[clinton/guile-figl.git] / upstream-doc / man2 / xhtml / gluNurbsCallback.xml

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<?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>gluNurbsCallback</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="gluNurbsCallback"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>gluNurbsCallback — define a callback for a NURBS object</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">gluNurbsCallback</b>(</code></td><td>GLUnurbs*  </td><td><var class="pdparam">nurb</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">which</var>, </td></tr><tr><td> </td><td>_GLUfuncptr  </td><td><var class="pdparam">CallBackFunc</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>nurb</code></em></span></dt><dd><p>
                    Specifies the NURBS object (created with <a class="citerefentry" href="gluNewNurbsRenderer.xml"><span class="citerefentry"><span class="refentrytitle">gluNewNurbsRenderer</span></span></a>).
                </p></dd><dt><span class="term"><em class="parameter"><code>which</code></em></span></dt><dd><p>
                    Specifies the callback being defined. 
                    Valid values are <code class="constant">GLU_NURBS_BEGIN</code>, <code class="constant">GLU_NURBS_VERTEX</code>, <code class="constant">GLU_NURBS_NORMAL</code>, <code class="constant">GLU_NURBS_COLOR</code>, <code class="constant">GLU_NURBS_TEXTURE_COORD</code>, <code class="constant">GLU_NURBS_END</code>, <code class="constant">GLU_NURBS_BEGIN_DATA</code>, <code class="constant">GLU_NURBS_VERTEX_DATA</code>, <code class="constant">GLU_NURBS_NORMAL_DATA</code>, <code class="constant">GLU_NURBS_COLOR_DATA</code>, <code class="constant">GLU_NURBS_TEXTURE_COORD_DATA</code>, <code class="constant">GLU_NURBS_END_DATA</code>, and <code class="constant">GLU_NURBS_ERROR</code>.
                </p></dd><dt><span class="term"><em class="parameter"><code>CallBackFunc</code></em></span></dt><dd><p>
                    Specifies the function that the callback calls.
                </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
            <code class="function">gluNurbsCallback</code> is used to define a callback to be used by a NURBS 
            object.
            If the specified callback is already defined, then it is replaced.  If 
            <em class="parameter"><code>CallBackFunc</code></em> is NULL, then this callback will not get
            invoked and the related data, if any, will be lost.
        </p><p>
            Except the error callback, these callbacks are used by NURBS tessellator (when <code class="constant">GLU_NURBS_MODE</code> is set to be <code class="constant">GLU_NURBS_TESSELLATOR</code>) to return back the OpenGL
            polygon primitives resulting from the tessellation. Note that there are two
            versions of each callback: one with a user data pointer and one without. If both versions for a particular callback are specified then the callback with 
            the user data pointer will be used. Note that ``userData'' is a copy of the pointer that was specified at the last call to <code class="function">gluNurbsCallbackData</code>.
        </p><p>
            The error callback function is effective no matter which value that
            <code class="constant">GLU_NURBS_MODE</code> is set to.
            All other callback functions are effective only when <code class="constant">GLU_NURBS_MODE</code>
            is set to <code class="constant">GLU_NURBS_TESSELLATOR</code>.
        </p><p>
            The legal callbacks are as follows:
        </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GLU_NURBS_BEGIN</code></span></dt><dd><p>
                    </p><p>
                        The begin callback indicates the start of a primitive. The function
                        takes a single argument of type GLenum, which can be one of 
                        <code class="constant">GLU_LINES</code>, <code class="constant">GLU_LINE_STRIP</code>, <code class="constant">GLU_TRIANGLE_FAN</code>, <code class="constant">GLU_TRIANGLE_STRIP</code>, <code class="constant">GLU_TRIANGLES</code>, or <code class="constant">GLU_QUAD_STRIP</code>. The
                        default begin callback function is NULL. The function prototype
                        for this callback looks like:
                        </p><pre class="programlisting">
void begin( GLenum type );
                        </pre><p>
                    </p></dd><dt><span class="term"><code class="constant">GLU_NURBS_BEGIN_DATA</code></span></dt><dd><p>
                    </p><p>
                        The same as the <code class="constant">GLU_NURBS_BEGIN</code> callback except that it takes an
                        additional pointer argument. This pointer is a copy of the pointer that
                        was specified at the last call to <code class="function">gluNurbsCallbackData</code>.  The
                        default callback function is NULL. The function prototype for this
                        callback function looks like:
                        </p><pre class="programlisting">
void beginData(GLenum type, void *userData);
                        </pre><p>
                    </p></dd><dt><span class="term"><code class="constant">GLU_NURBS_VERTEX</code></span></dt><dd><p>
                    </p><p>
                        The vertex callback indicates a vertex of the primitive. The
                        coordinates of the vertex are stored in the parameter ``vertex''. All
                        the generated vertices have dimension 3; that is, homogeneous
                        coordinates have been transformed into affine coordinates. The default
                        vertex callback function is NULL. The function prototype for this
                        callback function looks like:
                        </p><pre class="programlisting">
void vertex( GLfloat *vertex );
                        </pre><p>
                    </p></dd><dt><span class="term"><code class="constant">GLU_NURBS_VERTEX_DATA</code></span></dt><dd><p>
                    </p><p>
                        This is the same as the <code class="constant">GLU_NURBS_VERTEX</code> callback, except that
                        it takes an additional pointer argument. This pointer is a copy of the
                        pointer that was specified at the last call to
                        <code class="function">gluNurbsCallbackData</code>.  The default callback function is NULL. The
                        function prototype for this callback function looks like:
                        </p><pre class="programlisting">
void vertexData( GLfloat *vertex, void *userData );
                        </pre><p>
                    </p></dd><dt><span class="term"><code class="constant">GLU_NURBS_NORMAL</code></span></dt><dd><p>
                    </p><p>
                        The normal callback is invoked as the vertex normal is generated.
                        The components of the normal are stored in the parameter ``normal.''
                        In the case of a NURBS curve, the callback function is effective only when 
                        the user provides a normal map (<code class="constant">GLU_MAP1_NORMAL</code>).
                        In the case of a NURBS surface, if a normal map (<code class="constant">GLU_MAP2_NORMAL</code>)
                        is provided, then the generated normal is computed from the normal map.
                        If a normal map is not provided, then a surface normal is computed in
                        a manner similar to that described for evaluators when <code class="constant">GLU_AUTO_NORMAL</code>
                        is enabled. 
                        The default normal callback function is NULL. The function
                        prototype for this callback function looks like:
                        </p><pre class="programlisting">
void normal( GLfloat *normal );
                        </pre><p>
                    </p></dd><dt><span class="term"><code class="constant">GLU_NURBS_NORMAL_DATA</code></span></dt><dd><p>
                    </p><p>
                        The same as the <code class="constant">GLU_NURBS_NORMAL</code> callback except that it
                        takes an additional pointer argument. This pointer is a copy of the pointer
                        that was specified at the last call to <code class="function">gluNurbsCallbackData</code>.  The default callback function is NULL. The function prototype for this callback function looks like:
                        </p><pre class="programlisting">
void normalData( GLfloat *normal, void *userData );
                        </pre><p>
                    </p></dd><dt><span class="term"><code class="constant">GLU_NURBS_COLOR</code></span></dt><dd><p>
                    </p><p>
                        The color callback is invoked as the color of a vertex is generated.
                        The components of the color are stored in the parameter ``color.''
                        This callback is effective only when the user provides a color map
                        (<code class="constant">GLU_MAP1_COLOR_4</code> or <code class="constant">GLU_MAP2_COLOR_4</code>). ``color'' contains four
                        components: R, G, B, A. The default color callback function is NULL.
                        The prototype for this callback function looks like:
                        </p><pre class="programlisting">
void color( GLfloat *color );
                        </pre><p>
                    </p></dd><dt><span class="term"><code class="constant">GLU_NURBS_COLOR_DATA</code></span></dt><dd><p>
                    </p><p>
                        The same as the <code class="constant">GLU_NURBS_COLOR</code> callback except that it
                        takes an additional pointer argument. This pointer is a copy of the pointer
                        that was specified at the last call to <code class="function">gluNurbsCallbackData</code>.  The default callback function is NULL. The function prototype for this callback function looks like:
                        </p><pre class="programlisting">
void colorData( GLfloat *color, void *userData );
                        </pre><p>
                    </p></dd><dt><span class="term"><code class="constant">GLU_NURBS_TEXTURE_COORD</code></span></dt><dd><p>
                    </p><p>
                        The texture callback is invoked as the texture coordinates 
                        of a vertex are generated. These coordinates are stored in the parameter
                        ``texCoord.'' The number of texture coordinates can be 1, 2, 3, or 4 depending
                        on which type of texture map is specified 
                        (<code class="constant">GLU_MAP1_TEXTURE_COORD_1</code>,
                        <code class="constant">GLU_MAP1_TEXTURE_COORD_2</code>,
                        <code class="constant">GLU_MAP1_TEXTURE_COORD_3</code>,
                        <code class="constant">GLU_MAP1_TEXTURE_COORD_4</code>,
                        <code class="constant">GLU_MAP2_TEXTURE_COORD_1</code>,
                        <code class="constant">GLU_MAP2_TEXTURE_COORD_2</code>,
                        <code class="constant">GLU_MAP2_TEXTURE_COORD_3</code>,
                        <code class="constant">GLU_MAP2_TEXTURE_COORD_4</code>).
                        If no texture map is specified, this callback function will not be called.
                        The default texture callback function is NULL. The function prototype
                        for this callback function looks like:
                        </p><pre class="programlisting">
void texCoord( GLfloat *texCoord );
                        </pre><p>
                    </p></dd><dt><span class="term"> <code class="constant">GLU_NURBS_TEXTURE_COORD_DATA</code></span></dt><dd><p>
                    </p><p>
                        This is the same as the <code class="constant">GLU_NURBS_TEXTURE_COORD</code> callback, except that it
                        takes an additional pointer argument. This pointer is a copy of the pointer
                        that was specified at the last call to <code class="function">gluNurbsCallbackData</code>.  The default callback function is NULL. The function prototype for this callback function looks like:
                        </p><pre class="programlisting">
void texCoordData( GLfloat *texCoord, void *userData );
                        </pre><p>
                    </p></dd><dt><span class="term"><code class="constant">GLU_NURBS_END</code></span></dt><dd><p>
                    </p><p>
                        The end callback is invoked at the end of a primitive. The default end callback function is NULL. The function prototype for this callback function looks like:
                        </p><pre class="programlisting">
void end( void );
                        </pre><p>
                    </p></dd><dt><span class="term"><code class="constant">GLU_NURBS_END_DATA</code></span></dt><dd><p>
                    </p><p>
                        This is the same as the <code class="constant">GLU_NURBS_END</code> callback, except that it
                        takes an additional pointer argument. This pointer is a copy of the pointer
                        that was specified at the last call to <code class="function">gluNurbsCallbackData</code>.  The default callback function is NULL. The function prototype for this callback function looks like:
                        </p><pre class="programlisting">
void endData( void  *userData );
                        </pre><p>
                    </p></dd><dt><span class="term"><code class="constant">GLU_NURBS_ERROR</code></span></dt><dd><p>
                    </p><p>
                        The error function is called when an error is encountered.
                        Its single argument
                        is of type GLenum, and it indicates the specific error that occurred.
                        There are 37 errors unique to NURBS, named
                        <code class="constant">GLU_NURBS_ERROR1</code> through <code class="constant">GLU_NURBS_ERROR37</code>. 
                        Character strings describing these errors can be retrieved with
                        <a class="citerefentry" href="gluErrorString.xml"><span class="citerefentry"><span class="refentrytitle">gluErrorString</span></span></a>.
                    </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
            <code class="function">gluNurbsCallback</code> is available only if the GLU version is 1.2 or greater.
        </p><p>
            GLU version 1.2 supports only the <code class="constant">GLU_ERROR</code> parameter for
            <em class="parameter"><code>which</code></em>. The <code class="constant">GLU_ERROR</code> value is deprecated in GLU version 1.3 in
            favor of <code class="constant">GLU_NURBS_ERROR</code>.  All other accepted values for <em class="parameter"><code>CallBackFunc</code></em>
            are available only if the GLU version is 1.3 or greater.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
            <a class="citerefentry" href="gluErrorString.xml"><span class="citerefentry"><span class="refentrytitle">gluErrorString</span></span></a>,
            <a class="citerefentry" href="gluNewNurbsRenderer.xml"><span class="citerefentry"><span class="refentrytitle">gluNewNurbsRenderer</span></span></a>,
            <code class="function">gluNurbsCallbackData</code>,
            <a class="citerefentry" href="gluNurbsProperty.xml"><span class="citerefentry"><span class="refentrytitle">gluNurbsProperty</span></span></a>
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
            Copyright <span class="trademark"></span>© 1991-2006
            Silicon Graphics, Inc. This document is licensed under the SGI
            Free Software B License. For details, see
            <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
        </p></div></div></body></html>
Commit	Line	Data
7faf1d71 AW	1	<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd">
	2	<!-- saved from url=(0013)about:internet -->
	3	<?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>gluNurbsCallback</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="gluNurbsCallback"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>gluNurbsCallback — define a callback for a NURBS object</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">gluNurbsCallback</b>(</code></td><td>GLUnurbs* </td><td><var class="pdparam">nurb</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">which</var>, </td></tr><tr><td> </td><td>_GLUfuncptr </td><td><var class="pdparam">CallBackFunc</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>nurb</code></em></span></dt><dd><p>
	4	Specifies the NURBS object (created with <a class="citerefentry" href="gluNewNurbsRenderer.xml"><span class="citerefentry"><span class="refentrytitle">gluNewNurbsRenderer</span></span></a>).
	5	</p></dd><dt><span class="term"><em class="parameter"><code>which</code></em></span></dt><dd><p>
	6	Specifies the callback being defined.
	7	Valid values are <code class="constant">GLU_NURBS_BEGIN</code>, <code class="constant">GLU_NURBS_VERTEX</code>, <code class="constant">GLU_NURBS_NORMAL</code>, <code class="constant">GLU_NURBS_COLOR</code>, <code class="constant">GLU_NURBS_TEXTURE_COORD</code>, <code class="constant">GLU_NURBS_END</code>, <code class="constant">GLU_NURBS_BEGIN_DATA</code>, <code class="constant">GLU_NURBS_VERTEX_DATA</code>, <code class="constant">GLU_NURBS_NORMAL_DATA</code>, <code class="constant">GLU_NURBS_COLOR_DATA</code>, <code class="constant">GLU_NURBS_TEXTURE_COORD_DATA</code>, <code class="constant">GLU_NURBS_END_DATA</code>, and <code class="constant">GLU_NURBS_ERROR</code>.
	8	</p></dd><dt><span class="term"><em class="parameter"><code>CallBackFunc</code></em></span></dt><dd><p>
	9	Specifies the function that the callback calls.
	10	</p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
	11	<code class="function">gluNurbsCallback</code> is used to define a callback to be used by a NURBS
	12	object.
	13	If the specified callback is already defined, then it is replaced. If
	14	<em class="parameter"><code>CallBackFunc</code></em> is NULL, then this callback will not get
	15	invoked and the related data, if any, will be lost.
	16	</p><p>
	17	Except the error callback, these callbacks are used by NURBS tessellator (when <code class="constant">GLU_NURBS_MODE</code> is set to be <code class="constant">GLU_NURBS_TESSELLATOR</code>) to return back the OpenGL
	18	polygon primitives resulting from the tessellation. Note that there are two
	19	versions of each callback: one with a user data pointer and one without. If both versions for a particular callback are specified then the callback with
	20	the user data pointer will be used. Note that ``userData'' is a copy of the pointer that was specified at the last call to <code class="function">gluNurbsCallbackData</code>.
	21	</p><p>
	22	The error callback function is effective no matter which value that
	23	<code class="constant">GLU_NURBS_MODE</code> is set to.
	24	All other callback functions are effective only when <code class="constant">GLU_NURBS_MODE</code>
	25	is set to <code class="constant">GLU_NURBS_TESSELLATOR</code>.
	26	</p><p>
	27	The legal callbacks are as follows:
	28	</p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GLU_NURBS_BEGIN</code></span></dt><dd><p>
	29	</p><p>
	30	The begin callback indicates the start of a primitive. The function
	31	takes a single argument of type GLenum, which can be one of
	32	<code class="constant">GLU_LINES</code>, <code class="constant">GLU_LINE_STRIP</code>, <code class="constant">GLU_TRIANGLE_FAN</code>, <code class="constant">GLU_TRIANGLE_STRIP</code>, <code class="constant">GLU_TRIANGLES</code>, or <code class="constant">GLU_QUAD_STRIP</code>. The
	33	default begin callback function is NULL. The function prototype
	34	for this callback looks like:
	35	</p><pre class="programlisting">
	36	void begin( GLenum type );
	37	</pre><p>
	38	</p></dd><dt><span class="term"><code class="constant">GLU_NURBS_BEGIN_DATA</code></span></dt><dd><p>
	39	</p><p>
	40	The same as the <code class="constant">GLU_NURBS_BEGIN</code> callback except that it takes an
	41	additional pointer argument. This pointer is a copy of the pointer that
	42	was specified at the last call to <code class="function">gluNurbsCallbackData</code>. The
	43	default callback function is NULL. The function prototype for this
	44	callback function looks like:
	45	</p><pre class="programlisting">
	46	void beginData(GLenum type, void *userData);
	47	</pre><p>
	48	</p></dd><dt><span class="term"><code class="constant">GLU_NURBS_VERTEX</code></span></dt><dd><p>
	49	</p><p>
	50	The vertex callback indicates a vertex of the primitive. The
	51	coordinates of the vertex are stored in the parameter ``vertex''. All
	52	the generated vertices have dimension 3; that is, homogeneous
	53	coordinates have been transformed into affine coordinates. The default
	54	vertex callback function is NULL. The function prototype for this
	55	callback function looks like:
	56	</p><pre class="programlisting">
	57	void vertex( GLfloat *vertex );
	58	</pre><p>
	59	</p></dd><dt><span class="term"><code class="constant">GLU_NURBS_VERTEX_DATA</code></span></dt><dd><p>
	60	</p><p>
	61	This is the same as the <code class="constant">GLU_NURBS_VERTEX</code> callback, except that
	62	it takes an additional pointer argument. This pointer is a copy of the
	63	pointer that was specified at the last call to
	64	<code class="function">gluNurbsCallbackData</code>. The default callback function is NULL. The
65	function prototype for this callback function looks like:
66	</p><pre class="programlisting">
67	void vertexData( GLfloat vertex, void userData );
68	</pre><p>
69	</p></dd><dt><span class="term"><code class="constant">GLU_NURBS_NORMAL</code></span></dt><dd><p>
70	</p><p>
71	The normal callback is invoked as the vertex normal is generated.
72	The components of the normal are stored in the parameter ``normal.''
73	In the case of a NURBS curve, the callback function is effective only when
74	the user provides a normal map (<code class="constant">GLU_MAP1_NORMAL</code>).
75	In the case of a NURBS surface, if a normal map (<code class="constant">GLU_MAP2_NORMAL</code>)
76	is provided, then the generated normal is computed from the normal map.
77	If a normal map is not provided, then a surface normal is computed in
78	a manner similar to that described for evaluators when <code class="constant">GLU_AUTO_NORMAL</code>
79	is enabled.
80	The default normal callback function is NULL. The function
81	prototype for this callback function looks like:
82	</p><pre class="programlisting">
83	void normal( GLfloat *normal );
84	</pre><p>
85	</p></dd><dt><span class="term"><code class="constant">GLU_NURBS_NORMAL_DATA</code></span></dt><dd><p>
86	</p><p>
87	The same as the <code class="constant">GLU_NURBS_NORMAL</code> callback except that it
88	takes an additional pointer argument. This pointer is a copy of the pointer
89	that was specified at the last call to <code class="function">gluNurbsCallbackData</code>. The default callback function is NULL. The function prototype for this callback function looks like:
90	</p><pre class="programlisting">
91	void normalData( GLfloat normal, void userData );
92	</pre><p>
93	</p></dd><dt><span class="term"><code class="constant">GLU_NURBS_COLOR</code></span></dt><dd><p>
94	</p><p>
95	The color callback is invoked as the color of a vertex is generated.
96	The components of the color are stored in the parameter ``color.''
97	This callback is effective only when the user provides a color map
98	(<code class="constant">GLU_MAP1_COLOR_4</code> or <code class="constant">GLU_MAP2_COLOR_4</code>). ``color'' contains four
99	components: R, G, B, A. The default color callback function is NULL.
100	The prototype for this callback function looks like:
101	</p><pre class="programlisting">
102	void color( GLfloat *color );
103	</pre><p>
104	</p></dd><dt><span class="term"><code class="constant">GLU_NURBS_COLOR_DATA</code></span></dt><dd><p>
105	</p><p>
106	The same as the <code class="constant">GLU_NURBS_COLOR</code> callback except that it
107	takes an additional pointer argument. This pointer is a copy of the pointer
108	that was specified at the last call to <code class="function">gluNurbsCallbackData</code>. The default callback function is NULL. The function prototype for this callback function looks like:
109	</p><pre class="programlisting">
110	void colorData( GLfloat color, void userData );
111	</pre><p>
112	</p></dd><dt><span class="term"><code class="constant">GLU_NURBS_TEXTURE_COORD</code></span></dt><dd><p>
113	</p><p>
114	The texture callback is invoked as the texture coordinates
115	of a vertex are generated. These coordinates are stored in the parameter
116	``texCoord.'' The number of texture coordinates can be 1, 2, 3, or 4 depending
117	on which type of texture map is specified
118	(<code class="constant">GLU_MAP1_TEXTURE_COORD_1</code>,
119	<code class="constant">GLU_MAP1_TEXTURE_COORD_2</code>,
120	<code class="constant">GLU_MAP1_TEXTURE_COORD_3</code>,
121	<code class="constant">GLU_MAP1_TEXTURE_COORD_4</code>,
122	<code class="constant">GLU_MAP2_TEXTURE_COORD_1</code>,
123	<code class="constant">GLU_MAP2_TEXTURE_COORD_2</code>,
124	<code class="constant">GLU_MAP2_TEXTURE_COORD_3</code>,
125	<code class="constant">GLU_MAP2_TEXTURE_COORD_4</code>).
126	If no texture map is specified, this callback function will not be called.
127	The default texture callback function is NULL. The function prototype
128	for this callback function looks like:
129	</p><pre class="programlisting">
130	void texCoord( GLfloat *texCoord );
131	</pre><p>
132	</p></dd><dt><span class="term"> <code class="constant">GLU_NURBS_TEXTURE_COORD_DATA</code></span></dt><dd><p>
133	</p><p>
134	This is the same as the <code class="constant">GLU_NURBS_TEXTURE_COORD</code> callback, except that it
135	takes an additional pointer argument. This pointer is a copy of the pointer
136	that was specified at the last call to <code class="function">gluNurbsCallbackData</code>. The default callback function is NULL. The function prototype for this callback function looks like:
137	</p><pre class="programlisting">
138	void texCoordData( GLfloat texCoord, void userData );
139	</pre><p>
140	</p></dd><dt><span class="term"><code class="constant">GLU_NURBS_END</code></span></dt><dd><p>
141	</p><p>
142	The end callback is invoked at the end of a primitive. The default end callback function is NULL. The function prototype for this callback function looks like:
143	</p><pre class="programlisting">
144	void end( void );
145	</pre><p>
146	</p></dd><dt><span class="term"><code class="constant">GLU_NURBS_END_DATA</code></span></dt><dd><p>
147	</p><p>
148	This is the same as the <code class="constant">GLU_NURBS_END</code> callback, except that it
149	takes an additional pointer argument. This pointer is a copy of the pointer
150	that was specified at the last call to <code class="function">gluNurbsCallbackData</code>. The default callback function is NULL. The function prototype for this callback function looks like:
151	</p><pre class="programlisting">
152	void endData( void *userData );
153	</pre><p>
154	</p></dd><dt><span class="term"><code class="constant">GLU_NURBS_ERROR</code></span></dt><dd><p>
155	</p><p>
156	The error function is called when an error is encountered.
157	Its single argument
158	is of type GLenum, and it indicates the specific error that occurred.
159	There are 37 errors unique to NURBS, named
160	<code class="constant">GLU_NURBS_ERROR1</code> through <code class="constant">GLU_NURBS_ERROR37</code>.
161	Character strings describing these errors can be retrieved with
162	<a class="citerefentry" href="gluErrorString.xml"><span class="citerefentry"><span class="refentrytitle">gluErrorString</span></span></a>.
163	</p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
164	<code class="function">gluNurbsCallback</code> is available only if the GLU version is 1.2 or greater.
165	</p><p>
166	GLU version 1.2 supports only the <code class="constant">GLU_ERROR</code> parameter for
167	<em class="parameter"><code>which</code></em>. The <code class="constant">GLU_ERROR</code> value is deprecated in GLU version 1.3 in
168	favor of <code class="constant">GLU_NURBS_ERROR</code>. All other accepted values for <em class="parameter"><code>CallBackFunc</code></em>
169	are available only if the GLU version is 1.3 or greater.
170	</p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
171	<a class="citerefentry" href="gluErrorString.xml"><span class="citerefentry"><span class="refentrytitle">gluErrorString</span></span></a>,
172	<a class="citerefentry" href="gluNewNurbsRenderer.xml"><span class="citerefentry"><span class="refentrytitle">gluNewNurbsRenderer</span></span></a>,
173	<code class="function">gluNurbsCallbackData</code>,
174	<a class="citerefentry" href="gluNurbsProperty.xml"><span class="citerefentry"><span class="refentrytitle">gluNurbsProperty</span></span></a>
175	</p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
176	Copyright <span class="trademark"></span>© 1991-2006
177	Silicon Graphics, Inc. This document is licensed under the SGI
178	Free Software B License. For details, see
179	<a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
180	</p></div></div></body></html>