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Add the /rendering/scene/scattering property to allow the weather system to contoll the amount of light scattering (or absorption) of the fog

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This commit is contained in:
Erik Hofman 2011-06-04 13:11:56 +02:00
parent f28ddb0b5a
commit c346bcee77
2 changed files with 32 additions and 20 deletions
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48
src/Time/light.cxx
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@ -76,7 +76,9 @@ FGLight::FGLight ()
_cloud_color(0, 0, 0, 0),
_adj_fog_color(0, 0, 0, 0),
_adj_sky_color(0, 0, 0, 0),
_humidity(69.5),
_saturation(1.0),
_scattering(0.8),
_dt_total(0)
{
}
@ -140,8 +142,14 @@ void FGLight::reinit () {
void FGLight::bind () {
SGPropertyNode *prop = globals->get_props();
prop->tie("/sim/time/sun-angle-rad",SGRawValuePointer<double>(&_sun_angle));
// Write Only
prop->tie("/rendering/scene/saturation",SGRawValuePointer<float>(&_saturation));
prop->tie("/rendering/scene/scattering",SGRawValuePointer<float>(&_scattering));
prop->tie("/environment/relative-humidity",SGRawValuePointer<float>(&_humidity));
// Read Only
prop->tie("/sim/time/sun-angle-rad",SGRawValuePointer<double>(&_sun_angle));
prop->tie("/rendering/scene/ambient/red",SGRawValuePointer<float>(&_scene_ambient[0]));
prop->tie("/rendering/scene/ambient/green",SGRawValuePointer<float>(&_scene_ambient[1]));
prop->tie("/rendering/scene/ambient/blue",SGRawValuePointer<float>(&_scene_ambient[2]));
@ -170,8 +178,11 @@ void FGLight::bind () {
void FGLight::unbind () {
SGPropertyNode *prop = globals->get_props();
prop->untie("/sim/time/sun-angle-rad");
prop->untie("/rendering/scene/saturation");
prop->untie("/rendering/scene/scattering");
prop->untie("/environment/relative-humidity");
prop->untie("/sim/time/sun-angle-rad");
prop->untie("/rendering/scene/ambient/red");
prop->untie("/rendering/scene/ambient/green");
prop->untie("/rendering/scene/ambient/blue");
@ -214,8 +225,7 @@ void FGLight::update_sky_color () {
// calculate lighting parameters based on sun's relative angle to
// local up
static SGConstPropertyNode_ptr humidity = fgGetNode("/environment/relative-humidity");
float av = humidity->getFloatValue() * 45;
float av = _humidity * 45;
float visibility_log = log(av)/11.0;
float visibility_inv = (45000.0 - av)/45000.0;
@ -224,6 +234,8 @@ void FGLight::update_sky_color () {
if (_saturation < 0.0) _saturation = 0.0;
else if (_saturation > 1.0) _saturation = 1.0;
if (_scattering < 0.0) _scattering = 0.0;
else if (_scattering > 1.0) _scattering = 1.0;
float ambient = _ambient_tbl->interpolate( deg ) + visibility_inv/10;
float diffuse = _diffuse_tbl->interpolate( deg );
@ -242,7 +254,7 @@ void FGLight::update_sky_color () {
// sky_brightness = 0.15; // used to force a dark sky (when testing)
// set fog and cloud color
float sqrt_sky_brightness = 1.0 - sqrt(1.0 - sky_brightness);
float sqrt_sky_brightness = (1.0 - sqrt(1.0 - sky_brightness))*_scattering;
_fog_color[0] = base_fog_color[0] * sqrt_sky_brightness;
_fog_color[1] = base_fog_color[1] * sqrt_sky_brightness;
_fog_color[2] = base_fog_color[2] * sqrt_sky_brightness;
@ -373,11 +385,10 @@ void FGLight::update_adj_fog_color () {
sif = 1e-4;
float rf1 = fabs((hor_rotation - SGD_PI) / SGD_PI); // 0.0 .. 1.0
float rf2 = avf * pow(rf1*rf1, 1/sif) * 1.0639 * _saturation;
float rf2 = avf * pow(rf1*rf1, 1/sif) * 1.0639 * _saturation * _scattering;
float rf3 = 1.0 - rf2;
gamma = system_gamma * (0.9 - sif*avf);
_adj_fog_color[0] = rf3 * _fog_color[0] + rf2 * s_red;
_adj_fog_color[1] = rf3 * _fog_color[1] + rf2 * s_green;
_adj_fog_color[2] = rf3 * _fog_color[2] + rf2 * s_blue;
@ -399,23 +410,19 @@ void FGLight::updateSunPos()
SG_LOG( SG_EVENT, SG_DEBUG, " Updating Sun position" );
SG_LOG( SG_EVENT, SG_DEBUG, " Gst = " << t->getGst() );
double sun_l;
double sun_gc_lat;
fgSunPositionGST(t->getGst(), &sun_l, &sun_gc_lat);
set_sun_lon(sun_l);
fgSunPositionGST(t->getGst(), &_sun_lon, &_sun_lat);
// It might seem that sun_gc_lat needs to be converted to geodetic
// latitude here, but it doesn't. The sun latitude is the latitude
// of the point on the earth where the up vector has the same
// angle from geocentric Z as the sun direction. But geodetic
// latitude is defined as 90 - angle of up vector from Z!
set_sun_lat(sun_gc_lat);
SGVec3d sunpos(SGVec3d::fromGeoc(SGGeoc::fromRadM(sun_l, sun_gc_lat,
SGVec3d sunpos(SGVec3d::fromGeoc(SGGeoc::fromRadM(_sun_lon, _sun_lat,
SGGeodesy::EQURAD)));
SG_LOG( SG_EVENT, SG_DEBUG, " t->cur_time = " << t->get_cur_time() );
SG_LOG( SG_EVENT, SG_DEBUG,
" Sun Geocentric lat = " << sun_gc_lat
<< " Geodcentric lat = " << sun_gc_lat );
" Sun Geocentric lat = " << _sun_lat
<< " Geodcentric lat = " << _sun_lat );
// update the sun light vector
sun_vec() = SGVec4f(toVec3f(normalize(sunpos)), 0);
@ -431,15 +438,16 @@ void FGLight::updateSunPos()
// cout << "nsun = " << nsun[0] << "," << nsun[1] << ","
// << nsun[2] << endl;
set_sun_angle( acos( dot ( world_up, nsun ) ) );
_sun_angle = acos( dot ( world_up, nsun ) );
SG_LOG( SG_EVENT, SG_DEBUG, "sun angle relative to current location = "
<< get_sun_angle() );
// Get direction to the sun in the local frame.
SGVec3d local_sun_vec = hlOr.transform(nsun);
// Angle from south. XXX Is this correct in the southern hemisphere?
double angle = atan2(local_sun_vec.x(), -local_sun_vec.y());
set_sun_rotation(angle);
// cout << " Sky needs to rotate = " << angle << " rads = "
// << angle * SGD_RADIANS_TO_DEGREES << " degrees." << endl;
_sun_rotation = atan2(local_sun_vec.x(), -local_sun_vec.y());
// cout << " Sky needs to rotate = " << _sun_rotation << " rads = "
// << _sun_rotation * SGD_RADIANS_TO_DEGREES << " degrees." << endl;
}

4
src/Time/light.hxx
View file

@ -96,7 +96,11 @@ private:
// clear sky and fog color adjusted for sunset effects
SGVec4f _adj_fog_color;
SGVec4f _adj_sky_color;
// input parameters affected by the weather system
float _humidity;
float _saturation;
float _scattering;
double _dt_total;