1 // sky.cxx -- ssg based sky model
3 // Written by Curtis Olson, started December 1997.
4 // SSG-ified by Curtis Olson, February 2000.
6 // Copyright (C) 1997-2000 Curtis L. Olson - http://www.flightgear.org/~curt
8 // This library is free software; you can redistribute it and/or
9 // modify it under the terms of the GNU Library General Public
10 // License as published by the Free Software Foundation; either
11 // version 2 of the License, or (at your option) any later version.
13 // This library is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 // Library General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
25 # include <simgear_config.h>
28 #include <simgear/math/sg_random.h>
31 #include "cloudfield.hxx"
34 SGSky::SGSky( void ) {
35 effective_visibility = visibility = 10000.0;
37 // near cloud visibility state variables
46 pre_root = new osg::Group;
47 post_root = new osg::Group;
48 cloud_root = new osg::Group;
50 pre_selector = new osg::Switch;
51 post_selector = new osg::Switch;
53 pre_transform = new osg::MatrixTransform;
54 post_transform = new osg::MatrixTransform;
64 // initialize the sky and connect the components to the scene graph at
65 // the provided branch
66 void SGSky::build( double h_radius_m, double v_radius_m,
67 double sun_size, double moon_size,
68 int nplanets, SGVec3d planet_data[7],
69 int nstars, SGVec3d star_data[], SGPropertyNode *property_tree_node )
72 pre_transform->addChild( dome->build( h_radius_m, v_radius_m ) );
74 planets = new SGStars;
75 pre_transform->addChild(planets->build(nplanets, planet_data, h_radius_m));
78 pre_transform->addChild( stars->build(nstars, star_data, h_radius_m) );
81 pre_transform->addChild( moon->build(tex_path, moon_size) );
84 pre_transform->addChild( oursun->build(tex_path, sun_size, property_tree_node ) );
86 pre_selector->addChild( pre_transform.get() );
88 post_selector->addChild( post_transform.get() );
90 pre_root->addChild( pre_selector.get() );
91 post_root->addChild( post_selector.get() );
95 // repaint the sky components based on current value of sun_angle,
96 // sky, and fog colors.
98 // sun angle in degrees relative to verticle
99 // 0 degrees = high noon
100 // 90 degrees = sun rise/set
101 // 180 degrees = darkest midnight
102 bool SGSky::repaint( const SGSkyColor &sc )
104 if ( effective_visibility > 1000.0 ) {
106 dome->repaint( sc.sky_color, sc.fog_color, sc.sun_angle,
107 effective_visibility );
109 stars->repaint( sc.sun_angle, sc.nstars, sc.star_data );
110 planets->repaint( sc.sun_angle, sc.nplanets, sc.planet_data );
111 oursun->repaint( sc.sun_angle, effective_visibility );
112 moon->repaint( sc.moon_angle );
114 for ( unsigned i = 0; i < cloud_layers.size(); ++i ) {
115 if (cloud_layers[i]->getCoverage() != SGCloudLayer::SG_CLOUD_CLEAR){
116 cloud_layers[i]->repaint( sc.cloud_color );
128 // reposition the sky at the specified origin and orientation
130 // lon specifies a rotation about the Z axis
131 // lat specifies a rotation about the new Y axis
132 // spin specifies a rotation about the new Z axis (this allows
133 // additional orientation for the sunrise/set effects and is used by
134 // the skydome and perhaps clouds.
135 bool SGSky::reposition( SGSkyState &st, double dt )
138 double angle = st.gst * 15; // degrees
140 dome->reposition( st.zero_elev, st.alt, st.lon, st.lat, st.spin );
142 stars->reposition( st.view_pos, angle );
143 planets->reposition( st.view_pos, angle );
145 oursun->reposition( st.view_pos, angle,
146 st.sun_ra, st.sun_dec, st.sun_dist, st.lat, st.alt, st.sun_angle );
148 moon->reposition( st.view_pos, angle,
149 st.moon_ra, st.moon_dec, st.moon_dist );
151 for ( unsigned i = 0; i < cloud_layers.size(); ++i ) {
152 if ( cloud_layers[i]->getCoverage() != SGCloudLayer::SG_CLOUD_CLEAR ) {
153 cloud_layers[i]->reposition( st.zero_elev, st.view_up,
154 st.lon, st.lat, st.alt, dt );
156 cloud_layers[i]->getNode()->setAllChildrenOff();
163 SGSky::add_cloud_layer( SGCloudLayer * layer )
165 cloud_layers.push_back(layer);
166 cloud_root->addChild(layer->getNode());
170 SGSky::get_cloud_layer (int i) const
172 return cloud_layers[i];
176 SGSky::get_cloud_layer (int i)
178 return cloud_layers[i];
182 SGSky::get_cloud_layer_count () const
184 return cloud_layers.size();
187 // modify the current visibility based on cloud layers, thickness,
188 // transition range, and simulated "puffs".
189 void SGSky::modify_vis( float alt, float time_factor ) {
190 float effvis = visibility;
192 for ( int i = 0; i < (int)cloud_layers.size(); ++i ) {
193 float asl = cloud_layers[i]->getElevation_m();
194 float thickness = cloud_layers[i]->getThickness_m();
195 float transition = cloud_layers[i]->getTransition_m();
199 if ( cloud_layers[i]->getCoverage() == SGCloudLayer::SG_CLOUD_CLEAR ) {
200 // less than 50% coverage -- assume we're in the clear for now
202 } else if ( alt < asl - transition ) {
205 } else if ( alt < asl ) {
206 // in lower transition
207 ratio = (asl - alt) / transition;
208 } else if ( alt < asl + thickness ) {
211 } else if ( alt < asl + thickness + transition ) {
212 // in upper transition
213 ratio = (alt - (asl + thickness)) / transition;
219 if ( cloud_layers[i]->getCoverage() == SGCloudLayer::SG_CLOUD_CLEAR ||
220 cloud_layers[i]->get_layer3D()->is3D() && SGCloudField::enable3D) {
221 // do nothing, clear layers aren't drawn, don't affect
222 // visibility andn dont' need to be faded in or out.
223 } else if ( (cloud_layers[i]->getCoverage() ==
224 SGCloudLayer::SG_CLOUD_FEW)
225 || (cloud_layers[i]->getCoverage() ==
226 SGCloudLayer::SG_CLOUD_SCATTERED) )
228 // set the alpha fade value for the cloud layer. For less
229 // dense cloud layers we fade the layer to nothing as we
230 // approach it because we stay clear visibility-wise as we
232 float temp = ratio * 2.0;
233 if ( temp > 1.0 ) { temp = 1.0; }
234 cloud_layers[i]->setAlpha( temp );
236 // don't touch visibility
238 // maintain full alpha for denser cloud layer types.
239 // Let's set the value explicitly in case someone changed
241 cloud_layers[i]->setAlpha( 1.0 );
243 // lower visibility as we approach the cloud layer.
244 // accumulate effects from multiple cloud layers
251 // calc chance of entering cloud puff
252 double rnd = sg_random();
253 double chance = rnd * rnd * rnd;
254 if ( chance > 0.95 /* * (diff - 25) / 50.0 */ ) {
256 puff_length = sg_random() * 2.0; // up to 2 seconds
257 puff_progression = 0.0;
262 // modify actual_visibility based on puff envelope
264 if ( puff_progression <= ramp_up ) {
265 double x = SGD_PI_2 * puff_progression / ramp_up;
266 double factor = 1.0 - sin( x );
267 // cout << "ramp up = " << puff_progression
268 // << " factor = " << factor << endl;
269 effvis = effvis * factor;
270 } else if ( puff_progression >= ramp_up + puff_length ) {
271 double x = SGD_PI_2 *
272 (puff_progression - (ramp_up + puff_length)) /
274 double factor = sin( x );
275 // cout << "ramp down = "
276 // << puff_progression - (ramp_up + puff_length)
277 // << " factor = " << factor << endl;
278 effvis = effvis * factor;
283 /* cout << "len = " << puff_length
285 << " factor = " << factor
286 << " actual_visibility = " << actual_visibility
289 // time_factor = ( global_multi_loop *
290 // current_options.get_speed_up() ) /
291 // (double)current_options.get_model_hz();
293 puff_progression += time_factor;
294 // cout << "time factor = " << time_factor << endl;
296 /* cout << "gml = " << global_multi_loop
297 << " speed up = " << current_options.get_speed_up()
298 << " hz = " << current_options.get_model_hz() << endl;
301 if ( puff_progression > puff_length + ramp_up + ramp_down) {
308 // never let visibility drop below 25 meters
309 if ( effvis <= 25.0 ) {
315 effective_visibility = effvis;