/************************************************************************** * sky.c -- model sky with an upside down "bowl" * * Written by Curtis Olson, started December 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) **************************************************************************/ #ifdef WIN32 # include #endif #include /* #include #include #include */ #include #include "../XGL/xgl.h" #include "sky.h" #include "../Time/fg_time.h" #include "../Aircraft/aircraft.h" #include "../Flight/flight.h" #include "../Include/constants.h" #include "../Main/views.h" #include "../Math/fg_random.h" /* #include "../Include/general.h" */ /* in meters of course */ #define CENTER_ELEV 25000.0 #define INNER_RADIUS 50000.0 #define INNER_ELEV 20000.0 #define MIDDLE_RADIUS 70000.0 #define MIDDLE_ELEV 8000.0 #define OUTER_RADIUS 80000.0 #define OUTER_ELEV 0.0 static float sky_inner[12][3]; static float sky_middle[12][3]; static float sky_outer[12][3]; /* Calculate the sky structure verticies */ void fgSkyInit() { float theta; int i; printf("Generating the sky dome vertices.\n"); for ( i = 0; i < 12; i++ ) { theta = (i * 30.0) * DEG_TO_RAD; sky_inner[i][0] = cos(theta) * INNER_RADIUS; sky_inner[i][1] = sin(theta) * INNER_RADIUS; sky_inner[i][2] = INNER_ELEV; printf(" %.2f %.2f\n", cos(theta) * INNER_RADIUS, sin(theta) * INNER_RADIUS); sky_middle[i][0] = cos((double)theta) * MIDDLE_RADIUS; sky_middle[i][1] = sin((double)theta) * MIDDLE_RADIUS; sky_middle[i][2] = MIDDLE_ELEV; sky_outer[i][0] = cos((double)theta) * OUTER_RADIUS; sky_outer[i][1] = sin((double)theta) * OUTER_RADIUS; sky_outer[i][2] = OUTER_ELEV; } } /* Draw the Sky */ void fgSkyRender() { struct fgFLIGHT *f; struct fgLIGHT *l; struct fgVIEW *v; float inner_color[4], middle_color[4], diff, east_dot, dot, angle; int i; f = ¤t_aircraft.flight; l = &cur_light_params; v = ¤t_view; printf("Rendering the sky.\n"); /* l->fog_color[0] = 1.0; l->fog_color[1] = 0.0; l->fog_color[2] = 0.0; l->fog_color[3] = 1.0; */ /* calculate transition colors between sky and fog */ for ( i = 0; i < 3; i++ ) { diff = l->sky_color[i] - l->fog_color[i]; inner_color[i] = l->sky_color[i] - diff * 0.3; middle_color[i] = l->sky_color[i] - diff * 1.0; } inner_color[3] = middle_color[3] = l->sky_color[3]; xglPushMatrix(); /* calculate the angle between v->surface_to_sun and * v->surface_east. We do this so we can sort out the acos() * ambiguity. I wish I could think of a more efficient way ... :-( */ east_dot = MAT3_DOT_PRODUCT(v->surface_to_sun, v->surface_east); printf(" East dot product = %.2f\n", east_dot); /* calculate the angle between v->surface_to_sun and * v->surface_south. this is how much we have to rotate the sky * for it to align with the sun */ dot = MAT3_DOT_PRODUCT(v->surface_to_sun, v->surface_south); printf(" Dot product = %.2f\n", dot); if ( east_dot >= 0 ) { angle = acos(dot); } else { angle = -acos(dot); } printf(" Sky needs to rotate = %.3f rads = %.1f degrees.\n", angle, angle * RAD_TO_DEG); /* Translate to view position */ xglTranslatef( v->cur_zero_elev.x, v->cur_zero_elev.y, v->cur_zero_elev.z ); /* printf(" Translated to %.2f %.2f %.2f\n", v->cur_zero_elev.x, v->cur_zero_elev.y, v->cur_zero_elev.z ); */ /* Rotate to proper orientation */ printf(" lon = %.2f lat = %.2f\n", FG_Longitude * RAD_TO_DEG, FG_Latitude * RAD_TO_DEG); xglRotatef( FG_Longitude * RAD_TO_DEG, 0.0, 0.0, 1.0 ); xglRotatef( 90.0 - FG_Latitude * RAD_TO_DEG, 0.0, 1.0, 0.0 ); xglRotatef( angle * RAD_TO_DEG, 0.0, 0.0, 1.0 ); /* Draw inner/center section of sky*/ xglBegin( GL_TRIANGLE_FAN ); xglColor4fv(l->sky_color); xglVertex3f(0.0, 0.0, CENTER_ELEV); xglColor4fv( inner_color ); for ( i = 0; i < 12; i++ ) { xglVertex3fv( sky_inner[i] ); } xglVertex3fv( sky_inner[0] ); xglEnd(); /* Draw the middle ring */ xglBegin( GL_TRIANGLE_STRIP ); for ( i = 0; i < 12; i++ ) { xglColor4fv( middle_color ); xglVertex3fv( sky_middle[i] ); xglColor4fv( inner_color ); xglVertex3fv( sky_inner[i] ); } xglColor4fv( middle_color ); xglColor4f(1.0, 0.0, 0.0, 1.0); xglVertex3fv( sky_middle[0] ); xglColor4fv( inner_color ); xglColor4f(1.0, 0.0, 0.0, 1.0); xglVertex3fv( sky_inner[0] ); xglEnd(); /* Draw the outer ring */ xglBegin( GL_TRIANGLE_STRIP ); for ( i = 0; i < 12; i++ ) { xglColor4fv( l->fog_color ); xglVertex3fv( sky_outer[i] ); xglColor4fv( middle_color ); xglVertex3fv( sky_middle[i] ); } xglColor4fv( l->fog_color ); xglVertex3fv( sky_outer[0] ); xglColor4fv( middle_color ); xglVertex3fv( sky_middle[0] ); xglEnd(); xglPopMatrix(); } /* $Log$ /* Revision 1.6 1997/12/22 04:14:34 curt /* Aligned sky with sun so dusk/dawn effects can be correct relative to the sun. /* * Revision 1.5 1997/12/19 23:34:59 curt * Lot's of tweaking with sky rendering and lighting. * * Revision 1.4 1997/12/19 16:45:02 curt * Working on scene rendering order and options. * * Revision 1.3 1997/12/18 23:32:36 curt * First stab at sky dome actually starting to look reasonable. :-) * * Revision 1.2 1997/12/18 04:07:03 curt * Worked on properly translating and positioning the sky dome. * * Revision 1.1 1997/12/17 23:14:30 curt * Initial revision. * Begin work on rendering the sky. (Rather than just using a clear screen.) * */