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+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
+ "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
+<refentry id="glGetTexLevelParameter">
+ <refmeta>
+ <refmetainfo>
+ <copyright>
+ <year>1991-2006</year>
+ <holder>Silicon Graphics, Inc.</holder>
+ </copyright>
+ </refmetainfo>
+ <refentrytitle>glGetTexLevelParameter</refentrytitle>
+ <manvolnum>3G</manvolnum>
+ </refmeta>
+ <refnamediv>
+ <refname>glGetTexLevelParameter</refname>
+ <refpurpose>return texture parameter values for a specific level of detail</refpurpose>
+ </refnamediv>
+ <refsynopsisdiv><title>C Specification</title>
+ <funcsynopsis>
+ <funcprototype>
+ <funcdef>void <function>glGetTexLevelParameterfv</function></funcdef>
+ <paramdef>GLenum <parameter>target</parameter></paramdef>
+ <paramdef>GLint <parameter>level</parameter></paramdef>
+ <paramdef>GLenum <parameter>pname</parameter></paramdef>
+ <paramdef>GLfloat * <parameter>params</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ <funcsynopsis>
+ <funcprototype>
+ <funcdef>void <function>glGetTexLevelParameteriv</function></funcdef>
+ <paramdef>GLenum <parameter>target</parameter></paramdef>
+ <paramdef>GLint <parameter>level</parameter></paramdef>
+ <paramdef>GLenum <parameter>pname</parameter></paramdef>
+ <paramdef>GLint * <parameter>params</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+ <!-- eqn: ignoring delim $$ -->
+ <refsect1 id="parameters"><title>Parameters</title>
+ <variablelist>
+ <varlistentry>
+ <term><parameter>target</parameter></term>
+ <listitem>
+ <para>
+ Specifies the symbolic name of the target texture,
+ one of
+ <constant>GL_TEXTURE_1D</constant>,
+ <constant>GL_TEXTURE_2D</constant>,
+ <constant>GL_TEXTURE_3D</constant>,
+ <constant>GL_TEXTURE_1D_ARRAY</constant>,
+ <constant>GL_TEXTURE_2D_ARRAY</constant>,
+ <constant>GL_TEXTURE_RECTANGLE</constant>,
+ <constant>GL_TEXTURE_2D_MULTISAMPLE</constant>,
+ <constant>GL_TEXTURE_2D_MULTISAMPLE_ARRAY</constant>,
+ <constant>GL_TEXTURE_CUBE_MAP_POSITIVE_X</constant>,
+ <constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_X</constant>,
+ <constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Y</constant>,
+ <constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</constant>,
+ <constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Z</constant>,
+ <constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</constant>,
+ <constant>GL_PROXY_TEXTURE_1D</constant>,
+ <constant>GL_PROXY_TEXTURE_2D</constant>,
+ <constant>GL_PROXY_TEXTURE_3D</constant>,
+ <constant>GL_PROXY_TEXTURE_1D_ARRAY</constant>,
+ <constant>GL_PROXY_TEXTURE_2D_ARRAY</constant>,
+ <constant>GL_PROXY_TEXTURE_RECTANGLE</constant>,
+ <constant>GL_PROXY_TEXTURE_2D_MULTISAMPLE</constant>,
+ <constant>GL_PROXY_TEXTURE_2D_MULTISAMPLE_ARRAY</constant>,
+ <constant>GL_PROXY_TEXTURE_CUBE_MAP</constant>, or
+ <constant>GL_TEXTURE_BUFFER</constant>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>level</parameter></term>
+ <listitem>
+ <para>
+ Specifies the level-of-detail number of the desired image.
+ Level 0 is the base image level.
+ Level
+ <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
+ is the
+ <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>th
+ mipmap reduction image.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>pname</parameter></term>
+ <listitem>
+ <para>
+ Specifies the symbolic name of a texture parameter.
+ <constant>GL_TEXTURE_WIDTH</constant>,
+ <constant>GL_TEXTURE_HEIGHT</constant>,
+ <constant>GL_TEXTURE_DEPTH</constant>,
+ <constant>GL_TEXTURE_INTERNAL_FORMAT</constant>,
+ <constant>GL_TEXTURE_BORDER</constant>,
+ <constant>GL_TEXTURE_RED_SIZE</constant>,
+ <constant>GL_TEXTURE_GREEN_SIZE</constant>,
+ <constant>GL_TEXTURE_BLUE_SIZE</constant>,
+ <constant>GL_TEXTURE_ALPHA_SIZE</constant>,
+ <constant>GL_TEXTURE_DEPTH_SIZE</constant>,
+ <constant>GL_TEXTURE_COMPRESSED</constant>, and
+ <constant>GL_TEXTURE_COMPRESSED_IMAGE_SIZE</constant>
+ are accepted.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>params</parameter></term>
+ <listitem>
+ <para>
+ Returns the requested data.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsect1 id="description"><title>Description</title>
+ <para>
+ <function>glGetTexLevelParameter</function> returns in <parameter>params</parameter> texture parameter values for a specific
+ level-of-detail value,
+ specified as <parameter>level</parameter>.
+ <parameter>target</parameter> defines the target texture,
+ either <constant>GL_TEXTURE_1D</constant>, <constant>GL_TEXTURE_2D</constant>, <constant>GL_TEXTURE_3D</constant>,
+ <constant>GL_PROXY_TEXTURE_1D</constant>,
+ <constant>GL_PROXY_TEXTURE_2D</constant>,
+ <constant>GL_PROXY_TEXTURE_3D</constant>,
+ <constant>GL_TEXTURE_CUBE_MAP_POSITIVE_X</constant>,
+ <constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_X</constant>,
+ <constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Y</constant>,
+ <constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</constant>,
+ <constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Z</constant>,
+ <constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</constant>, or
+ <constant>GL_PROXY_TEXTURE_CUBE_MAP</constant>.
+ </para>
+ <para>
+ <constant>GL_MAX_TEXTURE_SIZE</constant>, and <constant>GL_MAX_3D_TEXTURE_SIZE</constant> are not really
+ descriptive enough.
+ It has to report the largest square texture image that can be
+ accommodated with mipmaps and borders,
+ but a long skinny texture, or a texture without mipmaps and borders, may
+ easily fit in texture memory.
+ The proxy targets allow the user to more accurately query
+ whether the GL can accommodate a texture of a given configuration.
+ If the texture cannot be accommodated, the texture state variables, which
+ may be queried with <function>glGetTexLevelParameter</function>, are set to 0. If the texture can be accommodated,
+ the texture state values will be set as they would be set for a
+ non-proxy target.
+ </para>
+ <para>
+ <parameter>pname</parameter> specifies the texture parameter whose value or values
+ will be returned.
+ </para>
+ <para>
+ The accepted parameter names are as follows:
+ </para>
+ <variablelist>
+ <varlistentry>
+ <term><constant>GL_TEXTURE_WIDTH</constant></term>
+ <listitem>
+ <para>
+ </para>
+ <para>
+ <parameter>params</parameter> returns a single value,
+ the width of the texture image.
+ This value includes the border of the texture image. The initial value is
+ 0.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_TEXTURE_HEIGHT</constant></term>
+ <listitem>
+ <para>
+ </para>
+ <para>
+ <parameter>params</parameter> returns a single value,
+ the height of the texture image.
+ This value includes the border of the texture image. The initial value is
+ 0.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_TEXTURE_DEPTH</constant></term>
+ <listitem>
+ <para>
+ </para>
+ <para>
+ <parameter>params</parameter> returns a single value,
+ the depth of the texture image.
+ This value includes the border of the texture image. The initial value is
+ 0.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_TEXTURE_INTERNAL_FORMAT</constant></term>
+ <listitem>
+ <para>
+ </para>
+ <para>
+ <parameter>params</parameter> returns a single value,
+ the internal format of the texture image.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_TEXTURE_RED_TYPE</constant>,</term>
+ <listitem>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_TEXTURE_GREEN_TYPE</constant>,</term>
+ <listitem>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_TEXTURE_BLUE_TYPE</constant>,</term>
+ <listitem>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_TEXTURE_ALPHA_TYPE</constant>,</term>
+ <listitem>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_TEXTURE_DEPTH_TYPE</constant></term>
+ <listitem>
+ <para>
+ </para>
+ <para>
+ The data type used to store the component.
+ The types <constant>GL_NONE</constant>, <constant>GL_SIGNED_NORMALIZED</constant>,
+ <constant>GL_UNSIGNED_NORMALIZED</constant>, <constant>GL_FLOAT</constant>,
+ <constant>GL_INT</constant>, and <constant>GL_UNSIGNED_INT</constant> may be returned
+ to indicate signed normalized fixed-point, unsigned normalized fixed-point, floating-point, integer unnormalized, and
+ unsigned integer unnormalized components, respectively.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_TEXTURE_RED_SIZE</constant>,</term>
+ <listitem>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_TEXTURE_GREEN_SIZE</constant>,</term>
+ <listitem>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_TEXTURE_BLUE_SIZE</constant>,</term>
+ <listitem>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_TEXTURE_ALPHA_SIZE</constant>,</term>
+ <listitem>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_TEXTURE_DEPTH_SIZE</constant></term>
+ <listitem>
+ <para>
+ </para>
+ <para>
+ The internal storage resolution of an individual component.
+ The resolution chosen by the GL will be a close match for the resolution
+ requested by the user with the component argument of <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>,
+ <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>, and
+ <citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>. The initial value is 0.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_TEXTURE_COMPRESSED</constant></term>
+ <listitem>
+ <para>
+ </para>
+ <para>
+ <parameter>params</parameter> returns a single boolean value indicating if the texture image is
+ stored in a compressed internal format. The initiali value is <constant>GL_FALSE</constant>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><constant>GL_TEXTURE_COMPRESSED_IMAGE_SIZE</constant></term>
+ <listitem>
+ <para>
+ </para>
+ <para>
+ <parameter>params</parameter> returns a single integer value, the number of unsigned bytes of the
+ compressed texture image that would be returned from
+ <citerefentry><refentrytitle>glGetCompressedTexImage</refentrytitle></citerefentry>.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsect1 id="notes"><title>Notes</title>
+ <para>
+ If an error is generated,
+ no change is made to the contents of <parameter>params</parameter>.
+ </para>
+ <para>
+ <function>glGetTexLevelParameter</function> returns the texture level parameters for the active texture unit.
+ </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 an
+ accepted value.
+ </para>
+ <para>
+ <constant>GL_INVALID_VALUE</constant> is generated if <parameter>level</parameter> is less than 0.
+ </para>
+ <para>
+ <constant>GL_INVALID_VALUE</constant> may be generated if <parameter>level</parameter> is greater
+ than
+ <inlineequation><mml:math>
+ <!-- eqn: log sub 2: -->
+ <mml:msub><mml:mi mathvariant="italic">log</mml:mi>
+ <mml:mn>2</mml:mn>
+ </mml:msub>
+ </mml:math></inlineequation>
+ <emphasis>max</emphasis>,
+ where <emphasis>max</emphasis> is the returned value of <constant>GL_MAX_TEXTURE_SIZE</constant>.
+ </para>
+ <para>
+ <constant>GL_INVALID_VALUE</constant> is generated if <parameter>target</parameter> is <constant>GL_TEXTURE_BUFFER</constant>
+ and <parameter>level</parameter> is not zero.
+ </para>
+ <para>
+ <constant>GL_INVALID_OPERATION</constant> is generated if
+ <constant>GL_TEXTURE_COMPRESSED_IMAGE_SIZE</constant> is queried on texture images with an
+ uncompressed internal format or on proxy targets.
+ </para>
+ </refsect1>
+ <refsect1 id="seealso"><title>See Also</title>
+ <para>
+ <citerefentry><refentrytitle>glActiveTexture</refentrytitle></citerefentry>,
+ <citerefentry><refentrytitle>glGetTexParameter</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>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>,
+ <citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>
+ </para>
+ </refsect1>
+ <refsect1 id="Copyright"><title>Copyright</title>
+ <para>
+ Copyright <trademark class="copyright"></trademark> 1991-2006
+ Silicon Graphics, Inc. Copyright <trademark class="copyright"></trademark> 2010
+ Khronos Group. 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>
HCoop / clinton / guile-figl.git / blobdiff