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flightgear/Time/light.cxx
curt 5e9a45af0c Adjusted dusk/dawn lighting ...
1998-08-06 12:47:22 +00:00

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//
// light.hxx -- lighting routines
//
// Written by Curtis Olson, started April 1998.
//
// Copyright (C) 1998 Curtis L. Olson - curt@me.umn.edu
//
// 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.
//
// $Id$
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#ifdef HAVE_WINDOWS_H
# include <windows.h>
#endif
#include <GL/glut.h>
#include <XGL/xgl.h>
#include <string.h>
#include <Aircraft/aircraft.h>
#include <Debug/fg_debug.h>
#include <Include/fg_constants.h>
#include <Main/options.hxx>
#include <Main/views.hxx>
#include <Math/fg_geodesy.h>
#include <Math/interpolater.hxx>
#include <Math/mat3.h>
#include <Math/polar3d.hxx>
#include "fg_time.hxx"
#include "light.hxx"
#include "sunpos.hxx"
fgLIGHT cur_light_params;
// Constructor
fgLIGHT::fgLIGHT( void ) {
}
// initialize lighting tables
void fgLIGHT::Init( void ) {
char path[256];
fgPrintf( FG_EVENT, FG_INFO,
"Initializing Lighting interpolation tables.\n" );
// build the path name to the ambient lookup table
current_options.get_fg_root(path);
strcat(path, "/Scenery/");
strcat(path, "Ambient");
// initialize ambient table
ambient_tbl = new fgINTERPTABLE(path);
// build the path name to the diffuse lookup table
current_options.get_fg_root(path);
strcat(path, "/Scenery/");
strcat(path, "Diffuse");
// initialize diffuse table
diffuse_tbl = new fgINTERPTABLE(path);
// build the path name to the sky lookup table
current_options.get_fg_root(path);
strcat(path, "/Scenery/");
strcat(path, "Sky");
// initialize sky table
sky_tbl = new fgINTERPTABLE(path);
}
// update lighting parameters based on current sun position
void fgLIGHT::Update( void ) {
fgFLIGHT *f;
fgTIME *t;
fgVIEW *v;
// if the 4th field is 0.0, this specifies a direction ...
GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
// base sky color
GLfloat base_sky_color[4] = {0.60, 0.60, 0.90, 1.0};
// base fog color
GLfloat base_fog_color[4] = {0.90, 0.90, 1.00, 1.0};
double deg, ambient, diffuse, sky_brightness;
f = current_aircraft.flight;
t = &cur_time_params;
v = &current_view;
fgPrintf( FG_EVENT, FG_INFO, "Updating light parameters.\n" );
// calculate lighting parameters based on sun's relative angle to
// local up
deg = sun_angle * 180.0 / FG_PI;
fgPrintf( FG_EVENT, FG_INFO, " Sun angle = %.2f.\n", deg );
ambient = ambient_tbl->interpolate( deg );
diffuse = diffuse_tbl->interpolate( deg );
sky_brightness = sky_tbl->interpolate( deg );
fgPrintf( FG_EVENT, FG_INFO,
" ambient = %.2f diffuse = %.2f sky = %.2f\n",
ambient, diffuse, sky_brightness );
// sky_brightness = 0.15; // used to force a dark sky (when testing)
// if ( ambient < 0.02 ) { ambient = 0.02; }
// if ( diffuse < 0.0 ) { diffuse = 0.0; }
// if ( sky_brightness < 0.1 ) { sky_brightness = 0.1; }
scene_ambient[0] = white[0] * ambient;
scene_ambient[1] = white[1] * ambient;
scene_ambient[2] = white[2] * ambient;
scene_diffuse[0] = white[0] * diffuse;
scene_diffuse[1] = white[1] * diffuse;
scene_diffuse[2] = white[2] * diffuse;
// set sky color
sky_color[0] = base_sky_color[0] * sky_brightness;
sky_color[1] = base_sky_color[1] * sky_brightness;
sky_color[2] = base_sky_color[2] * sky_brightness;
sky_color[3] = base_sky_color[3];
// set fog color
fog_color[0] = base_fog_color[0] * sky_brightness;
fog_color[1] = base_fog_color[1] * sky_brightness;
fog_color[2] = base_fog_color[2] * sky_brightness;
fog_color[3] = base_fog_color[3];
}
// calculate fog color adjusted for sunrise/sunset effects
void fgLIGHT::UpdateAdjFog( void ) {
fgFLIGHT *f;
fgVIEW *v;
double sun_angle_deg, rotation, param1[3], param2[3];
f = current_aircraft.flight;
v = &current_view;
fgPrintf( FG_EVENT, FG_DEBUG, "Updating adjusted fog parameters.\n" );
// set fog color (we'll try to match the sunset color in the
// direction we are looking
// first determine the difference between our view angle and local
// direction to the sun
rotation = -(sun_rotation + FG_PI) - (FG_Psi - v->view_offset) ;
while ( rotation < 0 ) {
rotation += FG_2PI;
}
while ( rotation > FG_2PI ) {
rotation -= FG_2PI;
}
rotation *= RAD_TO_DEG;
// fgPrintf( FG_EVENT, FG_INFO,
// " View to sun difference in degrees = %.2f\n", rotation);
// next check if we are in a sunset/sunrise situation
sun_angle_deg = sun_angle * RAD_TO_DEG;
if ( (sun_angle_deg > 80.0) && (sun_angle_deg < 100.0) ) {
/* 0.0 - 0.6 */
param1[0] = (10.0 - fabs(90.0 - sun_angle_deg)) / 10.0;
param1[1] = (10.0 - fabs(90.0 - sun_angle_deg)) / 50.0;
param1[2] = 0.0;
} else {
param1[0] = param1[1] = param1[2] = 0.0;
}
if ( rotation - 180.0 <= 0.0 ) {
param2[0] = param1[0] * (180.0 - rotation) / 180.0;
param2[1] = param1[1] * (180.0 - rotation) / 180.0;
param2[2] = param1[2] * (180.0 - rotation) / 180.0;
// printf("param1[0] = %.2f param2[0] = %.2f\n", param1[0], param2[0]);
} else {
param2[0] = param1[0] * (rotation - 180.0) / 180.0;
param2[1] = param1[1] * (rotation - 180.0) / 180.0;
param2[2] = param1[2] * (rotation - 180.0) / 180.0;
// printf("param1[0] = %.2f param2[0] = %.2f\n", param1[0], param2[0]);
}
adj_fog_color[0] = fog_color[0] + param2[0];
if ( adj_fog_color[0] > 1.0 ) { adj_fog_color[0] = 1.0; }
adj_fog_color[1] = fog_color[1] + param2[1];
if ( adj_fog_color[1] > 1.0 ) { adj_fog_color[1] = 1.0; }
adj_fog_color[2] = fog_color[2] + param2[2];
if ( adj_fog_color[2] > 1.0 ) { adj_fog_color[2] = 1.0; }
adj_fog_color[3] = fog_color[3];
}
// Destructor
fgLIGHT::~fgLIGHT( void ) {
}
// wrapper function for updating light parameters via the event scheduler
void fgLightUpdate ( void ) {
fgLIGHT *l;
l = &cur_light_params;
l->Update();
}
// $Log$
// Revision 1.14 1998/08/06 12:47:22 curt
// Adjusted dusk/dawn lighting ...
//
// Revision 1.13 1998/07/24 21:42:26 curt
// Output message tweaks.
//
// Revision 1.12 1998/07/22 21:45:38 curt
// fg_time.cxx: Removed call to ctime() in a printf() which should be harmless
// but seems to be triggering a bug.
// light.cxx: Added code to adjust fog color based on sunrise/sunset effects
// and view orientation. This is an attempt to match the fog color to the
// sky color in the center of the screen. You see discrepancies at the
// edges, but what else can be done?
// sunpos.cxx: Caculate local direction to sun here. (what compass direction
// do we need to face to point directly at sun)
//
// Revision 1.11 1998/07/13 21:02:08 curt
// Wrote access functions for current fgOPTIONS.
//
// Revision 1.10 1998/07/08 14:48:38 curt
// polar3d.h renamed to polar3d.hxx
//
// Revision 1.9 1998/05/29 20:37:51 curt
// Renamed <Table>.table to be <Table> so we can add a .gz under DOS.
//
// Revision 1.8 1998/05/20 20:54:16 curt
// Converted fgLIGHT to a C++ class.
//
// Revision 1.7 1998/05/13 18:26:50 curt
// Root path info moved to fgOPTIONS.
//
// Revision 1.6 1998/05/11 18:18:51 curt
// Made fog color slightly bluish.
//
// Revision 1.5 1998/05/03 00:48:38 curt
// polar.h -> polar3d.h
//
// Revision 1.4 1998/04/28 01:22:18 curt
// Type-ified fgTIME and fgVIEW.
//
// Revision 1.3 1998/04/26 05:10:04 curt
// "struct fgLIGHT" -> "fgLIGHT" because fgLIGHT is typedef'd.
//
// Revision 1.2 1998/04/24 00:52:30 curt
// Wrapped "#include <config.h>" in "#ifdef HAVE_CONFIG_H"
// Fog color fixes.
// Separated out lighting calcs into their own file.
//
// Revision 1.1 1998/04/22 13:24:06 curt
// C++ - ifiing the code a bit.
// Starting to reorginize some of the lighting calcs to use a table lookup.
//
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