320 lines
15 KiB
XML
320 lines
15 KiB
XML
<?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="glGetTexParameter">
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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>glGetTexParameter</refentrytitle>
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<manvolnum>3G</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>glGetTexParameter</refname>
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<refpurpose>return texture parameter values</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>glGetTexParameterfv</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>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>glGetTexParameteriv</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>params</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 symbolic name of the target texture.
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<constant>GL_TEXTURE_1D</constant>,
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<constant>GL_TEXTURE_2D</constant>,
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<constant>GL_TEXTURE_3D</constant>, and
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<constant>GL_TEXTURE_CUBE_MAP</constant>
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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>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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<constant>GL_TEXTURE_MAG_FILTER</constant>,
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<constant>GL_TEXTURE_MIN_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_RESIDENT</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>, and
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<constant>GL_GENERATE_MIPMAP</constant>
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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>params</parameter></term>
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<listitem>
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<para>
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Returns the texture parameters.
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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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<function>glGetTexParameter</function> returns in <parameter>params</parameter> the value or values of 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>, <constant>GL_TEXTURE_3D</constant>, or <constant>GL_TEXTURE_CUBE_MAP</constant>,
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to specify one-, two-, or three-dimensional or cube-mapped texturing.
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<parameter>pname</parameter> accepts the same symbols as <citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>,
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with the same interpretations:
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</para>
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<variablelist>
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<varlistentry>
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<term><constant>GL_TEXTURE_MAG_FILTER</constant></term>
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<listitem>
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<para>
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Returns the single-valued texture magnification filter,
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a symbolic constant. The initial value is <constant>GL_LINEAR</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><constant>GL_TEXTURE_MIN_FILTER</constant></term>
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<listitem>
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<para>
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Returns the single-valued texture minification filter,
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a symbolic constant. The initial value is <constant>GL_NEAREST_MIPMAP_LINEAR</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><constant>GL_TEXTURE_MIN_LOD</constant></term>
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<listitem>
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<para>
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Returns the single-valued texture minimum level-of-detail value. The
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initial value is
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<inlineequation><mml:math>
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<!-- eqn: -1000:-->
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<mml:mn>-1000</mml:mn>
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</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><constant>GL_TEXTURE_MAX_LOD</constant></term>
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<listitem>
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<para>
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Returns the single-valued texture maximum level-of-detail value. The
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initial value is 1000.
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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><constant>GL_TEXTURE_BASE_LEVEL</constant></term>
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<listitem>
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<para>
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Returns the single-valued base texture mipmap level. The initial value is 0.
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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><constant>GL_TEXTURE_MAX_LEVEL</constant></term>
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<listitem>
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<para>
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Returns the single-valued maximum texture mipmap array level. The initial
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value is 1000.
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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><constant>GL_TEXTURE_WRAP_S</constant></term>
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<listitem>
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<para>
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Returns the single-valued wrapping function for texture coordinate
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<inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>,
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a symbolic constant. The initial value is <constant>GL_REPEAT</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><constant>GL_TEXTURE_WRAP_T</constant></term>
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<listitem>
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<para>
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Returns the single-valued wrapping function for texture coordinate
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<inlineequation><mml:math><mml:mi mathvariant="italic">t</mml:mi></mml:math></inlineequation>,
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a symbolic constant. The initial value is <constant>GL_REPEAT</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><constant>GL_TEXTURE_WRAP_R</constant></term>
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<listitem>
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<para>
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Returns the single-valued wrapping function for texture coordinate
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<inlineequation><mml:math><mml:mi mathvariant="italic">r</mml:mi></mml:math></inlineequation>,
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a symbolic constant. The initial value is <constant>GL_REPEAT</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><constant>GL_TEXTURE_BORDER_COLOR</constant></term>
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<listitem>
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<para>
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Returns four integer or floating-point numbers that comprise the RGBA color
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of the texture border.
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Floating-point values are returned in the range
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<inlineequation><mml:math>
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<!-- eqn: [0,1]:-->
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<mml:mfenced open="[" close="]">
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<mml:mn>0</mml:mn>
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<mml:mn>1</mml:mn>
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</mml:mfenced>
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</mml:math></inlineequation>.
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Integer values are returned as a linear mapping of the internal floating-point
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representation such that 1.0 maps to the most positive representable
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integer and
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<inlineequation><mml:math>
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<!-- eqn: -1.0:-->
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<mml:mn>-1.0</mml:mn>
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</mml:math></inlineequation>
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maps to the most negative representable
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integer. The initial value is (0, 0, 0, 0).
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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><constant>GL_TEXTURE_PRIORITY</constant></term>
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<listitem>
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<para>
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Returns the residence priority of the target texture (or the named
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texture bound to it). The initial value is 1.
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See <citerefentry><refentrytitle>glPrioritizeTextures</refentrytitle></citerefentry>.
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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><constant>GL_TEXTURE_RESIDENT</constant></term>
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<listitem>
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<para>
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Returns the residence status of the target texture.
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If the value returned in <parameter>params</parameter> is <constant>GL_TRUE</constant>, the texture is
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resident in texture memory.
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See <citerefentry><refentrytitle>glAreTexturesResident</refentrytitle></citerefentry>.
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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><constant>GL_TEXTURE_COMPARE_MODE</constant></term>
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<listitem>
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<para>
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Returns a single-valued texture comparison mode, a symbolic constant. The
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initial value is <constant>GL_NONE</constant>. See <citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>.
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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><constant>GL_TEXTURE_COMPARE_FUNC</constant></term>
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<listitem>
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<para>
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Returns a single-valued texture comparison function, a symbolic constant. The
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initial value is <constant>GL_LEQUAL</constant>. See <citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>.
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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><constant>GL_DEPTH_TEXTURE_MODE</constant></term>
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<listitem>
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<para>
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Returns a single-valued texture format indicating how the depth values
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should be converted into color components. The initial value is
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<constant>GL_LUMINANCE</constant>. See <citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>.
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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><constant>GL_GENERATE_MIPMAP</constant></term>
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<listitem>
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<para>
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Returns a single boolean value indicating if automatic mipmap level updates
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are enabled.
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See <citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>.
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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="notes"><title>Notes</title>
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<para>
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<constant>GL_TEXTURE_PRIORITY</constant> and <constant>GL_TEXTURE_RESIDENT</constant> are
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available only if the GL version is 1.1 or greater.
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</para>
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<para>
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<constant>GL_TEXTURE_3D</constant>,
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<constant>GL_TEXTURE_MIN_LOD</constant>, <constant>GL_TEXTURE_MAX_LOD</constant>, <constant>GL_TEXTURE_BASE_LEVEL</constant>,
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<constant>GL_TEXTURE_MAX_LEVEL</constant>, and <constant>GL_TEXTURE_WRAP_R</constant> are available only
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if the GL version is 1.2 or greater.
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</para>
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<para>
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<constant>GL_TEXTURE_COMPARE_MODE</constant>, <constant>GL_TEXTURE_COMPARE_FUNC</constant>, and
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<constant>GL_GENERATE_MIPMAP</constant> is available only if the GL version is 1.4 or
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greater.
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</para>
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<para>
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If an error is generated,
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no change is made to the contents of <parameter>params</parameter>.
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</para>
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</refsect1>
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<refsect1 id="errors"><title>Errors</title>
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<para>
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<constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> or <parameter>pname</parameter> is not an
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accepted value.
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</para>
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<para>
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<constant>GL_INVALID_OPERATION</constant> is generated if <function>glGetTexParameter</function>
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is executed between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>
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and the corresponding execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
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</para>
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</refsect1>
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<refsect1 id="seealso"><title>See Also</title>
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<para>
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<citerefentry><refentrytitle>glAreTexturesResident</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>glPrioritizeTextures</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>
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</para>
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</refsect1>
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<refsect1 id="Copyright"><title>Copyright</title>
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<para>
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Copyright <trademark class="copyright"></trademark> 1991-2006
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Silicon Graphics, Inc. This document is licensed under the SGI
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Free Software B License. For details, see
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<ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
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</para>
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</refsect1>
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</refentry>
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