freeglut.lsm:3 Removed 'beta' label for next release, thanks to Bernhard Kaindl.
[freeglut] / doc / freeglut_user_interface.html
1 <!DOCTYPE html PUBLIC "-//w3c//dtd html 4.0 transitional//en">
2 <html>
3 <head>
4         
5   <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
6         
7   <meta name="Author" content="John F. Fay">
8         
9   <meta name="GENERATOR" content="Mozilla/4.77 [en] (Windows NT 5.0; U) [Netscape]">
10   <title>FREEGLUT Application Program Interface</title>
11 </head>
12   <body>
13     
14 <dl>
15 <center>  
16 <h1> The Open-Source</h1>
17  </center>
18 <center>  
19 <h1> OpenGL Utility Toolkit</h1>
20  </center>
21 <center>  
22 <h1> (<i>freeglut</i> 2.0.0)</h1>
23  </center>
24 <center>  
25 <h1> Application Programming Interface</h1>
26  </center>
27 </dl>
28     
29 <center>  
30 <h1> Version 4.0</h1>
31  </center>
32     
33 <center>  
34 <h2> The <i>freeglut</i> Programming Consortium</h2>
35  </center>
36     
37 <center>  
38 <h2> July, 2003</h2>
39  </center>
40     
41 <p><br>
42  OpenGL is a trademark of Silicon Graphics, Inc. X Window System is a trademark 
43 of X Consortium, Inc.&nbsp; Spaceball is a registered trademark of Spatial 
44 Systems Inc. <br>
45  The authors have taken care in preparation of this documentation but make 
46 no expressed or implied warranty of any kind and assumes no responsibility
47  for errors or omissions. No liability is assumed for incidental or consequential
48  damages in connection with or arising from the use of information or programs
49  contained herein. <br>
50  &nbsp; </p>
51  
52 <h1> 1.0&nbsp;<a name="Contents"></a>
53   Contents</h1>
54   1.0&nbsp; <a href="#Contents">Contents</a>
55    
56 <p>2.0&nbsp; <a href="#Introduction">Introduction</a>
57   </p>
58  
59 <p>3.0&nbsp; <a href="#Background">Background</a>
60   </p>
61  
62 <blockquote>3.1&nbsp; Design Philosophy <br>
63  3.2&nbsp; Conventions <br>
64  3.3&nbsp; Terminology <br>
65  3.4&nbsp; Differences from GLUT 3.7</blockquote>
66       
67   <p><br>
68  4.0&nbsp; <a href="#Initialization">Initialization Functions</a>
69   </p>
70    
71   <blockquote>4.1&nbsp; glutInit <br>
72  4.2&nbsp; glutInitWindowPosition, glutInitWindowSize <br>
73  4.3&nbsp; glutInitDisplayMode <br>
74  4.4&nbsp; glutInitDisplayString</blockquote>
75         
76     <p><br>
77  5.0&nbsp; <a href="#EventProcessing">Event Processing Functions</a>
78   </p>
79      
80     <blockquote>5.1&nbsp; glutMainLoop <br>
81  5.2&nbsp; glutMainLoopEvent <br>
82  5.3&nbsp; glutLeaveMainLoop</blockquote>
83           
84       <p><br>
85  6.0&nbsp; <a href="#Window">Window Functions</a>
86   </p>
87        
88       <blockquote>6.1&nbsp; glutCreateWindow <br>
89  6.2&nbsp; glutCreateSubwindow <br>
90  6.3&nbsp; glutDestroyWindow <br>
91  6.4&nbsp; glutSetWindow, glutGetWindow <br>
92  6.5&nbsp; glutSetWindowTitle, glutSetIconTitle <br>
93  6.6&nbsp; glutReshapeWindow <br>
94  6.7&nbsp; glutPositionWindow <br>
95  6.8&nbsp; glutShowWindow, glutHideWindow, glutIconifyWindow <br>
96  6.9&nbsp; glutPushWindow, glutPopWindow <br>
97  6.10&nbsp; glutFullScreen</blockquote>
98             
99         <p><br>
100  7.0&nbsp; <a href="#Display">Display Functions</a>
101   </p>
102          
103         <blockquote>7.1&nbsp; glutPostRedisplay <br>
104  7.2&nbsp; glutPostWindowRedisplay <br>
105  7.3&nbsp; glutSwapBuffers</blockquote>
106               
107           <p><br>
108  8.0&nbsp; <a href="#MouseCursor">Mouse Cursor Functions</a>
109   </p>
110            
111           <blockquote>8.1&nbsp; glutSetCursor <br>
112  8.2&nbsp; glutWarpPointer</blockquote>
113                 
114             <p><br>
115  9.0&nbsp; <a href="#Overlay">Overlay Functions</a>
116   </p>
117              
118             <blockquote>9.1&nbsp; glutEstablishOverlay <br>
119  9.2&nbsp; glutRemoveOverlay <br>
120  9.3&nbsp; glutUseLayer <br>
121  9.4&nbsp; glutPostOverlayRedisplay <br>
122  9.5&nbsp; glutPostWindowOverlayRedisplay <br>
123  9.6&nbsp; glutShowOverlay, glutHideOverlay</blockquote>
124                   
125               <p><br>
126  10.0&nbsp; <a href="#Menu">Menu Functions</a>
127   </p>
128                
129               <blockquote>10.1&nbsp; glutCreateMenu <br>
130  10.2&nbsp; glutDestroyMenu <br>
131  10.3&nbsp; glutGetMenu, glutSetMenu <br>
132  10.4&nbsp; glutAddMenuEntry <br>
133  10.5&nbsp; glutAddSubMenu <br>
134  10.6&nbsp; glutChangeToMenuEntry <br>
135  10.7&nbsp; glutChangeToSubMenu <br>
136  10.8&nbsp; glutRemoveMenuItem <br>
137  10.9&nbsp; glutAttachMenu, glutDetachMenu</blockquote>
138                     
139                 <p><br>
140  11.0&nbsp; <a href="#GlobalCallback">Global Callback Registration Functions</a>
141   </p>
142                  
143                 <blockquote>11.1&nbsp; glutTimerFunc <br>
144  11.2&nbsp; glutIdleFunc</blockquote>
145                       
146                   <p><br>
147  12.0&nbsp; <a href="#WindowCallback">Window-Specific Callback Registration
148  Functions</a>
149   </p>
150                    
151                   <blockquote>12.1&nbsp; glutDisplayFunc <br>
152  12.2&nbsp; glutOverlayDisplayFunc <br>
153  12.3&nbsp; glutReshapeFunc <br>
154  12.4&nbsp; glutCloseFunc <br>
155  12.5&nbsp; glutKeyboardFunc <br>
156  12.6&nbsp; glutSpecialFunc <br>
157  12.7&nbsp; glutKeyboardUpFunc <br>
158  12.8&nbsp; glutSpecialUpFunc <br>
159  12.9&nbsp; glutMouseFunc <br>
160  12.10&nbsp; glutMotionFunc, glutPassiveMotionFunc <br>
161  12.11&nbsp; glutVisibilityFunc <br>
162  12.12&nbsp; glutEntryFunc <br>
163  12.13&nbsp; glutJoystickFunc <br>
164  12.14&nbsp; glutSpaceballMotionFunc <br>
165  12.15&nbsp; glutSpaceballRotateFunc <br>
166  12.16&nbsp; glutSpaceballButtonFunc <br>
167  12.17&nbsp; glutButtonBoxFunc <br>
168  12.18&nbsp; glutDialsFunc <br>
169  12.19&nbsp; glutTabletMotionFunc <br>
170  12.20&nbsp; glutTabletButtonFunc                      
171                     <p>12.21&nbsp; glutMenuStatusFunc <br>
172  12.22&nbsp; glutWindowStatusFunc</p>
173                      </blockquote>
174                         
175                     <p><br>
176  13.0&nbsp; <a href="#StateSetting">State Setting and Retrieval Functions</a>
177   </p>
178                      
179                     <blockquote>13.1&nbsp; glutSetOption <br>
180  13.2&nbsp; glutGet <br>
181  13.3&nbsp; glutDeviceGet <br>
182  13.4&nbsp; glutGetModifiers <br>
183  13.5&nbsp; glutLayerGet <br>
184  13.6&nbsp; glutExtensionSupported<br>
185 13.7 &nbsp;glutGetProcAddress<br>
186                       </blockquote>
187                        
188                       <p><br>
189  14.0&nbsp; <a href="#FontRendering">Font Rendering Functions</a>
190   </p>
191                        
192                       <blockquote>14.1&nbsp; glutBitmapCharacter <br>
193  14.2&nbsp; glutBitmapString <br>
194  14.3&nbsp; glutBitmapWidth <br>
195  14.4&nbsp; glutBitmapLength <br>
196  14.5&nbsp; glutBitmapHeight <br>
197  14.6&nbsp; glutStrokeCharacter <br>
198  14.7&nbsp; glutStrokeString <br>
199  14.8&nbsp; glutStrokeWidth <br>
200  14.9&nbsp; glutStrokeLength <br>
201  14.10&nbsp; glutStrokeHeight</blockquote>
202                             
203                         <p><br>
204  15.0&nbsp; <a href="#GeometricObject">Geometric Object Rendering Functions</a>
205   </p>
206                          
207                         <blockquote>15.1&nbsp; glutWireSphere, glutSolidSphere
208                            <br>
209  15.2&nbsp; glutWireTorus, glutSolidTorus <br>
210  15.3&nbsp; glutWireCone, glutSolidCone <br>
211  15.4&nbsp; glutWireCube, glutSolidCube <br>
212  15.5&nbsp; glutWireTetrahedron, glutSolidTetrahedron <br>
213  15.6&nbsp; glutWireOctahedron, glutSolidOctahedron <br>
214  15.7&nbsp; glutWireDodecahedron, glutSolidDodecahedron <br>
215  15.8&nbsp; glutWireIcosahedron, glutSolidIcosahedron <br>
216  15.9&nbsp; glutWireRhombicDodecahedron, glutSolidRhombicDodecahedron <br>
217  15.10&nbsp; glutWireTeapot, glutSolidTeapot</blockquote>
218                               
219                           <p><br>
220  16.0&nbsp; <a href="#GameMode">Game Mode Functions</a>
221   </p>
222                            
223                           <blockquote>16.1&nbsp; glutGameModeString <br>
224  16.2&nbsp; glutEnterGameMode, glutLeaveGameMode <br>
225  16.3&nbsp; glutGameModeGet</blockquote>
226                                 
227                             <p><br>
228  17.0&nbsp; <a href="#VideoResize">Video Resize Functions</a>
229   </p>
230                              
231                             <blockquote>17.1&nbsp; glutVideoResizeGet <br>
232  17.2&nbsp; glutSetupVideoResizing, glutStopVideoResizing <br>
233  17.3&nbsp; glutVideoResize <br>
234  17.4&nbsp; glutVideoPan</blockquote>
235                                   
236                               <p><br>
237  18.0&nbsp; <a href="#ColorMap">Color Map Functions</a>
238   </p>
239                                
240                               <blockquote>18.1&nbsp; glutSetColor, glutGetColor
241                                  <br>
242  18.2&nbsp; glutCopyColormap</blockquote>
243                                     
244                                 <p><br>
245  19.0&nbsp; <a href="#Miscellaneous">Miscellaneous Functions</a>
246   </p>
247                                  
248                                 <blockquote>19.1&nbsp; glutIgnoreKeyRepeat, 
249 glutSetKeyRepeat <br>
250  19.2&nbsp; glutForceJoystickFunc <br>
251  19.3&nbsp; glutReportErrors</blockquote>
252                                       
253                                   <p><br>
254  20.0&nbsp; <a href="#UsageNotes">Usage Notes</a>
255   </p>
256                                    
257                                   <p>21.0&nbsp; <a href="#ImplementationNotes">
258  Implementation Notes</a>
259   </p>
260                                    
261                                   <p>22.0&nbsp; <a href="#GLUT_State">GLUT 
262 State</a>
263   </p>
264                                    
265                                   <p>23.0&nbsp; <a href="#Freeglut.h_Header">
266  "freeglut.h" Header File</a>
267   </p>
268                                    
269                                   <p>24.0&nbsp; <a href="#References">References</a>
270   </p>
271                                    
272                                   <p>25.0&nbsp; <a href="#Index">Index</a>
273   <br>
274  &nbsp; <br>
275  &nbsp; </p>
276                                    
277                                   <h1> 2.0&nbsp;<a name="Introduction"></a>
278   Introduction</h1>
279   &nbsp;                                    
280                                   <h1> 3.0&nbsp;<a name="Background"></a>
281   Background</h1>
282   The OpenGL programming world owes a tremendous debt to Mr. Mark J. Kilgard
283  for writing the OpenGL Utility Toolkit, or GLUT.&nbsp; The GLUT library
284 of functions allows an application programmer to create, control, and manipulate
285  windows independent of what operating system the program is running on.&nbsp;
286  By hiding the dependency on the operating system from the application programmer,
287  he allowed people to write truly portable OpenGL applications.         
288                           
289                                   <p>&nbsp;&nbsp;&nbsp; Mr. Kilgard copyrighted 
290 his library and gave it a rather unusual license.&nbsp; Under his license, 
291 people are allowed freely to copy and distribute the libraries and the source 
292 code, but they are not allowed to modify it.&nbsp; For a long time this did 
293 not matter because the GLUT library worked so well and because Mr. Kilgard 
294 was releasing updates on a regular basis.&nbsp; But with the passage of time, 
295 people started wanting some slightly different behaviours in their windowing 
296 system.&nbsp; When Mr. Kilgard stopped supporting the GLUT library in 1999, 
297 having moved on to bigger and better things, this started to become a problem.
298                                    </p>
299                                    
300                                   <p>&nbsp;&nbsp;&nbsp; In December 1999, 
301 Mr. Pawel Olzsta started work on an open-source clone of the GLUT library.&nbsp; 
302 This open-source clone, which does not use any of the GLUT source code, has 
303 evolved into the present <i>freeglut</i> library.&nbsp; This documentation 
304 specifies the application program interface to the <i>freeglut</i> library.
305                                    </p>
306                                    
307                                   <h2> 3.1&nbsp; Design Philosophy</h2>
308                                       
309                                   <h2> 3.2&nbsp; Conventions</h2>
310                                       
311                                   <h2> 3.3&nbsp; Terminology</h2>
312                                       
313                                   <h2> 3.4&nbsp; Differences from GLUT 3.7</h2>
314   Since the <i>freeglut</i> library was developed in order to update GLUT,
315  it is natural that there will be some differences between the two.&nbsp;
316 Each function in the API notes any differences between the GLUT and the <i>
317 freeglut</i>  function behaviours.&nbsp; The important ones are summarized
318 here.                                    
319                                   <h3> 3.4.1&nbsp; glutMainLoop Behaviour</h3>
320   One of the commonest complaints about the GLUT library was that once an
321 application called "<tt>glutMainLoop</tt>", it never got control back.&nbsp;
322 There was no way for an application to loop in GLUT for a while, possibly
323 as a subloop while a specific window was open, and then return to the calling
324 function.&nbsp; A new function, "<tt>glutMainLoopEvent</tt>", has been added
325 to allow this functionality.&nbsp; Another function, "<tt>glutLeaveMainLoop</tt>
326 ", has also been added to allow the application to tell <i>freeglut</i> to clean
327 up and close down.                                    
328                                   <h3> 3.4.2&nbsp; Action on Window Closure</h3>
329   Another difficulty with GLUT, especially with multiple-window programs,
330 is that if the user clicks on the "x" in the window header the application
331 exits immediately.&nbsp; The application programmer can now set an option,
332 "<tt> GLUT_ACTION_ON_WINDOW_CLOSE</tt>", to specify whether execution should
333 continue, whether GLUT should return control to the main program, or whether
334 GLUT should simply exit (the default).                                  
335  
336                                   <h3>3.4.3&nbsp; Changes to Callbacks<br>
337                                    </h3>
338  Several new callbacks have been added and several callbacks which were specific 
339 to Silicon Graphics hardware have not been implemented.&nbsp; Most or all 
340 of the new callbacks are listed in the GLUT Version 4 "glut.h" header file 
341 but did not make it into the documentation.&nbsp; The new callbacks consist 
342 of regular and special key release callbacks, a joystick callback, a menu 
343 state callback (with one argument, distinct from the menu status callback 
344 which has three arguments), and a window status callback <br>
345  (also with one argument).&nbsp; Unsupported callbacks are the three Spaceball 
346 callbacks, the ButtonBox callback, the Dials callback, and the two Tablet 
347 callbacks.&nbsp; If the user has a need for an unsupported callback he should 
348 contact the <i>freeglut</i> development team.<br>
349                                    
350                                   <h3>3.4.4&nbsp; String Rendering<br>
351                                    </h3>
352  New functions have been added to render full character strings (including 
353 carriage returns) rather than rendering one character at a time.&nbsp; More 
354 functions return the widths of character strings and the font heights, in 
355 pixels for bitmapped fonts and in OpenGL units for the stroke fonts.<br>
356                                    
357                                   <h3>3.4.5&nbsp; Geometry Rendering<br>
358                                    </h3>
359  Two functions have been added to render a wireframe and a solid rhombic
360 dodecahedron.                                    
361                                   <h3> 3.4.5&nbsp; Extension Function Queries</h3>
362  glutGetProcAddress is a wrapper for the glXGetProcAddressARB and wglGetProcAddress
363 functions. 
364                                   <h1> 4.0&nbsp;<a name="Initialization"></a>
365   Initialization Functions</h1>
366                                       
367                                   <h2> 4.1&nbsp; glutInit</h2>
368                                       
369                                   <h2> 4.2&nbsp; glutInitWindowPosition, glutInitWindowSize</h2>
370   The "<tt>glutInitWindowPosition</tt> " and "<tt>glutInitWindowSize</tt>
371 "  functions specify a desired position and size for windows that <i>freeglut</i>
372   will create in the future.                                    
373                                   <p><b>Usage</b> </p>
374                                    
375                                   <p><tt>void glutInitWindowPosition ( int 
376 x, int y ) ;</tt> <br>
377                                    <tt>void glutInitWindowSize ( int width, 
378 int height ) ;</tt> </p>
379                                    
380                                   <p><b>Description</b> </p>
381                                    
382                                   <p>The "<tt>glutInitWindowPosition</tt>
383   " and "<tt>glutInitWindowSize</tt>" functions specify a desired position 
384 and size for windows that <i>freeglut</i> will create in the future.&nbsp; 
385 The position is measured in pixels from the upper left hand corner of the 
386 screen, with "x" increasing to the right and "y" increasing towards the bottom 
387 of the screen.&nbsp; The size is measured in pixels.&nbsp; <i>Freeglut</i>
388   does not promise to follow these specifications in creating its windows, 
389 it certainly makes an attempt to. </p>
390                                    
391                                   <p>The position and size of a window are 
392 a matter of some subtlety.&nbsp; Most windows have a usable area surrounded 
393 by a border and with a title bar on the top.&nbsp; The border and title bar 
394 are commonly called "decorations."&nbsp; The position of the window unfortunately 
395 varies with the operating system.&nbsp; On Linux, it is the coordinates of 
396 the upper left-hand corner of its decorations.&nbsp; On Windows, it is the 
397 coordinates of the upper left hand corner of its usable interior.&nbsp; For 
398 both operating systems, the size of the window is the size of the usable interior.
399                                   </p>
400                                    
401                                   <p>Windows has some additional quirks which 
402 the application programmer should know about.&nbsp; First, the minimum y-coordinate 
403 of a window decoration is zero.&nbsp; (This is a feature of <i>freeglut</i>
404   and can be adjusted if so desired.)&nbsp; Second, there appears to be a 
405 minimum window width on Windows which is 104 pixels.&nbsp; The user may specify 
406 a smaller width, but the Windows system calls ignore it.&nbsp; It is also 
407 impossible to make a window narrower than this by dragging on its corner.
408                                    </p>
409                                    
410                                   <p><b>Changes From GLUT</b> </p>
411                                    
412                                   <p>For some reason, GLUT is not affected 
413 by the 104-pixel minimum window width.&nbsp; If the user clicks on the corner 
414 of a window which is narrower than this amount, the window will immediately 
415 snap out to this width, but the application can call "<tt>glutReshapeWindow</tt>
416   " and make a window narrower again. </p>
417                                    
418                                   <h2> 4.3&nbsp; glutInitDisplayMode</h2>
419                                       
420                                   <h2> 4.4&nbsp; glutInitDisplayString</h2>
421                                       
422                                   <h1> 5.0&nbsp;<a name="EventProcessing"></a>
423   Event Processing Functions</h1>
424   After an application has finished initializing its windows and menus, it
425  enters an event loop.&nbsp; Within this loop, <i>freeglut</i> polls the
426 data entry devices (keyboard, mouse, etc.) and calls the application's appropriate 
427 callbacks.                                    
428                                   <p>In GLUT, control never returned from 
429 the event loop (as invoked by the "<tt>glutMainLoop</tt>" function) to the 
430 calling function.&nbsp; This prevented an application from having re-entrant 
431 code, in which GLUT could be invoked from within a callback, and it prevented 
432 the application from doing any post-processing (such as freeing allocated 
433 memory) after GLUT had closed down.&nbsp; <i>Freeglut</i> allows the application 
434 programmer to specify more direct control over the event loop by means of 
435 two new functions.&nbsp; The first, "<tt>glutMainLoopEvent</tt>", processes 
436 a single iteration of the event loop and allows the application to use a different
437 event loop controller or to contain re-entrant code.&nbsp; The second, "<tt>
438 glutLeaveMainLoop</tt>", causes the event loop to exit nicely; this is preferable
439 to the application's calling "<tt>exit</tt>" from within a GLUT callback.
440                                   </p>
441                                    
442                                   <h2> 5.1&nbsp; glutMainLoop</h2>
443   The "<tt>glutMainLoop</tt>" function enters the event loop.           
444                         
445                                   <p><b>Usage</b> </p>
446                                    
447                                   <p><tt>void glutMainLoop ( void ) ;</tt>
448   </p>
449                                    
450                                   <p><b>Description</b> </p>
451                                    
452                                   <p>The&nbsp; "<tt>glutMainLoop</tt>" function 
453 causes the program to enter the window event loop.&nbsp; An application should 
454 call this function at most once.&nbsp; It will call any application callback 
455 functions as required to process mouse clicks, mouse motion, key presses, 
456 and so on. </p>
457                                    
458                                   <p><b>Changes From GLUT</b> </p>
459                                    
460                                   <p>In GLUT, there was absolutely no way 
461 for the application programmer to have control return from the "<tt>glutMainLoop</tt>
462   " function to the calling function.&nbsp; <i>Freeglut</i> allows the programmer 
463 to force this by setting the "<tt>GLUT_ACTION_ON_WINDOW_CLOSE</tt>" option 
464 and invoking the "<tt>glutLeaveMainLoop</tt>" function from one of the callbacks.&nbsp;
465  Stopping the program this way is preferable to simply calling "<tt>exit</tt>
466   " from within a callback because this allows <i>freeglut</i> to free allocated
467  memory and otherwise clean up after itself.&nbsp; (I know I just said this,
468  but I think it is important enough that it bears repeating.) </p>
469                                    
470                                   <h2> 5.2&nbsp; glutMainLoopEvent</h2>
471   The "<tt>glutMainLoopEvent</tt>" function processes a single iteration
472 in the <i>freeglut</i> event loop.                                    
473                                   <p><b>Usage</b> </p>
474                                    
475                                   <p><tt>void glutMainLoopEvent ( void ) ;</tt>
476  </p>
477                                    
478                                   <p><b>Description</b> </p>
479                                    
480                                   <p>The&nbsp; "<tt>glutMainLoopEvent</tt>
481   " function causes <i>freeglut</i> to process one iteration's worth of events 
482 in its event loop.&nbsp; This allows the application to control its own event 
483 loop and still use the <i>freeglut</i> windowing system. </p>
484                                    
485                                   <p><b>Changes From GLUT</b> </p>
486                                    
487                                   <p>GLUT does not include this function.
488                                    </p>
489                                    
490                                   <h2> 5.3&nbsp; glutLeaveMainLoop</h2>
491   The "<tt>glutLeaveMainLoop</tt>" function causes <i>freeglut</i> to stop
492  its event loop.                                    
493                                   <p><b>Usage</b> </p>
494                                    
495                                   <p><tt>void glutLeaveMainLoop ( void ) ;</tt>
496  </p>
497                                    
498                                   <p><b>Description</b> </p>
499                                    
500                                   <p>The&nbsp; "<tt>glutLeaveMainLoop</tt>
501   " function causes <i>freeglut</i> to stop the event loop.&nbsp; If the
502 "<tt>  GLUT_ACTION_ON_WINDOW_CLOSE</tt>" option has been set to "<tt>GLUT_ACTION_CONTINUE_EXECUTION</tt>
503   ", control will return to the function which called "<tt>glutMainLoop</tt>
504   "; otherwise the application will exit. </p>
505                                    
506                                   <p>If the application has two nested calls 
507 to "<tt>glutMainLoop</tt>" and calls "<tt>glutLeaveMainLoop</tt>", the behaviour 
508 of <i>freeglut</i> is undefined.&nbsp; It may leave only the inner nested 
509 loop or it may leave both loops.&nbsp; If the reader has a strong preference 
510 for one behaviour over the other he should contact the <i>freeglut</i> Programming 
511 Consortium and ask for the code to be fixed. </p>
512                                    
513                                   <p><b>Changes From GLUT</b> </p>
514                                    
515                                   <p>GLUT does not include this function.
516                                    </p>
517                                    
518                                   <h1> 6.0&nbsp;<a name="Window"></a>
519   Window Functions</h1>
520                                       
521                                   <h2> 6.1&nbsp; glutCreateWindow</h2>
522                                       
523                                   <h2> 6.2&nbsp; glutCreateSubwindow</h2>
524                                       
525                                   <h2> 6.3&nbsp; glutDestroyWindow</h2>
526                                       
527                                   <h2> 6.4&nbsp; glutSetWindow, glutGetWindow</h2>
528                                       
529                                   <h2> 6.5&nbsp; glutSetWindowTitle, glutSetIconTitle</h2>
530                                       
531                                   <h2> 6.6&nbsp; glutReshapeWindow</h2>
532                                       
533                                   <h2> 6.7&nbsp; glutPositionWindow</h2>
534                                       
535                                   <h2> 6.8&nbsp; glutShowWindow, glutHideWindow, 
536 glutIconifyWindow</h2>
537                                       
538                                   <h2> 6.9&nbsp; glutPushWindow, glutPopWindow</h2>
539                                       
540                                   <h2> 6.10&nbsp; glutFullScreen</h2>
541                                       
542                                   <h1> 7.0&nbsp;<a name="Display"></a>
543   Display Functions</h1>
544                                       
545                                   <h2> 7.1&nbsp; glutPostRedisplay</h2>
546                                       
547                                   <h2> 7.2&nbsp; glutPostWindowRedisplay</h2>
548                                       
549                                   <h2> 7.3&nbsp; glutSwapBuffers</h2>
550                                       
551                                   <h1> 8.0&nbsp;<a name="MouseCursor"></a>
552   Mouse Cursor Functions</h1>
553                                       
554                                   <h2> 8.1&nbsp; glutSetCursor</h2>
555                                       
556                                   <h2> 8.2&nbsp; glutWarpPointer</h2>
557                                       
558                                   <h1> 9.0&nbsp;<a name="Overlay"></a>
559   Overlay Functions</h1>
560   <i>Freeglut</i> does not allow overlays, although it does "answer the mail"
561  with function stubs so that GLUT-based programs can compile and link against
562                                    <i>freeglut</i> without modification.&nbsp; 
563 If the reader needs overlays, he should contact the <i>freeglut</i> Programming 
564 Consortium and ask for them to be implemented.&nbsp; He should also be prepared 
565 to assist in the implementation.                                    
566                                   <h2> 9.1&nbsp; glutEstablishOverlay</h2>
567   The "<tt>glutEstablishOverlay</tt>" function is not implemented in <i>freeglut</i>
568  .                                    
569                                   <p><b>Usage</b> </p>
570                                    
571                                   <p><tt>void glutEstablishOverlay ( void 
572 ) ;</tt> </p>
573                                    
574                                   <p><b>Description</b> </p>
575                                    
576                                   <p>The "<tt>glutEstablishOverlay</tt>" function
577 is not implemented in <i>freeglut</i>. </p>
578                                    
579                                   <p><b>Changes From GLUT</b> </p>
580                                    
581                                   <p>GLUT implements this function. </p>
582                                    
583                                   <h2> 9.2&nbsp; glutRemoveOverlay</h2>
584   The "<tt>glutRemoveOverlay</tt>" function is not implemented in <i>freeglut</i>
585  .                                    
586                                   <p><b>Usage</b> </p>
587                                    
588                                   <p><tt>void glutRemoveOverlay ( void ) ;</tt>
589  </p>
590                                    
591                                   <p><b>Description</b> </p>
592                                    
593                                   <p>The "<tt>glutRemoveOverlay</tt>" function 
594 is not implemented in <i>freeglut</i>. </p>
595                                    
596                                   <p><b>Changes From GLUT</b> </p>
597                                    
598                                   <p>GLUT implements this function. </p>
599                                    
600                                   <h2> 9.3&nbsp; glutUseLayer</h2>
601   The "<tt>glutUseLayer</tt>" function is not implemented in <i>freeglut</i>
602  .                                    
603                                   <p><b>Usage</b> </p>
604                                    
605                                   <p><tt>void glutUseLayer (&nbsp; GLenum 
606 layer ) ;</tt> </p>
607                                    
608                                   <p><b>Description</b> </p>
609                                    
610                                   <p>The "<tt>glutUseLayer</tt>" function 
611 is not implemented in <i>freeglut</i>. </p>
612                                    
613                                   <p><b>Changes From GLUT</b> </p>
614                                    
615                                   <p>GLUT implements this function. </p>
616                                    
617                                   <h2> 9.4&nbsp; glutPostOverlayRedisplay</h2>
618   The "<tt>glutPostOverlayRedisplay</tt> " function is not implemented in
619                                   <i> freeglut</i>.                     
620               
621                                   <p><b>Usage</b> </p>
622                                    
623                                   <p><tt>void glutPostOverlayRedisplay ( void
624 ) ;</tt> </p>
625                                    
626                                   <p><b>Description</b> </p>
627                                    
628                                   <p>The "<tt>glutPostOverlayRedisplay</tt>
629   " function is not implemented in <i>freeglut</i>. </p>
630                                    
631                                   <p><b>Changes From GLUT</b> </p>
632                                    
633                                   <p>GLUT implements this function. </p>
634                                    
635                                   <h2> 9.5&nbsp; glutPostWindowOverlayRedisplay</h2>
636   The "<tt>glutPostWindowOverlayRedisplay</tt> " function is not implemented
637  in <i>freeglut</i>.                                    
638                                   <p><b>Usage</b> </p>
639                                    
640                                   <p><tt>void glutPostWindowOverlayRedisplay 
641 ( int window ) ;</tt> </p>
642                                    
643                                   <p><b>Description</b> </p>
644                                    
645                                   <p>The "<tt>glutPostWindowOverlayRedisplay</tt>
646   " function is not implemented in <i>freeglut</i>. </p>
647                                    
648                                   <p><b>Changes From GLUT</b> </p>
649                                    
650                                   <p>GLUT implements this function. </p>
651                                    
652                                   <h2> 9.6&nbsp; glutShowOverlay, glutHideOverlay</h2>
653   The "<tt>glutShowOverlay</tt>" and "<tt>glutHideOverlay</tt>" functions
654 are not implemented in <i>freeglut</i> .                                
655    
656                                   <p><b>Usage</b> </p>
657                                    
658                                   <p><tt>void glutShowOverlay( void ) ;</tt>
659   <br>
660                                    <tt>void glutHideOverlay( void ) ;</tt>
661   </p>
662                                    
663                                   <p><b>Description</b> </p>
664                                    
665                                   <p>The "<tt>glutShowOverlay</tt>" and "<tt>
666 glutHideOverlay</tt>" functions are not implemented in <i>freeglut</i> .
667                                   </p>
668                                    
669                                   <p><b>Changes From GLUT</b> </p>
670                                    
671                                   <p>GLUT implements these functions. </p>
672                                    
673                                   <h1> 10.0&nbsp;<a name="Menu"></a>
674   Menu Functions</h1>
675                                       
676                                   <h2> 10.1&nbsp; glutCreateMenu</h2>
677                                       
678                                   <h2> 10.2&nbsp; glutDestroyMenu</h2>
679                                       
680                                   <h2> 10.3&nbsp; glutGetMenu, glutSetMenu</h2>
681                                       
682                                   <h2> 10.4&nbsp; glutAddMenuEntry</h2>
683                                       
684                                   <h2> 10.5&nbsp; glutAddSubMenu</h2>
685                                       
686                                   <h2> 10.6&nbsp; glutChangeToMenuEntry</h2>
687                                       
688                                   <h2> 10.7&nbsp; glutChangeToSubMenu</h2>
689                                       
690                                   <h2> 10.8&nbsp; glutRemoveMenuItem</h2>
691                                       
692                                   <h2> 10.9&nbsp; glutAttachMenu, glutDetachMenu</h2>
693                                       
694                                   <h1> 11.0&nbsp;<a name="GlobalCallback"></a>
695   Global Callback Registration Functions</h1>
696                                       
697                                   <h2> 11.1&nbsp; glutTimerFunc</h2>
698                                       
699                                   <h2> 11.2&nbsp; glutIdleFunc</h2>
700   The "<tt>glutIdleFunc</tt>" function sets the global idle callback. <i>
701 Freeglut</i>  calls the idle callback when there are no inputs from the user.
702                                    
703                                   <p><b>Usage</b> </p>
704                                    
705                                   <p><tt>void glutIdleFunc ( void (*func) 
706 ( void ) ) ;</tt> </p>
707                                    
708                                   <p><tt>func&nbsp;&nbsp;&nbsp; </tt>The new
709 global idle callback function </p>
710                                    
711                                   <p><b>Description</b> </p>
712                                    
713                                   <p>The&nbsp; "<tt>glutIdleFunc</tt>" function 
714 specifies the function that <i>freeglut</i> will call to perform background 
715 processing tasks such as continuous animation when window system events are 
716 not being received.&nbsp; If enabled, this function is called continuously 
717 from <i>freeglut</i> while no events are received.&nbsp; The callback function 
718 has no parameters and returns no value.&nbsp; <i>Freeglut</i> does not change 
719 the <i>current window</i> or the <i>current menu</i> before invoking the idle
720 callback; programs with multiple windows or menus must explicitly set the
721                                   <i>current window</i> and <i>current menu</i>
722  and not rely on its current setting. <br>
723  &nbsp;&nbsp;&nbsp; The amount of computation and rendering done in an idle 
724 callback should be minimized to avoid affecting the program's interactive
725  response.&nbsp; In general, no more than a single frame of rendering should
726  be done in a single invocation of an idle callback. <br>
727  &nbsp;&nbsp;&nbsp; Calling "<tt>glutIdleFunc</tt>" with a NULL argument
728 disables the call to an idle callback. </p>
729                                    
730                                   <p><b>Changes From GLUT</b> </p>
731                                    
732                                   <p>Application programmers should note that
733 if they have specified the "continue execution" action on window closure, 
734                                   <i>freeglut</i> will continue to call the 
735 idle callback after the user has closed a window by clicking on the "x" in 
736 the window header bar.&nbsp; If the idle callback renders a particular window 
737 (this is considered bad form but is frequently done anyway), the programmer 
738 should supply a window closure callback for that window which changes or disables
739 the idle callback. </p>
740                                    
741                                   <h1> 12.0&nbsp;<a name="WindowCallback"></a>
742   Window-Specific Callback Registration Functions</h1>
743                                       
744                                   <h2> 12.1&nbsp; glutDisplayFunc</h2>
745                                       
746                                   <h2> 12.2&nbsp; glutOverlayDisplayFunc</h2>
747                                       
748                                   <h2> 12.3&nbsp; glutReshapeFunc</h2>
749                                       
750                                   <h2> 12.4&nbsp; glutCloseFunc</h2>
751                                       
752                                   <h2> 12.5&nbsp; glutKeyboardFunc</h2>
753                                       
754                                   <h2> 12.6&nbsp; glutSpecialFunc</h2>
755   The "<tt>glutSpecialFunc</tt>" function sets the window's special key press
756  callback. <i>Freeglut</i> calls the special key press callback when the
757 user presses a special key.                                    
758                                   <p><b>Usage</b> </p>
759                                    
760                                   <p><tt>void glutSpecialFunc ( void (*func) 
761 ( int key, int x, int y ) ) ;</tt> </p>
762                                    
763                                   <p><tt>func&nbsp;&nbsp;&nbsp; </tt>The window's
764 new special key press callback function <br>
765                                    <tt>key&nbsp;&nbsp;&nbsp;&nbsp; </tt>The 
766 key whose press triggers the callback <br>
767                                    <tt>x&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
768                                   </tt>The x-coordinate of the mouse relative 
769 to the window at the time the key is pressed <br>
770                                    <tt>y&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
771                                   </tt>The y-coordinate of the mouse relative 
772 to the window at the time the key is pressed </p>
773                                    
774                                   <p><b>Description</b> </p>
775                                    
776                                   <p>The&nbsp; "<tt>glutSpecialFunc</tt>" 
777 function specifies the function that <i>freeglut</i> will call when the user 
778 presses a special key on the keyboard.&nbsp; The callback function has one 
779 argument:&nbsp; the name of the function to be invoked ("called back") at 
780 the time at which the special key is pressed.&nbsp; The function returns no
781 value.&nbsp; <i>Freeglut</i> sets the <i>current window</i> to the window 
782 which is active when the callback is invoked.&nbsp; "Special keys" are the 
783 function keys, the arrow keys, the Page Up and Page Down keys, and the Insert 
784 key.&nbsp; The Delete key is considered to be a regular key. <br>
785  &nbsp;&nbsp;&nbsp; Calling "<tt>glutSpecialUpFunc</tt>" with a NULL argument 
786 disables the call to the window's special key press callback. </p>
787                                    
788                                   <p>&nbsp;&nbsp;&nbsp; The "<tt>key</tt>
789 " argument may take one of the following defined constant values: </p>
790                                    
791                                   <ul>
792   <li> <tt>GLUT_KEY_F1, GLUT_KEY_F2, ..., GLUT_KEY_F12</tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
793  - F1 through F12 keys</li>
794    <li> <tt>GLUT_KEY_PAGE_UP, GLUT_KEY_PAGE_DOWN</tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
795  - Page Up and Page Down keys</li>
796    <li> <tt>GLUT_KEY_HOME, GLUT_KEY_END</tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
797  - Home and End keys</li>
798    <li> <tt>GLUT_KEY_LEFT, GLUT_KEY_RIGHT, GLUT_KEY_UP, GLUT_KEY_DOWN</tt>
799   - arrow keys</li>
800    <li> <tt>GLUT_KEY_INSERT</tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
801  - Insert key</li>
802                                      
803                                   </ul>
804   <b>Changes From GLUT</b>                                    
805                                   <p>None. </p>
806                                    
807                                   <h2> 12.7&nbsp; glutKeyboardUpFunc</h2>
808   The "<tt>glutKeyboardUpFunc</tt>" function sets the window's key release
809  callback. <i>Freeglut</i> calls the key release callback when the user releases 
810 a key.                                    
811                                   <p><b>Usage</b> </p>
812                                    
813                                   <p><tt>void glutKeyboardUpFunc ( void (*func) 
814 ( unsigned char key, int x, int y ) ) ;</tt> </p>
815                                    
816                                   <p><tt>func&nbsp;&nbsp;&nbsp; </tt>The window's
817 new key release callback function <br>
818                                    <tt>key&nbsp;&nbsp;&nbsp;&nbsp; </tt>The 
819 key whose release triggers the callback <br>
820                                    <tt>x&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
821                                   </tt>The x-coordinate of the mouse relative 
822 to the window at the time the key is released <br>
823                                    <tt>y&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
824                                   </tt>The y-coordinate of the mouse relative 
825 to the window at the time the key is released </p>
826                                    
827                                   <p><b>Description</b> </p>
828                                    
829                                   <p>The&nbsp; "<tt>glutKeyboardUpFunc</tt>
830 " function specifies the function that <i>freeglut</i> will call when the 
831 user releases a key from the keyboard.&nbsp; The callback function has one 
832 argument:&nbsp; the name of the function to be invoked ("called back") at 
833 the time at which the key is released.&nbsp; The function returns no value.&nbsp; 
834                                   <i>Freeglut</i> sets the <i>current window</i>
835   to the window which is active when the callback is invoked. <br>
836  &nbsp;&nbsp;&nbsp; While <i>freeglut</i> checks for upper or lower case
837 letters, it does not do so for non-alphabetical characters.&nbsp; Nor does
838 it account for the Caps-Lock key being on.&nbsp; The operating system may
839 send some unexpected characters to <i>freeglut</i>, such as "8" when the
840 user is pressing the Shift key.&nbsp; <i>Freeglut</i> also invokes the callback
841 when the user releases the Control, Alt, or Shift keys, among others.&nbsp;
842 Releasing the Delete key causes this function to be invoked with a value
843 of 127 for "<tt>key</tt>". <br>
844  &nbsp;&nbsp;&nbsp; Calling "<tt>glutKeyboardUpFunc</tt>" with a NULL argument 
845 disables the call to the window's key release callback. </p>
846                                    
847                                   <p><b>Changes From GLUT</b> </p>
848                                    
849                                   <p>This function is not implemented in GLUT
850 versions before Version 4.&nbsp; It has been designed to be as close to GLUT
851 as possible.&nbsp; Users who find differences should contact the        
852                           <i>freeglut</i>&nbsp;Programming Consortium  to
853 have them fixed. </p>
854                                    
855                                   <h2> 12.8&nbsp; glutSpecialUpFunc</h2>
856   The "<tt>glutSpecialUpFunc</tt>" function sets the window's special key
857 release callback. <i>Freeglut</i> calls the special key release callback
858 when the user releases a special key.                                   
859                                   <p><b>Usage</b> </p>
860                                    
861                                   <p><tt>void glutSpecialUpFunc ( void (*func) 
862 ( int key, int x, int y ) ) ;</tt> </p>
863                                    
864                                   <p><tt>func&nbsp;&nbsp;&nbsp; </tt>The window's
865 new special key release callback function <br>
866                                    <tt>key&nbsp;&nbsp;&nbsp;&nbsp; </tt>The 
867 key whose release triggers the callback <br>
868                                    <tt>x&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
869                                   </tt>The x-coordinate of the mouse relative 
870 to the window at the time the key is released <br>
871                                    <tt>y&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
872                                   </tt>The y-coordinate of the mouse relative 
873 to the window at the time the key is released </p>
874                                    
875                                   <p><b>Description</b> </p>
876                                    
877                                   <p>The&nbsp; "<tt>glutSpecialUpFunc</tt>
878 " function specifies the function that <i>freeglut</i> will call when the 
879 user releases a special key from the keyboard.&nbsp; The callback function 
880 has one argument:&nbsp; the name of the function to be invoked ("called back") 
881 at the time at which the special key is released.&nbsp; The function returns 
882 no value.&nbsp; <i>Freeglut</i> sets the <i>current window</i> to the window 
883 which is active when the callback is invoked.&nbsp; "Special keys" are the 
884 function keys, the arrow keys, the Page Up and Page Down keys, and the Insert 
885 key.&nbsp; The Delete key is considered to be a regular key. <br>
886  &nbsp;&nbsp;&nbsp; Calling "<tt>glutSpecialUpFunc</tt>" with a NULL argument 
887 disables the call to the window's special key release callback. </p>
888                                    
889                                   <p>&nbsp;&nbsp;&nbsp; The "<tt>key</tt>
890 " argument may take one of the following defined constant values: </p>
891                                    
892                                   <ul>
893   <li> <tt>GLUT_KEY_F1, GLUT_KEY_F2, ..., GLUT_KEY_F12</tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
894  - F1 through F12 keys</li>
895    <li> <tt>GLUT_KEY_PAGE_UP, GLUT_KEY_PAGE_DOWN</tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
896  - Page Up and Page Down keys</li>
897    <li> <tt>GLUT_KEY_HOME, GLUT_KEY_END</tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
898  - Home and End keys</li>
899    <li> <tt>GLUT_KEY_LEFT, GLUT_KEY_RIGHT, GLUT_KEY_UP, GLUT_KEY_DOWN</tt>
900   - arrow keys</li>
901    <li> <tt>GLUT_KEY_INSERT</tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
902  - Insert key</li>
903                                      
904                                   </ul>
905   <b>Changes From GLUT</b>                                    
906                                   <p>This function is not implemented in GLUT
907 versions before Version 4.&nbsp; It has been designed to be as close to GLUT
908 as possible.&nbsp; Users who find differences should contact the        
909                           <i>freeglut</i>&nbsp;Programming Consortium  to
910 have them fixed. </p>
911                                    
912                                   <h2> 12.9&nbsp; glutMouseFunc</h2>
913                                       
914                                   <h2> 12.10&nbsp; glutMotionFunc, glutPassiveMotionFunc</h2>
915                                       
916                                   <h2> 12.11&nbsp; glutVisibilityFunc</h2>
917                                       
918                                   <h2> 12.12&nbsp; glutEntryFunc</h2>
919                                       
920                                   <h2> 12.13&nbsp; glutJoystickFunc</h2>
921                                       
922                                   <h2> 12.14&nbsp; glutSpaceballMotionFunc</h2>
923     The "<tt>glutSpaceballMotionFunc</tt>" function is not implemented in 
924                                   <i>freeglut</i>, although the library does 
925 "answer the mail" to the extent that a call to the function will not produce 
926 an error..                                    
927                                   <p><b>Usage</b></p>
928                                    
929                                   <p><tt>void glutSpaceballMotionFunc ( void 
930 (* callback)( int x, int y, int z )</tt><tt> ) ;</tt></p>
931                                    
932                                   <p><b>Description</b></p>
933                                    
934                                   <p>The "<tt>glutSpaceballMotionFunc</tt>
935  " function is not implemented in <i>freeglut</i>. </p>
936                                    
937                                   <p><b>Changes From GLUT</b></p>
938                                    
939                                   <p>GLUT implements this function. </p>
940                                    
941                                   <h2> 12.15&nbsp; glutSpaceballRotateFunc</h2>
942     The "<tt>glutSpaceballRotateFunc</tt>" function is not implemented in 
943                                   <i>freeglut</i>, although the library does 
944 "answer the mail" to the extent that a call to the function will not produce 
945 an error..                                     
946                                   <p><b>Usage</b></p>
947                                    
948                                   <p><tt>void glutSpaceballRotateFunc ( void 
949 (* callback)( int x, int y, int z )</tt><tt> ) ;</tt></p>
950                                    
951                                   <p><b>Description</b></p>
952                                    
953                                   <p>The "<tt>glutSpaceballRotateFunc</tt>
954  " function is not implemented in <i>freeglut</i>. </p>
955                                    
956                                   <p><b>Changes From GLUT</b></p>
957                                    
958                                   <p>GLUT implements this function. </p>
959                                    
960                                   <h2> 12.16&nbsp; glutSpaceballButtonFunc</h2>
961     The "<tt>glutSpaceballButtonFunc</tt>" function is not implemented in 
962                                   <i>freeglut</i>, although the library does 
963 "answer the mail" to the extent that a call to the function will not produce 
964 an error..                                     
965                                   <p><b>Usage</b></p>
966                                    
967                                   <p><tt>void glutSpaceballButtonFunc ( void 
968 (* callback)( int button, int updown )</tt><tt> ) ;</tt></p>
969                                    
970                                   <p><b>Description</b></p>
971                                    
972                                   <p>The "<tt>glutSpaceballButtonFunc</tt>
973  " function is not implemented in <i>freeglut</i>. </p>
974                                    
975                                   <p><b>Changes From GLUT</b></p>
976                                    
977                                   <p>GLUT implements this function. </p>
978                                    
979                                   <h2> 12.17&nbsp; glutButtonBoxFunc</h2>
980     The "<tt>glutSpaceballButtonBoxFunc</tt>" function is not implemented 
981 in <i>freeglut</i>, although the library does "answer the mail" to the extent 
982 that a call to the function will not produce an error..                 
983                    
984                                   <p><b>Usage</b></p>
985                                    
986                                   <p><tt>void glutSpaceballButtonBoxFunc (
987 void (* callback)( int button, int updown )</tt><tt> ) ;</tt></p>
988                                    
989                                   <p><b>Description</b></p>
990                                    
991                                   <p>The "<tt>glutSpaceballButtonBoxFunc</tt>
992  " function is not implemented in <i>freeglut</i>. </p>
993                                    
994                                   <p><b>Changes From GLUT</b></p>
995                                    
996                                   <p>GLUT implements this function. </p>
997                                    
998                                   <h2> 12.18&nbsp; glutDialsFunc</h2>
999     The "<tt>glutDialsFunc</tt>" function is not implemented in <i>freeglut</i>
1000  , although the library does "answer the mail" to the extent that a call
1001 to the function will not produce an error..                             
1002        
1003                                   <p><b>Usage</b></p>
1004                                    
1005                                   <p><tt>void glutDialsFunc ( void (* callback)( 
1006 int dial, int value )</tt><tt> ) ;</tt></p>
1007                                    
1008                                   <p><b>Description</b></p>
1009                                    
1010                                   <p>The "<tt>glutDialsFunc</tt>" function 
1011 is not implemented in <i>freeglut</i>. </p>
1012                                    
1013                                   <p><b>Changes From GLUT</b></p>
1014                                    
1015                                   <p>GLUT implements this function. </p>
1016                                    
1017                                   <h2> 12.19&nbsp; glutTabletMotionFunc</h2>
1018     The "<tt>glutTabletMotionFunc</tt>" function is not implemented in <i>
1019  freeglut</i>, although the library does "answer the mail" to the extent
1020 that a call to the function will not produce an error..                 
1021                     
1022                                   <p><b>Usage</b></p>
1023                                    
1024                                   <p><tt>void glutTabletMotionFunc ( void 
1025 (* callback)( int x, int y )</tt><tt> ) ;</tt></p>
1026                                    
1027                                   <p><b>Description</b></p>
1028                                    
1029                                   <p>The "<tt>glutTabletMotionFunc</tt>" function
1030 is not implemented in <i>freeglut</i>. </p>
1031                                    
1032                                   <p><b>Changes From GLUT</b></p>
1033                                    
1034                                   <p>GLUT implements this function. </p>
1035                                    
1036                                   <h2> 12.20&nbsp; glutTabletButtonFunc</h2>
1037     The "<tt>glutTabletButtonFunc</tt>" function is not implemented in <i>
1038  freeglut</i>, although the library does "answer the mail" to the extent
1039 that a call to the function will not produce an error..                 
1040                    
1041                                   <p><b>Usage</b></p>
1042                                    
1043                                   <p><tt>void glutTabletButtonFunc ( void 
1044 (* callback)( int button, int updown, int x, int y )</tt><tt> ) ;</tt></p>
1045                                    
1046                                   <p><b>Description</b></p>
1047                                    
1048                                   <p>The "<tt>glutTabletButtonFunc</tt>" function
1049 is not implemented in <i>freeglut</i>. </p>
1050                                    
1051                                   <p><b>Changes From GLUT</b></p>
1052                                    
1053                                   <p>GLUT implements this function. </p>
1054                                    
1055                                   <h2> 12.21&nbsp; glutMenuStatusFunc</h2>
1056                                       
1057                                   <h2> 12.22&nbsp; glutWindowStatusFunc</h2>
1058                                       
1059                                   <h1> 13.0&nbsp;<a name="StateSetting"></a>
1060   State Setting and Retrieval Functions</h1>
1061                                       
1062                                   <h2> 13.1&nbsp; glutSetOption</h2>
1063                                       
1064                                   <h2> 13.2&nbsp; glutGet</h2>
1065                                       
1066
1067 <p>
1068 The following state variables may be queried with "<tt>glutGet</tt>".
1069 The returned value is an integer.
1070 </p>
1071
1072 <p>
1073 These queries are with respect to the current window:
1074 </p>
1075
1076 <ul>
1077 <li>GLUT_WINDOW_X - window X position
1078 <li>GLUT_WINDOW_Y - window Y position
1079 <li>GLUT_WINDOW_WIDTH - window width
1080 <li>GLUT_WINDOW_HEIGHT - window height
1081 <li>GLUT_WINDOW_BUFFER_SIZE - number of color or color index bits per pixel
1082 <li>GLUT_WINDOW_STENCIL_SIZE - number of bits per stencil value
1083 <li>GLUT_WINDOW_DEPTH_SIZE - number of bits per depth value
1084 <li>GLUT_WINDOW_RED_SIZE - number of bits per red value
1085 <li>GLUT_WINDOW_GREEN_SIZE - number of bits per green value
1086 <li>GLUT_WINDOW_BLUE_SIZE - number of bits per blue value
1087 <li>GLUT_WINDOW_ALPHA_SIZE - number of bits per alpha value
1088 <li>GLUT_WINDOW_ACCUM_RED_SIZE - number of red bits in the accumulation buffer
1089 <li>GLUT_WINDOW_ACCUM_GREEN_SIZE - number of green bits in the accumulation buffer
1090 <li>GLUT_WINDOW_ACCUM_BLUE_SIZE - number of blue bits in the accumulation buffer
1091 <li>GLUT_WINDOW_ACCUM_ALPHA_SIZE - number of alpha bits in the accumulation buffer
1092 <li>GLUT_WINDOW_DOUBLEBUFFER - 1 if the color buffer is double buffered, 0 otherwise
1093 <li>GLUT_WINDOW_RGBA - 1 if the color buffers are RGB[A], 0 for color index
1094 <li>GLUT_WINDOW_PARENT - parent window ID
1095 <li>GLUT_WINDOW_NUM_CHILDREN - number of child windows
1096 <li>GLUT_WINDOW_COLORMAP_SIZE - number of entries in the window's colormap
1097 <li>GLUT_WINDOW_NUM_SAMPLES - number of samples per pixel if using multisampling
1098 <li>GLUT_WINDOW_STEREO - 1 if the window supports stereo, 0 otherwise
1099 <li>GLUT_WINDOW_CURSOR - current cursor
1100 <li>GLUT_WINDOW_FORMAT_ID - on Windows, return the pixel format number of the current window
1101 </ul>
1102
1103 <p>
1104 These queries do not depend on the current window.
1105 </p>
1106
1107 <ul>
1108 <li>GLUT_SCREEN_WIDTH - width of the screen in pixels
1109 <li>GLUT_SCREEN_HEIGHT - height of the screen in pixels
1110 <li>GLUT_SCREEN_WIDTH_MM - width of the screen in millimeters
1111 <li>GLUT_SCREEN_HEIGHT_MM - height of the screen in millimeters
1112 <li>GLUT_MENU_NUM_ITEMS - number of items in the current menu
1113 <li>GLUT_DISPLAY_MODE_POSSIBLE - return 1 if the current display mode is supported, 0 otherwise
1114 <li>GLUT_INIT_WINDOW_X - X position last set by glutInitWindowPosition
1115 <li>GLUT_INIT_WINDOW_Y - Y position last set by glutInitWindowPosition
1116 <li>GLUT_INIT_WINDOW_WIDTH - width last set by glutInitWindowSize
1117 <li>GLUT_INIT_WINDOW_HEIGHT - height last set by glutInitWindowSize
1118 <li>GLUT_INIT_DISPLAY_MODE - display mode last set by glutInitDisplayMode
1119 <li>GLUT_ELAPSED_TIME - time (in milliseconds) elapsed since glutInit or glutGet(GLUT_ELAPSED_TIME) was first called
1120 <li>GLUT_INIT_STATE - ?
1121 <li>GLUT_VERSION - Return value will be X*10000+Y*100+Z where X is the
1122     major version, Y is the minor version and Z is the patch level.
1123     This query is only supported in <i>freeglut</i> (version 2.0.0 or later).
1124 </ul>
1125
1126
1127                                   <h2> 13.3&nbsp; glutDeviceGet</h2>
1128                                       
1129                                   <h2> 13.4&nbsp; glutGetModifiers</h2>
1130                                       
1131                                   <h2> 13.5&nbsp; glutLayerGet</h2>
1132                                       
1133                                   <h2> 13.6&nbsp; glutExtensionSupported</h2>
1134                                       
1135                                   <h2> 13.7&nbsp; glutGetProcAddress</h2>
1136                                   <p><tt>glutGetProcAddress</tt> returns
1137 a pointer to a named GL or <i>freeglut</i> function. </p>
1138                                   <p><b>Usage</b></p>
1139                                   <p><tt>void *glutGetProcAddress ( const
1140 char *procName ) ;</tt></p>
1141                                   <p><tt>procName&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
1142                                   </tt>Name of an OpenGL or GLUT function. 
1143                                   </p>
1144                                   <p><b>Description</b></p>
1145                                   <p><tt>glutGetProcAddress</tt> is useful
1146 for dealing with OpenGL extensions. If an application calls OpenGL extension
1147 functions directly, that application will only link/run with an OpenGL library
1148 that supports the extension. By using a function pointer returned from glutGetProcAddress(),
1149 the application will avoid this hard dependency and be more portable and interoperate
1150 better with various implementations of OpenGL. </p>
1151                                   <p> Both OpenGL functions and <i>freeglut</i>
1152 functions can be queried with this function. </p>
1153                                   <p><b>Changes From GLUT</b> </p>
1154                                    
1155                                   <p>GLUT does not include this function.
1156                                    </p>
1157                                    
1158                                   <h1> 14.0&nbsp;<a name="FontRendering"></a>
1159   Font Rendering Functions</h1>
1160   <i>Freeglut</i> supports two types of font rendering:&nbsp; bitmap fonts,
1161  which are rendered using the "<tt>glBitmap</tt>" function call, and stroke
1162  fonts, which are rendered as sequences of OpenGL line segments.&nbsp; Because
1163  they are rendered as bitmaps, the bitmap fonts tend to render more quickly
1164  than stroke fonts, but they are less flexible in terms of scaling and rendering.&nbsp;
1165  Bitmap font characters are positioned with calls to the "<tt>glRasterPos*</tt>
1166   " functions while stroke font characters use the OpenGL transformations
1167 to position characters.                                    
1168                                   <p>&nbsp;&nbsp;&nbsp; It should be noted 
1169 that <i>freeglut</i> fonts are similar but not identical to GLUT fonts.&nbsp; 
1170 At the moment, <i>freeglut</i> fonts do not support the "`" (backquote) and 
1171 "|" (vertical line) characters; in their place it renders asterisks. </p>
1172                                    
1173                                   <p>&nbsp;&nbsp;&nbsp; <i>Freeglut</i> supports 
1174 the following bitmap fonts: </p>
1175                                    
1176                                   <ul>
1177   <li> <tt>GLUT_BITMAP_8_BY_13</tt> - A variable-width font with every character
1178  fitting in a rectangle of 13 pixels high by at most 8 pixels wide.</li>
1179    <li> <tt>GLUT_BITMAP_9_BY_15</tt> - A variable-width font with every character
1180  fitting in a rectangle of 15 pixels high by at most 9 pixels wide.</li>
1181    <li> <tt>GLUT_BITMAP_TIMES_ROMAN_10</tt> - A 10-point variable-width Times 
1182 Roman font.</li>
1183    <li> <tt>GLUT_BITMAP_TIMES_ROMAN_24</tt> - A 24-point variable-width Times 
1184 Roman font.</li>
1185    <li> <tt>GLUT_BITMAP_HELVETICA_10</tt> - A 10-point variable-width Helvetica
1186  font.</li>
1187    <li> <tt>GLUT_BITMAP_HELVETICA_12</tt> - A 12-point variable-width Helvetica
1188  font.</li>
1189    <li> <tt>GLUT_BITMAP_HELVETICA_18</tt> - A 18-point variable-width Helvetica
1190  font.</li>
1191                                      
1192                                   </ul>
1193   <i>Freeglut</i> calls "<tt>glRasterPos4v</tt>" to advance the cursor by
1194 the width of a character and to render carriage returns when appropriate.&nbsp;
1195  It does not use any display lists in it rendering in bitmap fonts.     
1196                               
1197                                   <p>&nbsp;&nbsp;&nbsp; <i>Freeglut</i> supports 
1198 the following stroke fonts: </p>
1199                                    
1200                                   <ul>
1201   <li> <tt>GLUT_STROKE_ROMAN</tt> - A proportionally-spaced Roman Simplex 
1202 font</li>
1203    <li> <tt>GLUT_STROKE_MONO_ROMAN</tt> - A fixed-width Roman Simplex font</li>
1204                                      
1205                                   </ul>
1206   <i>Freeglut</i> does not use any display lists in its rendering of stroke
1207  fonts.&nbsp; It calls "<tt>glTranslatef</tt>" to advance the cursor by the 
1208 width of a character and to render carriage returns when appropriate.   
1209                                 
1210                                   <h2> 14.1&nbsp; glutBitmapCharacter</h2>
1211   The "<tt>glutBitmapCharacter</tt>" function renders a single bitmapped
1212 character in the <i>current window</i> using the specified font.        
1213                            
1214                                   <p><b>Usage</b> </p>
1215                                    
1216                                   <p><tt>void glutBitmapCharacter ( void *font,
1217 int character ) ;</tt> </p>
1218                                    
1219                                   <p><tt>font&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1220                                   </tt>The bitmapped font to use in rendering 
1221 the character <br>
1222                                    <tt>character&nbsp;&nbsp; </tt>The ASCII 
1223 code of the character to be rendered </p>
1224                                    
1225                                   <p><b>Description</b> </p>
1226                                    
1227                                   <p>The&nbsp; "<tt>glutBitmapCharacter</tt>
1228   " function renders the given character in the specified bitmap font.&nbsp; 
1229                                   <i>Freeglut</i> automatically sets the necessary
1230 pixel unpack storage modes and restores the existing modes when it has finished.&nbsp;
1231 Before the first call to "<tt>glutBitMapCharacter</tt>  " the application
1232 program should call "<tt>glRasterPos*</tt>" to set the  position of the character
1233 in the window.&nbsp; The "<tt>glutBitmapCharacter</tt> " function advances
1234 the cursor position as part of its call to "<tt>glBitmap</tt> " and so the
1235 application does not need to call "<tt>glRasterPos*</tt>" again  for successive
1236 characters on the same line. </p>
1237                                    
1238                                   <p><b>Changes From GLUT</b> </p>
1239                                    
1240                                   <p>Nonexistent characters are rendered as
1241 asterisks.&nbsp; The rendering position in <i>freeglut</i> is apparently off
1242 from GLUT's position by a few pixels vertically and one or two pixels horizontally.
1243                                   </p>
1244                                    
1245                                   <h2> 14.2&nbsp; glutBitmapString</h2>
1246   The "<tt>glutBitmapString</tt>" function renders a string of bitmapped
1247 characters in the <i>current window</i> using the specified font.       
1248                             
1249                                   <p><b>Usage</b> </p>
1250                                    
1251                                   <p><tt>void glutBitmapString ( void *font, 
1252 char *string ) ;</tt> </p>
1253                                    
1254                                   <p><tt>font&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1255                                   </tt>The bitmapped font to use in rendering 
1256 the character string <br>
1257                                    <tt>string&nbsp;&nbsp;&nbsp; </tt>String 
1258 of characters to be rendered </p>
1259                                    
1260                                   <p><b>Description</b> </p>
1261                                    
1262                                   <p>The&nbsp; "<tt>glutBitmapString</tt>
1263   " function renders the given character string in the specified bitmap font.&nbsp; 
1264                                   <i>Freeglut</i> automatically sets the necessary
1265 pixel unpack storage modes and restores the existing modes when it has finished.&nbsp;
1266 Before calling "<tt>glutBitMapString</tt>" the application program should
1267 call "<tt>glRasterPos*</tt>" to set the position of the string in the window.&nbsp;
1268 The "<tt>glutBitmapString</tt>" function handles carriage returns.&nbsp;
1269 Nonexistent characters are rendered as asterisks. </p>
1270                                    
1271                                   <p><b>Changes From GLUT</b> </p>
1272                                    
1273                                   <p>GLUT does not include this function.
1274                                    </p>
1275                                    
1276                                   <h2> 14.3&nbsp; glutBitmapWidth</h2>
1277   The "<tt>glutBitmapWidth</tt>" function returns the width in pixels of
1278 a single bitmapped character in the specified font.                     
1279               
1280                                   <p><b>Usage</b> </p>
1281                                    
1282                                   <p><tt>int glutBitmapWidth ( void *font, 
1283 int character ) ;</tt> </p>
1284                                    
1285                                   <p><tt>font&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1286                                   </tt>The bitmapped font to use in calculating 
1287 the character width <br>
1288                                    <tt>character&nbsp;&nbsp; </tt>The ASCII 
1289 code of the character </p>
1290                                    
1291                                   <p><b>Description</b> </p>
1292                                    
1293                                   <p>The&nbsp; "<tt>glutBitmapWidth</tt>" 
1294 function returns the width of the given character in the specified bitmap 
1295 font.&nbsp; Because the font is bitmapped, the width is an exact integer.
1296                                    </p>
1297                                    
1298                                   <p><b>Changes From GLUT</b> </p>
1299                                    
1300                                   <p>Nonexistent characters return the width 
1301 of an asterisk. </p>
1302                                    
1303                                   <h2> 14.4&nbsp; glutBitmapLength</h2>
1304   The "<tt>glutBitmapLength</tt>" function returns the width in pixels of
1305 a string of bitmapped characters in the specified font.                 
1306                   
1307                                   <p><b>Usage</b> </p>
1308                                    
1309                                   <p><tt>int glutBitmapLength ( void *font, 
1310 char *string ) ;</tt> </p>
1311                                    
1312                                   <p><tt>font&nbsp;&nbsp;&nbsp; </tt>The bitmapped
1313 font to use in calculating the character width <br>
1314                                    <tt>string&nbsp; </tt>String of characters 
1315 whose width is to be calculated </p>
1316                                    
1317                                   <p><b>Description</b> </p>
1318                                    
1319                                   <p>The&nbsp; "<tt>glutBitmapLength</tt>
1320   " function returns the width in pixels of the given character string in 
1321 the specified bitmap font.&nbsp; Because the font is bitmapped, the width 
1322 is an exact integer:&nbsp; the return value is identical to the sum of the 
1323 character widths returned by a series of calls to "<tt>glutBitmapWidth</tt>
1324 ".&nbsp; The width of nonexistent characters is counted to be the width of 
1325 an asterisk. </p>
1326                                    
1327                                   <p>&nbsp;&nbsp;&nbsp; If the string contains 
1328 one or more carriage returns, <i>freeglut</i> calculates the widths in pixels 
1329 of the lines separately and returns the largest width. </p>
1330                                    
1331                                   <p><b>Changes From GLUT</b> </p>
1332                                    
1333                                   <p>GLUT does not include this function.
1334                                    </p>
1335                                    
1336                                   <h2> 14.5&nbsp; glutBitmapHeight</h2>
1337   The "<tt>glutBitmapHeight</tt>" function returns the height in pixels of
1338  the specified font.                                    
1339                                   <p><b>Usage</b> </p>
1340                                    
1341                                   <p><tt>int glutBitmapHeight ( void *font 
1342 ) ;</tt> </p>
1343                                    
1344                                   <p><tt>font&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1345                                   </tt>The bitmapped font to use in calculating 
1346 the character height </p>
1347                                    
1348                                   <p><b>Description</b> </p>
1349                                    
1350                                   <p>The&nbsp; "<tt>glutBitmapHeight</tt>
1351   " function returns the height of a character in the specified bitmap font.&nbsp; 
1352 Because the font is bitmapped, the height is an exact integer.&nbsp; The fonts
1353 are designed such that all characters have (nominally) the same height.  
1354                                  </p>
1355                                    
1356                                   <p><b>Changes From GLUT</b> </p>
1357                                    
1358                                   <p>GLUT does not include this function.
1359                                    </p>
1360                                    
1361                                   <h2> 14.6&nbsp; glutStrokeCharacter</h2>
1362   The "<tt>glutStrokeCharacter</tt>" function renders a single stroke character
1363  in the <i>current window</i> using the specified font.                 
1364                   
1365                                   <p><b>Usage</b> </p>
1366                                    
1367                                   <p><tt>void glutStrokeCharacter ( void *font,
1368 int character ) ;</tt> </p>
1369                                    
1370                                   <p><tt>font&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1371                                   </tt>The stroke font to use in rendering 
1372 the character <br>
1373                                    <tt>character&nbsp;&nbsp; </tt>The ASCII 
1374 code of the character to be rendered </p>
1375                                    
1376                                   <p><b>Description</b> </p>
1377                                    
1378                                   <p>The&nbsp; "<tt>glutStrokeCharacter</tt>
1379   " function renders the given character in the specified stroke font.&nbsp; 
1380 Before the first call to "<tt>glutStrokeCharacter</tt>" the application program 
1381 should call the OpenGL transformation (positioning and scaling) functions 
1382 to set the position of the character in the window.&nbsp; The "<tt>glutStrokeCharacter</tt>
1383   " function advances the cursor position by a call to "<tt>glTranslatef</tt>
1384   " and so the application does not need to call the OpenGL positioning functions
1385  again for successive characters on the same line. </p>
1386                                    
1387                                   <p><b>Changes From GLUT</b> </p>
1388                                    
1389                                   <p>Nonexistent characters are rendered as
1390 asterisks. </p>
1391                                    
1392                                   <h2> 14.7&nbsp; glutStrokeString</h2>
1393   The "<tt>glutStrokeString</tt>" function renders a string of characters
1394 in the <i>current window</i> using the specified stroke font.           
1395                         
1396                                   <p><b>Usage</b> </p>
1397                                    
1398                                   <p><tt>void glutStrokeString ( void *font, 
1399 char *string ) ;</tt> </p>
1400                                    
1401                                   <p><tt>font&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1402                                   </tt>The stroke font to use in rendering 
1403 the character string <br>
1404                                    <tt>string&nbsp;&nbsp;&nbsp; </tt>String 
1405 of characters to be rendered </p>
1406                                    
1407                                   <p><b>Description</b> </p>
1408                                    
1409                                   <p>The&nbsp; "<tt>glutStrokeString</tt>
1410   " function renders the given character string in the specified stroke font.&nbsp; 
1411 Before calling "<tt>glutStrokeString</tt>" the application program should 
1412 call the OpenGL transformation (positioning and scaling) functions to set 
1413 the position of the string in the window.&nbsp; The "<tt>glutStrokeString</tt>
1414   " function handles carriage returns.&nbsp; Nonexistent characters are rendered 
1415 as asterisks. </p>
1416                                    
1417                                   <p><b>Changes From GLUT</b> </p>
1418                                    
1419                                   <p>GLUT does not include this function.
1420                                    </p>
1421                                    
1422                                   <h2> 14.8&nbsp; glutStrokeWidth</h2>
1423   The "<tt>glutStrokeWidth</tt>" function returns the width in pixels of
1424 a single character in the specified stroke font.                        
1425            
1426                                   <p><b>Usage</b> </p>
1427                                    
1428                                   <p><tt>int glutStrokeWidth ( void *font, 
1429 int character ) ;</tt> </p>
1430                                    
1431                                   <p><tt>font&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1432                                   </tt>The stroke font to use in calculating 
1433 the character width <br>
1434                                    <tt>character&nbsp;&nbsp; </tt>The ASCII 
1435 code of the character </p>
1436                                    
1437                                   <p><b>Description</b> </p>
1438                                    
1439                                   <p>The&nbsp; "<tt>glutStrokeWidth</tt>" 
1440 function returns the width of the given character in the specified stroke 
1441 font.&nbsp; Because the font is a stroke font, the width is actually a floating-point 
1442 number; the function rounds it to the nearest integer for the return value.
1443                                    </p>
1444                                    
1445                                   <p><b>Changes From GLUT</b> </p>
1446                                    
1447                                   <p>Nonexistent characters return the width 
1448 of an asterisk. </p>
1449                                    
1450                                   <h2> 14.9&nbsp; glutStrokeLength</h2>
1451   The "<tt>glutStrokeLength</tt>" function returns the width in pixels of
1452 a string of characters in the specified stroke font.                    
1453                
1454                                   <p><b>Usage</b> </p>
1455                                    
1456                                   <p><tt>int glutStrokeLength ( void *font, 
1457 char *string ) ;</tt> </p>
1458                                    
1459                                   <p><tt>font&nbsp;&nbsp;&nbsp; </tt>The stroke
1460 font to use in calculating the character width <br>
1461                                    <tt>string&nbsp; </tt>String of characters 
1462 whose width is to be calculated </p>
1463                                    
1464                                   <p><b>Description</b> </p>
1465                                    
1466                                   <p>The&nbsp; "<tt>glutStrokeLength</tt>
1467   " function returns the width in pixels of the given character string in 
1468 the specified stroke font.&nbsp; Because the font is a stroke font, the width 
1469 of an individual character is a floating-point number.&nbsp; <i>Freeglut</i>
1470   adds the floating-point widths and rounds the funal result to return the 
1471 integer value.&nbsp; Thus the return value may differ from the sum of the 
1472 character widths returned by a series of calls to "<tt>glutStrokeWidth</tt>
1473   ".&nbsp; The width of nonexistent characters is counted to be the width 
1474 of an asterisk. </p>
1475                                    
1476                                   <p>&nbsp;&nbsp;&nbsp; If the string contains 
1477 one or more carriage returns, <i>freeglut</i> calculates the widths in pixels 
1478 of the lines separately and returns the largest width. </p>
1479                                    
1480                                   <p><b>Changes From GLUT</b> </p>
1481                                    
1482                                   <p>GLUT does not include this function.
1483                                    </p>
1484                                    
1485                                   <h2> 14.10&nbsp; glutStrokeHeight</h2>
1486   The "<tt>glutStrokeHeight</tt>" function returns the height in pixels of
1487  the specified font.                                    
1488                                   <p><b>Usage</b> </p>
1489                                    
1490                                   <p><tt>GLfloat glutStrokeHeight ( void *font
1491 ) ;</tt> </p>
1492                                    
1493                                   <p><tt>font&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1494                                   </tt>The stroke font to use in calculating 
1495 the character height </p>
1496                                    
1497                                   <p><b>Description</b> </p>
1498                                    
1499                                   <p>The&nbsp; "<tt>glutStrokeHeight</tt>
1500   " function returns the height of a character in the specified stroke font.&nbsp; 
1501 The application programmer should note that, unlike the other <i>freeglut</i>
1502   font functions, this one returns a floating-point number.&nbsp; The fonts 
1503 are designed such that all characters have (nominally) the same height. </p>
1504                                    
1505                                   <p><b>Changes From GLUT</b> </p>
1506                                    
1507                                   <p>GLUT does not include this function.
1508                                    </p>
1509                                    
1510                                   <h1> 15.0&nbsp;<a name="GeometricObject"></a>
1511   Geometric Object Rendering Functions</h1>
1512   <i>Freeglut</i> includes eighteen routines for generating easily-recognizable
1513  3-d geometric objects.&nbsp; These routines are effectively the same ones
1514  that are included in the GLUT library, and reflect the functionality available
1515  in the <i>aux</i> toolkit described in the <i>OpenGL Programmer's Guide</i>
1516   .&nbsp; They are included to allow programmers to create with a single
1517 line of code a three-dimensional object which can be used to test a variety
1518 of OpenGL functionality.&nbsp; None of the routines generates a display list 
1519 for the object which it draws.&nbsp; The functions generate normals appropriate 
1520 for lighting but, except for the teapon functions, do not generate texture 
1521 coordinates.                                    
1522                                   <h2> 15.1&nbsp; glutWireSphere, glutSolidSphere</h2>
1523   The "<tt>glutWireSphere</tt>" and "<tt>glutSolidSphere</tt>" functions
1524 draw a wireframe and solid sphere respectively.                         
1525           
1526                                   <p><b>Usage</b> </p>
1527                                    
1528                                   <p><tt>void glutWireSphere ( GLdouble dRadius, 
1529 GLint slices, GLint stacks ) ;</tt> </p>
1530                                    
1531                                   <p><tt>void glutSolidSphere ( GLdouble dRadius,
1532 GLint slices, GLint stacks ) ;</tt> </p>
1533                                    
1534                                   <p><tt>dRadius&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1535                                   </tt>The desired radius of the sphere </p>
1536                                    
1537                                   <p><tt>slices&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1538                                   </tt>The desired number of slices (divisions 
1539 in the longitudinal direction) in the sphere </p>
1540                                    
1541                                   <p><tt>stacks&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1542                                   </tt>The desired number of stacks (divisions 
1543 in the latitudinal direction) in the sphere.&nbsp; The number of points in 
1544 this direction, including the north and south poles, is <tt>stacks+1</tt>
1545   </p>
1546                                    
1547                                   <p><b>Description</b> </p>
1548                                    
1549                                   <p>The "<tt>glutWireSphere</tt>" and "<tt>
1550   glutSolidSphere</tt>" functions render a sphere centered at the origin
1551 of the modeling coordinate system.&nbsp; The north and south poles of the
1552 sphere are on the positive and negative Z-axes respectively and the prime
1553 meridian crosses the positive X-axis. </p>
1554                                    
1555                                   <p><b>Changes From GLUT</b> </p>
1556                                    
1557                                   <p>None that we know of. </p>
1558                                    
1559                                   <h2> 15.2&nbsp; glutWireTorus, glutSolidTorus</h2>
1560   The "<tt>glutWireTorus</tt>" and "<tt>glutSolidTorus</tt>" functions draw
1561  a wireframe and solid torus (donut shape) respectively.                
1562                    
1563                                   <p><b>Usage</b> </p>
1564                                    
1565                                   <p><tt>void glutWireTorus ( GLdouble dInnerRadius, 
1566 GLdouble dOuterRadius, GLint nSides, GLint nRings ) ;</tt> </p>
1567                                    
1568                                   <p><tt>void glutSolidTorus ( GLdouble dInnerRadius, 
1569 GLdouble dOuterRadius, GLint nSides, GLint nRings ) ;</tt> </p>
1570                                    
1571                                   <p><tt>dInnerRadius&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1572                                   </tt>The desired inner radius of the torus, 
1573 from the origin to the circle defining the centers of the outer circles </p>
1574                                    
1575                                   <p><tt>dOuterRadius&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1576                                   </tt>The desired outer radius of the torus, 
1577 from the center of the outer circle to the actual surface of the torus </p>
1578                                    
1579                                   <p><tt>nSides&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1580                                   </tt>The desired number of segments in a
1581 single outer circle of the torus </p>
1582                                    
1583                                   <p><tt>nRings&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1584                                   </tt>The desired number of outer circles 
1585 around the origin of the torus </p>
1586                                    
1587                                   <p><b>Description</b> </p>
1588                                    
1589                                   <p>The "<tt>glutWireTorus</tt>" and "<tt>
1590   glutSolidTorus</tt>" functions render a torus centered at the origin of 
1591 the modeling coordinate system.&nbsp; The torus is circularly symmetric about 
1592 the Z-axis and starts at the positive X-axis. </p>
1593                                    
1594                                   <p><b>Changes From GLUT</b> </p>
1595                                    
1596                                   <p>None that we know of. </p>
1597                                    
1598                                   <h2> 15.3&nbsp; glutWireCone, glutSolidCone</h2>
1599   The "<tt>glutWireCone</tt>" and "<tt>glutSolidCone</tt>" functions draw
1600 a wireframe and solid cone respectively.                                
1601    
1602                                   <p><b>Usage</b> </p>
1603                                    
1604                                   <p><tt>void glutWireCone ( GLdouble base, 
1605 GLdouble height, GLint slices, GLint stacks ) ;</tt> </p>
1606                                    
1607                                   <p><tt>void glutSolidCone ( GLdouble base, 
1608 GLdouble height, GLint slices, GLint stacks ) ;</tt> </p>
1609                                    
1610                                   <p><tt>base&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1611                                   </tt>The desired radius of the base of the
1612 cone </p>
1613                                    
1614                                   <p><tt>height&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1615                                   </tt>The desired height of the cone </p>
1616                                    
1617                                   <p><tt>slices&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1618                                   </tt>The desired number of slices around 
1619 the base of the cone </p>
1620                                    
1621                                   <p><tt>stacks&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1622                                   </tt>The desired number of segments between 
1623 the base and the tip of the cone (the number of points, including the tip, 
1624 is <tt>stacks + 1</tt>) </p>
1625                                    
1626                                   <p><b>Description</b> </p>
1627                                    
1628                                   <p>The "<tt>glutWireCone</tt>" and "<tt>
1629   glutSolidCone</tt>" functions render a right circular cone with a base
1630 centered at the origin and in the X-Y plane and its tip on the positive Z-axis.&nbsp; 
1631 The wire cone is rendered with triangular elements. </p>
1632                                    
1633                                   <p><b>Changes From GLUT</b> </p>
1634                                    
1635                                   <p>None that we know of. </p>
1636                                    
1637                                   <h2> 15.4&nbsp; glutWireCube, glutSolidCube</h2>
1638   The "<tt>glutWireCube</tt>" and "<tt>glutSolidCube</tt>" functions draw
1639 a wireframe and solid cube respectively.                                
1640    
1641                                   <p><b>Usage</b> </p>
1642                                    
1643                                   <p><tt>void glutWireCube ( GLdouble dSize 
1644 ) ;</tt> </p>
1645                                    
1646                                   <p><tt>void glutSolidCube ( GLdouble dSize 
1647 ) ;</tt> </p>
1648                                    
1649                                   <p><tt>dSize&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1650                                   </tt>The desired length of an edge of the 
1651 cube </p>
1652                                    
1653                                   <p><b>Description</b> </p>
1654                                    
1655                                   <p>The "<tt>glutWireCube</tt>" and "<tt>
1656   glutSolidCube</tt>" functions render a cube of the desired size, centered 
1657 at the origin.&nbsp; Its faces are normal to the coordinate directions. </p>
1658                                    
1659                                   <p><b>Changes From GLUT</b> </p>
1660                                    
1661                                   <p>None that we know of. </p>
1662                                    
1663                                   <h2> 15.5&nbsp; glutWireTetrahedron, glutSolidTetrahedron</h2>
1664   The "<tt>glutWireTetrahedron</tt>" and "<tt>glutSolidTetrahedron</tt>"
1665 functions draw a wireframe and solid tetrahedron (four-sided Platonic solid)
1666 respectively.                                    
1667                                   <p><b>Usage</b> </p>
1668                                    
1669                                   <p><tt>void glutWireTetrahedron ( void )
1670 ;</tt> </p>
1671                                    
1672                                   <p><tt>void glutSolidTetrahedron ( void 
1673 ) ;</tt> </p>
1674                                    
1675                                   <p><b>Description</b> </p>
1676                                    
1677                                   <p>The "<tt>glutWireTetrahedron</tt>" and 
1678 "<tt>glutSolidTetrahedron</tt>" functions render a tetrahedron whose corners 
1679 are each a distance of one from the origin.&nbsp; The length of each side 
1680 is 2/3 sqrt(6).&nbsp; One corner is on the positive X-axis and another is 
1681 in the X-Y plane with a positive Y-coordinate. </p>
1682                                    
1683                                   <p><b>Changes From GLUT</b> </p>
1684                                    
1685                                   <p>None that we know of. </p>
1686                                    
1687                                   <h2> 15.6&nbsp; glutWireOctahedron, glutSolidOctahedron</h2>
1688   The "<tt>glutWireOctahedron</tt>" and "<tt>glutSolidOctahedron</tt>" functions
1689  draw a wireframe and solid octahedron (eight-sided Platonic solid) respectively.
1690                                    
1691                                   <p><b>Usage</b> </p>
1692                                    
1693                                   <p><tt>void glutWireOctahedron ( void ) 
1694 ;</tt> </p>
1695                                    
1696                                   <p><tt>void glutSolidOctahedron ( void )
1697 ;</tt> </p>
1698                                    
1699                                   <p><b>Description</b> </p>
1700                                    
1701                                   <p>The "<tt>glutWireOctahedron</tt>" and 
1702 "<tt>glutSolidOctahedron</tt>" functions render an octahedron whose corners 
1703 are each a distance of one from the origin.&nbsp; The length of each side 
1704 is sqrt(2).&nbsp; The corners are on the positive and negative coordinate 
1705 axes. </p>
1706                                    
1707                                   <p><b>Changes From GLUT</b> </p>
1708                                    
1709                                   <p>None that we know of. </p>
1710                                    
1711                                   <h2> 15.7&nbsp; glutWireDodecahedron, glutSolidDodecahedron</h2>
1712   The "<tt>glutWireDodecahedron</tt>" and "<tt>glutSolidDodecahedron</tt>
1713 "  functions draw a wireframe and solid dodecahedron (twelve-sided Platonic
1714 solid) respectively.                                    
1715                                   <p><b>Usage</b> </p>
1716                                    
1717                                   <p><tt>void glutWireDodecahedron ( void 
1718 ) ;</tt> </p>
1719                                    
1720                                   <p><tt>void glutSolidDodecahedron ( void 
1721 ) ;</tt> </p>
1722                                    
1723                                   <p><b>Description</b> </p>
1724                                    
1725                                   <p>The "<tt>glutWireDodecahedron</tt>" and
1726 "<tt>glutSolidDodecahedron</tt>" functions render a dodecahedron whose corners
1727 are each a distance of sqrt(3) from the origin.&nbsp; The length of each
1728 side is sqrt(5)-1.&nbsp; There are twenty corners; interestingly enough,
1729 eight of them coincide with the corners of a cube with sizes of length 2.
1730                                   </p>
1731                                    
1732                                   <p><b>Changes From GLUT</b> </p>
1733                                    
1734                                   <p>None that we know of. </p>
1735                                    
1736                                   <h2> 15.8&nbsp; glutWireIcosahedron, glutSolidIcosahedron</h2>
1737   The "<tt>glutWireIcosahedron</tt>" and "<tt>glutSolidIcosahedron</tt>"
1738 functions draw a wireframe and solid icosahedron (twenty-sided Platonic solid)
1739 respectively.                                    
1740                                   <p><b>Usage</b> </p>
1741                                    
1742                                   <p><tt>void glutWireIcosahedron ( void )
1743 ;</tt> </p>
1744                                    
1745                                   <p><tt>void glutSolidIcosahedron ( void 
1746 ) ;</tt> </p>
1747                                    
1748                                   <p><b>Description</b> </p>
1749                                    
1750                                   <p>The "<tt>glutWireIcosahedron</tt>" and 
1751 "<tt>glutSolidIcosahedron</tt>" functions render an icosahedron whose corners 
1752 are each a unit distance from the origin.&nbsp; The length of each side is 
1753 slightly greater than one.&nbsp; Two of the corners lie on the positive and 
1754 negative X-axes. </p>
1755                                    
1756                                   <p><b>Changes From GLUT</b> </p>
1757                                    
1758                                   <p>None that we know of. </p>
1759                                    
1760                                   <h2> 15.7&nbsp; glutWireRhombicDodecahedron, 
1761 glutSolidRhombicDodecahedron</h2>
1762   The "<tt>glutWireRhombicDodecahedron</tt>" and "<tt>glutSolidRhombicDodecahedron</tt>
1763   " functions draw a wireframe and solid rhombic dodecahedron (twelve-sided
1764  semi-regular solid) respectively.                                    
1765                                   <p><b>Usage</b> </p>
1766                                    
1767                                   <p><tt>void glutWireRhombicDodecahedron 
1768 ( void ) ;</tt> </p>
1769                                    
1770                                   <p><tt>void glutSolidRhombicDodecahedron 
1771 ( void ) ;</tt> </p>
1772                                    
1773                                   <p><b>Description</b> </p>
1774                                    
1775                                   <p>The "<tt>glutWireRhombicDodecahedron</tt>
1776   " and "<tt>glutSolidRhombicDodecahedron</tt>" functions render a rhombic 
1777 dodecahedron whose corners are at most a distance of one from the origin.&nbsp; 
1778 The rhombic dodecahedron has faces which are identical rhombuses (rhombi?) 
1779 but which have some vertices at which three faces meet and some vertices at
1780 which four faces meet.&nbsp; The length of each side is sqrt(3)/2.&nbsp; Vertices
1781 at which four faces meet are found at (0, 0, <u>+</u>1) and (<u>  +</u>sqrt(2)/2,
1782                                   <u>+</u>sqrt(2)/2, 0). </p>
1783                                    
1784                                   <p><b>Changes From GLUT</b> </p>
1785                                    
1786                                   <p>GLUT does not include these functions.
1787                                    </p>
1788                                    
1789                                   <h2> 15.10&nbsp; glutWireTeapot, glutSolidTeapot</h2>
1790   The "<tt>glutWireTeapot</tt>" and "<tt>glutSolidTeapot</tt>" functions
1791 draw a wireframe and solid teapot respectively.                         
1792           
1793                                   <p><b>Usage</b> </p>
1794                                    
1795                                   <p><tt>void glutWireTeapot ( GLdouble dSize 
1796 ) ;</tt> </p>
1797                                    
1798                                   <p><tt>void glutSolidTeapot ( GLdouble dSize
1799 ) ;</tt> </p>
1800                                    
1801                                   <p><tt>dSize&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
1802                                   </tt>The desired size of the teapot </p>
1803                                    
1804                                   <p><b>Description</b> </p>
1805                                    
1806                                   <p>The "<tt>glutWireTeapot</tt>" and "<tt>
1807   glutSolidTeapot</tt>" functions render a teapot of the desired size, centered 
1808 at the origin.&nbsp; This is the famous OpenGL teapot [add reference]. </p>
1809                                    
1810                                   <p><b>Changes From GLUT</b> </p>
1811                                    
1812                                   <p>None that we know of. </p>
1813                                    
1814                                   <h1> 16.0&nbsp;<a name="GameMode"></a>
1815   Game Mode Functions</h1>
1816                                       
1817                                   <h2> 16.1&nbsp; glutGameModeString</h2>
1818                                       
1819                                   <h2> 16.2&nbsp; glutEnterGameMode, glutLeaveGameMode</h2>
1820                                       
1821                                   <h2> 16.3&nbsp; glutGameModeGet</h2>
1822                                       
1823                                   <h1> 17.0&nbsp;<a name="VideoResize"></a>
1824   Video Resize Functions</h1>
1825                                       
1826                                   <h2> 17.1&nbsp; glutVideoResizeGet</h2>
1827                                       
1828                                   <h2> 17.2&nbsp; glutSetupVideoResizing, 
1829 glutStopVideoResizing</h2>
1830                                       
1831                                   <h2> 17.3&nbsp; glutVideoResize</h2>
1832                                       
1833                                   <h2> 17.4&nbsp; glutVideoPan</h2>
1834                                       
1835                                   <h1> 18.0&nbsp;<a name="ColorMap"></a>
1836   Color Map Functions</h1>
1837                                       
1838                                   <h2> 18.1&nbsp; glutSetColor, glutGetColor</h2>
1839                                       
1840                                   <h2> 18.2&nbsp; glutCopyColormap</h2>
1841                                       
1842                                   <h1> 19.0&nbsp;<a name="Miscellaneous"></a>
1843   Miscellaneous Functions</h1>
1844                                       
1845                                   <h2> 19.1&nbsp; glutIgnoreKeyRepeat, glutSetKeyRepeat</h2>
1846                                       
1847                                   <h2> 19.2&nbsp; glutForceJoystickFunc</h2>
1848                                       
1849                                   <h2> 19.3&nbsp; glutReportErrors</h2>
1850                                       
1851                                   <h1> 20.0&nbsp;<a name="UsageNotes"></a>
1852   Usage Notes</h1>
1853                                       
1854                                   <p> The following environment variables
1855 are recognized by <i>freeglut</i>: </p>
1856                                   <ul>
1857                                     <li>DISPLAY - specifies a display name.<br>
1858                                     </li>
1859                                     <li>GLUT_FPS - specifies a time interval
1860 (in milliseconds) for reporting framerate messages to stderr.  For example,
1861 if FREEGLUT_FPS is set to 5000, every 5 seconds a message will be printed
1862 to stderr showing the current frame rate.  The frame rate is measured by counting
1863 the number of times glutSwapBuffers() is called over the time interval.</li>
1864                                     <li>GLUT_ICON - specifies the icon that
1865 goes in the upper left-hand corner of the <i>freeglut</i><i> </i>windows </li>
1866                                   </ul>
1867                                   <h1> 21.0&nbsp;<a name="ImplementationNotes"></a>
1868   Implementation Notes</h1>
1869                                       
1870 <h1> 22.0&nbsp;<a name="GLUT_State"></a>
1871 GLUT State</h1>
1872                                       
1873 <h1> 23.0&nbsp;<a name="Freeglut.h_Header"></a>
1874 "freeglut.h" Header File</h1>
1875                                       
1876
1877 <p>
1878 Application programmers who are porting their GLUT programs to <i>freeglut</i> may continue
1879 to include <tt>&lt;GL/glut.h&gt;</tt> in their programs.
1880 Programs which use the <i>freeglut</i>-specific extensions to GLUT should include
1881 <tt>&lt;GL/freeglut.h&gt;</tt>.  One possible arrangement is as follows:
1882 </p>
1883
1884 <pre>
1885 #ifdef FREEGLUT
1886 #include &lt;GL/freeglut_ext.h&gt;
1887 #else
1888 #include &lt;GL/glut.h&gt;
1889 #endif
1890 </pre>
1891
1892 <p>
1893 Compile-time <i>freeglut</i> version testing can be done as follows:
1894 </p>
1895
1896 <pre>
1897 #ifdef FREEGLUT_VERSION_2_0
1898   code specific to freeglut 2.0 or later here
1899 #endif
1900 </pre>
1901
1902 <p>
1903 In future releases, FREEGLUT_VERSION_2_1, FREEGLUT_VERSION_2_2, etc will
1904 be defined.  This scheme mimics OpenGL conventions.
1905 </p>
1906
1907 <p>
1908 The <i>freeglut</i> version can be queried at runtime by calling
1909 glutGet(GLUT_VERSION).
1910 The result will be X*10000+Y*100+Z where X is the major version, Y is the
1911 minor version and Z is the patch level.
1912 </p>
1913 <p>
1914 This may be used as follows:
1915 </p>
1916
1917 <pre>
1918 if (glutGet(GLUT_VERSION) < 20001) {
1919     printf("Sorry, you need freeglut version 2.0.1 or later to run this program.\n");
1920     exit(1);
1921 }
1922 </pre>
1923
1924
1925
1926 <h1> 24.0&nbsp;<a name="References"></a>
1927 References</h1>
1928                                       
1929 <h1> 25.0&nbsp;<a name="Index"></a>
1930 Index</h1>
1931 &nbsp;                                    
1932 <p>&nbsp; <br>
1933  &nbsp; <br>
1934  &nbsp; <br>
1935  &nbsp; <br>
1936  &nbsp; <br>
1937  &nbsp; <br>
1938  &nbsp; <br>
1939  &nbsp; <br>
1940  &nbsp; <br>
1941  &nbsp; <br>
1942  &nbsp; <br>
1943  &nbsp; <br>
1944  &nbsp; <br>
1945  &nbsp; <br>
1946  &nbsp; <br>
1947  &nbsp; <br>
1948  &nbsp; <br>
1949  &nbsp; <br>
1950  &nbsp; <br>
1951  &nbsp; <br>
1952  &nbsp; <br>
1953  &nbsp; <br>
1954  &nbsp; </p>
1955                                    
1956                                   </body>
1957                                   </html>