simgear/Scenery/sky.c

200 lines
5.3 KiB
C

/**************************************************************************
* 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 <windows.h>
#endif
#include <math.h>
/*
#include <stdio.h>
#include <string.h>
#include <time.h>
*/
#include <GL/glut.h>
#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;
int i;
f = &current_aircraft.flight;
l = &cur_light_params;
v = &current_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();
/* 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 );
/* 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 );
xglVertex3fv( sky_middle[0] );
xglColor4fv( inner_color );
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 1.5 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.)
*
*/