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flightgear/Time/light.cxx
curt ffa2a0feb3 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)
1998-07-22 21:45:37 +00:00

275 lines
8.1 KiB
C++

//
// 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 - 0.4 */
param1[0] = (10.0 - fabs(90.0 - sun_angle_deg)) / 25.0;
param1[1] = (10.0 - fabs(90.0 - sun_angle_deg)) / 35.0;
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 1.12 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.
//