294 lines
8.6 KiB
C++
294 lines
8.6 KiB
C++
//
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// light.cxx -- lighting routines
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//
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// Written by Curtis Olson, started April 1998.
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//
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// Copyright (C) 1998 Curtis L. Olson - curt@me.umn.edu
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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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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#ifdef HAVE_WINDOWS_H
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# include <windows.h>
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#endif
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#include <GL/gl.h>
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#include <simgear/compiler.h>
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#ifdef SG_MATH_EXCEPTION_CLASH
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# define exception c_exception
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#endif
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#ifdef SG_HAVE_STD_INCLUDES
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# include <cmath>
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#else
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# include <math.h>
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#endif
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#include <string>
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SG_USING_STD(string);
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#include <simgear/constants.h>
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#include <simgear/debug/logstream.hxx>
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#include <simgear/math/interpolater.hxx>
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#include <simgear/math/polar3d.hxx>
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#include <simgear/misc/sg_path.hxx>
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#include <simgear/scene/sky/sky.hxx>
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#include <simgear/screen/colors.hxx>
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#include <Main/main.hxx>
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#include <Main/globals.hxx>
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#include <Main/fg_props.hxx>
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#include <Main/viewer.hxx>
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#include "light.hxx"
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#include "sunpos.hxx"
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// Constructor
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FGLight::FGLight ()
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: _prev_sun_angle(-9999.0),
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_dt_total( 0.0 )
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{
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}
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// Destructor
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FGLight::~FGLight ()
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{
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}
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// initialize lighting tables
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void FGLight::init () {
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SG_LOG( SG_EVENT, SG_INFO,
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"Initializing Lighting interpolation tables." );
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// build the path names of the lookup tables
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SGPath path( globals->get_fg_root() );
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// initialize ambient, diffuse and specular tables
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SGPath ambient_path = path;
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ambient_path.append( "Lighting/ambient" );
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_ambient_tbl = new SGInterpTable( ambient_path.str() );
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SGPath diffuse_path = path;
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diffuse_path.append( "Lighting/diffuse" );
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_diffuse_tbl = new SGInterpTable( diffuse_path.str() );
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SGPath specular_path = path;
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specular_path.append( "Lighting/specular" );
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_specular_tbl = new SGInterpTable( specular_path.str() );
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// initialize sky table
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SGPath sky_path = path;
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sky_path.append( "Lighting/sky" );
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_sky_tbl = new SGInterpTable( sky_path.str() );
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}
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void FGLight::reinit () {
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_prev_sun_angle = -9999.0;
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_dt_total = 0;
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fgUpdateSunPos();
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fgUpdateMoonPos();
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update_sky_color();
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update_adj_fog_color();
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}
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void FGLight::bind () {
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}
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void FGLight::unbind () {
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}
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// update lighting parameters based on current sun position
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void FGLight::update( double dt ) {
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update_adj_fog_color();
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_dt_total += dt;
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if (_dt_total >= 0.5) {
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_dt_total -= 0.5;
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fgUpdateSunPos();
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fgUpdateMoonPos();
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}
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if (_prev_sun_angle != _sun_angle) {
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_prev_sun_angle = _sun_angle;
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update_sky_color();
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}
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}
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void FGLight::update_sky_color () {
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// if the 4th field is 0.0, this specifies a direction ...
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const GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
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const GLfloat base_sky_color[4] = { 0.39, 0.50, 0.74, 1.0 };
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const GLfloat base_fog_color[4] = { 0.84, 0.87, 1.0, 1.0 };
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SG_LOG( SG_EVENT, SG_INFO, "Updating light parameters." );
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// calculate lighting parameters based on sun's relative angle to
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// local up
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float deg = _sun_angle * SGD_RADIANS_TO_DEGREES;
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SG_LOG( SG_EVENT, SG_INFO, " Sun angle = " << deg );
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float ambient = _ambient_tbl->interpolate( deg );
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float diffuse = _diffuse_tbl->interpolate( deg );
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float specular = _specular_tbl->interpolate( deg );
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float sky_brightness = _sky_tbl->interpolate( deg );
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SG_LOG( SG_EVENT, SG_INFO,
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" ambient = " << ambient << " diffuse = " << diffuse
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<< " specular = " << specular << " sky = " << sky_brightness );
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// sky_brightness = 0.15; // used to force a dark sky (when testing)
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// if ( ambient < 0.02 ) { ambient = 0.02; }
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// if ( diffuse < 0.0 ) { diffuse = 0.0; }
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// if ( sky_brightness < 0.1 ) { sky_brightness = 0.1; }
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// set sky color
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_sky_color[0] = base_sky_color[0] * sky_brightness;
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_sky_color[1] = base_sky_color[1] * sky_brightness;
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_sky_color[2] = base_sky_color[2] * sky_brightness;
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_sky_color[3] = base_sky_color[3];
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gamma_correct_rgb( _sky_color );
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// set cloud and fog color
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_cloud_color[0] = _fog_color[0] = base_fog_color[0] * sky_brightness;
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_cloud_color[1] = _fog_color[1] = base_fog_color[1] * sky_brightness;
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_cloud_color[2] = _fog_color[2] = base_fog_color[2] * sky_brightness;
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_cloud_color[3] = _fog_color[3] = base_fog_color[3];
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gamma_correct_rgb( _fog_color );
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// adjust the cloud colors for sunrise/sunset effects (darken them)
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if (_sun_angle > 1.0) {
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float sun2 = sqrt(_sun_angle);
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_cloud_color[0] /= sun2;
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_cloud_color[1] /= sun2;
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_cloud_color[2] /= sun2;
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}
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gamma_correct_rgb( _cloud_color );
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float *sun_color = thesky->get_sun_color();
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_scene_ambient[0] = ((sun_color[0]*0.25 + _cloud_color[0]*0.75) + ambient) / 2;
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_scene_ambient[1] = ((sun_color[1]*0.25 + _cloud_color[1]*0.75) + ambient) / 2;
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_scene_ambient[2] = ((sun_color[2]*0.25 + _cloud_color[2]*0.75) + ambient) / 2;
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_scene_ambient[3] = 1.0;
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_scene_diffuse[0] = (sun_color[0]*0.25 + _fog_color[0]*0.75) * diffuse;
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_scene_diffuse[1] = (sun_color[1]*0.25 + _fog_color[1]*0.75) * diffuse;
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_scene_diffuse[2] = (sun_color[2]*0.25 + _fog_color[2]*0.75) * diffuse;
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_scene_diffuse[3] = 1.0;
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_scene_specular[0] = sun_color[0] * specular;
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_scene_specular[1] = sun_color[1] * specular;
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_scene_specular[2] = sun_color[2] * specular;
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_scene_specular[3] = 1.0;
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}
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// calculate fog color adjusted for sunrise/sunset effects
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void FGLight::update_adj_fog_color () {
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double heading = globals->get_current_view()->getHeading_deg()
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* SGD_DEGREES_TO_RADIANS;
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double heading_offset = globals->get_current_view()->getHeadingOffset_deg()
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* SGD_DEGREES_TO_RADIANS;
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SG_LOG( SG_EVENT, SG_DEBUG, "Updating adjusted fog parameters." );
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// set fog color (we'll try to match the sunset color in the
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// direction we are looking
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// Do some sanity checking ...
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if ( _sun_rotation < -2.0 * SGD_2PI || _sun_rotation > 2.0 * SGD_2PI ) {
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SG_LOG( SG_EVENT, SG_ALERT, "Sun rotation bad = " << _sun_rotation );
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exit(-1);
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}
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if ( heading < -2.0 * SGD_2PI || heading > 2.0 * SGD_2PI ) {
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SG_LOG( SG_EVENT, SG_ALERT, "Heading rotation bad = " << heading );
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exit(-1);
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}
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if ( heading_offset < -2.0 * SGD_2PI || heading_offset > 2.0 * SGD_2PI ) {
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SG_LOG( SG_EVENT, SG_ALERT, "Heading offset bad = " << heading_offset );
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exit(-1);
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}
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double rotation;
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// first determine the difference between our view angle and local
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// direction to the sun
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rotation = -(_sun_rotation + SGD_PI) - heading + heading_offset;
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while ( rotation < 0 ) {
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rotation += SGD_2PI;
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}
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while ( rotation > SGD_2PI ) {
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rotation -= SGD_2PI;
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}
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// revert to unmodified values before usign them.
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//
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float *sun_color = thesky->get_sun_color();
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gamma_restore_rgb( _fog_color );
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// Calculate the fog color in the direction of the sun for
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// sunrise/sunset effects.
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//
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float s_red = (_fog_color[0] + 2 * sun_color[0]*sun_color[0]) / 3;
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float s_green = (_fog_color[1] + 2 * sun_color[1]*sun_color[1]) / 3;
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float s_blue = (_fog_color[2] + 2 * sun_color[2]) / 3;
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// interpolate beween the sunrise/sunset color and the color
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// at the opposite direction of this effect. Take in account
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// the current visibility.
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//
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float av = thesky->get_visibility();
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if (av > 45000)
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av = 45000;
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float avf = 0.87 - (45000 - av) / 83333.33;
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float sif = 0.5 - cos(_sun_angle*2)/2;
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float rf1 = fabs((rotation - SGD_PI) / SGD_PI); // 0.0 .. 1.0
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float rf2 = avf * pow(rf1 * rf1, 1/sif);
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float rf3 = 0.94 - rf2;
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_adj_fog_color[0] = rf3 * _fog_color[0] + rf2 * s_red;
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_adj_fog_color[1] = rf3 * _fog_color[1] + rf2 * s_green;
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_adj_fog_color[2] = rf3 * _fog_color[2] + rf2 * s_blue;
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gamma_correct_rgb( _adj_fog_color );
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// make sure the colors have their original value before they are being
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// used by the rest of the program.
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//
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gamma_correct_rgb( _fog_color );
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}
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