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>
32 #include <simgear/compiler.h>
36 #include <osg/Geometry>
39 #include <osg/MatrixTransform>
40 #include <osg/Material>
41 #include <osg/ShadeModel>
42 #include <osg/PrimitiveSet>
44 #include <simgear/debug/logstream.hxx>
45 #include <simgear/math/Math.hxx>
46 #include <simgear/scene/util/VectorArrayAdapter.hxx>
51 using namespace simgear;
53 // proportions of max dimensions fed to the build() routine
54 static const float center_elev = 1.0;
62 } domeParams[] = {{.5, .8660}, // 60deg from horizon
63 {.8660, .5}, // 30deg from horizon
64 // Original dome horizon vertices
65 {0.9701, 0.2425}, {0.9960, 0.0885},
66 {1.0, 0.0}, {0.9922, -0.1240}};
68 const int numRings = sizeof(domeParams) / sizeof(domeParams[0]);
69 const int numBands = 12;
72 static const float upper_radius = 0.9701; // (.6, 0.15)
73 static const float upper_elev = 0.2425;
75 static const float middle_radius = 0.9960; // (.9, .08)
76 static const float middle_elev = 0.0885;
78 static const float lower_radius = 1.0;
79 static const float lower_elev = 0.0;
81 static const float bottom_radius = 0.9922; // (.8, -.1)
82 static const float bottom_elev = -0.1240;
86 SGSkyDome::SGSkyDome( void ) {
92 SGSkyDome::~SGSkyDome( void ) {
95 // Generate indices for a dome mesh. Assume a center vertex at 0, then
96 // rings of vertices. Each ring's vertices are stored together. An
97 // even number of longitudinal bands are assumed.
101 // Calculate the index of a vertex in the grid by using its address in
102 // the array that holds its location.
105 VectorArrayAdapter<Vec3Array> gridAdapter;
107 GridIndex(Vec3Array& array, int rowStride, int baseOffset) :
108 gridAdapter(array, rowStride, baseOffset), grid(array)
111 unsigned short operator() (int ring, int band)
113 return (unsigned short)(&gridAdapter(ring, band) - &grid[0]);
117 void SGSkyDome::makeDome(int rings, int bands, DrawElementsUShort& elements)
119 std::back_insert_iterator<DrawElementsUShort> pusher
120 = std::back_inserter(elements);
121 GridIndex grid(*dome_vl, numBands, 1);
122 for (int i = 0; i < bands; i += 2) {
123 *pusher = 0; *pusher = grid(0, i); *pusher = grid(0, i + 1);
125 for (int j = 0; j < rings - 1; ++j) {
126 *pusher = grid(j, i); *pusher = grid(j, i + 1);
127 *pusher = grid(j + 1, i + 1);
128 *pusher = grid(j, i); *pusher = grid(j + 1, i + 1);
129 *pusher = grid(j + 1, i);
131 // and up the next one
132 for (int j = rings - 1; j > 0; --j) {
133 *pusher = grid(j, i + 1); *pusher = grid(j - 1, i + 1);
134 *pusher = grid(j, (i + 2) % bands);
135 *pusher = grid(j, (i + 2) % bands); *pusher = grid(j - 1, i + 1);
136 *pusher = grid(j - 1, (i + 2) % bands);
138 *pusher = grid(0, i + 1); *pusher = 0;
139 *pusher = grid(0, (i + 2) % bands);
143 // initialize the sky object and connect it into our scene graph
145 SGSkyDome::build( double hscale, double vscale ) {
147 osg::Geode* geode = new osg::Geode;
150 osg::StateSet* stateSet = geode->getOrCreateStateSet();
151 stateSet->setRenderBinDetails(-10, "RenderBin");
153 osg::ShadeModel* shadeModel = new osg::ShadeModel;
154 shadeModel->setMode(osg::ShadeModel::SMOOTH);
155 stateSet->setAttributeAndModes(shadeModel);
156 stateSet->setMode(GL_LIGHTING, osg::StateAttribute::OFF);
157 stateSet->setMode(GL_FOG, osg::StateAttribute::OFF);
158 stateSet->setMode(GL_DEPTH_TEST, osg::StateAttribute::OFF);
159 stateSet->setMode(GL_CULL_FACE, osg::StateAttribute::OFF);
160 stateSet->setMode(GL_BLEND, osg::StateAttribute::OFF);
161 stateSet->setMode(GL_ALPHA_TEST, osg::StateAttribute::OFF);
162 osg::Material* material = new osg::Material;
163 stateSet->setAttribute(material);
165 dome_vl = new osg::Vec3Array(1 + numRings * numBands);
166 dome_cl = new osg::Vec3Array(1 + numRings * numBands);
167 // generate the raw vertex data
169 (*dome_vl)[0].set(0.0, 0.0, center_elev * vscale);
170 simgear::VectorArrayAdapter<Vec3Array> vertices(*dome_vl, numBands, 1);
172 for ( int i = 0; i < numBands; ++i ) {
173 double theta = (i * 30) * SGD_DEGREES_TO_RADIANS;
174 double sTheta = hscale*sin(theta);
175 double cTheta = hscale*cos(theta);
176 for (int j = 0; j < numRings; ++j) {
177 vertices(j, i).set(cTheta * domeParams[j].radius,
178 sTheta * domeParams[j].radius,
179 domeParams[j].elev * vscale);
183 DrawElementsUShort* domeElements
184 = new osg::DrawElementsUShort(GL_TRIANGLES);
185 makeDome(numRings, numBands, *domeElements);
186 osg::Geometry* geom = new Geometry;
187 geom->setName("Dome Elements");
188 geom->setUseDisplayList(false);
189 geom->setVertexArray(dome_vl.get());
190 geom->setColorArray(dome_cl.get());
191 geom->setColorBinding(osg::Geometry::BIND_PER_VERTEX);
192 geom->setNormalBinding(osg::Geometry::BIND_OFF);
193 geom->addPrimitiveSet(domeElements);
194 geode->addDrawable(geom);
195 // force a repaint of the sky colors with ugly defaults
196 repaint(SGVec3f(1, 1, 1), SGVec3f(1, 1, 1), 0.0, 5000.0 );
197 dome_transform = new osg::MatrixTransform;
198 dome_transform->addChild(geode);
200 return dome_transform.get();
203 static void fade_to_black(osg::Vec3 sky_color[], float asl, int count) {
204 const float ref_asl = 10000.0f;
205 const float d = exp( - asl / ref_asl );
206 for(int i = 0; i < count ; i++)
210 inline void clampColor(osg::Vec3& color)
212 color.x() = osg::clampTo(color.x(), 0.0f, 1.0f);
213 color.y() = osg::clampTo(color.y(), 0.0f, 1.0f);
214 color.z() = osg::clampTo(color.z(), 0.0f, 1.0f);
217 // repaint the sky colors based on current value of sun_angle, sky,
218 // and fog colors. This updates the color arrays for ssgVtxTable.
219 // sun angle in degrees relative to verticle
220 // 0 degrees = high noon
221 // 90 degrees = sun rise/set
222 // 180 degrees = darkest midnight
224 SGSkyDome::repaint( const SGVec3f& sky_color, const SGVec3f& fog_color,
225 double sun_angle, double vis )
227 SGVec3f outer_param, outer_diff;
228 SGVec3f middle_param, middle_diff;
230 // Check for sunrise/sunset condition
231 if (sun_angle > 80) {
233 double sunAngleFactor = 10.0 - fabs(90.0 - sun_angle);
234 static const SGVec3f outerConstant(1.0 / 20.0, 1.0 / 40.0, -1.0 / 30.0);
235 static const SGVec3f middleConstant(1.0 / 40.0, 1.0 / 80.0, 0.0);
236 outer_param = sunAngleFactor * outerConstant;
237 middle_param = sunAngleFactor * middleConstant;
238 outer_diff = (1.0 / 6.0) * outer_param;
239 middle_diff = (1.0 / 6.0) * middle_param;
241 outer_param = SGVec3f(0, 0, 0);
242 middle_param = SGVec3f(0, 0, 0);
243 outer_diff = SGVec3f(0, 0, 0);
244 middle_diff = SGVec3f(0, 0, 0);
246 // printf(" outer_red_param = %.2f outer_red_diff = %.2f\n",
247 // outer_red_param, outer_red_diff);
249 // calculate transition colors between sky and fog
250 SGVec3f outer_amt = outer_param;
251 SGVec3f middle_amt = middle_param;
254 // First, recalulate the basic colors
257 // Magic factors for coloring the sky according visibility and
259 const double cvf = osg::clampBelow(vis, 45000.0);
260 const double vis_factor = osg::clampTo((vis - 1000.0) / 2000.0, 0.0, 1.0);
261 const float upperVisFactor = 1.0 - vis_factor * (0.7 + 0.3 * cvf/45000);
262 const float middleVisFactor = 1.0 - vis_factor * (0.1 + 0.85 * cvf/45000);
264 (*dome_cl)[0] = sky_color.osg();
265 simgear::VectorArrayAdapter<Vec3Array> colors(*dome_cl, numBands, 1);
266 const double saif = sun_angle/SG_PI;
267 static const SGVec3f blueShift(0.8, 1.0, 1.2);
268 const SGVec3f skyFogDelta = sky_color - fog_color;
269 // For now the colors of the upper two rings are linearly
270 // interpolated between the zenith color and the first horizon
273 for (int i = 0; i < 7; i++) {
274 SGVec3f diff = mult(skyFogDelta, blueShift);
275 diff *= (0.8 + saif - ((6-i)/10));
276 colors(2, i) = (sky_color - upperVisFactor * diff).osg();
277 colors(3, i) = (sky_color - middleVisFactor * diff + middle_amt).osg();
278 colors(4, i) = (fog_color + outer_amt).osg();
279 // Interpolate using distance along dome segment
280 colors(0, i) = simgear::math::lerp(sky_color.osg(), colors(2, i), .3942);
281 colors(1, i) = simgear::math::lerp(sky_color.osg(), colors(2, i), .7885);
282 for (int j = 0; j < numRings - 1; ++j)
283 clampColor(colors(j, i));
284 outer_amt -= outer_diff;
285 middle_amt -= middle_diff;
288 for (int i = 7; i < 12; ++i)
289 for (int j = 0; j < 5; ++j)
290 colors(j, i) = colors(j, 12 - i);
292 fade_to_black(&(*dome_cl)[0], asl * center_elev, 1);
293 for (int i = 0; i < numRings - 1; ++i)
294 fade_to_black(&colors(i, 0), (asl+0.05f) * domeParams[i].elev,
297 for ( int i = 0; i < numBands; i++ )
298 colors(numRings - 1, i) = fog_color.osg();
304 // reposition the sky at the specified origin and orientation
305 // lon specifies a rotation about the Z axis
306 // lat specifies a rotation about the new Y axis
307 // spin specifies a rotation about the new Z axis (and orients the
308 // sunrise/set effects
310 SGSkyDome::reposition( const SGVec3f& p, double _asl,
311 double lon, double lat, double spin ) {
314 osg::Matrix T, LON, LAT, SPIN;
316 // Translate to view position
317 // Point3D zero_elev = current_view.get_cur_zero_elev();
318 // xglTranslatef( zero_elev.x(), zero_elev.y(), zero_elev.z() );
319 T.makeTranslate( p.osg() );
321 // printf(" Translated to %.2f %.2f %.2f\n",
322 // zero_elev.x, zero_elev.y, zero_elev.z );
324 // Rotate to proper orientation
325 // printf(" lon = %.2f lat = %.2f\n",
326 // lon * SGD_RADIANS_TO_DEGREES,
327 // lat * SGD_RADIANS_TO_DEGREES);
328 // xglRotatef( lon * SGD_RADIANS_TO_DEGREES, 0.0, 0.0, 1.0 );
329 LON.makeRotate(lon, osg::Vec3(0, 0, 1));
331 // xglRotatef( 90.0 - f->get_Latitude() * SGD_RADIANS_TO_DEGREES,
333 LAT.makeRotate(90.0 * SGD_DEGREES_TO_RADIANS - lat, osg::Vec3(0, 1, 0));
335 // xglRotatef( l->sun_rotation * SGD_RADIANS_TO_DEGREES, 0.0, 0.0, 1.0 );
336 SPIN.makeRotate(spin, osg::Vec3(0, 0, 1));
338 dome_transform->setMatrix( SPIN*LAT*LON*T );