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>
29 #include <simgear/scene/util/RenderConstants.hxx>
32 #include "cloudfield.hxx"
35 SGSky::SGSky( void ) {
36 effective_visibility = visibility = 10000.0;
38 // near cloud visibility state variables
47 pre_root = new osg::Group;
48 pre_root->setNodeMask(simgear::BACKGROUND_BIT);
49 cloud_root = new osg::Group;
50 cloud_root->setNodeMask(simgear::BACKGROUND_BIT | simgear::MODEL_BIT);
52 pre_selector = new osg::Switch;
54 pre_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 pre_root->addChild( pre_selector.get() );
92 // repaint the sky components based on current value of sun_angle,
93 // sky, and fog colors.
95 // sun angle in degrees relative to verticle
96 // 0 degrees = high noon
97 // 90 degrees = sun rise/set
98 // 180 degrees = darkest midnight
99 bool SGSky::repaint( const SGSkyColor &sc )
101 if ( effective_visibility > 1000.0 ) {
103 dome->repaint( sc.sky_color, sc.fog_color, sc.sun_angle,
104 effective_visibility );
106 stars->repaint( sc.sun_angle, sc.nstars, sc.star_data );
107 planets->repaint( sc.sun_angle, sc.nplanets, sc.planet_data );
108 oursun->repaint( sc.sun_angle, effective_visibility );
109 moon->repaint( sc.moon_angle );
111 for ( unsigned i = 0; i < cloud_layers.size(); ++i ) {
112 if (cloud_layers[i]->getCoverage() != SGCloudLayer::SG_CLOUD_CLEAR){
113 cloud_layers[i]->repaint( sc.cloud_color );
125 // reposition the sky at the specified origin and orientation
127 // lon specifies a rotation about the Z axis
128 // lat specifies a rotation about the new Y axis
129 // spin specifies a rotation about the new Z axis (this allows
130 // additional orientation for the sunrise/set effects and is used by
131 // the skydome and perhaps clouds.
132 bool SGSky::reposition( SGSkyState &st, double dt )
135 double angle = st.gst * 15; // degrees
137 dome->reposition( st.zero_elev, st.alt, st.lon, st.lat, st.spin );
139 stars->reposition( st.view_pos, angle );
140 planets->reposition( st.view_pos, angle );
142 oursun->reposition( st.view_pos, angle,
143 st.sun_ra, st.sun_dec, st.sun_dist, st.lat, st.alt, st.sun_angle );
145 moon->reposition( st.view_pos, angle,
146 st.moon_ra, st.moon_dec, st.moon_dist );
148 for ( unsigned i = 0; i < cloud_layers.size(); ++i ) {
149 if ( cloud_layers[i]->getCoverage() != SGCloudLayer::SG_CLOUD_CLEAR ) {
150 cloud_layers[i]->reposition( st.zero_elev, st.view_up,
151 st.lon, st.lat, st.alt, dt );
153 cloud_layers[i]->getNode()->setAllChildrenOff();
160 SGSky::add_cloud_layer( SGCloudLayer * layer )
162 cloud_layers.push_back(layer);
163 cloud_root->addChild(layer->getNode());
167 SGSky::get_cloud_layer (int i) const
169 return cloud_layers[i];
173 SGSky::get_cloud_layer (int i)
175 return cloud_layers[i];
179 SGSky::get_cloud_layer_count () const
181 return cloud_layers.size();
184 // modify the current visibility based on cloud layers, thickness,
185 // transition range, and simulated "puffs".
186 void SGSky::modify_vis( float alt, float time_factor ) {
187 float effvis = visibility;
189 for ( int i = 0; i < (int)cloud_layers.size(); ++i ) {
190 float asl = cloud_layers[i]->getElevation_m();
191 float thickness = cloud_layers[i]->getThickness_m();
192 float transition = cloud_layers[i]->getTransition_m();
196 if ( cloud_layers[i]->getCoverage() == SGCloudLayer::SG_CLOUD_CLEAR ) {
197 // less than 50% coverage -- assume we're in the clear for now
199 } else if ( alt < asl - transition ) {
202 } else if ( alt < asl ) {
203 // in lower transition
204 ratio = (asl - alt) / transition;
205 } else if ( alt < asl + thickness ) {
208 } else if ( alt < asl + thickness + transition ) {
209 // in upper transition
210 ratio = (alt - (asl + thickness)) / transition;
216 if ( cloud_layers[i]->getCoverage() == SGCloudLayer::SG_CLOUD_CLEAR ||
217 cloud_layers[i]->get_layer3D()->is3D() && SGCloudField::enable3D) {
218 // do nothing, clear layers aren't drawn, don't affect
219 // visibility andn dont' need to be faded in or out.
220 } else if ( (cloud_layers[i]->getCoverage() ==
221 SGCloudLayer::SG_CLOUD_FEW)
222 || (cloud_layers[i]->getCoverage() ==
223 SGCloudLayer::SG_CLOUD_SCATTERED) )
225 // set the alpha fade value for the cloud layer. For less
226 // dense cloud layers we fade the layer to nothing as we
227 // approach it because we stay clear visibility-wise as we
229 float temp = ratio * 2.0;
230 if ( temp > 1.0 ) { temp = 1.0; }
231 cloud_layers[i]->setAlpha( temp );
233 // don't touch visibility
235 // maintain full alpha for denser cloud layer types.
236 // Let's set the value explicitly in case someone changed
238 cloud_layers[i]->setAlpha( 1.0 );
240 // lower visibility as we approach the cloud layer.
241 // accumulate effects from multiple cloud layers
248 // calc chance of entering cloud puff
249 double rnd = sg_random();
250 double chance = rnd * rnd * rnd;
251 if ( chance > 0.95 /* * (diff - 25) / 50.0 */ ) {
253 puff_length = sg_random() * 2.0; // up to 2 seconds
254 puff_progression = 0.0;
259 // modify actual_visibility based on puff envelope
261 if ( puff_progression <= ramp_up ) {
262 double x = SGD_PI_2 * puff_progression / ramp_up;
263 double factor = 1.0 - sin( x );
264 // cout << "ramp up = " << puff_progression
265 // << " factor = " << factor << endl;
266 effvis = effvis * factor;
267 } else if ( puff_progression >= ramp_up + puff_length ) {
268 double x = SGD_PI_2 *
269 (puff_progression - (ramp_up + puff_length)) /
271 double factor = sin( x );
272 // cout << "ramp down = "
273 // << puff_progression - (ramp_up + puff_length)
274 // << " factor = " << factor << endl;
275 effvis = effvis * factor;
280 /* cout << "len = " << puff_length
282 << " factor = " << factor
283 << " actual_visibility = " << actual_visibility
286 // time_factor = ( global_multi_loop *
287 // current_options.get_speed_up() ) /
288 // (double)current_options.get_model_hz();
290 puff_progression += time_factor;
291 // cout << "time factor = " << time_factor << endl;
293 /* cout << "gml = " << global_multi_loop
294 << " speed up = " << current_options.get_speed_up()
295 << " hz = " << current_options.get_model_hz() << endl;
298 if ( puff_progression > puff_length + ramp_up + ramp_down) {
305 // never let visibility drop below 25 meters
306 if ( effvis <= 25.0 ) {
312 effective_visibility = effvis;