/************************************************************************** * GLmain.c -- top level sim routines * * Written by Curtis Olson for OpenGL, started May 1997. * * Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * * $Id$ * (Log is kept at end of this file) **************************************************************************/ #include #ifdef WIN32 # include #endif #ifdef GLUT #include #include "GLUTkey.h" #endif #include "../constants.h" #include "../Aircraft/aircraft.h" #include "../Scenery/mesh.h" #include "../Scenery/scenery.h" #include "../Math/fg_geodesy.h" #include "../Math/fg_random.h" #include "../Math/mat3.h" #include "../Math/polar.h" #include "../Time/fg_timer.h" #include "../Time/sunpos.h" #include "../Weather/weather.h" /* This is a record containing all the info for the aircraft currently being operated */ struct aircraft_params current_aircraft; /* view parameters */ static GLfloat win_ratio = 1.0; /* sun direction */ static GLfloat sun_vec[4] = {1.0, 0.0, 0.0, 0.0 }; /* temporary hack */ /* extern struct mesh *mesh_ptr; */ /* Function prototypes */ /* GLint fgSceneryCompile_OLD(); */ /* static void fgSceneryDraw_OLD(); */ /* pointer to scenery structure */ /* static GLint scenery, runway; */ /* Another hack */ double fogDensity = 60000.0; /* in meters */ double view_offset = 0.0; double goal_view_offset = 0.0; /* Another hack */ #define DEFAULT_TIMER_HZ 20 #define DEFAULT_MULTILOOP 6 #define DEFAULT_MODEL_HZ (DEFAULT_TIMER_HZ * DEFAULT_MULTILOOP) double Simtime; /* Another hack */ int use_signals = 0; /************************************************************************** * fgInitVisuals() -- Initialize various GL/view parameters **************************************************************************/ static void fgInitVisuals() { /* if the 4th field is 0.0, this specifies a direction ... */ static GLfloat fogColor[4] = {0.65, 0.65, 0.85, 1.0}; glEnable( GL_DEPTH_TEST ); /* glFrontFace(GL_CW); */ glEnable( GL_CULL_FACE ); /* If enabled, normal vectors specified with glNormal are scaled to unit length after transformation. See glNormal. */ glEnable( GL_NORMALIZE ); glLightfv( GL_LIGHT0, GL_POSITION, sun_vec ); glEnable( GL_LIGHTING ); glEnable( GL_LIGHT0 ); glShadeModel( GL_FLAT ); /* glShadeModel( GL_SMOOTH ); */ glEnable( GL_FOG ); glFogi (GL_FOG_MODE, GL_LINEAR); /* glFogf (GL_FOG_START, 1.0); */ glFogf (GL_FOG_END, fogDensity); glFogfv (GL_FOG_COLOR, fogColor); /* glFogf (GL_FOG_DENSITY, fogDensity); */ /* glHint (GL_FOG_HINT, GL_FASTEST); */ glClearColor(0.6, 0.6, 0.9, 1.0); } /************************************************************************** * Update the view volume, position, and orientation **************************************************************************/ static void fgUpdateViewParams() { struct fgCartesianPoint view_pos /*, alt_up */; struct flight_params *f; MAT3mat R, TMP, UP, LOCAL, VIEW; MAT3vec vec, view_up, forward, view_forward, local_up; f = ¤t_aircraft.flight; /* Tell GL we are about to modify the projection parameters */ glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(45.0, 1.0/win_ratio, 1.0, 200000.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glLightfv( GL_LIGHT0, GL_POSITION, sun_vec ); /* calculate view position in current FG view coordinate system */ view_pos = fgPolarToCart(FG_Longitude, FG_Lat_geocentric, FG_Radius_to_vehicle * FEET_TO_METER + 1.0); view_pos.x -= scenery.center.x; view_pos.y -= scenery.center.y; view_pos.z -= scenery.center.z; printf("View pos = %.4f, %.4f, %.4f\n", view_pos.x, view_pos.y, view_pos.z); /* Derive the LOCAL aircraft rotation matrix (roll, pitch, yaw) */ MAT3_SET_VEC(vec, 0.0, 0.0, 1.0); MAT3rotate(R, vec, FG_Phi); /* printf("Roll matrix\n"); */ /* MAT3print(R, stdout); */ MAT3_SET_VEC(vec, 0.0, 1.0, 0.0); /* MAT3mult_vec(vec, vec, R); */ MAT3rotate(TMP, vec, FG_Theta); /* printf("Pitch matrix\n"); */ /* MAT3print(TMP, stdout); */ MAT3mult(R, R, TMP); MAT3_SET_VEC(vec, 1.0, 0.0, 0.0); /* MAT3mult_vec(vec, vec, R); */ /* MAT3rotate(TMP, vec, FG_Psi - FG_PI_2); */ MAT3rotate(TMP, vec, -FG_Psi); /* printf("Yaw matrix\n"); MAT3print(TMP, stdout); */ MAT3mult(LOCAL, R, TMP); /* printf("LOCAL matrix\n"); */ /* MAT3print(LOCAL, stdout); */ /* Derive the local UP transformation matrix based on *geodetic* * coordinates */ MAT3_SET_VEC(vec, 0.0, 0.0, 1.0); MAT3rotate(R, vec, FG_Longitude); /* R = rotate about Z axis */ /* printf("Longitude matrix\n"); */ /* MAT3print(R, stdout); */ MAT3_SET_VEC(vec, 0.0, 1.0, 0.0); MAT3mult_vec(vec, vec, R); MAT3rotate(TMP, vec, -FG_Latitude); /* TMP = rotate about X axis */ /* printf("Latitude matrix\n"); */ /* MAT3print(TMP, stdout); */ MAT3mult(UP, R, TMP); /* printf("Local up matrix\n"); */ /* MAT3print(UP, stdout); */ MAT3_SET_VEC(local_up, 1.0, 0.0, 0.0); MAT3mult_vec(local_up, local_up, UP); printf(" Local Up = (%.4f, %.4f, %.4f)\n", local_up[0], local_up[1], local_up[2]); /* Alternative method to Derive local up vector based on * *geodetic* coordinates */ /* alt_up = fgPolarToCart(FG_Longitude, FG_Latitude, 1.0); */ /* printf(" Alt Up = (%.4f, %.4f, %.4f)\n", alt_up.x, alt_up.y, alt_up.z); */ /* Derive the VIEW matrix */ MAT3mult(VIEW, LOCAL, UP); /* printf("VIEW matrix\n"); */ /* MAT3print(VIEW, stdout); */ /* generate the current up, forward, and fwrd-view vectors */ MAT3_SET_VEC(vec, 1.0, 0.0, 0.0); MAT3mult_vec(view_up, vec, VIEW); MAT3_SET_VEC(vec, 0.0, 0.0, 1.0); MAT3mult_vec(forward, vec, VIEW); printf("Forward vector is (%.2f,%.2f,%.2f)\n", forward[0], forward[1], forward[2]); MAT3rotate(TMP, view_up, view_offset); MAT3mult_vec(view_forward, forward, TMP); gluLookAt(view_pos.x, view_pos.y, view_pos.z, view_pos.x + view_forward[0], view_pos.y + view_forward[1], view_pos.z + view_forward[2], view_up[0], view_up[1], view_up[2]); } /************************************************************************** * Update all Visuals (redraws anything graphics related) **************************************************************************/ static void fgUpdateVisuals( void ) { /* update view volume parameters */ fgUpdateViewParams(); glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ); /* Tell GL we are switching to model view parameters */ glMatrixMode(GL_MODELVIEW); /* glLoadIdentity(); */ /* draw scenery */ fgSceneryRender(); #ifdef GLUT glutSwapBuffers(); #endif } /************************************************************************** * Update internal time dependent calculations (i.e. flight model) **************************************************************************/ void fgUpdateTimeDepCalcs(int multi_loop) { struct flight_params *f; struct fgCartesianPoint sunpos; double sun_lon, sun_gd_lat, sun_gc_lat, sl_radius; int i; f = ¤t_aircraft.flight; /* update the flight model */ if ( multi_loop < 0 ) { multi_loop = DEFAULT_MULTILOOP; } /* printf("updating flight model x %d\n", multi_loop); */ fgFlightModelUpdate(FG_LARCSIM, f, multi_loop); /* refresh sun position */ fgSunPosition(time(NULL), &sun_lon, &sun_gd_lat); fgGeodToGeoc(sun_gd_lat, 0, &sl_radius, &sun_gc_lat); sunpos = fgPolarToCart(sun_lon, sun_gc_lat, sl_radius); printf("Sun position is (%.2f, %.2f, %.2f)\n", sunpos.x, sunpos.y, sunpos.z); /* not necessary to divide, but I'm just doing it by a "random" * constant to get near the magnitude of the number down to the * 0.0 - 1.0 range */ sun_vec[0] = -sunpos.x; sun_vec[1] = -sunpos.y; sun_vec[2] = -sunpos.z; sun_vec[3] = 0.0; /* make this a directional light source only */ /* update the view angle */ for ( i = 0; i < multi_loop; i++ ) { if ( fabs(goal_view_offset - view_offset) < 0.05 ) { view_offset = goal_view_offset; break; } else { /* move view_offset towards goal_view_offset */ if ( goal_view_offset > view_offset ) { if ( goal_view_offset - view_offset < FG_PI ) { view_offset += 0.01; } else { view_offset -= 0.01; } } else { if ( view_offset - goal_view_offset < FG_PI ) { view_offset -= 0.01; } else { view_offset += 0.01; } } if ( view_offset > FG_2PI ) { view_offset -= FG_2PI; } else if ( view_offset < 0 ) { view_offset += FG_2PI; } } } } void fgInitTimeDepCalcs() { /* initialize timer */ #ifdef USE_ITIMER fgTimerInit( 1.0 / DEFAULT_TIMER_HZ, fgUpdateTimeDepCalcs ); #endif USE_ITIMER } /************************************************************************** * Scenery management routines **************************************************************************/ /* static void fgSceneryInit_OLD() { */ /* make scenery */ /* scenery = fgSceneryCompile_OLD(); runway = fgRunwayHack_OLD(0.69, 53.07); } */ /* create the scenery */ /* GLint fgSceneryCompile_OLD() { GLint scenery; scenery = mesh2GL(mesh_ptr_OLD); return(scenery); } */ /* hack in a runway */ /* GLint fgRunwayHack_OLD(double width, double length) { static GLfloat concrete[4] = { 0.5, 0.5, 0.5, 1.0 }; static GLfloat line[4] = { 0.9, 0.9, 0.9, 1.0 }; int i; int num_lines = 16; float line_len, line_width_2, cur_pos; runway = glGenLists(1); glNewList(runway, GL_COMPILE); */ /* draw concrete */ /* glBegin(GL_POLYGON); glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, concrete ); glNormal3f(0.0, 0.0, 1.0); glVertex3d( 0.0, -width/2.0, 0.0); glVertex3d( 0.0, width/2.0, 0.0); glVertex3d(length, width/2.0, 0.0); glVertex3d(length, -width/2.0, 0.0); glEnd(); */ /* draw center line */ /* glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, line ); line_len = length / ( 2 * num_lines + 1); printf("line_len = %.3f\n", line_len); line_width_2 = 0.02; cur_pos = line_len; for ( i = 0; i < num_lines; i++ ) { glBegin(GL_POLYGON); glVertex3d( cur_pos, -line_width_2, 0.005); glVertex3d( cur_pos, line_width_2, 0.005); cur_pos += line_len; glVertex3d( cur_pos, line_width_2, 0.005); glVertex3d( cur_pos, -line_width_2, 0.005); cur_pos += line_len; glEnd(); } glEndList(); return(runway); } */ /* draw the scenery */ /*static void fgSceneryDraw_OLD() { static float z = 32.35; glPushMatrix(); glCallList(scenery); printf("*** Drawing runway at %.2f\n", z); glTranslatef( -398391.28, 120070.41, 32.35); glRotatef(170.0, 0.0, 0.0, 1.0); glCallList(runway); glPopMatrix(); } */ /* What should we do when we have nothing else to do? How about get * ready for the next move and update the display? */ static void fgMainLoop( void ) { static int remainder = 0; int elapsed, multi_loop; double rough_elev; struct flight_params *f; f = ¤t_aircraft.flight; elapsed = fgGetTimeInterval(); printf("Time interval is = %d, previous remainder is = %d\n", elapsed, remainder); printf("--> Frame rate is = %.2f\n", 1000.0 / (float)elapsed); elapsed += remainder; multi_loop = ((float)elapsed * 0.001) * DEFAULT_MODEL_HZ; remainder = elapsed - ((multi_loop*1000) / DEFAULT_MODEL_HZ); printf("Model iterations needed = %d, new remainder = %d\n", multi_loop, remainder); aircraft_debug(1); fgUpdateVisuals(); if ( ! use_signals ) { /* flight model */ fgUpdateTimeDepCalcs(multi_loop); } /* I'm just sticking this here for now, it should probably move * eventually */ rough_elev = mesh_altitude(FG_Longitude * RAD_TO_ARCSEC, FG_Latitude * RAD_TO_ARCSEC); printf("Ground elevation is %.2f meters here.\n", rough_elev); /* FG_Runway_altitude = rough_elev * METER_TO_FEET; */ if ( FG_Altitude * FEET_TO_METER < rough_elev + 3.758099) { /* set this here, otherwise if we set runway height above our current height we get a really nasty bounce. */ FG_Runway_altitude = FG_Altitude - 3.758099; /* now set aircraft altitude above ground */ FG_Altitude = rough_elev * METER_TO_FEET + 3.758099; printf("<*> resetting altitude to %.0f meters\n", FG_Altitude * FEET_TO_METER); } /* update the weather for our current position */ fgWeatherUpdate(FG_Longitude * RAD_TO_ARCSEC, FG_Latitude * RAD_TO_ARCSEC, FG_Altitude * FEET_TO_METER); } /************************************************************************** * Handle new window size or exposure **************************************************************************/ static void fgReshape( int width, int height ) { /* Do this so we can call fgReshape(0,0) ourselves without having to know * what the values of width & height are. */ if ( (height > 0) && (width > 0) ) { win_ratio = (GLfloat) height / (GLfloat) width; } /* Inform gl of our view window size */ glViewport(0, 0, (GLint)width, (GLint)height); fgUpdateViewParams(); glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ); } /************************************************************************** * Main ... **************************************************************************/ int main( int argc, char *argv[] ) { struct flight_params *f; double rough_elev; f = ¤t_aircraft.flight; printf("Flight Gear: prototype code to test OpenGL, LaRCsim, and VRML\n\n"); /********************************************************************** * Initialize the Window/Graphics environment. **********************************************************************/ #ifdef GLUT /* initialize GLUT */ glutInit(&argc, argv); /* Define Display Parameters */ glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE ); /* Define initial window size */ glutInitWindowSize(640, 480); /* Initialize windows */ glutCreateWindow("Flight Gear"); #endif /* seed the random number generater */ fg_srandom(); /* setup view parameters, only makes GL calls */ fgInitVisuals(); /**************************************************************** * The following section sets up the flight model EOM parameters and * should really be read in from one or more files. ****************************************************************/ /* Globe Aiport, AZ */ FG_Runway_altitude = 3234.5; FG_Runway_latitude = 120070.41; FG_Runway_longitude = -398391.28; FG_Runway_heading = 102.0 * DEG_TO_RAD; /* Initial Position */ FG_Latitude = ( 120070.41 / 3600.0 ) * DEG_TO_RAD; FG_Longitude = ( -398391.28 / 3600.0 ) * DEG_TO_RAD; FG_Altitude = FG_Runway_altitude + 3.758099; /* FG_Latitude = 0.0; */ /* FG_Longitude = 0.0; */ /* FG_Altitude = 15000.0; */ printf("Initial position is: (%.4f, %.4f, %.2f)\n", FG_Latitude, FG_Longitude, FG_Altitude); /* Initial Velocity */ FG_V_north = 0.0 /* 7.287719E+00 */; FG_V_east = 0.0 /* 1.521770E+03 */; FG_V_down = 0.0 /* -1.265722E-05 */; /* Initial Orientation */ FG_Phi = -2.658474E-06; FG_Theta = 7.401790E-03; /* FG_Psi = 270.0 * DEG_TO_RAD; */ FG_Psi = 0.0 * DEG_TO_RAD; /* Initial Angular B rates */ FG_P_body = 7.206685E-05; FG_Q_body = 0.000000E+00; FG_R_body = 9.492658E-05; FG_Earth_position_angle = 0.000000E+00; /* Mass properties and geometry values */ FG_Mass = 8.547270E+01; FG_I_xx = 1.048000E+03; FG_I_yy = 3.000000E+03; FG_I_zz = 3.530000E+03; FG_I_xz = 0.000000E+00; /* CG position w.r.t. ref. point */ FG_Dx_cg = 0.000000E+00; FG_Dy_cg = 0.000000E+00; FG_Dz_cg = 0.000000E+00; /* Set initial position and slew parameters */ /* fgSlewInit(-398391.3, 120070.41, 244, 3.1415); */ /* GLOBE Airport */ /* fgSlewInit(-335340,162540, 15, 4.38); */ /* fgSlewInit(-398673.28,120625.64, 53, 4.38); */ /* Initialize the Scenery Management system */ fgSceneryInit(); /* Tell the Scenery Management system where we are so it can load * the correct scenery data */ fgSceneryUpdate(FG_Latitude, FG_Longitude, FG_Altitude); /* I'm just sticking this here for now, it should probably move * eventually */ rough_elev = mesh_altitude(FG_Longitude * RAD_TO_DEG * 3600.0, FG_Latitude * RAD_TO_DEG * 3600.0); printf("Ground elevation is %.2f meters here.\n", rough_elev); if ( rough_elev > -9990.0 ) { FG_Runway_altitude = rough_elev * METER_TO_FEET; } if ( FG_Altitude < FG_Runway_altitude ) { FG_Altitude = FG_Runway_altitude + 3.758099; } /* end of thing that I just stuck in that I should probably move */ /* Initialize the flight model data structures base on above values */ fgFlightModelInit( FG_LARCSIM, f, 1.0 / DEFAULT_MODEL_HZ ); if ( use_signals ) { /* init timer routines, signals, etc. Arrange for an alarm signal to be generated, etc. */ fgInitTimeDepCalcs(); } /* Initialize the weather modeling subsystem */ fgWeatherInit(); /********************************************************************** * Initialize the Event Handlers. **********************************************************************/ #ifdef GLUT /* call fgReshape() on window resizes */ glutReshapeFunc( fgReshape ); /* call key() on keyboard event */ glutKeyboardFunc( GLUTkey ); glutSpecialFunc( GLUTspecialkey ); /* call fgMainLoop() whenever there is nothing else to do */ glutIdleFunc( fgMainLoop ); /* draw the scene */ glutDisplayFunc( fgUpdateVisuals ); /* pass control off to the GLUT event handler */ glutMainLoop(); #endif return(0); } #ifdef NO_PRINTF #include int printf (const char *format, ...) { } #endif /* $Log$ /* Revision 1.3 1997/08/06 00:24:22 curt /* Working on correct real time sun lighting. /* * Revision 1.2 1997/08/04 20:25:15 curt * Organizational tweaking. * * Revision 1.1 1997/08/02 18:45:00 curt * Renamed GLmain.c GLUTmain.c * * Revision 1.43 1997/08/02 16:23:47 curt * Misc. tweaks. * * Revision 1.42 1997/08/01 19:43:33 curt * Making progress with coordinate system overhaul. * * Revision 1.41 1997/07/31 22:52:37 curt * Working on redoing internal coordinate systems & scenery transformations. * * Revision 1.40 1997/07/30 16:12:42 curt * Moved fg_random routines from Util/ to Math/ * * Revision 1.39 1997/07/21 14:45:01 curt * Minor tweaks. * * Revision 1.38 1997/07/19 23:04:47 curt * Added an initial weather section. * * Revision 1.37 1997/07/19 22:34:02 curt * Moved PI definitions to ../constants.h * Moved random() stuff to ../Utils/ and renamed fg_random() * * Revision 1.36 1997/07/18 23:41:25 curt * Tweaks for building with Cygnus Win32 compiler. * * Revision 1.35 1997/07/18 14:28:34 curt * Hacked in some support for wind/turbulence. * * Revision 1.34 1997/07/16 20:04:48 curt * Minor tweaks to aid Win32 port. * * Revision 1.33 1997/07/12 03:50:20 curt * Added an #include to help compiling for Win32 * * Revision 1.32 1997/07/11 03:23:18 curt * Solved some scenery display/orientation problems. Still have a positioning * (or transformation?) problem. * * Revision 1.31 1997/07/11 01:29:58 curt * More tweaking of terrian floor. * * Revision 1.30 1997/07/10 04:26:37 curt * We now can interpolated ground elevation for any position in the grid. We * can use this to enforce a "hard" ground. We still need to enforce some * bounds checking so that we don't try to lookup data points outside the * grid data set. * * Revision 1.29 1997/07/09 21:31:12 curt * Working on making the ground "hard." * * Revision 1.28 1997/07/08 18:20:12 curt * Working on establishing a hard ground. * * Revision 1.27 1997/07/07 20:59:49 curt * Working on scenery transformations to enable us to fly fluidly over the * poles with no discontinuity/distortion in scenery. * * Revision 1.26 1997/07/05 20:43:34 curt * renamed mat3 directory to Math so we could add other math related routines. * * Revision 1.25 1997/06/29 21:19:17 curt * Working on scenery management system. * * Revision 1.24 1997/06/26 22:14:53 curt * Beginning work on a scenery management system. * * Revision 1.23 1997/06/26 19:08:33 curt * Restructuring make, adding automatic "make dep" support. * * Revision 1.22 1997/06/25 15:39:47 curt * Minor changes to compile with rsxnt/win32. * * Revision 1.21 1997/06/22 21:44:41 curt * Working on intergrating the VRML (subset) parser. * * Revision 1.20 1997/06/21 17:12:53 curt * Capitalized subdirectory names. * * Revision 1.19 1997/06/18 04:10:31 curt * A couple more runway tweaks ... * * Revision 1.18 1997/06/18 02:21:24 curt * Hacked in a runway * * Revision 1.17 1997/06/17 16:51:58 curt * Timer interval stuff now uses gettimeofday() instead of ftime() * * Revision 1.16 1997/06/17 04:19:16 curt * More timer related tweaks with respect to view direction changes. * * Revision 1.15 1997/06/17 03:41:10 curt * Nonsignal based interval timing is now working. * This would be a good time to look at cleaning up the code structure a bit. * * Revision 1.14 1997/06/16 19:32:51 curt * Starting to add general timer support. * * Revision 1.13 1997/06/02 03:40:06 curt * A tiny bit more view tweaking. * * Revision 1.12 1997/06/02 03:01:38 curt * Working on views (side, front, back, transitions, etc.) * * Revision 1.11 1997/05/31 19:16:25 curt * Elevator trim added. * * Revision 1.10 1997/05/31 04:13:52 curt * WE CAN NOW FLY!!! * * Continuing work on the LaRCsim flight model integration. * Added some MSFS-like keyboard input handling. * * Revision 1.9 1997/05/30 19:27:01 curt * The LaRCsim flight model is starting to look like it is working. * * Revision 1.8 1997/05/30 03:54:10 curt * Made a bit more progress towards integrating the LaRCsim flight model. * * Revision 1.7 1997/05/29 22:39:49 curt * Working on incorporating the LaRCsim flight model. * * Revision 1.6 1997/05/29 12:31:39 curt * Minor tweaks, moving towards general flight model integration. * * Revision 1.5 1997/05/29 02:33:23 curt * Updated to reflect changing interfaces in other "modules." * * Revision 1.4 1997/05/27 17:44:31 curt * Renamed & rearranged variables and routines. Added some initial simple * timer/alarm routines so the flight model can be updated on a regular * interval. * * Revision 1.3 1997/05/23 15:40:25 curt * Added GNU copyright headers. * Fog now works! * * Revision 1.2 1997/05/23 00:35:12 curt * Trying to get fog to work ... * * Revision 1.1 1997/05/21 15:57:51 curt * Renamed due to added GLUT support. * * Revision 1.3 1997/05/19 18:22:42 curt * Parameter tweaking ... starting to stub in fog support. * * Revision 1.2 1997/05/17 00:17:34 curt * Trying to stub in support for standard OpenGL. * * Revision 1.1 1997/05/16 16:05:52 curt * Initial revision. * */