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flightgear/Astro/sky.c
curt 50c0f6c9e6 Incorporated HUD changes and struct/typedef changes from Charlie Hotchkiss 
<chotchkiss@namg.us.anritsu.com>
1998-02-07 15:29:31 +00:00

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/**************************************************************************
* 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 <Astro/sky.h>
#include <Time/event.h>
#include <Time/fg_time.h>
#include <Aircraft/aircraft.h>
#include <Flight/flight.h>
#include <Include/fg_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
#define BOTTOM_RADIUS 50000.0
#define BOTTOM_ELEV -2000.0
static float inner_vertex[12][3];
static float middle_vertex[12][3];
static float outer_vertex[12][3];
static float bottom_vertex[12][3];
static float inner_color[12][4];
static float middle_color[12][4];
static float outer_color[12][4];
/* Calculate the sky structure vertices */
void fgSkyVerticesInit( void ) {
float theta;
int i;
printf(" Generating the sky dome vertices.\n");
for ( i = 0; i < 12; i++ ) {
theta = (i * 30.0) * DEG_TO_RAD;
inner_vertex[i][0] = cos(theta) * INNER_RADIUS;
inner_vertex[i][1] = sin(theta) * INNER_RADIUS;
inner_vertex[i][2] = INNER_ELEV;
/* printf(" %.2f %.2f\n", cos(theta) * INNER_RADIUS,
sin(theta) * INNER_RADIUS); */
middle_vertex[i][0] = cos((double)theta) * MIDDLE_RADIUS;
middle_vertex[i][1] = sin((double)theta) * MIDDLE_RADIUS;
middle_vertex[i][2] = MIDDLE_ELEV;
outer_vertex[i][0] = cos((double)theta) * OUTER_RADIUS;
outer_vertex[i][1] = sin((double)theta) * OUTER_RADIUS;
outer_vertex[i][2] = OUTER_ELEV;
bottom_vertex[i][0] = cos((double)theta) * BOTTOM_RADIUS;
bottom_vertex[i][1] = sin((double)theta) * BOTTOM_RADIUS;
bottom_vertex[i][2] = BOTTOM_ELEV;
}
}
/* (Re)calculate the sky colors at each vertex */
void fgSkyColorsInit( void ) {
struct fgLIGHT *l;
float sun_angle, diff;
float outer_param[3], outer_amt[3], outer_diff[3];
float middle_param[3], middle_amt[3], middle_diff[3];
int i, j;
l = &cur_light_params;
printf(" Generating the sky colors for each vertex.\n");
/* setup for the possibility of sunset effects */
sun_angle = l->sun_angle * RAD_TO_DEG;
printf(" Sun angle in degrees = %.2f\n", sun_angle);
if ( (sun_angle > 80.0) && (sun_angle < 100.0) ) {
/* 0.0 - 0.4 */
outer_param[0] = (10.0 - fabs(90.0 - sun_angle)) / 25.0;
outer_param[1] = (10.0 - fabs(90.0 - sun_angle)) / 45.0;
outer_param[2] = 0.0;
middle_param[0] = (10.0 - fabs(90.0 - sun_angle)) / 40.0;
middle_param[1] = (10.0 - fabs(90.0 - sun_angle)) / 60.0;
middle_param[2] = 0.0;
outer_diff[0] = outer_param[0] / 6.0;
outer_diff[1] = outer_param[1] / 6.0;
outer_diff[2] = outer_param[2] / 6.0;
middle_diff[0] = middle_param[0] / 6.0;
middle_diff[1] = middle_param[1] / 6.0;
middle_diff[2] = middle_param[2] / 6.0;
} else {
outer_param[0] = outer_param[1] = outer_param[2] = 0.0;
middle_param[0] = middle_param[1] = middle_param[2] = 0.0;
outer_diff[0] = outer_diff[1] = outer_diff[2] = 0.0;
middle_diff[0] = middle_diff[1] = middle_diff[2] = 0.0;
}
/* printf(" outer_red_param = %.2f outer_red_diff = %.2f\n",
outer_red_param, outer_red_diff); */
/* calculate transition colors between sky and fog */
for ( j = 0; j < 3; j++ ) {
outer_amt[j] = outer_param[j];
middle_amt[j] = middle_param[j];
}
for ( i = 0; i < 6; i++ ) {
for ( j = 0; j < 3; j++ ) {
diff = l->sky_color[j] - l->fog_color[j];
inner_color[i][j] = l->sky_color[j] - diff * 0.3;
middle_color[i][j] = l->sky_color[j] - diff * 0.9 + middle_amt[j];
outer_color[i][j] = l->fog_color[j] + outer_amt[j];
if ( middle_color[i][j] > 1.00 ) { middle_color[i][j] = 1.00; }
if ( middle_color[i][j] < 0.10 ) { middle_color[i][j] = 0.10; }
if ( outer_color[i][j] > 1.00 ) { outer_color[i][j] = 1.00; }
if ( outer_color[i][j] < 0.10 ) { outer_color[i][j] = 0.10; }
}
inner_color[i][3] = middle_color[i][3] = outer_color[i][3] =
l->sky_color[3];
for ( j = 0; j < 3; j++ ) {
outer_amt[j] -= outer_diff[j];
middle_amt[j] -= middle_diff[j];
}
/*
printf("inner_color[%d] = %.2f %.2f %.2f %.2f\n", i, inner_color[i][0],
inner_color[i][1], inner_color[i][2], inner_color[i][3]);
printf("middle_color[%d] = %.2f %.2f %.2f %.2f\n", i,
middle_color[i][0], middle_color[i][1], middle_color[i][2],
middle_color[i][3]);
printf("outer_color[%d] = %.2f %.2f %.2f %.2f\n", i,
outer_color[i][0], outer_color[i][1], outer_color[i][2],
outer_color[i][3]);
*/
}
for ( j = 0; j < 3; j++ ) {
outer_amt[j] = 0.0;
middle_amt[j] = 0.0;
}
for ( i = 6; i < 12; i++ ) {
for ( j = 0; j < 3; j++ ) {
diff = l->sky_color[j] - l->fog_color[j];
inner_color[i][j] = l->sky_color[j] - diff * 0.3;
middle_color[i][j] = l->sky_color[j] - diff * 0.9 + middle_amt[j];
outer_color[i][j] = l->fog_color[j] + outer_amt[j];
if ( middle_color[i][j] > 1.00 ) { middle_color[i][j] = 1.00; }
if ( middle_color[i][j] < 0.10 ) { middle_color[i][j] = 0.10; }
if ( outer_color[i][j] > 1.00 ) { outer_color[i][j] = 1.00; }
if ( outer_color[i][j] < 0.15 ) { outer_color[i][j] = 0.15; }
}
inner_color[i][3] = middle_color[i][3] = outer_color[i][3] =
l->sky_color[3];
for ( j = 0; j < 3; j++ ) {
outer_amt[j] += outer_diff[j];
middle_amt[j] += middle_diff[j];
}
/*
printf("inner_color[%d] = %.2f %.2f %.2f %.2f\n", i, inner_color[i][0],
inner_color[i][1], inner_color[i][2], inner_color[i][3]);
printf("middle_color[%d] = %.2f %.2f %.2f %.2f\n", i,
middle_color[i][0], middle_color[i][1], middle_color[i][2],
middle_color[i][3]);
printf("outer_color[%d] = %.2f %.2f %.2f %.2f\n", i,
outer_color[i][0], outer_color[i][1], outer_color[i][2],
outer_color[i][3]);
*/
}
}
/* Initialize the sky structure and colors */
void fgSkyInit( void ) {
printf("Initializing the sky\n");
fgSkyVerticesInit();
/* regester fgSkyColorsInit() as an event to be run periodically */
fgEventRegister("fgSkyColorsInit()", fgSkyColorsInit,
FG_EVENT_READY, 30000);
}
/* Draw the Sky */
void fgSkyRender( void ) {
fgFLIGHT *f;
struct fgLIGHT *l;
struct fgVIEW *v;
float /* inner_color[4], middle_color[4], diff, */ east_dot, dot, angle;
int i;
f = current_aircraft.flight;
l = &cur_light_params;
v = &current_view;
/* printf("Rendering the sky.\n"); */
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);
for ( i = 0; i < 12; i++ ) {
xglColor4fv( inner_color[i] );
xglVertex3fv( inner_vertex[i] );
}
xglColor4fv( inner_color[0] );
xglVertex3fv( inner_vertex[0] );
xglEnd();
/* Draw the middle ring */
xglBegin( GL_TRIANGLE_STRIP );
for ( i = 0; i < 12; i++ ) {
xglColor4fv( middle_color[i] );
xglVertex3fv( middle_vertex[i] );
xglColor4fv( inner_color[i] );
xglVertex3fv( inner_vertex[i] );
}
xglColor4fv( middle_color[0] );
/* xglColor4f(1.0, 0.0, 0.0, 1.0); */
xglVertex3fv( middle_vertex[0] );
xglColor4fv( inner_color[0] );
/* xglColor4f(1.0, 0.0, 0.0, 1.0); */
xglVertex3fv( inner_vertex[0] );
xglEnd();
/* Draw the outer ring */
xglBegin( GL_TRIANGLE_STRIP );
for ( i = 0; i < 12; i++ ) {
xglColor4fv( outer_color[i] );
xglVertex3fv( outer_vertex[i] );
xglColor4fv( middle_color[i] );
xglVertex3fv( middle_vertex[i] );
}
xglColor4fv( outer_color[0] );
xglVertex3fv( outer_vertex[0] );
xglColor4fv( middle_color[0] );
xglVertex3fv( middle_vertex[0] );
xglEnd();
/* Draw the bottom skirt */
xglBegin( GL_TRIANGLE_STRIP );
for ( i = 0; i < 12; i++ ) {
xglColor4fv( l->fog_color );
xglVertex3fv( bottom_vertex[i] );
xglColor4fv( outer_color[i] );
xglVertex3fv( outer_vertex[i] );
}
xglColor4fv( l->fog_color );
xglVertex3fv( bottom_vertex[0] );
xglColor4fv( outer_color[0] );
xglVertex3fv( outer_vertex[0] );
xglEnd();
xglPopMatrix();
}
/* $Log$
/* Revision 1.6 1998/02/07 15:29:32 curt
/* Incorporated HUD changes and struct/typedef changes from Charlie Hotchkiss
/* <chotchkiss@namg.us.anritsu.com>
/*
* Revision 1.5 1998/01/27 00:47:48 curt
* Incorporated Paul Bleisch's <bleisch@chromatic.com> new debug message
* system and commandline/config file processing code.
*
* Revision 1.4 1998/01/26 15:54:28 curt
* Added a "skirt" to try to help hide gaps between scenery and sky. This will
* have to be revisited in the future.
*
* Revision 1.3 1998/01/19 19:26:59 curt
* Merged in make system changes from Bob Kuehne <rpk@sgi.com>
* This should simplify things tremendously.
*
* Revision 1.2 1998/01/19 18:40:17 curt
* Tons of little changes to clean up the code and to remove fatal errors
* when building with the c++ compiler.
*
* Revision 1.1 1998/01/07 03:16:19 curt
* Moved from .../Src/Scenery/ to .../Src/Astro/
*
* Revision 1.11 1997/12/30 22:22:38 curt
* Further integration of event manager.
*
* Revision 1.10 1997/12/30 20:47:53 curt
* Integrated new event manager with subsystem initializations.
*
* Revision 1.9 1997/12/30 13:06:57 curt
* A couple lighting tweaks ...
*
* Revision 1.8 1997/12/23 04:58:38 curt
* Tweaked the sky coloring a bit to build in structures to allow finer rgb
* control.
*
* Revision 1.7 1997/12/22 23:45:48 curt
* First stab at sunset/sunrise sky glow effects.
*
* 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.)
*
*/
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