[clinton/guile-figl.git] / upstream-doc / man2 / glGetLight.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="glGetLight">
    <refmeta>
        <refmetainfo>
            <copyright>
                <year>1991-2006</year>
                <holder>Silicon Graphics, Inc.</holder>
            </copyright>
        </refmetainfo>
        <refentrytitle>glGetLight</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glGetLight</refname>
        <refpurpose>return light source parameter values</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glGetLightfv</function></funcdef>
                <paramdef>GLenum <parameter>light</parameter></paramdef>
                <paramdef>GLenum <parameter>pname</parameter></paramdef>
                <paramdef>GLfloat * <parameter>params</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glGetLightiv</function></funcdef>
                <paramdef>GLenum <parameter>light</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>light</parameter></term>
            <listitem>
                <para>
                    Specifies a light source.
                    The number of possible lights depends on the implementation,
                    but at least eight lights are supported.
                    They are identified by symbolic names of the form <constant>GL_LIGHT</constant>
                    <inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>
                    where 
                    <inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>
                    ranges from 0 to the value of <constant>GL_MAX_LIGHTS</constant> - 1.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>pname</parameter></term>
            <listitem>
                <para>
                    Specifies a light source parameter for <parameter>light</parameter>.
                    Accepted symbolic names are
                    <constant>GL_AMBIENT</constant>,
                    <constant>GL_DIFFUSE</constant>,
                    <constant>GL_SPECULAR</constant>,
                    <constant>GL_POSITION</constant>,
                    <constant>GL_SPOT_DIRECTION</constant>,
                    <constant>GL_SPOT_EXPONENT</constant>,
                    <constant>GL_SPOT_CUTOFF</constant>,
                    <constant>GL_CONSTANT_ATTENUATION</constant>,
                    <constant>GL_LINEAR_ATTENUATION</constant>, and
                    <constant>GL_QUADRATIC_ATTENUATION</constant>.
                </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>glGetLight</function> returns in <parameter>params</parameter> the value or values of a light source parameter.
            <parameter>light</parameter> names the light and is a symbolic name of the form <constant>GL_LIGHT</constant>
            <inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>
            where i ranges from 0 to the value of <constant>GL_MAX_LIGHTS</constant> - 1.
            <constant>GL_MAX_LIGHTS</constant> is an implementation dependent constant that is
            greater than or equal to eight.
            <parameter>pname</parameter> specifies one of ten light source parameters,
            again by symbolic name.
        </para>
        <para>
            The following parameters are defined:
        </para>
        <variablelist>
            <varlistentry>
                <term><constant>GL_AMBIENT</constant></term>
                <listitem>
                    <para>
                        <parameter>params</parameter> returns four integer or floating-point values representing the
                        ambient intensity of the light source.
                        Integer values,
                        when requested,
                        are linearly mapped from the internal floating-point representation
                        such that 1.0 maps to the most positive representable integer value,
                        and 
                        <inlineequation><mml:math>
                            <!-- eqn: -1.0:-->
                            <mml:mn>-1.0</mml:mn>
                        </mml:math></inlineequation>
                        maps to the most negative representable integer value.
                        If the internal value is outside the range 
                        <inlineequation><mml:math>
                            <!-- eqn: [-1,1]:-->
                            <mml:mfenced open="[" close="]">
                                <mml:mn>-1</mml:mn>
                                <mml:mn>1</mml:mn>
                            </mml:mfenced>
                        </mml:math></inlineequation>,
                        the corresponding integer return value is undefined. The initial value is
                        (0, 0, 0, 1).
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_DIFFUSE</constant></term>
                <listitem>
                    <para>
                        <parameter>params</parameter> returns four integer or floating-point values representing the
                        diffuse intensity of the light source.
                        Integer values,
                        when requested,
                        are linearly mapped from the internal floating-point representation
                        such that 1.0 maps to the most positive representable integer value,
                        and 
                        <inlineequation><mml:math>
                            <!-- eqn: -1.0:-->
                            <mml:mn>-1.0</mml:mn>
                        </mml:math></inlineequation>
                        maps to the most negative representable integer value.
                        If the internal value is outside the range 
                        <inlineequation><mml:math>
                            <!-- eqn: [-1,1]:-->
                            <mml:mfenced open="[" close="]">
                                <mml:mn>-1</mml:mn>
                                <mml:mn>1</mml:mn>
                            </mml:mfenced>
                        </mml:math></inlineequation>,
                        the corresponding integer return value is undefined. The initial value
                        for <constant>GL_LIGHT0</constant> is (1, 1, 1, 1); for other lights, the
                        initial value is (0, 0, 0, 0).
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_SPECULAR</constant></term>
                <listitem>
                    <para>
                        <parameter>params</parameter> returns four integer or floating-point values representing the
                        specular intensity of the light source.
                        Integer values,
                        when requested,
                        are linearly mapped from the internal floating-point representation
                        such that 1.0 maps to the most positive representable integer value,
                        and 
                        <inlineequation><mml:math>
                            <!-- eqn: -1.0:-->
                            <mml:mn>-1.0</mml:mn>
                        </mml:math></inlineequation>
                        maps to the most negative representable integer value.
                        If the internal value is outside the range 
                        <inlineequation><mml:math>
                            <!-- eqn: [-1,1]:-->
                            <mml:mfenced open="[" close="]">
                                <mml:mn>-1</mml:mn>
                                <mml:mn>1</mml:mn>
                            </mml:mfenced>
                        </mml:math></inlineequation>,
                        the corresponding integer return value is undefined. The initial value
                        for <constant>GL_LIGHT0</constant> is (1, 1, 1, 1); for other lights, the
                        initial value is (0, 0, 0, 0).
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_POSITION</constant></term>
                <listitem>
                    <para>
                        <parameter>params</parameter> returns four integer or floating-point values representing the
                        position of the light source.
                        Integer values,
                        when requested,
                        are computed by rounding the internal floating-point values to the
                        nearest integer value.
                        The returned values are those maintained in eye coordinates.
                        They will not be equal to the values specified using <citerefentry><refentrytitle>glLight</refentrytitle></citerefentry>,
                        unless the modelview matrix was identity at the time <citerefentry><refentrytitle>glLight</refentrytitle></citerefentry> was
                        called. The initial value is (0, 0, 1, 0).
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_SPOT_DIRECTION</constant></term>
                <listitem>
                    <para>
                        <parameter>params</parameter> returns three integer or floating-point values representing the
                        direction of the light source.
                        Integer values,
                        when requested,
                        are computed by rounding the internal floating-point values to the
                        nearest integer value.
                        The returned values are those maintained in eye coordinates.
                        They will not be equal to the values specified using <citerefentry><refentrytitle>glLight</refentrytitle></citerefentry>,
                        unless the modelview matrix was identity at the time <citerefentry><refentrytitle>glLight</refentrytitle></citerefentry> was called.
                        Although spot direction is normalized before being used in the lighting
                        equation,
                        the returned values are the transformed versions of the specified values
                        prior to normalization. The initial value is 
                        <inlineequation><mml:math>
                            <!-- eqn: (0, 0, -1):-->
                            <mml:mfenced open="(" close=")">
                                <mml:mn>0</mml:mn>
                                <mml:mn>0</mml:mn>
                                <mml:mn>-1</mml:mn>
                            </mml:mfenced>
                        </mml:math></inlineequation>.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_SPOT_EXPONENT</constant></term>
                <listitem>
                    <para>
                        <parameter>params</parameter> returns a single integer or floating-point value representing the
                        spot exponent of the light.
                        An integer value,
                        when requested,
                        is computed by rounding the internal floating-point representation to
                        the nearest integer. The initial value is 0.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_SPOT_CUTOFF</constant></term>
                <listitem>
                    <para>
                        <parameter>params</parameter> returns a single integer or floating-point value representing the
                        spot cutoff angle of the light.
                        An integer value,
                        when requested,
                        is computed by rounding the internal floating-point representation to
                        the nearest integer. The initial value is 180.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_CONSTANT_ATTENUATION</constant></term>
                <listitem>
                    <para>
                        <parameter>params</parameter> returns a single integer or floating-point value representing the
                        constant (not distance-related) attenuation of the light.
                        An integer value,
                        when requested,
                        is computed by rounding the internal floating-point representation to
                        the nearest integer. The initial value is 1.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_LINEAR_ATTENUATION</constant></term>
                <listitem>
                    <para>
                        <parameter>params</parameter> returns a single integer or floating-point value representing the
                        linear attenuation of the light.
                        An integer value,
                        when requested,
                        is computed by rounding the internal floating-point representation to
                        the nearest integer. The initial value is 0.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_QUADRATIC_ATTENUATION</constant></term>
                <listitem>
                    <para>
                        <parameter>params</parameter> returns a single integer or floating-point value representing the
                        quadratic attenuation of the light.
                        An integer value,
                        when requested,
                        is computed by rounding the internal floating-point representation to
                        the nearest integer. The initial value is 0.
                    </para>
                </listitem>
            </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 id="notes"><title>Notes</title>
        <para>
            It is always the case that <constant>GL_LIGHT</constant>
            <inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>
            = <constant>GL_LIGHT0</constant> + 
            <inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>.
        </para>
        <para>
            If an error is generated,
            no change is made to the contents of <parameter>params</parameter>.
        </para>
    </refsect1>
    <refsect1 id="errors"><title>Errors</title>
        <para>
            <constant>GL_INVALID_ENUM</constant> is generated if <parameter>light</parameter> or <parameter>pname</parameter> is not an
            accepted value.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if <function>glGetLight</function>
            is executed between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>
            and the corresponding execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
        </para>
    </refsect1>
    <refsect1 id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glLight</refentrytitle></citerefentry>
        </para>
    </refsect1>
    <refsect1 id="Copyright"><title>Copyright</title>
        <para>
            Copyright <trademark class="copyright"></trademark> 1991-2006
            Silicon Graphics, Inc. This document is licensed under the SGI
            Free Software B License. For details, see
            <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
        </para>
    </refsect1>
</refentry>
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="glGetLight">
	5	<refmeta>
	6	<refmetainfo>
	7	<copyright>
	8	<year>1991-2006</year>
	9	<holder>Silicon Graphics, Inc.</holder>
	10	</copyright>
	11	</refmetainfo>
	12	<refentrytitle>glGetLight</refentrytitle>
	13	<manvolnum>3G</manvolnum>
	14	</refmeta>
	15	<refnamediv>
	16	<refname>glGetLight</refname>
	17	<refpurpose>return light source parameter values</refpurpose>
	18	</refnamediv>
	19	<refsynopsisdiv><title>C Specification</title>
	20	<funcsynopsis>
	21	<funcprototype>
	22	<funcdef>void <function>glGetLightfv</function></funcdef>
	23	<paramdef>GLenum <parameter>light</parameter></paramdef>
	24	<paramdef>GLenum <parameter>pname</parameter></paramdef>
	25	<paramdef>GLfloat * <parameter>params</parameter></paramdef>
	26	</funcprototype>
	27	</funcsynopsis>
	28	<funcsynopsis>
	29	<funcprototype>
	30	<funcdef>void <function>glGetLightiv</function></funcdef>
	31	<paramdef>GLenum <parameter>light</parameter></paramdef>
	32	<paramdef>GLenum <parameter>pname</parameter></paramdef>
	33	<paramdef>GLint * <parameter>params</parameter></paramdef>
	34	</funcprototype>
	35	</funcsynopsis>
	36	</refsynopsisdiv>
	37	<!-- eqn: ignoring delim $$ -->
	38	<refsect1 id="parameters"><title>Parameters</title>
	39	<variablelist>
	40	<varlistentry>
	41	<term><parameter>light</parameter></term>
	42	<listitem>
	43	<para>
	44	Specifies a light source.
	45	The number of possible lights depends on the implementation,
	46	but at least eight lights are supported.
	47	They are identified by symbolic names of the form <constant>GL_LIGHT</constant>
	48	<inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>
	49	where
	50	<inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>
	51	ranges from 0 to the value of <constant>GL_MAX_LIGHTS</constant> - 1.
	52	</para>
	53	</listitem>
	54	</varlistentry>
	55	<varlistentry>
	56	<term><parameter>pname</parameter></term>
	57	<listitem>
	58	<para>
	59	Specifies a light source parameter for <parameter>light</parameter>.
	60	Accepted symbolic names are
	61	<constant>GL_AMBIENT</constant>,
	62	<constant>GL_DIFFUSE</constant>,
	63	<constant>GL_SPECULAR</constant>,
	64	<constant>GL_POSITION</constant>,
65	<constant>GL_SPOT_DIRECTION</constant>,
66	<constant>GL_SPOT_EXPONENT</constant>,
67	<constant>GL_SPOT_CUTOFF</constant>,
68	<constant>GL_CONSTANT_ATTENUATION</constant>,
69	<constant>GL_LINEAR_ATTENUATION</constant>, and
70	<constant>GL_QUADRATIC_ATTENUATION</constant>.
71	</para>
72	</listitem>
73	</varlistentry>
74	<varlistentry>
75	<term><parameter>params</parameter></term>
76	<listitem>
77	<para>
78	Returns the requested data.
79	</para>
80	</listitem>
81	</varlistentry>
82	</variablelist>
83	</refsect1>
84	<refsect1 id="description"><title>Description</title>
85	<para>
86	<function>glGetLight</function> returns in <parameter>params</parameter> the value or values of a light source parameter.
87	<parameter>light</parameter> names the light and is a symbolic name of the form <constant>GL_LIGHT</constant>
88	<inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>
89	where i ranges from 0 to the value of <constant>GL_MAX_LIGHTS</constant> - 1.
90	<constant>GL_MAX_LIGHTS</constant> is an implementation dependent constant that is
91	greater than or equal to eight.
92	<parameter>pname</parameter> specifies one of ten light source parameters,
93	again by symbolic name.
94	</para>
95	<para>
96	The following parameters are defined:
97	</para>
98	<variablelist>
99	<varlistentry>
100	<term><constant>GL_AMBIENT</constant></term>
101	<listitem>
102	<para>
103	<parameter>params</parameter> returns four integer or floating-point values representing the
104	ambient intensity of the light source.
105	Integer values,
106	when requested,
107	are linearly mapped from the internal floating-point representation
108	such that 1.0 maps to the most positive representable integer value,
109	and
110	<inlineequation><mml:math>
111	<!-- eqn: -1.0:-->
112	<mml:mn>-1.0</mml:mn>
113	</mml:math></inlineequation>
114	maps to the most negative representable integer value.
115	If the internal value is outside the range
116	<inlineequation><mml:math>
117	<!-- eqn: [-1,1]:-->
118	<mml:mfenced open="[" close="]">
119	<mml:mn>-1</mml:mn>
120	<mml:mn>1</mml:mn>
121	</mml:mfenced>
122	</mml:math></inlineequation>,
123	the corresponding integer return value is undefined. The initial value is
124	(0, 0, 0, 1).
125	</para>
126	</listitem>
127	</varlistentry>
128	<varlistentry>
129	<term><constant>GL_DIFFUSE</constant></term>
130	<listitem>
131	<para>
132	<parameter>params</parameter> returns four integer or floating-point values representing the
133	diffuse intensity of the light source.
134	Integer values,
135	when requested,
136	are linearly mapped from the internal floating-point representation
137	such that 1.0 maps to the most positive representable integer value,
138	and
139	<inlineequation><mml:math>
140	<!-- eqn: -1.0:-->
141	<mml:mn>-1.0</mml:mn>
142	</mml:math></inlineequation>
143	maps to the most negative representable integer value.
144	If the internal value is outside the range
145	<inlineequation><mml:math>
146	<!-- eqn: [-1,1]:-->
147	<mml:mfenced open="[" close="]">
148	<mml:mn>-1</mml:mn>
149	<mml:mn>1</mml:mn>
150	</mml:mfenced>
151	</mml:math></inlineequation>,
152	the corresponding integer return value is undefined. The initial value
153	for <constant>GL_LIGHT0</constant> is (1, 1, 1, 1); for other lights, the
154	initial value is (0, 0, 0, 0).
155	</para>
156	</listitem>
157	</varlistentry>
158	<varlistentry>
159	<term><constant>GL_SPECULAR</constant></term>
160	<listitem>
161	<para>
162	<parameter>params</parameter> returns four integer or floating-point values representing the
163	specular intensity of the light source.
164	Integer values,
165	when requested,
166	are linearly mapped from the internal floating-point representation
167	such that 1.0 maps to the most positive representable integer value,
168	and
169	<inlineequation><mml:math>
170	<!-- eqn: -1.0:-->
171	<mml:mn>-1.0</mml:mn>
172	</mml:math></inlineequation>
173	maps to the most negative representable integer value.
174	If the internal value is outside the range
175	<inlineequation><mml:math>
176	<!-- eqn: [-1,1]:-->
177	<mml:mfenced open="[" close="]">
178	<mml:mn>-1</mml:mn>
179	<mml:mn>1</mml:mn>
180	</mml:mfenced>
181	</mml:math></inlineequation>,
182	the corresponding integer return value is undefined. The initial value
183	for <constant>GL_LIGHT0</constant> is (1, 1, 1, 1); for other lights, the
184	initial value is (0, 0, 0, 0).
185	</para>
186	</listitem>
187	</varlistentry>
188	<varlistentry>
189	<term><constant>GL_POSITION</constant></term>
190	<listitem>
191	<para>
192	<parameter>params</parameter> returns four integer or floating-point values representing the
193	position of the light source.
194	Integer values,
195	when requested,
196	are computed by rounding the internal floating-point values to the
197	nearest integer value.
198	The returned values are those maintained in eye coordinates.
199	They will not be equal to the values specified using <citerefentry><refentrytitle>glLight</refentrytitle></citerefentry>,
200	unless the modelview matrix was identity at the time <citerefentry><refentrytitle>glLight</refentrytitle></citerefentry> was
201	called. The initial value is (0, 0, 1, 0).
202	</para>
203	</listitem>
204	</varlistentry>
205	<varlistentry>
206	<term><constant>GL_SPOT_DIRECTION</constant></term>
207	<listitem>
208	<para>
209	<parameter>params</parameter> returns three integer or floating-point values representing the
210	direction of the light source.
211	Integer values,
212	when requested,
213	are computed by rounding the internal floating-point values to the
214	nearest integer value.
215	The returned values are those maintained in eye coordinates.
216	They will not be equal to the values specified using <citerefentry><refentrytitle>glLight</refentrytitle></citerefentry>,
217	unless the modelview matrix was identity at the time <citerefentry><refentrytitle>glLight</refentrytitle></citerefentry> was called.
218	Although spot direction is normalized before being used in the lighting
219	equation,
220	the returned values are the transformed versions of the specified values
221	prior to normalization. The initial value is
222	<inlineequation><mml:math>
223	<!-- eqn: (0, 0, -1):-->
224	<mml:mfenced open="(" close=")">
225	<mml:mn>0</mml:mn>
226	<mml:mn>0</mml:mn>
227	<mml:mn>-1</mml:mn>
228	</mml:mfenced>
229	</mml:math></inlineequation>.
230	</para>
231	</listitem>
232	</varlistentry>
233	<varlistentry>
234	<term><constant>GL_SPOT_EXPONENT</constant></term>
235	<listitem>
236	<para>
237	<parameter>params</parameter> returns a single integer or floating-point value representing the
238	spot exponent of the light.
239	An integer value,
240	when requested,
241	is computed by rounding the internal floating-point representation to
242	the nearest integer. The initial value is 0.
243	</para>
244	</listitem>
245	</varlistentry>
246	<varlistentry>
247	<term><constant>GL_SPOT_CUTOFF</constant></term>
248	<listitem>
249	<para>
250	<parameter>params</parameter> returns a single integer or floating-point value representing the
251	spot cutoff angle of the light.
252	An integer value,
253	when requested,
254	is computed by rounding the internal floating-point representation to
255	the nearest integer. The initial value is 180.
256	</para>
257	</listitem>
258	</varlistentry>
259	<varlistentry>
260	<term><constant>GL_CONSTANT_ATTENUATION</constant></term>
261	<listitem>
262	<para>
263	<parameter>params</parameter> returns a single integer or floating-point value representing the
264	constant (not distance-related) attenuation of the light.
265	An integer value,
266	when requested,
267	is computed by rounding the internal floating-point representation to
268	the nearest integer. The initial value is 1.
269	</para>
270	</listitem>
271	</varlistentry>
272	<varlistentry>
273	<term><constant>GL_LINEAR_ATTENUATION</constant></term>
274	<listitem>
275	<para>
276	<parameter>params</parameter> returns a single integer or floating-point value representing the
277	linear attenuation of the light.
278	An integer value,
279	when requested,
280	is computed by rounding the internal floating-point representation to
281	the nearest integer. The initial value is 0.
282	</para>
283	</listitem>
284	</varlistentry>
285	<varlistentry>
286	<term><constant>GL_QUADRATIC_ATTENUATION</constant></term>
287	<listitem>
288	<para>
289	<parameter>params</parameter> returns a single integer or floating-point value representing the
290	quadratic attenuation of the light.
291	An integer value,
292	when requested,
293	is computed by rounding the internal floating-point representation to
294	the nearest integer. The initial value is 0.
295	</para>
296	</listitem>
297	</varlistentry>
298	</variablelist>
299	</refsect1>
300	<refsect1 id="notes"><title>Notes</title>
301	<para>
302	It is always the case that <constant>GL_LIGHT</constant>
303	<inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>
304	= <constant>GL_LIGHT0</constant> +
305	<inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>.
306	</para>
307	<para>
308	If an error is generated,
309	no change is made to the contents of <parameter>params</parameter>.
310	</para>
311	</refsect1>
312	<refsect1 id="errors"><title>Errors</title>
313	<para>
314	<constant>GL_INVALID_ENUM</constant> is generated if <parameter>light</parameter> or <parameter>pname</parameter> is not an
315	accepted value.
316	</para>
317	<para>
318	<constant>GL_INVALID_OPERATION</constant> is generated if <function>glGetLight</function>
319	is executed between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>
320	and the corresponding execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
321	</para>
322	</refsect1>
323	<refsect1 id="seealso"><title>See Also</title>
324	<para>
325	<citerefentry><refentrytitle>glLight</refentrytitle></citerefentry>
326	</para>
327	</refsect1>
328	<refsect1 id="Copyright"><title>Copyright</title>
329	<para>
330	Copyright <trademark class="copyright"></trademark> 1991-2006
331	Silicon Graphics, Inc. This document is licensed under the SGI
332	Free Software B License. For details, see
333	<ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
334	</para>
335	</refsect1>
336	</refentry>