[clinton/guile-figl.git] / upstream-doc / man3 / glGetTexLevelParameter.xml

<?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>2013</year>
                <holder>Khronos Group</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_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
            but a long skinny texture, or a texture without mipmaps 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.
                        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.
                        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.
                        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> 2010-2013
            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>
Commit	Line	Data
7faf1d71 AW	1	<?xml version="1.0" encoding="UTF-8"?>
	2	<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
	3	"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
	4	<refentry id="glGetTexLevelParameter">
	5	<refmeta>
	6	<refmetainfo>
	7	<copyright>
c7b31271 DH	8	<year>2013</year>
c7b31271 DH	9	<holder>Khronos Group</holder>
7faf1d71 AW	10	</copyright>
	11	</refmetainfo>
	12	<refentrytitle>glGetTexLevelParameter</refentrytitle>
	13	<manvolnum>3G</manvolnum>
	14	</refmeta>
	15	<refnamediv>
	16	<refname>glGetTexLevelParameter</refname>
	17	<refpurpose>return texture parameter values for a specific level of detail</refpurpose>
	18	</refnamediv>
	19	<refsynopsisdiv><title>C Specification</title>
	20	<funcsynopsis>
	21	<funcprototype>
	22	<funcdef>void <function>glGetTexLevelParameterfv</function></funcdef>
	23	<paramdef>GLenum <parameter>target</parameter></paramdef>
	24	<paramdef>GLint <parameter>level</parameter></paramdef>
	25	<paramdef>GLenum <parameter>pname</parameter></paramdef>
	26	<paramdef>GLfloat * <parameter>params</parameter></paramdef>
	27	</funcprototype>
	28	</funcsynopsis>
	29	<funcsynopsis>
	30	<funcprototype>
	31	<funcdef>void <function>glGetTexLevelParameteriv</function></funcdef>
	32	<paramdef>GLenum <parameter>target</parameter></paramdef>
	33	<paramdef>GLint <parameter>level</parameter></paramdef>
	34	<paramdef>GLenum <parameter>pname</parameter></paramdef>
	35	<paramdef>GLint * <parameter>params</parameter></paramdef>
	36	</funcprototype>
	37	</funcsynopsis>
	38	</refsynopsisdiv>
	39	<!-- eqn: ignoring delim $$ -->
	40	<refsect1 id="parameters"><title>Parameters</title>
	41	<variablelist>
	42	<varlistentry>
	43	<term><parameter>target</parameter></term>
	44	<listitem>
	45	<para>
	46	Specifies the symbolic name of the target texture,
	47	one of
	48	<constant>GL_TEXTURE_1D</constant>,
	49	<constant>GL_TEXTURE_2D</constant>,
	50	<constant>GL_TEXTURE_3D</constant>,
	51	<constant>GL_TEXTURE_1D_ARRAY</constant>,
	52	<constant>GL_TEXTURE_2D_ARRAY</constant>,
	53	<constant>GL_TEXTURE_RECTANGLE</constant>,
	54	<constant>GL_TEXTURE_2D_MULTISAMPLE</constant>,
	55	<constant>GL_TEXTURE_2D_MULTISAMPLE_ARRAY</constant>,
	56	<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_X</constant>,
	57	<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_X</constant>,
	58	<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Y</constant>,
	59	<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</constant>,
	60	<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Z</constant>,
	61	<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</constant>,
	62	<constant>GL_PROXY_TEXTURE_1D</constant>,
	63	<constant>GL_PROXY_TEXTURE_2D</constant>,
	64	<constant>GL_PROXY_TEXTURE_3D</constant>,
	65	<constant>GL_PROXY_TEXTURE_1D_ARRAY</constant>,
	66	<constant>GL_PROXY_TEXTURE_2D_ARRAY</constant>,
	67	<constant>GL_PROXY_TEXTURE_RECTANGLE</constant>,
	68	<constant>GL_PROXY_TEXTURE_2D_MULTISAMPLE</constant>,
	69	<constant>GL_PROXY_TEXTURE_2D_MULTISAMPLE_ARRAY</constant>,
	70	<constant>GL_PROXY_TEXTURE_CUBE_MAP</constant>, or
	71	<constant>GL_TEXTURE_BUFFER</constant>.
	72	</para>
	73	</listitem>
74	</varlistentry>
75	<varlistentry>
76	<term><parameter>level</parameter></term>
77	<listitem>
78	<para>
79	Specifies the level-of-detail number of the desired image.
80	Level 0 is the base image level.
81	Level
82	<inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
83	is the
84	<inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>th
85	mipmap reduction image.
86	</para>
87	</listitem>
88	</varlistentry>
89	<varlistentry>
90	<term><parameter>pname</parameter></term>
91	<listitem>
92	<para>
93	Specifies the symbolic name of a texture parameter.
94	<constant>GL_TEXTURE_WIDTH</constant>,
95	<constant>GL_TEXTURE_HEIGHT</constant>,
96	<constant>GL_TEXTURE_DEPTH</constant>,
97	<constant>GL_TEXTURE_INTERNAL_FORMAT</constant>,
7faf1d71 AW	98	<constant>GL_TEXTURE_RED_SIZE</constant>,
	99	<constant>GL_TEXTURE_GREEN_SIZE</constant>,
	100	<constant>GL_TEXTURE_BLUE_SIZE</constant>,
	101	<constant>GL_TEXTURE_ALPHA_SIZE</constant>,
	102	<constant>GL_TEXTURE_DEPTH_SIZE</constant>,
	103	<constant>GL_TEXTURE_COMPRESSED</constant>, and
	104	<constant>GL_TEXTURE_COMPRESSED_IMAGE_SIZE</constant>
	105	are accepted.
	106	</para>
	107	</listitem>
	108	</varlistentry>
	109	<varlistentry>
	110	<term><parameter>params</parameter></term>
	111	<listitem>
	112	<para>
	113	Returns the requested data.
	114	</para>
	115	</listitem>
	116	</varlistentry>
	117	</variablelist>
	118	</refsect1>
	119	<refsect1 id="description"><title>Description</title>
	120	<para>
	121	<function>glGetTexLevelParameter</function> returns in <parameter>params</parameter> texture parameter values for a specific
	122	level-of-detail value,
	123	specified as <parameter>level</parameter>.
	124	<parameter>target</parameter> defines the target texture,
	125	either <constant>GL_TEXTURE_1D</constant>, <constant>GL_TEXTURE_2D</constant>, <constant>GL_TEXTURE_3D</constant>,
	126	<constant>GL_PROXY_TEXTURE_1D</constant>,
	127	<constant>GL_PROXY_TEXTURE_2D</constant>,
	128	<constant>GL_PROXY_TEXTURE_3D</constant>,
	129	<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_X</constant>,
	130	<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_X</constant>,
	131	<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Y</constant>,
	132	<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</constant>,
	133	<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Z</constant>,
	134	<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</constant>, or
	135	<constant>GL_PROXY_TEXTURE_CUBE_MAP</constant>.
	136	</para>
	137	<para>
	138	<constant>GL_MAX_TEXTURE_SIZE</constant>, and <constant>GL_MAX_3D_TEXTURE_SIZE</constant> are not really
	139	descriptive enough.
	140	It has to report the largest square texture image that can be
c7b31271 DH	141	accommodated with mipmaps
c7b31271 DH	142	but a long skinny texture, or a texture without mipmaps may
7faf1d71 AW	143	easily fit in texture memory.
	144	The proxy targets allow the user to more accurately query
	145	whether the GL can accommodate a texture of a given configuration.
	146	If the texture cannot be accommodated, the texture state variables, which
	147	may be queried with <function>glGetTexLevelParameter</function>, are set to 0. If the texture can be accommodated,
	148	the texture state values will be set as they would be set for a
	149	non-proxy target.
	150	</para>
	151	<para>
	152	<parameter>pname</parameter> specifies the texture parameter whose value or values
	153	will be returned.
	154	</para>
	155	<para>
	156	The accepted parameter names are as follows:
	157	</para>
	158	<variablelist>
	159	<varlistentry>
	160	<term><constant>GL_TEXTURE_WIDTH</constant></term>
	161	<listitem>
	162	<para>
	163	</para>
	164	<para>
	165	<parameter>params</parameter> returns a single value,
	166	the width of the texture image.
c7b31271	167	The initial value is 0.
7faf1d71 AW	168	</para>
	169	</listitem>
	170	</varlistentry>
	171	<varlistentry>
	172	<term><constant>GL_TEXTURE_HEIGHT</constant></term>
	173	<listitem>
	174	<para>
	175	</para>
	176	<para>
	177	<parameter>params</parameter> returns a single value,
	178	the height of the texture image.
c7b31271	179	The initial value is 0.
7faf1d71 AW	180	</para>
	181	</listitem>
	182	</varlistentry>
	183	<varlistentry>
	184	<term><constant>GL_TEXTURE_DEPTH</constant></term>
	185	<listitem>
	186	<para>
	187	</para>
	188	<para>
	189	<parameter>params</parameter> returns a single value,
	190	the depth of the texture image.
c7b31271	191	The initial value is 0.
7faf1d71 AW	192	</para>
	193	</listitem>
	194	</varlistentry>
	195	<varlistentry>
	196	<term><constant>GL_TEXTURE_INTERNAL_FORMAT</constant></term>
	197	<listitem>
	198	<para>
	199	</para>
	200	<para>
	201	<parameter>params</parameter> returns a single value,
	202	the internal format of the texture image.
	203	</para>
	204	</listitem>
	205	</varlistentry>
	206	<varlistentry>
	207	<term><constant>GL_TEXTURE_RED_TYPE</constant>,</term>
	208	<listitem>
	209	</listitem>
	210	</varlistentry>
	211	<varlistentry>
	212	<term><constant>GL_TEXTURE_GREEN_TYPE</constant>,</term>
	213	<listitem>
	214	</listitem>
	215	</varlistentry>
	216	<varlistentry>
	217	<term><constant>GL_TEXTURE_BLUE_TYPE</constant>,</term>
	218	<listitem>
	219	</listitem>
	220	</varlistentry>
	221	<varlistentry>
	222	<term><constant>GL_TEXTURE_ALPHA_TYPE</constant>,</term>
	223	<listitem>
	224	</listitem>
	225	</varlistentry>
	226	<varlistentry>
	227	<term><constant>GL_TEXTURE_DEPTH_TYPE</constant></term>
	228	<listitem>
	229	<para>
	230	</para>
	231	<para>
	232	The data type used to store the component.
	233	The types <constant>GL_NONE</constant>, <constant>GL_SIGNED_NORMALIZED</constant>,
	234	<constant>GL_UNSIGNED_NORMALIZED</constant>, <constant>GL_FLOAT</constant>,
	235	<constant>GL_INT</constant>, and <constant>GL_UNSIGNED_INT</constant> may be returned
	236	to indicate signed normalized fixed-point, unsigned normalized fixed-point, floating-point, integer unnormalized, and
	237	unsigned integer unnormalized components, respectively.
	238	</para>
	239	</listitem>
	240	</varlistentry>
	241	<varlistentry>
	242	<term><constant>GL_TEXTURE_RED_SIZE</constant>,</term>
	243	<listitem>
	244	</listitem>
	245	</varlistentry>
	246	<varlistentry>
	247	<term><constant>GL_TEXTURE_GREEN_SIZE</constant>,</term>
	248	<listitem>
	249	</listitem>
	250	</varlistentry>
	251	<varlistentry>
	252	<term><constant>GL_TEXTURE_BLUE_SIZE</constant>,</term>
	253	<listitem>
	254	</listitem>
	255	</varlistentry>
256	<varlistentry>
257	<term><constant>GL_TEXTURE_ALPHA_SIZE</constant>,</term>
258	<listitem>
259	</listitem>
260	</varlistentry>
261	<varlistentry>
262	<term><constant>GL_TEXTURE_DEPTH_SIZE</constant></term>
263	<listitem>
264	<para>
265	</para>
266	<para>
267	The internal storage resolution of an individual component.
268	The resolution chosen by the GL will be a close match for the resolution
269	requested by the user with the component argument of <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>,
270	<citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>, and
271	<citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>. The initial value is 0.
272	</para>
273	</listitem>
274	</varlistentry>
275	<varlistentry>
276	<term><constant>GL_TEXTURE_COMPRESSED</constant></term>
277	<listitem>
278	<para>
279	</para>
280	<para>
281	<parameter>params</parameter> returns a single boolean value indicating if the texture image is
282	stored in a compressed internal format. The initiali value is <constant>GL_FALSE</constant>.
283	</para>
284	</listitem>
285	</varlistentry>
286	<varlistentry>
287	<term><constant>GL_TEXTURE_COMPRESSED_IMAGE_SIZE</constant></term>
288	<listitem>
289	<para>
290	</para>
291	<para>
292	<parameter>params</parameter> returns a single integer value, the number of unsigned bytes of the
293	compressed texture image that would be returned from
294	<citerefentry><refentrytitle>glGetCompressedTexImage</refentrytitle></citerefentry>.
295	</para>
296	</listitem>
297	</varlistentry>
298	</variablelist>
299	</refsect1>
300	<refsect1 id="notes"><title>Notes</title>
301	<para>
302	If an error is generated,
303	no change is made to the contents of <parameter>params</parameter>.
304	</para>
305	<para>
306	<function>glGetTexLevelParameter</function> returns the texture level parameters for the active texture unit.
307	</para>
308	</refsect1>
309	<refsect1 id="errors"><title>Errors</title>
310	<para>
311	<constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> or <parameter>pname</parameter> is not an
312	accepted value.
313	</para>
314	<para>
315	<constant>GL_INVALID_VALUE</constant> is generated if <parameter>level</parameter> is less than 0.
316	</para>
317	<para>
318	<constant>GL_INVALID_VALUE</constant> may be generated if <parameter>level</parameter> is greater
319	than
320	<inlineequation><mml:math>
321	<!-- eqn: log sub 2: -->
322	<mml:msub><mml:mi mathvariant="italic">log</mml:mi>
323	<mml:mn>2</mml:mn>
324	</mml:msub>
325	</mml:math></inlineequation>
326	<emphasis>max</emphasis>,
327	where <emphasis>max</emphasis> is the returned value of <constant>GL_MAX_TEXTURE_SIZE</constant>.
328	</para>
329	<para>
330	<constant>GL_INVALID_VALUE</constant> is generated if <parameter>target</parameter> is <constant>GL_TEXTURE_BUFFER</constant>
331	and <parameter>level</parameter> is not zero.
332	</para>
333	<para>
334	<constant>GL_INVALID_OPERATION</constant> is generated if
335	<constant>GL_TEXTURE_COMPRESSED_IMAGE_SIZE</constant> is queried on texture images with an
336	uncompressed internal format or on proxy targets.
337	</para>
338	</refsect1>
339	<refsect1 id="seealso"><title>See Also</title>
340	<para>
341	<citerefentry><refentrytitle>glActiveTexture</refentrytitle></citerefentry>,
342	<citerefentry><refentrytitle>glGetTexParameter</refentrytitle></citerefentry>,
343	<citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>,
344	<citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>,
345	<citerefentry><refentrytitle>glCopyTexSubImage1D</refentrytitle></citerefentry>,
346	<citerefentry><refentrytitle>glCopyTexSubImage2D</refentrytitle></citerefentry>,
347	<citerefentry><refentrytitle>glCopyTexSubImage3D</refentrytitle></citerefentry>,
348	<citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>,
349	<citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
350	<citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,
351	<citerefentry><refentrytitle>glTexSubImage1D</refentrytitle></citerefentry>,
352	<citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>,
353	<citerefentry><refentrytitle>glTexSubImage3D</refentrytitle></citerefentry>,
354	<citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>
355	</para>
356	</refsect1>
357	<refsect1 id="Copyright"><title>Copyright</title>
358	<para>
359	Copyright <trademark class="copyright"></trademark> 1991-2006
c7b31271	360	Silicon Graphics, Inc. Copyright <trademark class="copyright"></trademark> 2010-2013
7faf1d71 AW	361	Khronos Group. This document is licensed under the SGI
	362	Free Software B License. For details, see
	363	<ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
	364	</para>
	365	</refsect1>
	366	</refentry>