upstream-man-pages/man2/glBegin.xml

   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="glBegin">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>1991-2006</year>
   9                 <holder>Silicon Graphics, Inc.</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>glBegin</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>glBegin</refname>
  17         <refpurpose>delimit the vertices of a primitive or a group of like primitives</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>C Specification</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>void <function>glBegin</function></funcdef>
  23                 <paramdef>GLenum <parameter>mode</parameter></paramdef>
  24             </funcprototype>
  25         </funcsynopsis>
  26     </refsynopsisdiv>
  27     <!-- eqn: ignoring delim $$ -->
  28     <refsect1 id="parameters"><title>Parameters</title>
  29         <variablelist>
  30         <varlistentry>
  31             <term><parameter>mode</parameter></term>
  32             <listitem>
  33                 <para>
  34                     Specifies the primitive or primitives that will be created from vertices
  35                     presented between <function>glBegin</function> and the subsequent <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
  36                     Ten symbolic constants are accepted:
  37                     <constant>GL_POINTS</constant>,
  38                     <constant>GL_LINES</constant>,
  39                     <constant>GL_LINE_STRIP</constant>,
  40                     <constant>GL_LINE_LOOP</constant>,
  41                     <constant>GL_TRIANGLES</constant>,
  42                     <constant>GL_TRIANGLE_STRIP</constant>,
  43                     <constant>GL_TRIANGLE_FAN</constant>,
  44                     <constant>GL_QUADS</constant>,
  45                     <constant>GL_QUAD_STRIP</constant>, and
  46                     <constant>GL_POLYGON</constant>.
  47                 </para>
  48             </listitem>
  49         </varlistentry>
  50         </variablelist>
  51     </refsect1>
  52     <refsynopsisdiv><title>C Specification</title>
  53         <funcsynopsis>
  54             <funcprototype>
  55                 <funcdef>void <function>glEnd</function></funcdef>
  56                 <paramdef><parameter>void</parameter></paramdef>
  57             </funcprototype>
  58         </funcsynopsis>
  59     </refsynopsisdiv>
  60     <refsect1 id="description"><title>Description</title>
  61         <para>
  62             <function>glBegin</function> and <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry> delimit the vertices that define a primitive or
  63             a group of like primitives.
  64             <function>glBegin</function> accepts a single argument that specifies in which of ten ways the
  65             vertices are interpreted.
  66             Taking
  67             <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
  68             as an integer count starting at one,
  69             and
  70             <inlineequation><mml:math><mml:mi mathvariant="italic">N</mml:mi></mml:math></inlineequation>
  71             as the total number of vertices specified,
  72             the interpretations are as follows:
  73         </para>
  74         <variablelist>
  75             <varlistentry>
  76                 <term><constant>GL_POINTS</constant></term>
  77                 <listitem>
  78                     <para>
  79                         Treats each vertex as a single point.
  80                         Vertex
  81                         <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
  82                         defines point
  83                         <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>.
  84                         <inlineequation><mml:math><mml:mi mathvariant="italic">N</mml:mi></mml:math></inlineequation>
  85                         points are drawn.
  86                     </para>
  87                 </listitem>
  88             </varlistentry>
  89             <varlistentry>
  90                 <term><constant>GL_LINES</constant></term>
  91                 <listitem>
  92                     <para>
  93                         Treats each pair of vertices as an independent line segment.
  94                         Vertices
  95                         <inlineequation><mml:math>
  96                             <!-- eqn: 2n - 1:-->
  97                             <mml:mrow>
  98                                 <mml:mn>2</mml:mn>
  99                                 <mml:mo>&it;</mml:mo>
 100                                 <mml:mi mathvariant="italic">n</mml:mi>
 101                                 <mml:mo>-</mml:mo>
 102                                 <mml:mn>1</mml:mn>
 103                             </mml:mrow>
 104                         </mml:math></inlineequation>
 105                         and
 106                         <inlineequation><mml:math>
 107                             <!-- eqn: 2n:-->
 108                             <mml:mrow>
 109                                 <mml:mn>2</mml:mn>
 110                                 <mml:mo>&it;</mml:mo>
 111                                 <mml:mi mathvariant="italic">n</mml:mi>
 112                             </mml:mrow>
 113                         </mml:math></inlineequation>
 114                         define line
 115                         <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>.
 116                         <inlineequation><mml:math>
 117                             <!-- eqn: N/2:-->
 118                             <mml:mfrac>
 119                                 <mml:mi mathvariant="italic">N</mml:mi>
 120                                 <mml:mn>2</mml:mn>
 121                             </mml:mfrac>
 122                         </mml:math></inlineequation>
 123                         lines are drawn.
 124                     </para>
 125                 </listitem>
 126             </varlistentry>
 127             <varlistentry>
 128                 <term><constant>GL_LINE_STRIP</constant></term>
 129                 <listitem>
 130                     <para>
 131                         Draws a connected group of line segments from the first vertex
 132                         to the last.
 133                         Vertices
 134                         <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
 135                         and
 136                         <inlineequation><mml:math>
 137                             <!-- eqn: n + 1:-->
 138                             <mml:mrow>
 139                                 <mml:mi mathvariant="italic">n</mml:mi>
 140                                 <mml:mo>+</mml:mo>
 141                                 <mml:mn>1</mml:mn>
 142                             </mml:mrow>
 143                         </mml:math></inlineequation>
 144                         define line
 145                         <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>.
 146                         <inlineequation><mml:math>
 147                             <!-- eqn: N - 1:-->
 148                             <mml:mrow>
 149                                 <mml:mi mathvariant="italic">N</mml:mi>
 150                                 <mml:mo>-</mml:mo>
 151                                 <mml:mn>1</mml:mn>
 152                             </mml:mrow>
 153                         </mml:math></inlineequation>
 154                         lines are drawn.
 155                     </para>
 156                 </listitem>
 157             </varlistentry>
 158             <varlistentry>
 159                 <term><constant>GL_LINE_LOOP</constant></term>
 160                 <listitem>
 161                     <para>
 162                         Draws a connected group of line segments from the first vertex
 163                         to the last,
 164                         then back to the first.
 165                         Vertices
 166                         <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
 167                         and
 168                         <inlineequation><mml:math>
 169                             <!-- eqn: n + 1:-->
 170                             <mml:mrow>
 171                                 <mml:mi mathvariant="italic">n</mml:mi>
 172                                 <mml:mo>+</mml:mo>
 173                                 <mml:mn>1</mml:mn>
 174                             </mml:mrow>
 175                         </mml:math></inlineequation>
 176                         define line
 177                         <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>.
 178                         The last line, however, is defined by vertices
 179                         <inlineequation><mml:math><mml:mi mathvariant="italic">N</mml:mi></mml:math></inlineequation>
 180                         and
 181                         <inlineequation><mml:math>
 182                             <!-- eqn: 1:-->
 183                             <mml:mn>1</mml:mn>
 184                         </mml:math></inlineequation>.
 185                         <inlineequation><mml:math><mml:mi mathvariant="italic">N</mml:mi></mml:math></inlineequation>
 186                         lines are drawn.
 187                     </para>
 188                 </listitem>
 189             </varlistentry>
 190             <varlistentry>
 191                 <term><constant>GL_TRIANGLES</constant></term>
 192                 <listitem>
 193                     <para>
 194                         Treats each triplet of vertices as an independent triangle.
 195                         Vertices
 196                         <inlineequation><mml:math>
 197                             <!-- eqn: 3n - 2:-->
 198                             <mml:mrow>
 199                                 <mml:mn>3</mml:mn>
 200                                 <mml:mo>&it;</mml:mo>
 201                                 <mml:mi mathvariant="italic">n</mml:mi>
 202                                 <mml:mo>-</mml:mo>
 203                                 <mml:mn>2</mml:mn>
 204                             </mml:mrow>
 205                         </mml:math></inlineequation>,
 206                         <inlineequation><mml:math>
 207                             <!-- eqn: 3n - 1:-->
 208                             <mml:mrow>
 209                                 <mml:mn>3</mml:mn>
 210                                 <mml:mo>&it;</mml:mo>
 211                                 <mml:mi mathvariant="italic">n</mml:mi>
 212                                 <mml:mo>-</mml:mo>
 213                                 <mml:mn>1</mml:mn>
 214                             </mml:mrow>
 215                         </mml:math></inlineequation>,
 216                         and
 217                         <inlineequation><mml:math>
 218                             <!-- eqn: 3n:-->
 219                             <mml:mrow>
 220                                 <mml:mn>3</mml:mn>
 221                                 <mml:mo>&it;</mml:mo>
 222                                 <mml:mi mathvariant="italic">n</mml:mi>
 223                             </mml:mrow>
 224                         </mml:math></inlineequation>
 225                         define triangle
 226                         <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>.
 227                         <inlineequation><mml:math>
 228                             <!-- eqn: N/3:-->
 229                             <mml:mfrac>
 230                                 <mml:mi mathvariant="italic">N</mml:mi>
 231                                 <mml:mn>3</mml:mn>
 232                             </mml:mfrac>
 233                         </mml:math></inlineequation>
 234                         triangles are drawn.
 235                     </para>
 236                 </listitem>
 237             </varlistentry>
 238             <varlistentry>
 239                 <term><constant>GL_TRIANGLE_STRIP</constant></term>
 240                 <listitem>
 241                     <para>
 242                         Draws a connected group of triangles.  One triangle is defined for each
 243                         vertex presented after the first two vertices.  For odd
 244                         <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>,
 245                         vertices
 246                         <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>,
 247                         <inlineequation><mml:math>
 248                             <!-- eqn: n + 1:-->
 249                             <mml:mrow>
 250                                 <mml:mi mathvariant="italic">n</mml:mi>
 251                                 <mml:mo>+</mml:mo>
 252                                 <mml:mn>1</mml:mn>
 253                             </mml:mrow>
 254                         </mml:math></inlineequation>,
 255                         and
 256                         <inlineequation><mml:math>
 257                             <!-- eqn: n + 2:-->
 258                             <mml:mrow>
 259                                 <mml:mi mathvariant="italic">n</mml:mi>
 260                                 <mml:mo>+</mml:mo>
 261                                 <mml:mn>2</mml:mn>
 262                             </mml:mrow>
 263                         </mml:math></inlineequation>
 264                         define triangle
 265                         <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>.
 266                         For even
 267                         <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>,
 268                         vertices
 269                         <inlineequation><mml:math>
 270                             <!-- eqn: n + 1:-->
 271                             <mml:mrow>
 272                                 <mml:mi mathvariant="italic">n</mml:mi>
 273                                 <mml:mo>+</mml:mo>
 274                                 <mml:mn>1</mml:mn>
 275                             </mml:mrow>
 276                         </mml:math></inlineequation>,
 277                         <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>,
 278                         and
 279                         <inlineequation><mml:math>
 280                             <!-- eqn: n + 2:-->
 281                             <mml:mrow>
 282                                 <mml:mi mathvariant="italic">n</mml:mi>
 283                                 <mml:mo>+</mml:mo>
 284                                 <mml:mn>2</mml:mn>
 285                             </mml:mrow>
 286                         </mml:math></inlineequation>
 287                         define triangle
 288                         <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>.
 289                         <inlineequation><mml:math>
 290                             <!-- eqn: N - 2:-->
 291                             <mml:mrow>
 292                                 <mml:mi mathvariant="italic">N</mml:mi>
 293                                 <mml:mo>-</mml:mo>
 294                                 <mml:mn>2</mml:mn>
 295                             </mml:mrow>
 296                         </mml:math></inlineequation>
 297                         triangles are
 298                         drawn.
 299                     </para>
 300                 </listitem>
 301             </varlistentry>
 302             <varlistentry>
 303                 <term><constant>GL_TRIANGLE_FAN</constant></term>
 304                 <listitem>
 305                     <para>
 306                         Draws a connected group of triangles.
 307                         One triangle is defined for each vertex presented after the first two vertices.
 308                         Vertices
 309                         <inlineequation><mml:math>
 310                             <!-- eqn: 1:-->
 311                             <mml:mn>1</mml:mn>
 312                         </mml:math></inlineequation>,
 313                         <inlineequation><mml:math>
 314                             <!-- eqn: n + 1:-->
 315                             <mml:mrow>
 316                                 <mml:mi mathvariant="italic">n</mml:mi>
 317                                 <mml:mo>+</mml:mo>
 318                                 <mml:mn>1</mml:mn>
 319                             </mml:mrow>
 320                         </mml:math></inlineequation>,
 321                         and
 322                         <inlineequation><mml:math>
 323                             <!-- eqn: n + 2:-->
 324                             <mml:mrow>
 325                                 <mml:mi mathvariant="italic">n</mml:mi>
 326                                 <mml:mo>+</mml:mo>
 327                                 <mml:mn>2</mml:mn>
 328                             </mml:mrow>
 329                         </mml:math></inlineequation>
 330                         define triangle
 331                         <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>.
 332                         <inlineequation><mml:math>
 333                             <!-- eqn: N - 2:-->
 334                             <mml:mrow>
 335                                 <mml:mi mathvariant="italic">N</mml:mi>
 336                                 <mml:mo>-</mml:mo>
 337                                 <mml:mn>2</mml:mn>
 338                             </mml:mrow>
 339                         </mml:math></inlineequation>
 340                         triangles are drawn.
 341                     </para>
 342                 </listitem>
 343             </varlistentry>
 344             <varlistentry>
 345                 <term><constant>GL_QUADS</constant></term>
 346                 <listitem>
 347                     <para>
 348                         Treats each group of four vertices as an independent quadrilateral.
 349                         Vertices
 350                         <inlineequation><mml:math>
 351                             <!-- eqn: 4n - 3:-->
 352                             <mml:mrow>
 353                                 <mml:mn>4</mml:mn>
 354                                 <mml:mo>&it;</mml:mo>
 355                                 <mml:mi mathvariant="italic">n</mml:mi>
 356                                 <mml:mo>-</mml:mo>
 357                                 <mml:mn>3</mml:mn>
 358                             </mml:mrow>
 359                         </mml:math></inlineequation>,
 360                         <inlineequation><mml:math>
 361                             <!-- eqn: 4n - 2:-->
 362                             <mml:mrow>
 363                                 <mml:mn>4</mml:mn>
 364                                 <mml:mo>&it;</mml:mo>
 365                                 <mml:mi mathvariant="italic">n</mml:mi>
 366                                 <mml:mo>-</mml:mo>
 367                                 <mml:mn>2</mml:mn>
 368                             </mml:mrow>
 369                         </mml:math></inlineequation>,
 370                         <inlineequation><mml:math>
 371                             <!-- eqn: 4n - 1:-->
 372                             <mml:mrow>
 373                                 <mml:mn>4</mml:mn>
 374                                 <mml:mo>&it;</mml:mo>
 375                                 <mml:mi mathvariant="italic">n</mml:mi>
 376                                 <mml:mo>-</mml:mo>
 377                                 <mml:mn>1</mml:mn>
 378                             </mml:mrow>
 379                         </mml:math></inlineequation>,
 380                         and
 381                         <inlineequation><mml:math>
 382                             <!-- eqn: 4n:-->
 383                             <mml:mrow>
 384                                 <mml:mn>4</mml:mn>
 385                                 <mml:mo>&it;</mml:mo>
 386                                 <mml:mi mathvariant="italic">n</mml:mi>
 387                             </mml:mrow>
 388                         </mml:math></inlineequation>
 389                         define quadrilateral
 390                         <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>.
 391                         <inlineequation><mml:math>
 392                             <!-- eqn: N/4:-->
 393                             <mml:mfrac>
 394                                 <mml:mi mathvariant="italic">N</mml:mi>
 395                                 <mml:mn>4</mml:mn>
 396                             </mml:mfrac>
 397                         </mml:math></inlineequation>
 398                         quadrilaterals are drawn.
 399                     </para>
 400                 </listitem>
 401             </varlistentry>
 402             <varlistentry>
 403                 <term><constant>GL_QUAD_STRIP</constant></term>
 404                 <listitem>
 405                     <para>
 406                         Draws a connected group of quadrilaterals.
 407                         One quadrilateral is defined for each pair of vertices presented
 408                         after the first pair.
 409                         Vertices
 410                         <inlineequation><mml:math>
 411                             <!-- eqn: 2n - 1:-->
 412                             <mml:mrow>
 413                                 <mml:mn>2</mml:mn>
 414                                 <mml:mo>&it;</mml:mo>
 415                                 <mml:mi mathvariant="italic">n</mml:mi>
 416                                 <mml:mo>-</mml:mo>
 417                                 <mml:mn>1</mml:mn>
 418                             </mml:mrow>
 419                         </mml:math></inlineequation>,
 420                         <inlineequation><mml:math>
 421                             <!-- eqn: 2n:-->
 422                             <mml:mrow>
 423                                 <mml:mn>2</mml:mn>
 424                                 <mml:mo>&it;</mml:mo>
 425                                 <mml:mi mathvariant="italic">n</mml:mi>
 426                             </mml:mrow>
 427                         </mml:math></inlineequation>,
 428                         <inlineequation><mml:math>
 429                             <!-- eqn: 2n + 2:-->
 430                             <mml:mrow>
 431                                 <mml:mn>2</mml:mn>
 432                                 <mml:mo>&it;</mml:mo>
 433                                 <mml:mi mathvariant="italic">n</mml:mi>
 434                                 <mml:mo>+</mml:mo>
 435                                 <mml:mn>2</mml:mn>
 436                             </mml:mrow>
 437                         </mml:math></inlineequation>,
 438                         and
 439                         <inlineequation><mml:math>
 440                             <!-- eqn: 2n + 1:-->
 441                             <mml:mrow>
 442                                 <mml:mn>2</mml:mn>
 443                                 <mml:mo>&it;</mml:mo>
 444                                 <mml:mi mathvariant="italic">n</mml:mi>
 445                                 <mml:mo>+</mml:mo>
 446                                 <mml:mn>1</mml:mn>
 447                             </mml:mrow>
 448                         </mml:math></inlineequation>
 449                         define quadrilateral
 450                         <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>.
 451                         <inlineequation><mml:math>
 452                             <!-- eqn: N/2 - 1:-->
 453                             <mml:mrow>
 454                                 <mml:mfrac>
 455                                     <mml:mi mathvariant="italic">N</mml:mi>
 456                                     <mml:mn>2</mml:mn>
 457                                 </mml:mfrac>
 458                                 <mml:mo>-</mml:mo>
 459                                 <mml:mn>1</mml:mn>
 460                             </mml:mrow>
 461                         </mml:math></inlineequation>
 462                         quadrilaterals are drawn.
 463                         Note that the order in which vertices are used to construct a quadrilateral
 464                         from strip data is different from that used with independent data.
 465                     </para>
 466                 </listitem>
 467             </varlistentry>
 468             <varlistentry>
 469                 <term><constant>GL_POLYGON</constant></term>
 470                 <listitem>
 471                     <para>
 472                         Draws a single,
 473                         convex polygon.
 474                         Vertices
 475                         <inlineequation><mml:math>
 476                             <!-- eqn: 1:-->
 477                             <mml:mn>1</mml:mn>
 478                         </mml:math></inlineequation>
 479                         through
 480                         <inlineequation><mml:math><mml:mi mathvariant="italic">N</mml:mi></mml:math></inlineequation>
 481                         define this polygon.
 482                     </para>
 483                 </listitem>
 484             </varlistentry>
 485         </variablelist>
 486         <para>
 487             Only a subset of GL commands can be used between <function>glBegin</function> and <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
 488             The commands are
 489             <citerefentry><refentrytitle>glVertex</refentrytitle></citerefentry>,
 490             <citerefentry><refentrytitle>glColor</refentrytitle></citerefentry>,
 491             <citerefentry><refentrytitle>glSecondaryColor</refentrytitle></citerefentry>,
 492             <citerefentry><refentrytitle>glIndex</refentrytitle></citerefentry>,
 493             <citerefentry><refentrytitle>glNormal</refentrytitle></citerefentry>,
 494             <citerefentry><refentrytitle>glFogCoord</refentrytitle></citerefentry>,
 495             <citerefentry><refentrytitle>glTexCoord</refentrytitle></citerefentry>,
 496             <citerefentry><refentrytitle>glMultiTexCoord</refentrytitle></citerefentry>,
 497             <citerefentry><refentrytitle>glVertexAttrib</refentrytitle></citerefentry>,
 498             <citerefentry><refentrytitle>glEvalCoord</refentrytitle></citerefentry>,
 499             <citerefentry><refentrytitle>glEvalPoint</refentrytitle></citerefentry>,
 500             <citerefentry><refentrytitle>glArrayElement</refentrytitle></citerefentry>,
 501             <citerefentry><refentrytitle>glMaterial</refentrytitle></citerefentry>, and
 502             <citerefentry><refentrytitle>glEdgeFlag</refentrytitle></citerefentry>.
 503             Also,
 504             it is acceptable to use
 505             <citerefentry><refentrytitle>glCallList</refentrytitle></citerefentry> or
 506             <citerefentry><refentrytitle>glCallLists</refentrytitle></citerefentry> to execute
 507             display lists that include only the preceding commands.
 508             If any other GL command is executed between <function>glBegin</function> and <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>,
 509             the error flag is set and the command is ignored.
 510         </para>
 511         <para>
 512             Regardless of the value chosen for <parameter>mode</parameter>,
 513             there is no limit to the number of vertices that can be defined
 514             between <function>glBegin</function> and <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
 515             Lines,
 516             triangles,
 517             quadrilaterals,
 518             and polygons that are incompletely specified are not drawn.
 519             Incomplete specification results when either too few vertices are
 520             provided to specify even a single primitive or when an incorrect multiple
 521             of vertices is specified. The incomplete primitive is ignored; the rest are drawn.
 522         </para>
 523         <para>
 524             The minimum specification of vertices
 525             for each primitive is as follows:
 526             1 for a point,
 527             2 for a line,
 528             3 for a triangle,
 529             4 for a quadrilateral,
 530             and 3 for a polygon.
 531             Modes that require a certain multiple of vertices are
 532             <constant>GL_LINES</constant> (2),
 533             <constant>GL_TRIANGLES</constant> (3),
 534             <constant>GL_QUADS</constant> (4),
 535             and <constant>GL_QUAD_STRIP</constant> (2).
 536         </para>
 537     </refsect1>
 538     <refsect1 id="errors"><title>Errors</title>
 539         <para>
 540             <constant>GL_INVALID_ENUM</constant> is generated if <parameter>mode</parameter> is set to an unaccepted value.
 541         </para>
 542         <para>
 543             <constant>GL_INVALID_OPERATION</constant> is generated if <function>glBegin</function> is executed between a
 544             <function>glBegin</function>
 545             and the corresponding execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
 546         </para>
 547         <para>
 548             <constant>GL_INVALID_OPERATION</constant> is generated if <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry> is executed without being
 549             preceded by a <function>glBegin</function>.
 550         </para>
 551         <para>
 552             <constant>GL_INVALID_OPERATION</constant> is generated if a command other than
 553             <citerefentry><refentrytitle>glVertex</refentrytitle></citerefentry>,
 554             <citerefentry><refentrytitle>glColor</refentrytitle></citerefentry>,
 555             <citerefentry><refentrytitle>glSecondaryColor</refentrytitle></citerefentry>,
 556             <citerefentry><refentrytitle>glIndex</refentrytitle></citerefentry>,
 557             <citerefentry><refentrytitle>glNormal</refentrytitle></citerefentry>,
 558             <citerefentry><refentrytitle>glFogCoord</refentrytitle></citerefentry>,
 559             <citerefentry><refentrytitle>glTexCoord</refentrytitle></citerefentry>,
 560             <citerefentry><refentrytitle>glMultiTexCoord</refentrytitle></citerefentry>,
 561             <citerefentry><refentrytitle>glVertexAttrib</refentrytitle></citerefentry>,
 562             <citerefentry><refentrytitle>glEvalCoord</refentrytitle></citerefentry>,
 563             <citerefentry><refentrytitle>glEvalPoint</refentrytitle></citerefentry>,
 564             <citerefentry><refentrytitle>glArrayElement</refentrytitle></citerefentry>,
 565             <citerefentry><refentrytitle>glMaterial</refentrytitle></citerefentry>,
 566             <citerefentry><refentrytitle>glEdgeFlag</refentrytitle></citerefentry>,
 567             <citerefentry><refentrytitle>glCallList</refentrytitle></citerefentry>, or
 568             <citerefentry><refentrytitle>glCallLists</refentrytitle></citerefentry> is executed between
 569             the execution of <function>glBegin</function> and the corresponding
 570             execution <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
 571         </para>
 572         <para>
 573             Execution of
 574             <citerefentry><refentrytitle>glEnableClientState</refentrytitle></citerefentry>,
 575             <citerefentry><refentrytitle>glDisableClientState</refentrytitle></citerefentry>,
 576             <citerefentry><refentrytitle>glEdgeFlagPointer</refentrytitle></citerefentry>,
 577             <citerefentry><refentrytitle>glFogCoordPointer</refentrytitle></citerefentry>,
 578             <citerefentry><refentrytitle>glTexCoordPointer</refentrytitle></citerefentry>,
 579             <citerefentry><refentrytitle>glColorPointer</refentrytitle></citerefentry>,
 580             <citerefentry><refentrytitle>glSecondaryColorPointer</refentrytitle></citerefentry>,
 581             <citerefentry><refentrytitle>glIndexPointer</refentrytitle></citerefentry>,
 582             <citerefentry><refentrytitle>glNormalPointer</refentrytitle></citerefentry>,
 583             <citerefentry><refentrytitle>glVertexPointer</refentrytitle></citerefentry>,
 584             <citerefentry><refentrytitle>glVertexAttribPointer</refentrytitle></citerefentry>,
 585             <citerefentry><refentrytitle>glInterleavedArrays</refentrytitle></citerefentry>, or
 586             <citerefentry><refentrytitle>glPixelStore</refentrytitle></citerefentry> is not allowed after a call to <function>glBegin</function> and before
 587             the corresponding call to <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>,
 588             but an error may or may not be generated.
 589         </para>
 590     </refsect1>
 591     <refsect1 id="seealso"><title>See Also</title>
 592         <para>
 593             <citerefentry><refentrytitle>glArrayElement</refentrytitle></citerefentry>,
 594             <citerefentry><refentrytitle>glCallList</refentrytitle></citerefentry>,
 595             <citerefentry><refentrytitle>glCallLists</refentrytitle></citerefentry>,
 596             <citerefentry><refentrytitle>glColor</refentrytitle></citerefentry>,
 597             <citerefentry><refentrytitle>glEdgeFlag</refentrytitle></citerefentry>,
 598             <citerefentry><refentrytitle>glEvalCoord</refentrytitle></citerefentry>,
 599             <citerefentry><refentrytitle>glEvalPoint</refentrytitle></citerefentry>,
 600             <citerefentry><refentrytitle>glFogCoord</refentrytitle></citerefentry>,
 601             <citerefentry><refentrytitle>glIndex</refentrytitle></citerefentry>,
 602             <citerefentry><refentrytitle>glMaterial</refentrytitle></citerefentry>,
 603             <citerefentry><refentrytitle>glMultiTexCoord</refentrytitle></citerefentry>,
 604             <citerefentry><refentrytitle>glNormal</refentrytitle></citerefentry>,
 605             <citerefentry><refentrytitle>glSecondaryColor</refentrytitle></citerefentry>,
 606             <citerefentry><refentrytitle>glTexCoord</refentrytitle></citerefentry>,
 607             <citerefentry><refentrytitle>glVertex</refentrytitle></citerefentry>,
 608             <citerefentry><refentrytitle>glVertexAttrib</refentrytitle></citerefentry>
 609         </para>
 610     </refsect1>
 611     <refsect1 id="Copyright"><title>Copyright</title>
 612         <para>
 613             Copyright <trademark class="copyright"></trademark> 1991-2006
 614             Silicon Graphics, Inc. This document is licensed under the SGI
 615             Free Software B License. For details, see
 616             <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
 617         </para>
 618     </refsect1>
 619 </refentry>