|
||
|
|
<mml:mfenced open="{" close="">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mtable>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mn>1.0</mml:mn>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mn>0.0</mml:mn>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
</mml:mtable>
|
||
|
|
<mml:mo>⁢ </mml:mo>
|
||
|
|
<mml:mtable>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
<mml:mo>=</mml:mo>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">D</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">t</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
<mml:mo>≠</mml:mo>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">D</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">t</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
</mml:mtable>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></informalequation>
|
||
|
|
</entry>
|
||
|
|
</row>
|
||
|
|
<row>
|
||
|
|
<entry align="left">
|
||
|
|
<constant>GL_NOTEQUAL</constant>
|
||
|
|
</entry>
|
||
|
|
<entry align="left">
|
||
|
|
<informalequation><mml:math>
|
||
|
|
<!-- eqn: result = left { cpile {1.0 above 0.0} lpile {r <= {D sub t} above r > {D sub t}}:-->
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">result</mml:mi>
|
||
|
|
<mml:mo>=</mml:mo>
|
||
|
|
<mml:mfenced open="{" close="">
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mtable>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mn>1.0</mml:mn>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mn>0.0</mml:mn>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
</mml:mtable>
|
||
|
|
<mml:mo>⁢ </mml:mo>
|
||
|
|
<mml:mtable>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
<mml:mo>≠</mml:mo>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">D</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">t</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
<mml:mtr><mml:mtd>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">r</mml:mi>
|
||
|
|
<mml:mo>=</mml:mo>
|
||
|
|
<mml:mfenced open="" close="">
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">D</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">t</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mtd></mml:mtr>
|
||
|
|
</mml:mtable>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:mfenced>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math></informalequation>
|
||
|
|
</entry>
|
||
|
|
</row>
|
||
|
|
<row>
|
||
|
|
<entry align="left">
|
||
|
|
<constant>GL_ALWAYS</constant>
|
||
|
|
</entry>
|
||
|
|
<entry align="left">
|
||
|
|
<informalequation>
|
||
|
|
<mml:math>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">result</mml:mi>
|
||
|
|
<mml:mo>=</mml:mo>
|
||
|
|
<mml:mi>1.0</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math>
|
||
|
|
</informalequation>
|
||
|
|
</entry>
|
||
|
|
</row>
|
||
|
|
<row>
|
||
|
|
<entry align="left">
|
||
|
|
<constant>GL_NEVER</constant>
|
||
|
|
</entry>
|
||
|
|
<entry align="left">
|
||
|
|
<informalequation>
|
||
|
|
<mml:math>
|
||
|
|
<mml:mrow>
|
||
|
|
<mml:mi mathvariant="italic">result</mml:mi>
|
||
|
|
<mml:mo>=</mml:mo>
|
||
|
|
<mml:mi>0.0</mml:mi>
|
||
|
|
</mml:mrow>
|
||
|
|
</mml:math>
|
||
|
|
</informalequation>
|
||
|
|
</entry>
|
||
|
|
</row>
|
||
|
|
</tbody>
|
||
|
|
</tgroup>
|
||
|
|
</informaltable>
|
||
|
|
where <inlineequation><mml:math><mml:mi mathvariant="italic">r</mml:mi></mml:math></inlineequation>
|
||
|
|
is the current interpolated texture coordinate, and
|
||
|
|
<inlineequation><mml:math>
|
||
|
|
<!-- eqn: D sub t:-->
|
||
|
|
<mml:msub><mml:mi mathvariant="italic">D</mml:mi>
|
||
|
|
<mml:mi mathvariant="italic">t</mml:mi>
|
||
|
|
</mml:msub>
|
||
|
|
</mml:math></inlineequation>
|
||
|
|
is the depth texture value sampled from the currently bound depth texture.
|
||
|
|
<inlineequation><mml:math><mml:mi mathvariant="italic">result</mml:mi></mml:math></inlineequation>
|
||
|
|
is assigned to the either the luminance, intensity, or alpha (as
|
||
|
|
specified by <constant>GL_DEPTH_TEXTURE_MODE</constant>.)
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_DEPTH_TEXTURE_MODE</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Specifies a single symbolic constant indicating how depth values should be
|
||
|
|
treated during filtering and texture application. Accepted values are
|
||
|
|
<constant>GL_LUMINANCE</constant>, <constant>GL_INTENSITY</constant>, and <constant>GL_ALPHA</constant>. The initial value
|
||
|
|
is <constant>GL_LUMINANCE</constant>.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
<varlistentry>
|
||
|
|
<term><constant>GL_GENERATE_MIPMAP</constant></term>
|
||
|
|
<listitem>
|
||
|
|
<para>
|
||
|
|
Specifies a boolean value that indicates if all levels of a mipmap array
|
||
|
|
should be automatically updated when any modification to the base level
|
||
|
|
mipmap is done. The initial value is <constant>GL_FALSE</constant>.
|
||
|
|
</para>
|
||
|
|
</listitem>
|
||
|
|
</varlistentry>
|
||
|
|
</variablelist>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="notes"><title>Notes</title>
|
||
|
|
<para>
|
||
|
|
<constant>GL_TEXTURE_3D</constant>, <constant>GL_TEXTURE_MIN_LOD</constant>, <constant>GL_TEXTURE_MAX_LOD</constant>,
|
||
|
|
<constant>GL_CLAMP_TO_EDGE</constant>, <constant>GL_TEXTURE_BASE_LEVEL</constant>, and <constant>GL_TEXTURE_MAX_LEVEL</constant> are
|
||
|
|
available only if the GL version is 1.2 or greater.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<constant>GL_CLAMP_TO_BORDER</constant> is available only if the GL version is 1.3 or greater.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<constant>GL_MIRRORED_REPEAT</constant>, <constant>GL_TEXTURE_COMPARE_MODE</constant>,
|
||
|
|
<constant>GL_TEXTURE_COMPARE_FUNC</constant>, <constant>GL_DEPTH_TEXTURE_MODE</constant>, and
|
||
|
|
<constant>GL_GENERATE_MIPMAP</constant> are available only if the GL version is 1.4 or
|
||
|
|
greater.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<constant>GL_TEXTURE_COMPARE_FUNC</constant> allows the following additional comparison modes only
|
||
|
|
if the GL version is 1.5 or greater:
|
||
|
|
<constant>GL_LESS</constant>, <constant>GL_GREATER</constant>,
|
||
|
|
<constant>GL_EQUAL</constant>, <constant>GL_NOTEQUAL</constant>,
|
||
|
|
<constant>GL_ALWAYS</constant>, and <constant>GL_NEVER</constant>.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
Suppose that a program has enabled texturing (by calling <citerefentry><refentrytitle>glEnable</refentrytitle></citerefentry> with
|
||
|
|
argument <constant>GL_TEXTURE_1D</constant>, <constant>GL_TEXTURE_2D</constant>, or <constant>GL_TEXTURE_3D</constant>) and
|
||
|
|
has set <constant>GL_TEXTURE_MIN_FILTER</constant> to one of the functions that requires a
|
||
|
|
mipmap. If either the dimensions of the texture images currently defined
|
||
|
|
(with previous calls to <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>, or <citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>) do not
|
||
|
|
follow the proper sequence for mipmaps (described above), or there are
|
||
|
|
fewer texture images defined than are needed, or the set of texture images
|
||
|
|
have differing numbers of texture components, then it is as if texture
|
||
|
|
mapping were disabled.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
Linear filtering accesses the four nearest texture elements only in 2D
|
||
|
|
textures. In 1D textures, linear filtering accesses the two nearest
|
||
|
|
texture elements.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
For OpenGL versions 1.3 and greater, or when the <code>ARB_multitexture</code> extension is supported, <function>glTexParameter</function>
|
||
|
|
specifies the texture parameters for the active texture unit, specified
|
||
|
|
by calling <citerefentry><refentrytitle>glActiveTexture</refentrytitle></citerefentry>.
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="errors"><title>Errors</title>
|
||
|
|
<para>
|
||
|
|
<constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> or <parameter>pname</parameter> is not
|
||
|
|
one of the accepted defined values.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<constant>GL_INVALID_ENUM</constant> is generated if <parameter>params</parameter> should have a defined
|
||
|
|
constant value (based on the value of <parameter>pname</parameter>) and does not.
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<constant>GL_INVALID_OPERATION</constant> is generated if <function>glTexParameter</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>glGetTexParameter</refentrytitle></citerefentry>
|
||
|
|
</para>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glGetTexLevelParameter</refentrytitle></citerefentry>
|
||
|
|
</para>
|
||
|
|
</refsect1>
|
||
|
|
<refsect1 id="seealso"><title>See Also</title>
|
||
|
|
<para>
|
||
|
|
<citerefentry><refentrytitle>glActiveTexture</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glBindTexture</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glCopyPixels</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glCopyTexSubImage1D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glCopyTexSubImage2D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glCopyTexSubImage3D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glPixelStore</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glPixelTransfer</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glPrioritizeTextures</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexEnv</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexGen</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexSubImage1D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>,
|
||
|
|
<citerefentry><refentrytitle>glTexSubImage3D</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>
|