345 lines
10 KiB
C
345 lines
10 KiB
C
/**************************************************************************
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* sky.c -- model sky with an upside down "bowl"
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*
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* Written by Curtis Olson, started December 1997.
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*
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* Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* $Id$
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* (Log is kept at end of this file)
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**************************************************************************/
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#ifdef WIN32
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# include <windows.h>
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#endif
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#include <math.h>
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/*
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#include <stdio.h>
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#include <string.h>
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#include <time.h>
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*/
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#include <GL/glut.h>
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#include "../XGL/xgl.h"
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#include "sky.h"
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#include "../Time/fg_time.h"
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#include "../Aircraft/aircraft.h"
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#include "../Flight/flight.h"
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#include "../Include/constants.h"
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#include "../Main/views.h"
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#include "../Math/fg_random.h"
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/*
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#include "../Include/general.h"
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*/
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/* in meters of course */
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#define CENTER_ELEV 25000.0
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#define INNER_RADIUS 50000.0
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#define INNER_ELEV 20000.0
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#define MIDDLE_RADIUS 70000.0
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#define MIDDLE_ELEV 8000.0
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#define OUTER_RADIUS 80000.0
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#define OUTER_ELEV 0.0
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static float inner_vertex[12][3];
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static float middle_vertex[12][3];
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static float outer_vertex[12][3];
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static float inner_color[12][4];
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static float middle_color[12][4];
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static float outer_color[12][4];
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/* Calculate the sky structure vertices */
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void fgSkyVerticesInit() {
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float theta;
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int i;
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printf("Generating the sky dome vertices.\n");
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for ( i = 0; i < 12; i++ ) {
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theta = (i * 30.0) * DEG_TO_RAD;
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inner_vertex[i][0] = cos(theta) * INNER_RADIUS;
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inner_vertex[i][1] = sin(theta) * INNER_RADIUS;
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inner_vertex[i][2] = INNER_ELEV;
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printf(" %.2f %.2f\n", cos(theta) * INNER_RADIUS,
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sin(theta) * INNER_RADIUS);
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middle_vertex[i][0] = cos((double)theta) * MIDDLE_RADIUS;
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middle_vertex[i][1] = sin((double)theta) * MIDDLE_RADIUS;
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middle_vertex[i][2] = MIDDLE_ELEV;
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outer_vertex[i][0] = cos((double)theta) * OUTER_RADIUS;
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outer_vertex[i][1] = sin((double)theta) * OUTER_RADIUS;
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outer_vertex[i][2] = OUTER_ELEV;
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}
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}
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/* (Re)calculate the sky colors at each vertex */
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void fgSkyColorsInit() {
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struct fgLIGHT *l;
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float sun_angle, diff;
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float outer_param[3], outer_amt[3], outer_diff[3];
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float middle_param[3], middle_amt[3], middle_diff[3];
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int i, j;
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l = &cur_light_params;
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printf("Generating the sky colors for each vertex.\n");
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/* setup for the possibility of sunset effects */
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sun_angle = l->sun_angle * RAD_TO_DEG;
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printf(" Sun angle in degrees = %.2f\n", sun_angle);
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if ( (sun_angle > 80.0) && (sun_angle < 100.0) ) {
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/* 0.0 - 0.4 */
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outer_param[0] = (10.0 - fabs(90.0 - sun_angle)) / 25.0;
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outer_param[1] = (10.0 - fabs(90.0 - sun_angle)) / 45.0;
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outer_param[2] = 0.0;
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middle_param[0] = (10.0 - fabs(90.0 - sun_angle)) / 40.0;
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middle_param[1] = (10.0 - fabs(90.0 - sun_angle)) / 60.0;
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middle_param[2] = 0.0;
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outer_diff[0] = outer_param[0] / 6.0;
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outer_diff[1] = outer_param[1] / 6.0;
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outer_diff[2] = outer_param[2] / 6.0;
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middle_diff[0] = middle_param[0] / 6.0;
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middle_diff[1] = middle_param[1] / 6.0;
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middle_diff[2] = middle_param[2] / 6.0;
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} else {
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outer_param[0] = outer_param[1] = outer_param[2] = 0.0;
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middle_param[0] = middle_param[1] = middle_param[2] = 0.0;
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outer_diff[0] = outer_diff[1] = outer_diff[2] = 0.0;
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middle_diff[0] = middle_diff[1] = middle_diff[2] = 0.0;
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}
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/* printf(" outer_red_param = %.2f outer_red_diff = %.2f\n",
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outer_red_param, outer_red_diff); */
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/* calculate transition colors between sky and fog */
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for ( j = 0; j < 3; j++ ) {
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outer_amt[j] = outer_param[j];
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middle_amt[j] = middle_param[j];
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}
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for ( i = 0; i < 6; i++ ) {
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for ( j = 0; j < 3; j++ ) {
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diff = l->sky_color[j] - l->fog_color[j];
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inner_color[i][j] = l->sky_color[j] - diff * 0.3;
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middle_color[i][j] = l->sky_color[j] - diff * 0.9 + middle_amt[j];
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outer_color[i][j] = l->fog_color[j] + outer_amt[j];
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if ( middle_color[i][j] > 1.0 ) { middle_color[i][j] = 1.0; }
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if ( outer_color[i][j] > 1.0 ) { outer_color[i][j] = 1.0; }
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}
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inner_color[i][3] = middle_color[i][3] = outer_color[i][3] =
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l->sky_color[3];
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for ( j = 0; j < 3; j++ ) {
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outer_amt[j] -= outer_diff[j];
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middle_amt[j] -= middle_diff[j];
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}
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printf("inner_color[%d] = %.2f %.2f %.2f %.2f\n", i, inner_color[i][0],
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inner_color[i][1], inner_color[i][2], inner_color[i][3]);
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printf("middle_color[%d] = %.2f %.2f %.2f %.2f\n", i,
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middle_color[i][0], middle_color[i][1], middle_color[i][2],
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middle_color[i][3]);
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printf("outer_color[%d] = %.2f %.2f %.2f %.2f\n", i,
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outer_color[i][0], outer_color[i][1], outer_color[i][2],
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outer_color[i][3]);
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}
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for ( j = 0; j < 3; j++ ) {
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outer_amt[j] = 0.0;
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middle_amt[j] = 0.0;
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}
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for ( i = 6; i < 12; i++ ) {
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for ( j = 0; j < 3; j++ ) {
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diff = l->sky_color[j] - l->fog_color[j];
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inner_color[i][j] = l->sky_color[j] - diff * 0.3;
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middle_color[i][j] = l->sky_color[j] - diff * 0.9 + middle_amt[j];
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outer_color[i][j] = l->fog_color[j] + outer_amt[j];
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if ( middle_color[i][j] > 1.0 ) { middle_color[i][j] = 1.0; }
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if ( outer_color[i][j] > 1.0 ) { outer_color[i][j] = 1.0; }
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}
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inner_color[i][3] = middle_color[i][3] = outer_color[i][3] =
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l->sky_color[3];
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for ( j = 0; j < 3; j++ ) {
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outer_amt[j] += outer_diff[j];
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middle_amt[j] += middle_diff[j];
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}
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printf("inner_color[%d] = %.2f %.2f %.2f %.2f\n", i, inner_color[i][0],
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inner_color[i][1], inner_color[i][2], inner_color[i][3]);
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printf("middle_color[%d] = %.2f %.2f %.2f %.2f\n", i,
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middle_color[i][0], middle_color[i][1], middle_color[i][2],
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middle_color[i][3]);
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printf("outer_color[%d] = %.2f %.2f %.2f %.2f\n", i,
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outer_color[i][0], outer_color[i][1], outer_color[i][2],
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outer_color[i][3]);
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}
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}
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/* Initialize the sky structure and colors */
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void fgSkyInit() {
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fgSkyVerticesInit();
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fgSkyColorsInit();
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}
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/* Draw the Sky */
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void fgSkyRender() {
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struct fgFLIGHT *f;
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struct fgLIGHT *l;
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struct fgVIEW *v;
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float /* inner_color[4], middle_color[4], diff, */ east_dot, dot, angle;
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int i;
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f = ¤t_aircraft.flight;
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l = &cur_light_params;
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v = ¤t_view;
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printf("Rendering the sky.\n");
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xglPushMatrix();
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/* calculate the angle between v->surface_to_sun and
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* v->surface_east. We do this so we can sort out the acos()
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* ambiguity. I wish I could think of a more efficient way ... :-( */
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east_dot = MAT3_DOT_PRODUCT(v->surface_to_sun, v->surface_east);
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printf(" East dot product = %.2f\n", east_dot);
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/* calculate the angle between v->surface_to_sun and
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* v->surface_south. this is how much we have to rotate the sky
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* for it to align with the sun */
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dot = MAT3_DOT_PRODUCT(v->surface_to_sun, v->surface_south);
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printf(" Dot product = %.2f\n", dot);
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if ( east_dot >= 0 ) {
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angle = acos(dot);
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} else {
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angle = -acos(dot);
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}
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printf(" Sky needs to rotate = %.3f rads = %.1f degrees.\n",
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angle, angle * RAD_TO_DEG);
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/* Translate to view position */
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xglTranslatef( v->cur_zero_elev.x, v->cur_zero_elev.y, v->cur_zero_elev.z );
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/* printf(" Translated to %.2f %.2f %.2f\n",
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v->cur_zero_elev.x, v->cur_zero_elev.y, v->cur_zero_elev.z ); */
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/* Rotate to proper orientation */
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printf(" lon = %.2f lat = %.2f\n", FG_Longitude * RAD_TO_DEG,
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FG_Latitude * RAD_TO_DEG);
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xglRotatef( FG_Longitude * RAD_TO_DEG, 0.0, 0.0, 1.0 );
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xglRotatef( 90.0 - FG_Latitude * RAD_TO_DEG, 0.0, 1.0, 0.0 );
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xglRotatef( angle * RAD_TO_DEG, 0.0, 0.0, 1.0 );
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/* Draw inner/center section of sky*/
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xglBegin( GL_TRIANGLE_FAN );
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xglColor4fv(l->sky_color);
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xglVertex3f(0.0, 0.0, CENTER_ELEV);
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for ( i = 0; i < 12; i++ ) {
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xglColor4fv( inner_color[i] );
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xglVertex3fv( inner_vertex[i] );
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}
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xglColor4fv( inner_color[0] );
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xglVertex3fv( inner_vertex[0] );
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xglEnd();
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/* Draw the middle ring */
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xglBegin( GL_TRIANGLE_STRIP );
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for ( i = 0; i < 12; i++ ) {
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xglColor4fv( middle_color[i] );
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xglVertex3fv( middle_vertex[i] );
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xglColor4fv( inner_color[i] );
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xglVertex3fv( inner_vertex[i] );
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}
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xglColor4fv( middle_color[0] );
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/* xglColor4f(1.0, 0.0, 0.0, 1.0); */
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xglVertex3fv( middle_vertex[0] );
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xglColor4fv( inner_color[0] );
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/* xglColor4f(1.0, 0.0, 0.0, 1.0); */
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xglVertex3fv( inner_vertex[0] );
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xglEnd();
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/* Draw the outer ring */
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xglBegin( GL_TRIANGLE_STRIP );
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for ( i = 0; i < 12; i++ ) {
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xglColor4fv( outer_color[i] );
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xglVertex3fv( outer_vertex[i] );
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xglColor4fv( middle_color[i] );
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xglVertex3fv( middle_vertex[i] );
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}
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xglColor4fv( outer_color[0] );
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xglVertex3fv( outer_vertex[0] );
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xglColor4fv( middle_color[0] );
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xglVertex3fv( middle_vertex[0] );
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xglEnd();
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xglPopMatrix();
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}
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/* $Log$
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/* Revision 1.8 1997/12/23 04:58:38 curt
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/* Tweaked the sky coloring a bit to build in structures to allow finer rgb
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/* control.
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/*
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* Revision 1.7 1997/12/22 23:45:48 curt
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* First stab at sunset/sunrise sky glow effects.
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*
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* Revision 1.6 1997/12/22 04:14:34 curt
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* Aligned sky with sun so dusk/dawn effects can be correct relative to the sun.
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*
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* Revision 1.5 1997/12/19 23:34:59 curt
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* Lot's of tweaking with sky rendering and lighting.
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*
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* Revision 1.4 1997/12/19 16:45:02 curt
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* Working on scene rendering order and options.
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*
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* Revision 1.3 1997/12/18 23:32:36 curt
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* First stab at sky dome actually starting to look reasonable. :-)
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*
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* Revision 1.2 1997/12/18 04:07:03 curt
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* Worked on properly translating and positioning the sky dome.
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*
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* Revision 1.1 1997/12/17 23:14:30 curt
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* Initial revision.
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* Begin work on rendering the sky. (Rather than just using a clear screen.)
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*
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*/
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