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Differentiate between sun color (based in visibility) and scene color (based on humidity)

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ehofman
2009-08-16 08:42:23 +00:00
committed by Tim Moore
parent 1f1e28baf8
commit 0c39caa622
2 changed files with 118 additions and 117 deletions
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234
simgear/scene/sky/oursun.cxx
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@@ -81,10 +81,8 @@ SGSun::build( SGPath path, double sun_size, SGPropertyNode *property_tree_Node )
osg::Material* material = new osg::Material;
material->setColorMode(osg::Material::AMBIENT_AND_DIFFUSE);
material->setEmission(osg::Material::FRONT_AND_BACK,
osg::Vec4(0, 0, 0, 1));
material->setSpecular(osg::Material::FRONT_AND_BACK,
osg::Vec4(0, 0, 0, 1));
material->setEmission(osg::Material::FRONT_AND_BACK, osg::Vec4(0,0,0,1));
material->setSpecular(osg::Material::FRONT_AND_BACK, osg::Vec4(0,0,0,1));
stateSet->setAttribute(material);
osg::ShadeModel* shadeModel = new osg::ShadeModel;
@@ -118,6 +116,9 @@ SGSun::build( SGPath path, double sun_size, SGPropertyNode *property_tree_Node )
sun_cl = new osg::Vec4Array;
sun_cl->push_back(osg::Vec4(1, 1, 1, 1));
scene_cl = new osg::Vec4Array;
scene_cl->push_back(osg::Vec4(1, 1, 1, 1));
osg::Vec3Array* sun_vl = new osg::Vec3Array;
sun_vl->push_back(osg::Vec3(-sun_size, 0, -sun_size));
sun_vl->push_back(osg::Vec3(sun_size, 0, -sun_size));
@@ -217,7 +218,6 @@ SGSun::build( SGPath path, double sun_size, SGPropertyNode *property_tree_Node )
sun_transform->addChild( geode );
// force a repaint of the sun colors with arbitrary defaults
repaint( 0.0, 1.0 );
@@ -232,126 +232,126 @@ SGSun::build( SGPath path, double sun_size, SGPropertyNode *property_tree_Node )
// 180 degrees = darkest midnight
bool SGSun::repaint( double sun_angle, double new_visibility ) {
if ( visibility != new_visibility ) {
visibility = new_visibility;
if ( visibility != new_visibility ) {
visibility = new_visibility;
static const double sqrt_m_log01 = sqrt( -log( 0.01 ) );
sun_exp2_punch_through = sqrt_m_log01 / ( visibility * 15 );
}
if (new_visibility < 100.0) new_visibility = 100.0;
else if (new_visibility > 45000.0) new_visibility = 45000.0;
sun_exp2_punch_through = 2.0/log(visibility);
}
if ( prev_sun_angle != sun_angle ) {
prev_sun_angle = sun_angle;
if ( prev_sun_angle != sun_angle ) {
prev_sun_angle = sun_angle;
// determine how much aerosols are in the air (rough guess)
double aerosol_factor;
if ( visibility < 100 ){
aerosol_factor = 8000;
}
else {
aerosol_factor = 80.5 / log( visibility / 100 );
}
// determine how much aerosols are in the air (rough guess)
double aerosol_factor;
if ( visibility < 100 ) {
aerosol_factor = 8000;
}
else {
aerosol_factor = 80.5 / log( visibility / 100 );
}
// get environmental data from property tree or use defaults
double rel_humidity, density_avg;
// get environmental data from property tree or use defaults
double rel_humidity, density_avg;
if ( !env_node )
{
rel_humidity = 0.5;
density_avg = 0.7;
}
else
{
rel_humidity = env_node->getFloatValue( "relative-humidity" );
density_avg = env_node->getFloatValue( "atmosphere/density-tropo-avg" );
}
if ( !env_node ) {
rel_humidity = 0.5;
density_avg = 0.7;
}
else {
rel_humidity = env_node->getFloatValue( "relative-humidity" );
density_avg = env_node->getFloatValue( "atmosphere/density-tropo-avg" );
}
// ok, now let's go and generate the sun color
osg::Vec4 i_halo_color, o_halo_color, sun_color;
// ok, now let's go and generate the sun and scene color
osg::Vec4 i_halo_color, o_halo_color, scene_color, sun_color;
// Some comments:
// When the sunangle changes, light has to travel a longer distance through the atmosphere.
// So it's scattered more due to raleigh scattering, which affects blue more than green light.
// Red is almost not scattered and effectively only get's touched when the sun is near the horizon.
// Visability also affects suncolor inasmuch as more particles are in the air that cause more scattering.
// We base our calculation on the halo's color, which is most scattered.
// Some comments:
// * When the sunangle changes, light has to travel a longer
// distance through the atmosphere. So it's scattered more due
// to raleigh scattering, which affects blue more than green
// light.
// * Red is almost not scattered and effectively only get's
// touched when the sun is near the horizon.
// * Visability also affects suncolor inasmuch as more particles
// are in the air that cause more scattering.
// * We base our calculation on the halo's color, which is most
// scattered.
double red_scat_f, red_scat_corr_f, green_scat_f, blue_scat_f;
// Red - is almost not scattered
// Lambda is 700 nm
double red_scat_f = ( aerosol_factor * path_distance * density_avg ) / 5E+07;
sun_color[0] = 1 - red_scat_f;
i_halo_color[0] = 1 - ( 1.1 * red_scat_f );
o_halo_color[0] = 1 - ( 1.4 * red_scat_f );
// Green - 546.1 nm
double green_scat_f = ( aerosol_factor * path_distance * density_avg ) / 8.8938E+06;
sun_color[1] = 1 - green_scat_f;
i_halo_color[1] = 1 - ( 1.1 * green_scat_f );
o_halo_color[1] = 1 - ( 1.4 * green_scat_f );
// Blue - 435.8 nm
double blue_scat_f = ( aerosol_factor * path_distance * density_avg ) / 3.607E+06;
sun_color[2] = 1 - blue_scat_f;
i_halo_color[2] = 1 - ( 1.1 * blue_scat_f );
o_halo_color[2] = 1 - ( 1.4 * blue_scat_f );
// Alpha
sun_color[3] = 1;
i_halo_color[3] = 1;
o_halo_color[3] = blue_scat_f;
if ( ( new_visibility < 10000 ) && ( blue_scat_f > 1 )){
o_halo_color[3] = 2 - blue_scat_f;
}
// Now that we have the color calculated
// let's consider the saturation which is produced by mie scattering
double saturation = 1 - ( rel_humidity / 200 );
sun_color[1] += (( 1 - saturation ) * ( 1 - sun_color[1] ));
sun_color[2] += (( 1 - saturation ) * ( 1 - sun_color[2] ));
i_halo_color[1] += (( 1 - saturation ) * ( 1 - i_halo_color[1] ));
i_halo_color[2] += (( 1 - saturation ) * ( 1 - i_halo_color[2] ));
o_halo_color[1] += (( 1 - saturation ) * ( 1 - o_halo_color[1] ));
o_halo_color[2] += (( 1 - saturation ) * ( 1 - o_halo_color[2] ));
// just to make sure we're in the limits
if ( sun_color[0] < 0 ) sun_color[0] = 0;
else if ( sun_color[0] > 1) sun_color[0] = 1;
if ( i_halo_color[0] < 0 ) i_halo_color[0] = 0;
else if ( i_halo_color[0] > 1) i_halo_color[0] = 1;
if ( o_halo_color[0] < 0 ) o_halo_color[0] = 0;
else if ( o_halo_color[0] > 1) o_halo_color[0] = 1;
if ( sun_color[1] < 0 ) sun_color[1] = 0;
else if ( sun_color[1] > 1) sun_color[1] = 1;
if ( i_halo_color[1] < 0 ) i_halo_color[1] = 0;
else if ( i_halo_color[1] > 1) i_halo_color[1] = 1;
if ( o_halo_color[1] < 0 ) o_halo_color[1] = 0;
else if ( o_halo_color[1] > 1) o_halo_color[1] = 1;
if ( sun_color[2] < 0 ) sun_color[2] = 0;
else if ( sun_color[2] > 1) sun_color[2] = 1;
if ( i_halo_color[2] < 0 ) i_halo_color[2] = 0;
else if ( i_halo_color[2] > 1) i_halo_color[2] = 1;
if ( o_halo_color[2] < 0 ) o_halo_color[2] = 0;
else if ( o_halo_color[2] > 1) o_halo_color[2] = 1;
if ( o_halo_color[3] < 0 ) o_halo_color[3] = 0;
else if ( o_halo_color[3] > 1) o_halo_color[3] = 1;
// Red - is almost not scattered
// Lambda is 700 nm
gamma_correct_rgb( i_halo_color._v );
gamma_correct_rgb( o_halo_color._v );
gamma_correct_rgb( sun_color._v );
red_scat_f = (aerosol_factor * path_distance * density_avg)/5E+07;
red_scat_corr_f = sun_exp2_punch_through / (1 - red_scat_f);
sun_color[0] = 1;
scene_color[0] = 1 - red_scat_f;
(*sun_cl)[0] = sun_color;
sun_cl->dirty();
(*ihalo_cl)[0] = i_halo_color;
ihalo_cl->dirty();
(*ohalo_cl)[0] = o_halo_color;
ohalo_cl->dirty();
// Green - 546.1 nm
green_scat_f = (aerosol_factor * path_distance * density_avg)/8.8938E+06;
sun_color[1] = 1 - green_scat_f * red_scat_corr_f;
scene_color[1] = 1 - green_scat_f;
// Blue - 435.8 nm
blue_scat_f = (aerosol_factor * path_distance * density_avg)/3.607E+06;
sun_color[2] = 1 - blue_scat_f * red_scat_corr_f;
scene_color[2] = 1 - blue_scat_f;
// Alpha
sun_color[3] = 1;
scene_color[3] = 1;
// Now that we have the color calculated
// let's consider the saturation which is produced by mie scattering
double saturation = 1 - ( rel_humidity / 200 );
scene_color[1] += (( 1 - saturation ) * ( 1 - scene_color[1] ));
scene_color[2] += (( 1 - saturation ) * ( 1 - scene_color[2] ));
if (sun_color[0] > 1.0) sun_color[0] = 1.0;
if (sun_color[0] < 0.0) sun_color[0] = 0.0;
if (sun_color[1] > 1.0) sun_color[1] = 1.0;
if (sun_color[1] < 0.0) sun_color[1] = 0.0;
if (sun_color[2] > 1.0) sun_color[2] = 1.0;
if (sun_color[2] < 0.0) sun_color[2] = 0.0;
if (scene_color[0] > 1.0) scene_color[0] = 1.0;
if (scene_color[0] < 0.0) scene_color[0] = 0.0;
if (scene_color[1] > 1.0) scene_color[1] = 1.0;
if (scene_color[1] < 0.0) scene_color[1] = 0.0;
if (scene_color[2] > 1.0) scene_color[2] = 1.0;
if (scene_color[2] < 0.0) scene_color[2] = 0.0;
double scene_f = 0.5 * (1 / (1 - red_scat_f));
double sun_f = 1.0 - scene_f;
i_halo_color[0] = sun_f * sun_color[0] + scene_f * scene_color[0];
i_halo_color[1] = sun_f * sun_color[1] + scene_f * scene_color[1];
i_halo_color[2] = sun_f * sun_color[2] + scene_f * scene_color[2];
i_halo_color[3] = 1;
o_halo_color[0] = 0.2 * sun_color[0] + 0.8 * scene_color[0];
o_halo_color[1] = 0.2 * sun_color[1] + 0.8 * scene_color[1];
o_halo_color[2] = 0.2 * sun_color[2] + 0.8 * scene_color[2];
o_halo_color[3] = blue_scat_f;
if ((new_visibility < 10000) && (blue_scat_f > 1)) {
o_halo_color[3] = 2 - blue_scat_f;
}
if (o_halo_color[3] > 1) o_halo_color[3] = 1;
if (o_halo_color[3] < 0) o_halo_color[3] = 0;
gamma_correct_rgb( i_halo_color._v );
gamma_correct_rgb( o_halo_color._v );
gamma_correct_rgb( scene_color._v );
gamma_correct_rgb( sun_color._v );
(*sun_cl)[0] = sun_color;
sun_cl->dirty();
(*scene_cl)[0] = scene_color;
scene_cl->dirty();
(*ihalo_cl)[0] = i_halo_color;
ihalo_cl->dirty();
(*ohalo_cl)[0] = o_halo_color;
ohalo_cl->dirty();
}
return true;
@@ -364,7 +364,7 @@ bool SGSun::repaint( double sun_angle, double new_visibility ) {
// rotation (i.e. for the current time of day.)
// Then calculate stuff needed for the sun-coloring
bool SGSun::reposition( double rightAscension, double declination,
double sun_dist, double lat, double alt_asl, double sun_angle)
double sun_dist, double lat, double alt_asl, double sun_angle)
{
// GST - GMT sidereal time
osg::Matrix T2, RA, DEC;
@@ -420,5 +420,5 @@ bool SGSun::reposition( double rightAscension, double declination,
SGVec4f
SGSun::get_color()
{
return SGVec4f((*sun_cl)[0][0], (*sun_cl)[0][1], (*sun_cl)[0][2], (*sun_cl)[0][3]);
return SGVec4f((*scene_cl)[0][0], (*scene_cl)[0][1], (*scene_cl)[0][2], (*scene_cl)[0][3]);
}

1
simgear/scene/sky/oursun.hxx
View File

@@ -42,6 +42,7 @@ class SGSun : public SGReferenced {
osg::ref_ptr<osg::MatrixTransform> sun_transform;
osg::ref_ptr<osg::Vec4Array> sun_cl;
osg::ref_ptr<osg::Vec4Array> scene_cl;
osg::ref_ptr<osg::Vec4Array> ihalo_cl;
osg::ref_ptr<osg::Vec4Array> ohalo_cl;