1 // dome.cxx -- model sky with an upside down "bowl"
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.
23 # include <simgear_config.h>
28 #include <simgear/compiler.h>
32 #include <osg/Geometry>
35 #include <osg/MatrixTransform>
36 #include <osg/Material>
37 #include <osg/ShadeModel>
38 #include <osg/PrimitiveSet>
40 #include <simgear/debug/logstream.hxx>
41 #include <simgear/math/Math.hxx>
42 #include <simgear/scene/util/VectorArrayAdapter.hxx>
47 using namespace simgear;
49 // proportions of max dimensions fed to the build() routine
50 static const float center_elev = 1.0;
58 } domeParams[] = {{.5, .8660}, // 60deg from horizon
59 {.8660, .5}, // 30deg from horizon
60 // Original dome horizon vertices
61 {0.9701, 0.2425}, {0.9960, 0.0885},
62 {1.0, 0.0}, {0.9922, -0.1240}};
64 const int numRings = sizeof(domeParams) / sizeof(domeParams[0]);
65 const int numBands = 12;
68 static const float upper_radius = 0.9701; // (.6, 0.15)
69 static const float upper_elev = 0.2425;
71 static const float middle_radius = 0.9960; // (.9, .08)
72 static const float middle_elev = 0.0885;
74 static const float lower_radius = 1.0;
75 static const float lower_elev = 0.0;
77 static const float bottom_radius = 0.9922; // (.8, -.1)
78 static const float bottom_elev = -0.1240;
82 SGSkyDome::SGSkyDome( void ) {
88 SGSkyDome::~SGSkyDome( void ) {
91 // Generate indices for a dome mesh. Assume a center vertex at 0, then
92 // rings of vertices. Each ring's vertices are stored together. An
93 // even number of longitudinal bands are assumed.
97 // Calculate the index of a vertex in the grid by using its address in
98 // the array that holds its location.
101 VectorArrayAdapter<Vec3Array> gridAdapter;
103 GridIndex(Vec3Array& array, int rowStride, int baseOffset) :
104 gridAdapter(array, rowStride, baseOffset), grid(array)
107 unsigned short operator() (int ring, int band)
109 return (unsigned short)(&gridAdapter(ring, band) - &grid[0]);
113 void SGSkyDome::makeDome(int rings, int bands, DrawElementsUShort& elements)
115 std::back_insert_iterator<DrawElementsUShort> pusher
116 = std::back_inserter(elements);
117 GridIndex grid(*dome_vl, numBands, 1);
118 for (int i = 0; i < bands; i += 2) {
119 *pusher = 0; *pusher = grid(0, i); *pusher = grid(0, i + 1);
121 for (int j = 0; j < rings - 1; ++j) {
122 *pusher = grid(j, i); *pusher = grid(j, i + 1);
123 *pusher = grid(j + 1, i + 1);
124 *pusher = grid(j, i); *pusher = grid(j + 1, i + 1);
125 *pusher = grid(j + 1, i);
127 // and up the next one
128 for (int j = rings - 1; j > 0; --j) {
129 *pusher = grid(j, i + 1); *pusher = grid(j - 1, i + 1);
130 *pusher = grid(j, (i + 2) % bands);
131 *pusher = grid(j, (i + 2) % bands); *pusher = grid(j - 1, i + 1);
132 *pusher = grid(j - 1, (i + 2) % bands);
134 *pusher = grid(0, i + 1); *pusher = 0;
135 *pusher = grid(0, (i + 2) % bands);
139 // initialize the sky object and connect it into our scene graph
141 SGSkyDome::build( double hscale, double vscale ) {
143 osg::Geode* geode = new osg::Geode;
146 osg::StateSet* stateSet = geode->getOrCreateStateSet();
147 stateSet->setRenderBinDetails(-10, "RenderBin");
149 osg::ShadeModel* shadeModel = new osg::ShadeModel;
150 shadeModel->setMode(osg::ShadeModel::SMOOTH);
151 stateSet->setAttributeAndModes(shadeModel);
152 stateSet->setMode(GL_LIGHTING, osg::StateAttribute::OFF);
153 stateSet->setMode(GL_FOG, osg::StateAttribute::OFF);
154 stateSet->setMode(GL_DEPTH_TEST, osg::StateAttribute::OFF);
155 stateSet->setMode(GL_CULL_FACE, osg::StateAttribute::OFF);
156 stateSet->setMode(GL_BLEND, osg::StateAttribute::OFF);
157 stateSet->setMode(GL_ALPHA_TEST, osg::StateAttribute::OFF);
158 osg::Material* material = new osg::Material;
159 stateSet->setAttribute(material);
161 dome_vl = new osg::Vec3Array(1 + numRings * numBands);
162 dome_cl = new osg::Vec3Array(1 + numRings * numBands);
163 // generate the raw vertex data
165 (*dome_vl)[0].set(0.0, 0.0, center_elev * vscale);
166 simgear::VectorArrayAdapter<Vec3Array> vertices(*dome_vl, numBands, 1);
168 for ( int i = 0; i < numBands; ++i ) {
169 double theta = (i * 30) * SGD_DEGREES_TO_RADIANS;
170 double sTheta = hscale*sin(theta);
171 double cTheta = hscale*cos(theta);
172 for (int j = 0; j < numRings; ++j) {
173 vertices(j, i).set(cTheta * domeParams[j].radius,
174 sTheta * domeParams[j].radius,
175 domeParams[j].elev * vscale);
179 DrawElementsUShort* domeElements
180 = new osg::DrawElementsUShort(GL_TRIANGLES);
181 makeDome(numRings, numBands, *domeElements);
182 osg::Geometry* geom = new Geometry;
183 geom->setName("Dome Elements");
184 geom->setUseDisplayList(false);
185 geom->setVertexArray(dome_vl.get());
186 geom->setColorArray(dome_cl.get());
187 geom->setColorBinding(osg::Geometry::BIND_PER_VERTEX);
188 geom->setNormalBinding(osg::Geometry::BIND_OFF);
189 geom->addPrimitiveSet(domeElements);
190 geode->addDrawable(geom);
191 // force a repaint of the sky colors with ugly defaults
192 repaint(SGVec3f(1, 1, 1), SGVec3f(1, 1, 1), 0.0, 5000.0 );
193 dome_transform = new osg::MatrixTransform;
194 dome_transform->addChild(geode);
196 return dome_transform.get();
199 static void fade_to_black(osg::Vec3 sky_color[], float asl, int count) {
200 const float ref_asl = 10000.0f;
201 const float d = exp( - asl / ref_asl );
202 for(int i = 0; i < count ; i++)
206 inline void clampColor(osg::Vec3& color)
208 color.x() = osg::clampTo(color.x(), 0.0f, 1.0f);
209 color.y() = osg::clampTo(color.y(), 0.0f, 1.0f);
210 color.z() = osg::clampTo(color.z(), 0.0f, 1.0f);
213 // repaint the sky colors based on current value of sun_angle, sky,
214 // and fog colors. This updates the color arrays for ssgVtxTable.
215 // sun angle in degrees relative to verticle
216 // 0 degrees = high noon
217 // 90 degrees = sun rise/set
218 // 180 degrees = darkest midnight
220 SGSkyDome::repaint( const SGVec3f& sky_color, const SGVec3f& fog_color,
221 double sun_angle, double vis )
223 SGVec3f outer_param, outer_diff;
224 SGVec3f middle_param, middle_diff;
226 // Check for sunrise/sunset condition
227 if (sun_angle > 80) {
229 double sunAngleFactor = 10.0 - fabs(90.0 - sun_angle);
230 static const SGVec3f outerConstant(1.0 / 20.0, 1.0 / 40.0, -1.0 / 30.0);
231 static const SGVec3f middleConstant(1.0 / 40.0, 1.0 / 80.0, 0.0);
232 outer_param = sunAngleFactor * outerConstant;
233 middle_param = sunAngleFactor * middleConstant;
234 outer_diff = (1.0 / 6.0) * outer_param;
235 middle_diff = (1.0 / 6.0) * middle_param;
237 outer_param = SGVec3f(0, 0, 0);
238 middle_param = SGVec3f(0, 0, 0);
239 outer_diff = SGVec3f(0, 0, 0);
240 middle_diff = SGVec3f(0, 0, 0);
242 // printf(" outer_red_param = %.2f outer_red_diff = %.2f\n",
243 // outer_red_param, outer_red_diff);
245 // calculate transition colors between sky and fog
246 SGVec3f outer_amt = outer_param;
247 SGVec3f middle_amt = middle_param;
250 // First, recalulate the basic colors
253 // Magic factors for coloring the sky according visibility and
255 const double cvf = osg::clampBelow(vis, 45000.0);
256 const double vis_factor = osg::clampTo((vis - 1000.0) / 2000.0, 0.0, 1.0);
257 const float upperVisFactor = 1.0 - vis_factor * (0.7 + 0.3 * cvf/45000);
258 const float middleVisFactor = 1.0 - vis_factor * (0.1 + 0.85 * cvf/45000);
260 (*dome_cl)[0] = sky_color.osg();
261 simgear::VectorArrayAdapter<Vec3Array> colors(*dome_cl, numBands, 1);
262 const double saif = sun_angle/SG_PI;
263 static const SGVec3f blueShift(0.8, 1.0, 1.2);
264 const SGVec3f skyFogDelta = sky_color - fog_color;
265 // For now the colors of the upper two rings are linearly
266 // interpolated between the zenith color and the first horizon
269 for (int i = 0; i < 7; i++) {
270 SGVec3f diff = mult(skyFogDelta, blueShift);
271 diff *= (0.8 + saif - ((6-i)/10));
272 colors(2, i) = (sky_color - upperVisFactor * diff).osg();
273 colors(3, i) = (sky_color - middleVisFactor * diff + middle_amt).osg();
274 colors(4, i) = (fog_color + outer_amt).osg();
275 // Interpolate using distance along dome segment
276 colors(0, i) = simgear::math::lerp(sky_color.osg(), colors(2, i), .3942);
277 colors(1, i) = simgear::math::lerp(sky_color.osg(), colors(2, i), .7885);
278 for (int j = 0; j < numRings - 1; ++j)
279 clampColor(colors(j, i));
280 outer_amt -= outer_diff;
281 middle_amt -= middle_diff;
284 for (int i = 7; i < 12; ++i)
285 for (int j = 0; j < 5; ++j)
286 colors(j, i) = colors(j, 12 - i);
288 fade_to_black(&(*dome_cl)[0], asl * center_elev, 1);
289 for (int i = 0; i < numRings - 1; ++i)
290 fade_to_black(&colors(i, 0), (asl+0.05f) * domeParams[i].elev,
293 for ( int i = 0; i < numBands; i++ )
294 colors(numRings - 1, i) = fog_color.osg();
300 // reposition the sky at the specified origin and orientation
301 // lon specifies a rotation about the Z axis
302 // lat specifies a rotation about the new Y axis
303 // spin specifies a rotation about the new Z axis (and orients the
304 // sunrise/set effects
306 SGSkyDome::reposition( const SGVec3f& p, double _asl,
307 double lon, double lat, double spin ) {
310 osg::Matrix T, LON, LAT, SPIN;
312 // Translate to view position
313 // Point3D zero_elev = current_view.get_cur_zero_elev();
314 // xglTranslatef( zero_elev.x(), zero_elev.y(), zero_elev.z() );
315 T.makeTranslate( p.osg() );
317 // printf(" Translated to %.2f %.2f %.2f\n",
318 // zero_elev.x, zero_elev.y, zero_elev.z );
320 // Rotate to proper orientation
321 // printf(" lon = %.2f lat = %.2f\n",
322 // lon * SGD_RADIANS_TO_DEGREES,
323 // lat * SGD_RADIANS_TO_DEGREES);
324 // xglRotatef( lon * SGD_RADIANS_TO_DEGREES, 0.0, 0.0, 1.0 );
325 LON.makeRotate(lon, osg::Vec3(0, 0, 1));
327 // xglRotatef( 90.0 - f->get_Latitude() * SGD_RADIANS_TO_DEGREES,
329 LAT.makeRotate(90.0 * SGD_DEGREES_TO_RADIANS - lat, osg::Vec3(0, 1, 0));
331 // xglRotatef( l->sun_rotation * SGD_RADIANS_TO_DEGREES, 0.0, 0.0, 1.0 );
332 SPIN.makeRotate(spin, osg::Vec3(0, 0, 1));
334 dome_transform->setMatrix( SPIN*LAT*LON*T );