1 // ReaderWriterSPT.cxx -- Provide a paged database for flightgear scenery.
2 //
3 // Copyright (C) 2010 - 2013 Mathias Froehlich
4 //
5 // This program is free software; you can redistribute it and/or
6 // modify it under the terms of the GNU General Public License as
7 // published by the Free Software Foundation; either version 2 of the
8 // License, or (at your option) any later version.
9 //
10 // This program is distributed in the hope that it will be useful, but
11 // WITHOUT ANY WARRANTY; without even the implied warranty of
12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 // General Public License for more details.
14 //
15 // You should have received a copy of the GNU General Public License
16 // along with this program; if not, write to the Free Software
17 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 //
19
20 #ifdef HAVE_CONFIG_H
21 # include <simgear_config.h>
22 #endif
23
24 #include "ReaderWriterSPT.hxx"
25
26 #include <cassert>
27
28 #include <osg/Version>
29 #include <osg/CullFace>
30 #include <osg/PagedLOD>
31 #include <osg/MatrixTransform>
32 #include <osg/Texture2D>
33
34 #include <osgDB/FileNameUtils>
35 #include <osgDB/FileUtils>
36 #include <osgDB/ReadFile>
37
38 #include <simgear/scene/util/OsgMath.hxx>
39
40 #include "BucketBox.hxx"
41
42 namespace simgear {
43
44 // Cull away tiles that we watch from downside
45 struct ReaderWriterSPT::CullCallback : public osg::NodeCallback {
~CullCallbacksimgear::ReaderWriterSPT::CullCallback46 virtual ~CullCallback()
47 { }
operator ()simgear::ReaderWriterSPT::CullCallback48 virtual void operator()(osg::Node* node, osg::NodeVisitor* nv)
49 {
50 const osg::BoundingSphere& nodeBound = node->getBound();
51 // If the bounding sphere of the node is empty, there is nothing to do
52 if (!nodeBound.valid())
53 return;
54
55 // Culling away tiles that we look at from the downside.
56 // This is done by computing the maximum distance we can
57 // see something from the current eyepoint. If the sphere
58 // that is defined by this radius does no intersects the
59 // nodes sphere, then this tile is culled away.
60 // Computing this radius happens by two rectangular triangles:
61 // Let r be the view point. rmin is the minimum radius we find
62 // a ground surface we need to look above. rmax is the
63 // maximum object radius we expect any object.
64 //
65 // d1 d2
66 // x----x----x
67 // r\ rmin /rmax
68 // \ | /
69 // \ | /
70 // \|/
71 //
72 // The distance from the eyepoint to the point
73 // where the line of sight is perpandicular to
74 // the radius vector with minimal height is
75 // d1 = sqrt(r^2 - rmin^2).
76 // The distance from the point where the line of sight
77 // is perpandicular to the radius vector with minimal height
78 // to the highest possible object on earth with radius rmax is
79 // d2 = sqrt(rmax^2 - rmin^2).
80 // So the maximum distance we can see something on the earth
81 // from a viewpoint r is
82 // d = d1 + d2
83
84 // This is the equatorial earth radius minus 450m,
85 // little lower than Dead Sea.
86 float rmin = 6378137 - 450;
87 float rmin2 = rmin*rmin;
88 // This is the equatorial earth radius plus 9000m,
89 // little higher than Mount Everest.
90 float rmax = 6378137 + 9000;
91 float rmax2 = rmax*rmax;
92
93 // Check if we are looking from below any ground
94 osg::Vec3 viewPoint = nv->getViewPoint();
95 // blow the viewpoint up to a spherical earth with equatorial radius:
96 osg::Vec3 sphericViewPoint = viewPoint;
97 sphericViewPoint[2] *= 1.0033641;
98 float r2 = sphericViewPoint.length2();
99 if (r2 <= rmin2)
100 return;
101
102 // Due to this line of sight computation, the visible tiles
103 // are limited to be within a sphere with radius d1 + d2.
104 float d1 = sqrtf(r2 - rmin2);
105 float d2 = sqrtf(rmax2 - rmin2);
106 // Note that we again base the sphere around elliptic view point,
107 // but use the radius from the spherical computation.
108 if (!nodeBound.intersects(osg::BoundingSphere(viewPoint, d1 + d2)))
109 return;
110
111 traverse(node, nv);
112 }
113 };
114
115 struct ReaderWriterSPT::LocalOptions {
LocalOptionssimgear::ReaderWriterSPT::LocalOptions116 LocalOptions(const osgDB::Options* options) :
117 _options(options)
118 {
119 std::string pageLevelsString;
120 if (_options)
121 pageLevelsString = _options->getPluginStringData("SimGear::SPT_PAGE_LEVELS");
122
123 // Get the default if nothing given from outside
124 if (pageLevelsString.empty()) {
125 // We want an other level of indirection for paging
126 // Here we get about 12x12 deg tiles
127 _pageLevels.push_back(3);
128 // We want an other level of indirection for paging
129 // Here we get about 2x2 deg tiles
130 _pageLevels.push_back(5);
131 // We want an other level of indirection for paging
132 // Here we get about 0.5x0.5 deg tiles
133 _pageLevels.push_back(7);
134 } else {
135 // If configured from outside
136 std::stringstream ss(pageLevelsString);
137 while (ss.good()) {
138 unsigned level = ~0u;
139 ss >> level;
140 _pageLevels.push_back(level);
141 }
142 }
143 }
144
isPageLevelsimgear::ReaderWriterSPT::LocalOptions145 bool isPageLevel(unsigned level) const
146 {
147 return std::find(_pageLevels.begin(), _pageLevels.end(), level) != _pageLevels.end();
148 }
149
getLodPathForBucketBoxsimgear::ReaderWriterSPT::LocalOptions150 std::string getLodPathForBucketBox(const BucketBox& bucketBox) const
151 {
152 std::stringstream ss;
153 ss << "LOD/";
154 for (std::vector<unsigned>::const_iterator i = _pageLevels.begin(); i != _pageLevels.end(); ++i) {
155 if (bucketBox.getStartLevel() <= *i)
156 break;
157 ss << bucketBox.getParentBox(*i) << "/";
158 }
159 ss << bucketBox;
160 return ss.str();
161 }
162
getRangeMultipliersimgear::ReaderWriterSPT::LocalOptions163 float getRangeMultiplier() const
164 {
165 float rangeMultiplier = 2;
166 if (!_options)
167 return rangeMultiplier;
168 std::stringstream ss(_options->getPluginStringData("SimGear::SPT_RANGE_MULTIPLIER"));
169 ss >> rangeMultiplier;
170 return rangeMultiplier;
171 }
172
173 const osgDB::Options* _options;
174 std::vector<unsigned> _pageLevels;
175 };
176
ReaderWriterSPT()177 ReaderWriterSPT::ReaderWriterSPT()
178 {
179 supportsExtension("spt", "SimGear paged terrain meta database.");
180 }
181
~ReaderWriterSPT()182 ReaderWriterSPT::~ReaderWriterSPT()
183 {
184 }
185
186 const char*
className() const187 ReaderWriterSPT::className() const
188 {
189 return "simgear::ReaderWriterSPT";
190 }
191
192 osgDB::ReaderWriter::ReadResult
readObject(const std::string & fileName,const osgDB::Options * options) const193 ReaderWriterSPT::readObject(const std::string& fileName, const osgDB::Options* options) const
194 {
195 // We get called with different extensions. To make sure search continues,
196 // we need to return FILE_NOT_HANDLED in this case.
197 if (osgDB::getLowerCaseFileExtension(fileName) != "spt")
198 return ReadResult(ReadResult::FILE_NOT_HANDLED);
199 if (fileName != "state.spt")
200 return ReadResult(ReadResult::FILE_NOT_FOUND);
201
202 osg::StateSet* stateSet = new osg::StateSet;
203 stateSet->setAttributeAndModes(new osg::CullFace);
204
205 std::string imageFileName = options->getPluginStringData("SimGear::FG_WORLD_TEXTURE");
206 if (imageFileName.empty()) {
207 imageFileName = options->getPluginStringData("SimGear::FG_ROOT");
208 imageFileName = osgDB::concatPaths(imageFileName, "Textures");
209 imageFileName = osgDB::concatPaths(imageFileName, "Globe");
210 imageFileName = osgDB::concatPaths(imageFileName, "world.topo.bathy.200407.3x4096x2048.png");
211 }
212 #if OSG_VERSION_LESS_THAN(3,4,0)
213 if (osg::Image* image = osgDB::readImageFile(imageFileName, options)) {
214 #else
215 if (osg::Image* image = osgDB::readRefImageFile(imageFileName, options)) {
216 #endif
217 osg::Texture2D* texture = new osg::Texture2D;
218 texture->setImage(image);
219 texture->setWrap(osg::Texture2D::WRAP_S, osg::Texture2D::REPEAT);
220 texture->setWrap(osg::Texture2D::WRAP_T, osg::Texture2D::CLAMP);
221 stateSet->setTextureAttributeAndModes(0, texture);
222 }
223
224 return stateSet;
225 }
226
227 osgDB::ReaderWriter::ReadResult
228 ReaderWriterSPT::readNode(const std::string& fileName, const osgDB::Options* options) const
229 {
230 LocalOptions localOptions(options);
231
232 // The file name without path and without the spt extension
233 std::string strippedFileName = osgDB::getStrippedName(fileName);
234 if (strippedFileName == "earth")
235 return ReadResult(createTree(BucketBox(-180, -90, 360, 180), localOptions, true));
236
237 std::stringstream ss(strippedFileName);
238 BucketBox bucketBox;
239 ss >> bucketBox;
240 if (ss.fail())
241 return ReadResult::FILE_NOT_FOUND;
242
243 BucketBox bucketBoxList[2];
244 unsigned bucketBoxListSize = bucketBox.periodicSplit(bucketBoxList);
245 if (bucketBoxListSize == 0)
246 return ReadResult::FILE_NOT_FOUND;
247
248 if (bucketBoxListSize == 1)
249 return ReadResult(createTree(bucketBoxList[0], localOptions, true));
250
251 assert(bucketBoxListSize == 2);
252 osg::ref_ptr<osg::Group> group = new osg::Group;
253 group->addChild(createTree(bucketBoxList[0], localOptions, true));
254 group->addChild(createTree(bucketBoxList[1], localOptions, true));
255 return ReadResult(group);
256 }
257
258 osg::ref_ptr<osg::Node>
259 ReaderWriterSPT::createTree(const BucketBox& bucketBox, const LocalOptions& options, bool topLevel) const
260 {
261 if (bucketBox.getIsBucketSize()) {
262 std::string fileName;
263 fileName = bucketBox.getBucket().gen_index_str() + std::string(".stg");
264 #if OSG_VERSION_LESS_THAN(3,4,0)
265 return osgDB::readNodeFile(fileName, options._options);
266 #else
267 return osgDB::readRefNodeFile(fileName, options._options);
268 #endif
269 } else if (!topLevel && options.isPageLevel(bucketBox.getStartLevel())) {
270 return createPagedLOD(bucketBox, options);
271 } else {
272 BucketBox bucketBoxList[100];
273 unsigned numTiles = bucketBox.getSubDivision(bucketBoxList, 100);
274 if (numTiles == 0)
275 return 0;
276
277 if (numTiles == 1)
278 return createTree(bucketBoxList[0], options, false);
279
280 osg::ref_ptr<osg::Group> group = new osg::Group;
281 for (unsigned i = 0; i < numTiles; ++i) {
282 osg::ref_ptr<osg::Node> node = createTree(bucketBoxList[i], options, false);
283 if (!node.valid())
284 continue;
285 group->addChild(node.get());
286 }
287 if (!group->getNumChildren())
288 return 0;
289
290 return group;
291 }
292 }
293
294 osg::ref_ptr<osg::Node>
295 ReaderWriterSPT::createPagedLOD(const BucketBox& bucketBox, const LocalOptions& options) const
296 {
297 osg::ref_ptr<osg::PagedLOD> pagedLOD = new osg::PagedLOD;
298
299 pagedLOD->setCenterMode(osg::PagedLOD::USER_DEFINED_CENTER);
300 SGSpheref sphere = bucketBox.getBoundingSphere();
301 pagedLOD->setCenter(toOsg(sphere.getCenter()));
302 pagedLOD->setRadius(sphere.getRadius());
303
304 pagedLOD->setCullCallback(new CullCallback);
305
306 osg::ref_ptr<osgDB::Options> localOptions;
307 localOptions = static_cast<osgDB::Options*>(options._options->clone(osg::CopyOp()));
308 // FIXME:
309 // The particle systems have nodes with culling disabled.
310 // PagedLOD nodes with childnodes like this will never expire.
311 // So, for now switch them off.
312 localOptions->setPluginStringData("SimGear::PARTICLESYSTEM", "OFF");
313 pagedLOD->setDatabaseOptions(localOptions.get());
314
315 // The break point for the low level of detail to the high level of detail
316 float rangeMultiplier = options.getRangeMultiplier();
317 float range = rangeMultiplier*sphere.getRadius();
318
319 // Look for a low level of detail tile
320 std::string lodPath = options.getLodPathForBucketBox(bucketBox);
321 const char* extensions[] = { ".btg.gz", ".flt" };
322 for (unsigned i = 0; i < sizeof(extensions)/sizeof(extensions[0]); ++i) {
323 std::string fileName = osgDB::findDataFile(lodPath + extensions[i], options._options);
324 if (fileName.empty())
325 continue;
326 #if OSG_VERSION_LESS_THAN(3,4,0)
327 osg::ref_ptr<osg::Node> node = osgDB::readNodeFile(fileName, options._options);
328 #else
329 osg::ref_ptr<osg::Node> node = osgDB::readRefNodeFile(fileName, options._options);
330 #endif
331 if (!node.valid())
332 continue;
333 pagedLOD->addChild(node.get(), range, std::numeric_limits<float>::max());
334 break;
335 }
336 // Add the static sea level textured shell if there is nothing found
337 if (pagedLOD->getNumChildren() == 0) {
338 osg::ref_ptr<osg::Node> node = createSeaLevelTile(bucketBox, options._options);
339 if (node.valid())
340 pagedLOD->addChild(node.get(), range, std::numeric_limits<float>::max());
341 }
342
343 // Add the paged file name that creates the subtrees on demand
344 std::stringstream ss;
345 ss << bucketBox << ".spt";
346 pagedLOD->setFileName(pagedLOD->getNumChildren(), ss.str());
347 pagedLOD->setRange(pagedLOD->getNumChildren(), 0.0, range);
348
349 return pagedLOD;
350 }
351
352 osg::ref_ptr<osg::Node>
353 ReaderWriterSPT::createSeaLevelTile(const BucketBox& bucketBox, const LocalOptions& options) const
354 {
355 if (options._options->getPluginStringData("SimGear::FG_EARTH") != "ON")
356 return 0;
357
358 SGSpheref sphere = bucketBox.getBoundingSphere();
359 osg::Matrixd transform;
360 transform.makeTranslate(toOsg(-sphere.getCenter()));
361
362 osg::Vec3Array* vertices = new osg::Vec3Array;
363 osg::Vec3Array* normals = new osg::Vec3Array;
364 osg::Vec2Array* texCoords = new osg::Vec2Array;
365
366 unsigned widthLevel = bucketBox.getWidthLevel();
367 unsigned heightLevel = bucketBox.getHeightLevel();
368
369 unsigned incx = bucketBox.getWidthIncrement(widthLevel + 2);
370 incx = std::min(incx, bucketBox.getSize(0));
371 for (unsigned i = 0; incx != 0;) {
372 unsigned incy = bucketBox.getHeightIncrement(heightLevel + 2);
373 incy = std::min(incy, bucketBox.getSize(1));
374 for (unsigned j = 0; incy != 0;) {
375 SGVec3f v[6], n[6];
376 SGVec2f t[6];
377 unsigned num = bucketBox.getTileTriangles(i, j, incx, incy, v, n, t);
378 for (unsigned k = 0; k < num; ++k) {
379 vertices->push_back(transform.preMult(toOsg(v[k])));
380 normals->push_back(toOsg(n[k]));
381 texCoords->push_back(toOsg(t[k]));
382 }
383 j += incy;
384 incy = std::min(incy, bucketBox.getSize(1) - j);
385 }
386 i += incx;
387 incx = std::min(incx, bucketBox.getSize(0) - i);
388 }
389
390 osg::Vec4Array* colors = new osg::Vec4Array;
391 colors->push_back(osg::Vec4(1, 1, 1, 1));
392
393 osg::Geometry* geometry = new osg::Geometry;
394 geometry->setDataVariance(osg::Object::STATIC);
395 geometry->setUseVertexBufferObjects(true);
396 geometry->setVertexArray(vertices);
397 geometry->setNormalArray(normals);
398 geometry->setNormalBinding(osg::Geometry::BIND_PER_VERTEX);
399 geometry->setColorArray(colors);
400 geometry->setColorBinding(osg::Geometry::BIND_OVERALL);
401 geometry->setTexCoordArray(0, texCoords);
402
403 osg::DrawArrays* drawArrays = new osg::DrawArrays(osg::DrawArrays::TRIANGLES, 0, vertices->size());
404 drawArrays->setDataVariance(osg::Object::STATIC);
405 geometry->addPrimitiveSet(drawArrays);
406
407 osg::Geode* geode = new osg::Geode;
408 geode->setDataVariance(osg::Object::STATIC);
409 geode->addDrawable(geometry);
410 osg::ref_ptr<osg::StateSet> stateSet = getLowLODStateSet(options);
411 geode->setStateSet(stateSet.get());
412
413 transform.makeTranslate(toOsg(sphere.getCenter()));
414 osg::MatrixTransform* matrixTransform = new osg::MatrixTransform(transform);
415 matrixTransform->setDataVariance(osg::Object::STATIC);
416 matrixTransform->addChild(geode);
417
418 return matrixTransform;
419 }
420
421 osg::ref_ptr<osg::StateSet>
422 ReaderWriterSPT::getLowLODStateSet(const LocalOptions& options) const
423 {
424 osg::ref_ptr<osgDB::Options> localOptions;
425 localOptions = static_cast<osgDB::Options*>(options._options->clone(osg::CopyOp()));
426 localOptions->setObjectCacheHint(osgDB::Options::CACHE_ALL);
427
428 #if OSG_VERSION_LESS_THAN(3,4,0)
429 osg::ref_ptr<osg::Object> object = osgDB::readObjectFile("state.spt", localOptions.get());
430 #else
431 osg::ref_ptr<osg::Object> object = osgDB::readRefObjectFile("state.spt", localOptions.get());
432 #endif
433 if (!dynamic_cast<osg::StateSet*>(object.get()))
434 return 0;
435
436 return static_cast<osg::StateSet*>(object.get());
437 }
438
439 } // namespace simgear
440
441