[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>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>
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>
	8	<year>1991-2006</year>
	9	<holder>Silicon Graphics, Inc.</holder>
	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>,
98	<constant>GL_TEXTURE_BORDER</constant>,
99	<constant>GL_TEXTURE_RED_SIZE</constant>,
100	<constant>GL_TEXTURE_GREEN_SIZE</constant>,
101	<constant>GL_TEXTURE_BLUE_SIZE</constant>,
102	<constant>GL_TEXTURE_ALPHA_SIZE</constant>,
103	<constant>GL_TEXTURE_DEPTH_SIZE</constant>,
104	<constant>GL_TEXTURE_COMPRESSED</constant>, and
105	<constant>GL_TEXTURE_COMPRESSED_IMAGE_SIZE</constant>
106	are accepted.
107	</para>
108	</listitem>
109	</varlistentry>
110	<varlistentry>
111	<term><parameter>params</parameter></term>
112	<listitem>
113	<para>
114	Returns the requested data.
115	</para>
116	</listitem>
117	</varlistentry>
118	</variablelist>
119	</refsect1>
120	<refsect1 id="description"><title>Description</title>
121	<para>
122	<function>glGetTexLevelParameter</function> returns in <parameter>params</parameter> texture parameter values for a specific
123	level-of-detail value,
124	specified as <parameter>level</parameter>.
125	<parameter>target</parameter> defines the target texture,
126	either <constant>GL_TEXTURE_1D</constant>, <constant>GL_TEXTURE_2D</constant>, <constant>GL_TEXTURE_3D</constant>,
127	<constant>GL_PROXY_TEXTURE_1D</constant>,
128	<constant>GL_PROXY_TEXTURE_2D</constant>,
129	<constant>GL_PROXY_TEXTURE_3D</constant>,
130	<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_X</constant>,
131	<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_X</constant>,
132	<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Y</constant>,
133	<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</constant>,
134	<constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Z</constant>,
135	<constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</constant>, or
136	<constant>GL_PROXY_TEXTURE_CUBE_MAP</constant>.
137	</para>
138	<para>
139	<constant>GL_MAX_TEXTURE_SIZE</constant>, and <constant>GL_MAX_3D_TEXTURE_SIZE</constant> are not really
140	descriptive enough.
141	It has to report the largest square texture image that can be
142	accommodated with mipmaps and borders,
143	but a long skinny texture, or a texture without mipmaps and borders, may
144	easily fit in texture memory.
145	The proxy targets allow the user to more accurately query
146	whether the GL can accommodate a texture of a given configuration.
147	If the texture cannot be accommodated, the texture state variables, which
148	may be queried with <function>glGetTexLevelParameter</function>, are set to 0. If the texture can be accommodated,
149	the texture state values will be set as they would be set for a
150	non-proxy target.
151	</para>
152	<para>
153	<parameter>pname</parameter> specifies the texture parameter whose value or values
154	will be returned.
155	</para>
156	<para>
157	The accepted parameter names are as follows:
158	</para>
159	<variablelist>
160	<varlistentry>
161	<term><constant>GL_TEXTURE_WIDTH</constant></term>
162	<listitem>
163	<para>
164	</para>
165	<para>
166	<parameter>params</parameter> returns a single value,
167	the width of the texture image.
168	This value includes the border of the texture image. The initial value is
169	0.
170	</para>
171	</listitem>
172	</varlistentry>
173	<varlistentry>
174	<term><constant>GL_TEXTURE_HEIGHT</constant></term>
175	<listitem>
176	<para>
177	</para>
178	<para>
179	<parameter>params</parameter> returns a single value,
180	the height of the texture image.
181	This value includes the border of the texture image. The initial value is
182	0.
183	</para>
184	</listitem>
185	</varlistentry>
186	<varlistentry>
187	<term><constant>GL_TEXTURE_DEPTH</constant></term>
188	<listitem>
189	<para>
190	</para>
191	<para>
192	<parameter>params</parameter> returns a single value,
193	the depth of the texture image.
194	This value includes the border of the texture image. The initial value is
195	0.
196	</para>
197	</listitem>
198	</varlistentry>
199	<varlistentry>
200	<term><constant>GL_TEXTURE_INTERNAL_FORMAT</constant></term>
201	<listitem>
202	<para>
203	</para>
204	<para>
205	<parameter>params</parameter> returns a single value,
206	the internal format of the texture image.
207	</para>
208	</listitem>
209	</varlistentry>
210	<varlistentry>
211	<term><constant>GL_TEXTURE_RED_TYPE</constant>,</term>
212	<listitem>
213	</listitem>
214	</varlistentry>
215	<varlistentry>
216	<term><constant>GL_TEXTURE_GREEN_TYPE</constant>,</term>
217	<listitem>
218	</listitem>
219	</varlistentry>
220	<varlistentry>
221	<term><constant>GL_TEXTURE_BLUE_TYPE</constant>,</term>
222	<listitem>
223	</listitem>
224	</varlistentry>
225	<varlistentry>
226	<term><constant>GL_TEXTURE_ALPHA_TYPE</constant>,</term>
227	<listitem>
228	</listitem>
229	</varlistentry>
230	<varlistentry>
231	<term><constant>GL_TEXTURE_DEPTH_TYPE</constant></term>
232	<listitem>
233	<para>
234	</para>
235	<para>
236	The data type used to store the component.
237	The types <constant>GL_NONE</constant>, <constant>GL_SIGNED_NORMALIZED</constant>,
238	<constant>GL_UNSIGNED_NORMALIZED</constant>, <constant>GL_FLOAT</constant>,
239	<constant>GL_INT</constant>, and <constant>GL_UNSIGNED_INT</constant> may be returned
240	to indicate signed normalized fixed-point, unsigned normalized fixed-point, floating-point, integer unnormalized, and
241	unsigned integer unnormalized components, respectively.
242	</para>
243	</listitem>
244	</varlistentry>
245	<varlistentry>
246	<term><constant>GL_TEXTURE_RED_SIZE</constant>,</term>
247	<listitem>
248	</listitem>
249	</varlistentry>
250	<varlistentry>
251	<term><constant>GL_TEXTURE_GREEN_SIZE</constant>,</term>
252	<listitem>
253	</listitem>
254	</varlistentry>
255	<varlistentry>
256	<term><constant>GL_TEXTURE_BLUE_SIZE</constant>,</term>
257	<listitem>
258	</listitem>
259	</varlistentry>
260	<varlistentry>
261	<term><constant>GL_TEXTURE_ALPHA_SIZE</constant>,</term>
262	<listitem>
263	</listitem>
264	</varlistentry>
265	<varlistentry>
266	<term><constant>GL_TEXTURE_DEPTH_SIZE</constant></term>
267	<listitem>
268	<para>
269	</para>
270	<para>
271	The internal storage resolution of an individual component.
272	The resolution chosen by the GL will be a close match for the resolution
273	requested by the user with the component argument of <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>,
274	<citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>, and
275	<citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>. The initial value is 0.
276	</para>
277	</listitem>
278	</varlistentry>
279	<varlistentry>
280	<term><constant>GL_TEXTURE_COMPRESSED</constant></term>
281	<listitem>
282	<para>
283	</para>
284	<para>
285	<parameter>params</parameter> returns a single boolean value indicating if the texture image is
286	stored in a compressed internal format. The initiali value is <constant>GL_FALSE</constant>.
287	</para>
288	</listitem>
289	</varlistentry>
290	<varlistentry>
291	<term><constant>GL_TEXTURE_COMPRESSED_IMAGE_SIZE</constant></term>
292	<listitem>
293	<para>
294	</para>
295	<para>
296	<parameter>params</parameter> returns a single integer value, the number of unsigned bytes of the
297	compressed texture image that would be returned from
298	<citerefentry><refentrytitle>glGetCompressedTexImage</refentrytitle></citerefentry>.
299	</para>
300	</listitem>
301	</varlistentry>
302	</variablelist>
303	</refsect1>
304	<refsect1 id="notes"><title>Notes</title>
305	<para>
306	If an error is generated,
307	no change is made to the contents of <parameter>params</parameter>.
308	</para>
309	<para>
310	<function>glGetTexLevelParameter</function> returns the texture level parameters for the active texture unit.
311	</para>
312	</refsect1>
313	<refsect1 id="errors"><title>Errors</title>
314	<para>
315	<constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> or <parameter>pname</parameter> is not an
316	accepted value.
317	</para>
318	<para>
319	<constant>GL_INVALID_VALUE</constant> is generated if <parameter>level</parameter> is less than 0.
320	</para>
321	<para>
322	<constant>GL_INVALID_VALUE</constant> may be generated if <parameter>level</parameter> is greater
323	than
324	<inlineequation><mml:math>
325	<!-- eqn: log sub 2: -->
326	<mml:msub><mml:mi mathvariant="italic">log</mml:mi>
327	<mml:mn>2</mml:mn>
328	</mml:msub>
329	</mml:math></inlineequation>
330	<emphasis>max</emphasis>,
331	where <emphasis>max</emphasis> is the returned value of <constant>GL_MAX_TEXTURE_SIZE</constant>.
332	</para>
333	<para>
334	<constant>GL_INVALID_VALUE</constant> is generated if <parameter>target</parameter> is <constant>GL_TEXTURE_BUFFER</constant>
335	and <parameter>level</parameter> is not zero.
336	</para>
337	<para>
338	<constant>GL_INVALID_OPERATION</constant> is generated if
339	<constant>GL_TEXTURE_COMPRESSED_IMAGE_SIZE</constant> is queried on texture images with an
340	uncompressed internal format or on proxy targets.
341	</para>
342	</refsect1>
343	<refsect1 id="seealso"><title>See Also</title>
344	<para>
345	<citerefentry><refentrytitle>glActiveTexture</refentrytitle></citerefentry>,
346	<citerefentry><refentrytitle>glGetTexParameter</refentrytitle></citerefentry>,
347	<citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>,
348	<citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>,
349	<citerefentry><refentrytitle>glCopyTexSubImage1D</refentrytitle></citerefentry>,
350	<citerefentry><refentrytitle>glCopyTexSubImage2D</refentrytitle></citerefentry>,
351	<citerefentry><refentrytitle>glCopyTexSubImage3D</refentrytitle></citerefentry>,
352	<citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>,
353	<citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
354	<citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,
355	<citerefentry><refentrytitle>glTexSubImage1D</refentrytitle></citerefentry>,
356	<citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>,
357	<citerefentry><refentrytitle>glTexSubImage3D</refentrytitle></citerefentry>,
358	<citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>
359	</para>
360	</refsect1>
361	<refsect1 id="Copyright"><title>Copyright</title>
362	<para>
363	Copyright <trademark class="copyright"></trademark> 1991-2006
364	Silicon Graphics, Inc. Copyright <trademark class="copyright"></trademark> 2010
365	Khronos Group. This document is licensed under the SGI
366	Free Software B License. For details, see
367	<ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
368	</para>
369	</refsect1>
370	</refentry>