1 /**************************************************************************
2 * GLUTmain.c -- top level sim routines
4 * Written by Curtis Olson for OpenGL, started May 1997.
6 * Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of the
11 * License, or (at your option) any later version.
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 * (Log is kept at end of this file)
24 **************************************************************************/
32 #include "../XGL/xgl.h"
39 #include "../Include/constants.h"
40 #include "../Include/general.h"
42 #include "../Aircraft/aircraft.h"
43 #include "../Cockpit/cockpit.h"
44 #include "../Joystick/joystick.h"
45 #include "../Math/fg_geodesy.h"
46 #include "../Math/mat3.h"
47 #include "../Math/polar.h"
48 #include "../Scenery/mesh.h"
49 #include "../Scenery/scenery.h"
50 #include "../Time/fg_time.h"
51 #include "../Time/fg_timer.h"
52 #include "../Time/sunpos.h"
53 #include "../Weather/weather.h"
56 /* This is a record containing global housekeeping information */
57 struct fgGENERAL general;
60 static GLfloat win_ratio = 1.0;
63 static GLfloat fgFogColor[4] = {0.65, 0.65, 0.85, 1.0};
66 /* pointer to scenery structure */
67 /* static GLint scenery, runway; */
74 /* Yet another hack. This one used by the HUD code. Michele */
78 /**************************************************************************
79 * fgInitVisuals() -- Initialize various GL/view parameters
80 **************************************************************************/
82 static void fgInitVisuals() {
87 l = &cur_light_params;
91 xglEnable( GL_DEPTH_TEST );
92 /* xglFrontFace(GL_CW); */
93 xglEnable( GL_CULL_FACE );
95 /* xglDisable( GL_DITHER ); */
97 /* If enabled, normal vectors specified with glNormal are scaled
98 to unit length after transformation. See glNormal. */
99 xglEnable( GL_NORMALIZE );
101 xglEnable( GL_LIGHTING );
102 xglEnable( GL_LIGHT0 );
103 xglLightfv( GL_LIGHT0, GL_POSITION, l->sun_vec );
105 xglShadeModel( GL_FLAT ); /* xglShadeModel( GL_SMOOTH ); */
108 xglFogi (GL_FOG_MODE, GL_LINEAR);
109 /* xglFogf (GL_FOG_START, 1.0); */
110 xglFogf (GL_FOG_END, w->visibility);
111 xglFogfv (GL_FOG_COLOR, fgFogColor);
112 /* xglFogf (GL_FOG_DENSITY, w->visibility); */
113 /* xglHint (GL_FOG_HINT, GL_FASTEST); */
115 /* initial screen color */
116 xglClearColor(0.0, 0.0, 0.0, 1.0);
120 /**************************************************************************
121 * Update the view volume, position, and orientation
122 **************************************************************************/
124 static void fgUpdateViewParams() {
130 double x_2, x_4, x_8, x_10;
131 double light, ambient, diffuse, sky_brightness;
132 /* if the 4th field is 0.0, this specifies a direction ... */
133 /* clear color (sky) */
134 GLfloat sky_color[4] = {0.60, 0.60, 0.90, 1.0};
135 GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
137 f = ¤t_aircraft.flight;
138 l = &cur_light_params;
139 t = &cur_time_params;
144 /* Tell GL we are about to modify the projection parameters */
145 xglMatrixMode(GL_PROJECTION);
147 gluPerspective(55.0, 1.0/win_ratio, 1.0, 200000.0);
149 xglMatrixMode(GL_MODELVIEW);
152 /* set up our view volume */
153 gluLookAt(v->view_pos.x, v->view_pos.y, v->view_pos.z,
154 v->view_pos.x + v->view_forward[0],
155 v->view_pos.y + v->view_forward[1],
156 v->view_pos.z + v->view_forward[2],
157 v->view_up[0], v->view_up[1], v->view_up[2]);
159 /* set the sun position */
160 xglLightfv( GL_LIGHT0, GL_POSITION, l->sun_vec );
162 /* calculate lighting parameters based on sun's relative angle to
164 /* ya kind'a have to plot this to see the magic */
166 /* x = t->sun_angle^8 */
167 x_2 = l->sun_angle * l->sun_angle;
172 light = pow(1.1, -x_10 / 30.0);
173 ambient = 0.3 * light;
174 diffuse = 0.9 * light;
176 sky_brightness = 0.85 * pow(1.2, -x_8 / 20.0) + 0.15;
178 /* sky_brightness = 0.15; */ /* to force a dark sky (for testing) */
180 if ( ambient < 0.1 ) { ambient = 0.1; }
181 if ( diffuse < 0.0 ) { diffuse = 0.0; }
183 if ( sky_brightness < 0.0 ) { sky_brightness = 0.0; }
185 l->scene_ambient[0] = white[0] * ambient;
186 l->scene_ambient[1] = white[1] * ambient;
187 l->scene_ambient[2] = white[2] * ambient;
189 l->scene_diffuse[0] = white[0] * diffuse;
190 l->scene_diffuse[1] = white[1] * diffuse;
191 l->scene_diffuse[2] = white[2] * diffuse;
193 /* set lighting parameters */
194 xglLightfv(GL_LIGHT0, GL_AMBIENT, l->scene_ambient );
195 xglLightfv(GL_LIGHT0, GL_DIFFUSE, l->scene_diffuse );
198 l->scene_fog[0] = fgFogColor[0] * (ambient + diffuse);
199 l->scene_fog[1] = fgFogColor[1] * (ambient + diffuse);
200 l->scene_fog[2] = fgFogColor[2] * (ambient + diffuse);
201 l->scene_fog[3] = fgFogColor[3];
202 xglFogfv (GL_FOG_COLOR, l->scene_fog);
205 l->scene_clear[0] = sky_color[0] * sky_brightness;
206 l->scene_clear[1] = sky_color[1] * sky_brightness;
207 l->scene_clear[2] = sky_color[2] * sky_brightness;
208 l->scene_clear[3] = sky_color[3];
210 xglClearColor(l->scene_clear[0], l->scene_clear[1],
211 l->scene_clear[2], l->scene_clear[3]);
215 /**************************************************************************
216 * Update all Visuals (redraws anything graphics related)
217 **************************************************************************/
219 static void fgUpdateVisuals( void ) {
220 /* update view volume parameters */
221 fgUpdateViewParams();
223 xglClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
225 /* Tell GL we are switching to model view parameters */
226 xglMatrixMode(GL_MODELVIEW);
227 /* xglLoadIdentity(); */
232 /* draw astronomical objects */
245 /**************************************************************************
246 * Update internal time dependent calculations (i.e. flight model)
247 **************************************************************************/
249 void fgUpdateTimeDepCalcs(int multi_loop) {
255 f = ¤t_aircraft.flight;
256 t = &cur_time_params;
259 /* update the flight model */
260 if ( multi_loop < 0 ) {
261 multi_loop = DEFAULT_MULTILOOP;
264 /* printf("updating flight model x %d\n", multi_loop); */
265 fgFlightModelUpdate(FG_LARCSIM, f, multi_loop);
267 /* refresh shared sun position and sun_vec */
268 fgUpdateSunPos(scenery.center);
270 /* update the view angle */
271 for ( i = 0; i < multi_loop; i++ ) {
272 if ( fabs(v->goal_view_offset - v->view_offset) < 0.05 ) {
273 v->view_offset = v->goal_view_offset;
276 /* move v->view_offset towards v->goal_view_offset */
277 if ( v->goal_view_offset > v->view_offset ) {
278 if ( v->goal_view_offset - v->view_offset < FG_PI ) {
279 v->view_offset += 0.01;
281 v->view_offset -= 0.01;
284 if ( v->view_offset - v->goal_view_offset < FG_PI ) {
285 v->view_offset -= 0.01;
287 v->view_offset += 0.01;
290 if ( v->view_offset > FG_2PI ) {
291 v->view_offset -= FG_2PI;
292 } else if ( v->view_offset < 0 ) {
293 v->view_offset += FG_2PI;
300 void fgInitTimeDepCalcs() {
301 /* initialize timer */
304 fgTimerInit( 1.0 / DEFAULT_TIMER_HZ, fgUpdateTimeDepCalcs );
310 /**************************************************************************
311 * Scenery management routines
312 **************************************************************************/
314 /* static void fgSceneryInit_OLD() { */
316 /* scenery = fgSceneryCompile_OLD();
317 runway = fgRunwayHack_OLD(0.69, 53.07);
321 /* create the scenery */
322 /* GLint fgSceneryCompile_OLD() {
325 scenery = mesh2GL(mesh_ptr_OLD);
331 /* hack in a runway */
332 /* GLint fgRunwayHack_OLD(double width, double length) {
333 static GLfloat concrete[4] = { 0.5, 0.5, 0.5, 1.0 };
334 static GLfloat line[4] = { 0.9, 0.9, 0.9, 1.0 };
337 float line_len, line_width_2, cur_pos;
339 runway = xglGenLists(1);
340 xglNewList(runway, GL_COMPILE);
343 /* xglBegin(GL_POLYGON);
344 xglMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, concrete );
345 xglNormal3f(0.0, 0.0, 1.0);
347 xglVertex3d( 0.0, -width/2.0, 0.0);
348 xglVertex3d( 0.0, width/2.0, 0.0);
349 xglVertex3d(length, width/2.0, 0.0);
350 xglVertex3d(length, -width/2.0, 0.0);
353 /* draw center line */
354 /* xglMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, line );
355 line_len = length / ( 2 * num_lines + 1);
356 printf("line_len = %.3f\n", line_len);
359 for ( i = 0; i < num_lines; i++ ) {
360 xglBegin(GL_POLYGON);
361 xglVertex3d( cur_pos, -line_width_2, 0.005);
362 xglVertex3d( cur_pos, line_width_2, 0.005);
364 xglVertex3d( cur_pos, line_width_2, 0.005);
365 xglVertex3d( cur_pos, -line_width_2, 0.005);
376 /* draw the scenery */
377 /*static void fgSceneryDraw_OLD() {
378 static float z = 32.35;
382 xglCallList(scenery);
384 printf("*** Drawing runway at %.2f\n", z);
386 xglTranslatef( -398391.28, 120070.41, 32.35);
387 xglRotatef(170.0, 0.0, 0.0, 1.0);
394 /* What should we do when we have nothing else to do? How about get
395 * ready for the next move and update the display? */
396 static void fgMainLoop( void ) {
397 static int remainder = 0;
398 int elapsed, multi_loop;
402 struct fgAIRCRAFT *a;
406 a = ¤t_aircraft;
408 t = &cur_time_params;
414 /* fgJoystickRead( &joy_x, &joy_y, &joy_b1, &joy_b2 );
415 printf( "Joystick X %f Y %f B1 %d B2 %d\n",
416 joy_x, joy_y, joy_b1, joy_b2 );
418 fgAileronSet( joy_x ); */
420 /* update the weather for our current position */
421 fgWeatherUpdate(FG_Longitude * RAD_TO_ARCSEC,
422 FG_Latitude * RAD_TO_ARCSEC,
423 FG_Altitude * FEET_TO_METER);
425 /* Calculate model iterations needed */
426 elapsed = fgGetTimeInterval();
427 printf("Time interval is = %d, previous remainder is = %d\n", elapsed,
429 printf("--> Frame rate is = %.2f\n", 1000.0 / (float)elapsed);
430 elapsed += remainder;
432 multi_loop = ((float)elapsed * 0.001) * DEFAULT_MODEL_HZ;
433 remainder = elapsed - ((multi_loop*1000) / DEFAULT_MODEL_HZ);
434 printf("Model iterations needed = %d, new remainder = %d\n", multi_loop,
437 if ( ! use_signals ) {
439 fgUpdateTimeDepCalcs(multi_loop);
442 /* I'm just sticking this here for now, it should probably move
444 cur_elev = mesh_altitude(FG_Longitude * RAD_TO_ARCSEC,
445 FG_Latitude * RAD_TO_ARCSEC);
446 printf("Ground elevation is %.2f meters here.\n", cur_elev);
447 /* FG_Runway_altitude = cur_elev * METER_TO_FEET; */
449 if ( FG_Altitude * FEET_TO_METER < cur_elev + 3.758099) {
450 /* set this here, otherwise if we set runway height above our
451 current height we get a really nasty bounce. */
452 FG_Runway_altitude = FG_Altitude - 3.758099;
454 /* now set aircraft altitude above ground */
455 FG_Altitude = cur_elev * METER_TO_FEET + 3.758099;
456 printf("<*> resetting altitude to %.0f meters\n",
457 FG_Altitude * FEET_TO_METER);
460 fgAircraftOutputCurrent(a);
467 /**************************************************************************
468 * Handle new window size or exposure
469 **************************************************************************/
471 static void fgReshape( int width, int height ) {
472 /* Do this so we can call fgReshape(0,0) ourselves without having to know
473 * what the values of width & height are. */
474 if ( (height > 0) && (width > 0) ) {
475 win_ratio = (GLfloat) height / (GLfloat) width;
478 /* Inform gl of our view window size */
479 xglViewport(0, 0, (GLint)width, (GLint)height);
481 fgUpdateViewParams();
483 xglClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
487 /**************************************************************************
489 **************************************************************************/
491 int main( int argc, char *argv[] ) {
494 f = ¤t_aircraft.flight;
496 printf("Flight Gear: prototype version %s\n\n", VERSION);
498 /**********************************************************************
499 * Initialize the Window/Graphics environment.
500 **********************************************************************/
503 /* initialize GLUT */
504 xglutInit(&argc, argv);
506 /* Define Display Parameters */
507 xglutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
509 /* Define initial window size */
510 xglutInitWindowSize(640, 480);
512 /* Initialize windows */
513 xglutCreateWindow("Flight Gear");
516 /* This is the general house keeping init routine */
519 /* This is the top level init routine which calls all the other
520 * subsystem initialization routines. If you are adding a
521 * subsystem to flight gear, its initialization call should
522 * located in this routine.*/
525 /* setup view parameters, only makes GL calls */
529 /* init timer routines, signals, etc. Arrange for an alarm
530 signal to be generated, etc. */
531 fgInitTimeDepCalcs();
534 /**********************************************************************
535 * Initialize the Event Handlers.
536 **********************************************************************/
539 /* call fgReshape() on window resizes */
540 xglutReshapeFunc( fgReshape );
542 /* call key() on keyboard event */
543 xglutKeyboardFunc( GLUTkey );
544 glutSpecialFunc( GLUTspecialkey );
546 /* call fgMainLoop() whenever there is nothing else to do */
547 xglutIdleFunc( fgMainLoop );
550 xglutDisplayFunc( fgUpdateVisuals );
552 /* pass control off to the GLUT event handler */
562 int printf (const char *format, ...) {
568 /* Revision 1.33 1997/12/15 23:54:45 curt
569 /* Add xgl wrappers for debugging.
570 /* Generate terrain normals on the fly.
572 * Revision 1.32 1997/12/15 20:59:08 curt
575 * Revision 1.31 1997/12/12 21:41:25 curt
576 * More light/material property tweaking ... still a ways off.
578 * Revision 1.30 1997/12/12 19:52:47 curt
579 * Working on lightling and material properties.
581 * Revision 1.29 1997/12/11 04:43:54 curt
582 * Fixed sun vector and lighting problems. I thing the moon is now lit
585 * Revision 1.28 1997/12/10 22:37:45 curt
586 * Prepended "fg" on the name of all global structures that didn't have it yet.
587 * i.e. "struct WEATHER {}" became "struct fgWEATHER {}"
589 * Revision 1.27 1997/12/09 05:11:54 curt
590 * Working on tweaking lighting.
592 * Revision 1.26 1997/12/09 04:25:29 curt
593 * Working on adding a global lighting params structure.
595 * Revision 1.25 1997/12/08 22:54:09 curt
596 * Enabled GL_CULL_FACE.
598 * Revision 1.24 1997/11/25 19:25:32 curt
599 * Changes to integrate Durk's moon/sun code updates + clean up.
601 * Revision 1.23 1997/11/15 18:16:34 curt
604 * Revision 1.22 1997/10/30 12:38:41 curt
605 * Working on new scenery subsystem.
607 * Revision 1.21 1997/09/23 00:29:38 curt
608 * Tweaks to get things to compile with gcc-win32.
610 * Revision 1.20 1997/09/22 14:44:19 curt
611 * Continuing to try to align stars correctly.
613 * Revision 1.19 1997/09/18 16:20:08 curt
614 * At dusk/dawn add/remove stars in stages.
616 * Revision 1.18 1997/09/16 22:14:51 curt
617 * Tweaked time of day lighting equations. Don't draw stars during the day.
619 * Revision 1.17 1997/09/16 15:50:29 curt
620 * Working on star alignment and time issues.
622 * Revision 1.16 1997/09/13 02:00:06 curt
623 * Mostly working on stars and generating sidereal time for accurate star
626 * Revision 1.15 1997/09/05 14:17:27 curt
627 * More tweaking with stars.
629 * Revision 1.14 1997/09/05 01:35:53 curt
630 * Working on getting stars right.
632 * Revision 1.13 1997/09/04 02:17:34 curt
635 * Revision 1.12 1997/08/27 21:32:24 curt
636 * Restructured view calculation code. Added stars.
638 * Revision 1.11 1997/08/27 03:30:16 curt
639 * Changed naming scheme of basic shared structures.
641 * Revision 1.10 1997/08/25 20:27:22 curt
642 * Merged in initial HUD and Joystick code.
644 * Revision 1.9 1997/08/22 21:34:39 curt
645 * Doing a bit of reorganizing and house cleaning.
647 * Revision 1.8 1997/08/19 23:55:03 curt
648 * Worked on better simulating real lighting.
650 * Revision 1.7 1997/08/16 12:22:38 curt
651 * Working on improving the lighting/shading.
653 * Revision 1.6 1997/08/13 20:24:56 curt
654 * Changes due to changing sunpos interface.
656 * Revision 1.5 1997/08/06 21:08:32 curt
657 * Sun position now *really* works (I think) ... I still have sun time warping
658 * code in place, probably should remove it soon.
660 * Revision 1.4 1997/08/06 15:41:26 curt
661 * Working on correct sun position.
663 * Revision 1.3 1997/08/06 00:24:22 curt
664 * Working on correct real time sun lighting.
666 * Revision 1.2 1997/08/04 20:25:15 curt
667 * Organizational tweaking.
669 * Revision 1.1 1997/08/02 18:45:00 curt
670 * Renamed GLmain.c GLUTmain.c
672 * Revision 1.43 1997/08/02 16:23:47 curt
675 * Revision 1.42 1997/08/01 19:43:33 curt
676 * Making progress with coordinate system overhaul.
678 * Revision 1.41 1997/07/31 22:52:37 curt
679 * Working on redoing internal coordinate systems & scenery transformations.
681 * Revision 1.40 1997/07/30 16:12:42 curt
682 * Moved fg_random routines from Util/ to Math/
684 * Revision 1.39 1997/07/21 14:45:01 curt
687 * Revision 1.38 1997/07/19 23:04:47 curt
688 * Added an initial weather section.
690 * Revision 1.37 1997/07/19 22:34:02 curt
691 * Moved PI definitions to ../constants.h
692 * Moved random() stuff to ../Utils/ and renamed fg_random()
694 * Revision 1.36 1997/07/18 23:41:25 curt
695 * Tweaks for building with Cygnus Win32 compiler.
697 * Revision 1.35 1997/07/18 14:28:34 curt
698 * Hacked in some support for wind/turbulence.
700 * Revision 1.34 1997/07/16 20:04:48 curt
701 * Minor tweaks to aid Win32 port.
703 * Revision 1.33 1997/07/12 03:50:20 curt
704 * Added an #include <Windows32/Base.h> to help compiling for Win32
706 * Revision 1.32 1997/07/11 03:23:18 curt
707 * Solved some scenery display/orientation problems. Still have a positioning
708 * (or transformation?) problem.
710 * Revision 1.31 1997/07/11 01:29:58 curt
711 * More tweaking of terrian floor.
713 * Revision 1.30 1997/07/10 04:26:37 curt
714 * We now can interpolated ground elevation for any position in the grid. We
715 * can use this to enforce a "hard" ground. We still need to enforce some
716 * bounds checking so that we don't try to lookup data points outside the
719 * Revision 1.29 1997/07/09 21:31:12 curt
720 * Working on making the ground "hard."
722 * Revision 1.28 1997/07/08 18:20:12 curt
723 * Working on establishing a hard ground.
725 * Revision 1.27 1997/07/07 20:59:49 curt
726 * Working on scenery transformations to enable us to fly fluidly over the
727 * poles with no discontinuity/distortion in scenery.
729 * Revision 1.26 1997/07/05 20:43:34 curt
730 * renamed mat3 directory to Math so we could add other math related routines.
732 * Revision 1.25 1997/06/29 21:19:17 curt
733 * Working on scenery management system.
735 * Revision 1.24 1997/06/26 22:14:53 curt
736 * Beginning work on a scenery management system.
738 * Revision 1.23 1997/06/26 19:08:33 curt
739 * Restructuring make, adding automatic "make dep" support.
741 * Revision 1.22 1997/06/25 15:39:47 curt
742 * Minor changes to compile with rsxnt/win32.
744 * Revision 1.21 1997/06/22 21:44:41 curt
745 * Working on intergrating the VRML (subset) parser.
747 * Revision 1.20 1997/06/21 17:12:53 curt
748 * Capitalized subdirectory names.
750 * Revision 1.19 1997/06/18 04:10:31 curt
751 * A couple more runway tweaks ...
753 * Revision 1.18 1997/06/18 02:21:24 curt
756 * Revision 1.17 1997/06/17 16:51:58 curt
757 * Timer interval stuff now uses gettimeofday() instead of ftime()
759 * Revision 1.16 1997/06/17 04:19:16 curt
760 * More timer related tweaks with respect to view direction changes.
762 * Revision 1.15 1997/06/17 03:41:10 curt
763 * Nonsignal based interval timing is now working.
764 * This would be a good time to look at cleaning up the code structure a bit.
766 * Revision 1.14 1997/06/16 19:32:51 curt
767 * Starting to add general timer support.
769 * Revision 1.13 1997/06/02 03:40:06 curt
770 * A tiny bit more view tweaking.
772 * Revision 1.12 1997/06/02 03:01:38 curt
773 * Working on views (side, front, back, transitions, etc.)
775 * Revision 1.11 1997/05/31 19:16:25 curt
776 * Elevator trim added.
778 * Revision 1.10 1997/05/31 04:13:52 curt
781 * Continuing work on the LaRCsim flight model integration.
782 * Added some MSFS-like keyboard input handling.
784 * Revision 1.9 1997/05/30 19:27:01 curt
785 * The LaRCsim flight model is starting to look like it is working.
787 * Revision 1.8 1997/05/30 03:54:10 curt
788 * Made a bit more progress towards integrating the LaRCsim flight model.
790 * Revision 1.7 1997/05/29 22:39:49 curt
791 * Working on incorporating the LaRCsim flight model.
793 * Revision 1.6 1997/05/29 12:31:39 curt
794 * Minor tweaks, moving towards general flight model integration.
796 * Revision 1.5 1997/05/29 02:33:23 curt
797 * Updated to reflect changing interfaces in other "modules."
799 * Revision 1.4 1997/05/27 17:44:31 curt
800 * Renamed & rearranged variables and routines. Added some initial simple
801 * timer/alarm routines so the flight model can be updated on a regular
804 * Revision 1.3 1997/05/23 15:40:25 curt
805 * Added GNU copyright headers.
808 * Revision 1.2 1997/05/23 00:35:12 curt
809 * Trying to get fog to work ...
811 * Revision 1.1 1997/05/21 15:57:51 curt
812 * Renamed due to added GLUT support.
814 * Revision 1.3 1997/05/19 18:22:42 curt
815 * Parameter tweaking ... starting to stub in fog support.
817 * Revision 1.2 1997/05/17 00:17:34 curt
818 * Trying to stub in support for standard OpenGL.
820 * Revision 1.1 1997/05/16 16:05:52 curt