1 // groundcache.cxx -- carries a small subset of the scenegraph near the vehicle
3 // Written by Mathias Froehlich, started Nov 2004.
5 // Copyright (C) 2004 Mathias Froehlich - Mathias.Froehlich@web.de
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
29 #include <osg/CullFace>
30 #include <osg/Drawable>
32 #include <osg/Geometry>
33 #include <osg/TriangleFunctor>
35 #include <simgear/sg_inlines.h>
36 #include <simgear/constants.h>
37 #include <simgear/debug/logstream.hxx>
38 #include <simgear/math/sg_geodesy.hxx>
39 #include <simgear/scene/material/mat.hxx>
40 #include <simgear/scene/material/matlib.hxx>
41 #include <simgear/scene/util/SGNodeMasks.hxx>
43 #include <Main/globals.hxx>
44 #include <Scenery/scenery.hxx>
45 #include <Scenery/tilemgr.hxx>
46 #include <AIModel/AICarrier.hxx>
49 #include "groundcache.hxx"
51 /// Ok, variant that uses a infinite line istead of the ray.
52 /// also not that this only works if the ray direction is normalized.
54 intersectsInf(const SGRayd& ray, const SGSphered& sphere)
56 SGVec3d r = sphere.getCenter() - ray.getOrigin();
57 double projectedDistance = dot(r, ray.getDirection());
58 double dist = dot(r, r) - projectedDistance * projectedDistance;
59 return dist < sphere.getRadius2();
63 class SGExtendedTriangleFunctor : public osg::TriangleFunctor<T> {
65 // Ok, to be complete we should also implement the indexed variants
66 // For now this one appears to be enough ...
67 void drawArrays(GLenum mode, GLint first, GLsizei count)
69 if (_vertexArrayPtr==0 || count==0) return;
71 const osg::Vec3* vlast;
72 const osg::Vec3* vptr;
75 vlast = &_vertexArrayPtr[first+count];
76 for(vptr=&_vertexArrayPtr[first];vptr<vlast;vptr+=2)
77 this->operator()(*(vptr),*(vptr+1),_treatVertexDataAsTemporary);
80 vlast = &_vertexArrayPtr[first+count-1];
81 for(vptr=&_vertexArrayPtr[first];vptr<vlast;++vptr)
82 this->operator()(*(vptr),*(vptr+1),_treatVertexDataAsTemporary);
85 vlast = &_vertexArrayPtr[first+count-1];
86 for(vptr=&_vertexArrayPtr[first];vptr<vlast;++vptr)
87 this->operator()(*(vptr),*(vptr+1),_treatVertexDataAsTemporary);
88 this->operator()(_vertexArrayPtr[first+count-1],
89 _vertexArrayPtr[first],_treatVertexDataAsTemporary);
92 osg::TriangleFunctor<T>::drawArrays(mode, first, count);
97 using osg::TriangleFunctor<T>::_vertexArrayPtr;
98 using osg::TriangleFunctor<T>::_treatVertexDataAsTemporary;
101 class GroundCacheFillVisitor : public osg::NodeVisitor {
104 /// class to just redirect triangles to the GroundCacheFillVisitor
105 class GroundCacheFill {
107 void setGroundCacheFillVisitor(GroundCacheFillVisitor* gcfv)
108 { mGroundCacheFillVisitor = gcfv; }
110 void operator () (const osg::Vec3& v1, const osg::Vec3& v2,
111 const osg::Vec3& v3, bool)
112 { mGroundCacheFillVisitor->addTriangle(v1, v2, v3); }
114 void operator () (const osg::Vec3& v1, const osg::Vec3& v2, bool)
115 { mGroundCacheFillVisitor->addLine(v1, v2); }
118 GroundCacheFillVisitor* mGroundCacheFillVisitor;
122 GroundCacheFillVisitor(FGGroundCache* groundCache,
124 const SGVec3d& cacheReference,
126 double wireCacheRadius) :
127 osg::NodeVisitor(osg::NodeVisitor::TRAVERSE_ACTIVE_CHILDREN),
128 mGroundCache(groundCache)
130 setTraversalMask(SG_NODEMASK_TERRAIN_BIT);
134 mBackfaceCulling = false;
135 mCacheReference = cacheReference;
136 mLocalCacheReference = cacheReference;
137 mCacheRadius = cacheRadius;
138 mWireCacheRadius = wireCacheRadius;
140 mTriangleFunctor.setGroundCacheFillVisitor(this);
142 mGroundProperty.wire_id = -1;
143 mGroundProperty.vel = SGVec3d(0, 0, 0);
144 mGroundProperty.rot = SGVec3d(0, 0, 0);
145 mGroundProperty.pivot = SGVec3d(0, 0, 0);
148 void updateCullMode(osg::StateSet* stateSet)
153 osg::StateAttribute* stateAttribute;
154 stateAttribute = stateSet->getAttribute(osg::StateAttribute::CULLFACE);
157 osg::CullFace* cullFace = static_cast<osg::CullFace*>(stateAttribute);
158 mBackfaceCulling = cullFace->getMode() == osg::CullFace::BACK;
161 bool enterBoundingSphere(const osg::BoundingSphere& bs)
166 SGVec3d cntr(osg::Vec3d(bs.center())*mLocalToGlobal);
167 double rc = bs.radius() + mCacheRadius;
168 // Ok, this node might intersect the cache. Visit it in depth.
169 double centerDist2 = distSqr(mCacheReference, cntr);
170 if (centerDist2 < rc*rc) {
173 // Check if the down direction touches the bounding sphere of the node
174 // if so, do at least croase agl computations.
175 // Ther other thing is that we must check if we are in range of
177 double rw = bs.radius() + mWireCacheRadius;
178 if (rw*rw < centerDist2 &&
179 !intersectsInf(SGRayd(mCacheReference, mDown),
180 SGSphered(cntr, bs.radius())))
188 bool enterNode(osg::Node& node)
190 if (!enterBoundingSphere(node.getBound()))
193 updateCullMode(node.getStateSet());
195 FGGroundCache::GroundProperty& gp = mGroundProperty;
196 // get some material information for use in the gear model
197 gp.type = FGInterface::Unknown;
198 osg::Referenced* base = node.getUserData();
201 FGAICarrierHardware *ud =
202 dynamic_cast<FGAICarrierHardware*>(base);
207 case FGAICarrierHardware::Wire:
208 gp.type = FGInterface::Wire;
211 case FGAICarrierHardware::Catapult:
212 gp.type = FGInterface::Catapult;
215 gp.type = FGInterface::Solid;
218 // Copy the velocity from the carrier class.
219 ud->carrier->getVelocityWrtEarth(gp.vel, gp.rot, gp.pivot);
224 void fillWith(osg::Drawable* drawable)
226 bool oldSphIsec = sphIsec;
227 if (!enterBoundingSphere(drawable->getBound()))
230 bool oldBackfaceCulling = mBackfaceCulling;
231 updateCullMode(drawable->getStateSet());
233 FGGroundCache::GroundProperty& gp = mGroundProperty;
234 // get some material information for use in the gear model
235 gp.material = globals->get_matlib()->findMaterial(drawable->getStateSet());
237 gp.type = gp.material->get_solid() ? FGInterface::Solid : FGInterface::Water;
239 drawable->accept(mTriangleFunctor);
241 mBackfaceCulling = oldBackfaceCulling;
242 sphIsec = oldSphIsec;
245 virtual void apply(osg::Geode& geode)
247 bool oldBackfaceCulling = mBackfaceCulling;
248 bool oldSphIsec = sphIsec;
249 FGGroundCache::GroundProperty oldGp = mGroundProperty;
250 if (!enterNode(geode))
253 for(unsigned i = 0; i < geode.getNumDrawables(); ++i)
254 fillWith(geode.getDrawable(i));
255 sphIsec = oldSphIsec;
256 mGroundProperty = oldGp;
257 mBackfaceCulling = oldBackfaceCulling;
260 virtual void apply(osg::Group& group)
262 bool oldBackfaceCulling = mBackfaceCulling;
263 bool oldSphIsec = sphIsec;
264 FGGroundCache::GroundProperty oldGp = mGroundProperty;
265 if (!enterNode(group))
268 sphIsec = oldSphIsec;
269 mBackfaceCulling = oldBackfaceCulling;
270 mGroundProperty = oldGp;
273 virtual void apply(osg::Transform& transform)
275 if (!enterNode(transform))
277 bool oldBackfaceCulling = mBackfaceCulling;
278 bool oldSphIsec = sphIsec;
279 FGGroundCache::GroundProperty oldGp = mGroundProperty;
280 /// transform the caches center to local coords
281 osg::Matrix oldLocalToGlobal = mLocalToGlobal;
282 osg::Matrix oldGlobalToLocal = mGlobalToLocal;
283 transform.computeLocalToWorldMatrix(mLocalToGlobal, this);
284 transform.computeWorldToLocalMatrix(mGlobalToLocal, this);
286 SGVec3d oldLocalCacheReference = mLocalCacheReference;
287 mLocalCacheReference.osg() = mCacheReference.osg()*mGlobalToLocal;
288 SGVec3d oldLocalDown = mLocalDown;
289 mLocalDown.osg() = osg::Matrixd::transform3x3(mDown.osg(), mGlobalToLocal);
295 mLocalDown = oldLocalDown;
296 mLocalCacheReference = oldLocalCacheReference;
297 mLocalToGlobal = oldLocalToGlobal;
298 mGlobalToLocal = oldGlobalToLocal;
299 sphIsec = oldSphIsec;
300 mBackfaceCulling = oldBackfaceCulling;
301 mGroundProperty = oldGp;
304 void addTriangle(const osg::Vec3& v1, const osg::Vec3& v2,
313 // a bounding sphere in the node local system
314 SGVec3d boundCenter = (1.0/3)*(v[0] + v[1] + v[2]);
315 double boundRadius = std::max(distSqr(v[0], boundCenter),
316 distSqr(v[1], boundCenter));
317 boundRadius = std::max(boundRadius, distSqr(v[2], boundCenter));
318 boundRadius = sqrt(boundRadius);
320 SGRayd ray(mLocalCacheReference, mLocalDown);
322 // if we are not in the downward cylinder bail out
323 if (!intersectsInf(ray, SGSphered(boundCenter, boundRadius + mCacheRadius)))
326 SGTriangled triangle(v);
328 // The normal and plane in the node local coordinate system
329 SGVec3d n = cross(triangle.getEdge(0), triangle.getEdge(1));
330 if (0 < dot(mLocalDown, n)) {
331 if (mBackfaceCulling) {
332 // Surface points downwards, ignore for altitude computations.
339 // Only check if the triangle is in the cache sphere if the plane
340 // containing the triangle is near enough
342 double d = dot(n, v[0] - mLocalCacheReference);
343 if (d*d < mCacheRadius*dot(n, n)) {
344 // Check if the sphere around the vehicle intersects the sphere
345 // around that triangle. If so, put that triangle into the cache.
346 double r2 = boundRadius + mCacheRadius;
347 if (distSqr(boundCenter, mLocalCacheReference) < r2*r2) {
348 FGGroundCache::Triangle t;
349 t.triangle.setBaseVertex(SGVec3d(v[0].osg()*mLocalToGlobal));
350 t.triangle.setEdge(0, SGVec3d(osg::Matrixd::transform3x3(triangle.getEdge(0).osg(), mLocalToGlobal)));
351 t.triangle.setEdge(1, SGVec3d(osg::Matrixd::transform3x3(triangle.getEdge(1).osg(), mLocalToGlobal)));
353 t.sphere.setCenter(SGVec3d(boundCenter.osg()*mLocalToGlobal));
354 t.sphere.setRadius(boundRadius);
356 t.velocity = mGroundProperty.vel;
357 t.rotation = mGroundProperty.rot;
358 t.rotation_pivot = mGroundProperty.pivot;
359 t.type = mGroundProperty.type;
360 t.material = mGroundProperty.material;
361 mGroundCache->triangles.push_back(t);
366 // In case the cache is empty, we still provide agl computations.
367 // But then we use the old way of having a fixed elevation value for
368 // the whole lifetime of this cache.
370 if (intersects(isectpoint, triangle, ray, 1e-4)) {
371 mGroundCache->found_ground = true;
372 isectpoint.osg() = isectpoint.osg()*mLocalToGlobal;
373 double this_radius = length(isectpoint);
374 if (mGroundCache->ground_radius < this_radius) {
375 mGroundCache->ground_radius = this_radius;
376 mGroundCache->_type = mGroundProperty.type;
377 mGroundCache->_material = mGroundProperty.material;
382 void addLine(const osg::Vec3& v1, const osg::Vec3& v2)
384 SGVec3d gv1(osg::Vec3d(v1)*mLocalToGlobal);
385 SGVec3d gv2(osg::Vec3d(v2)*mLocalToGlobal);
387 SGVec3d boundCenter = 0.5*(gv1 + gv2);
388 double boundRadius = length(gv1 - boundCenter);
390 if (distSqr(boundCenter, mCacheReference)
391 < (boundRadius + mWireCacheRadius)*(boundRadius + mWireCacheRadius) ) {
392 if (mGroundProperty.type == FGInterface::Wire) {
393 FGGroundCache::Wire wire;
396 wire.velocity = mGroundProperty.vel;
397 wire.rotation = mGroundProperty.rot;
398 wire.rotation_pivot = mGroundProperty.pivot;
399 wire.wire_id = mGroundProperty.wire_id;
401 mGroundCache->wires.push_back(wire);
403 if (mGroundProperty.type == FGInterface::Catapult) {
404 FGGroundCache::Catapult cat;
405 // Trick to get the ends in the right order.
406 // Use the x axis in the original coordinate system. Choose the
407 // most negative x-axis as the one pointing forward
415 cat.velocity = mGroundProperty.vel;
416 cat.rotation = mGroundProperty.rot;
417 cat.rotation_pivot = mGroundProperty.pivot;
419 mGroundCache->catapults.push_back(cat);
424 SGExtendedTriangleFunctor<GroundCacheFill> mTriangleFunctor;
425 FGGroundCache* mGroundCache;
426 SGVec3d mCacheReference;
428 double mWireCacheRadius;
429 osg::Matrix mLocalToGlobal;
430 osg::Matrix mGlobalToLocal;
433 SGVec3d mLocalCacheReference;
435 bool mBackfaceCulling;
436 FGGroundCache::GroundProperty mGroundProperty;
439 FGGroundCache::FGGroundCache()
442 cache_ref_time = 0.0;
444 reference_wgs84_point = SGVec3d(0, 0, 0);
445 reference_vehicle_radius = 0.0;
446 found_ground = false;
449 FGGroundCache::~FGGroundCache()
454 FGGroundCache::velocityTransformTriangle(double dt,
455 SGTriangled& dst, SGSphered& sdst,
456 const FGGroundCache::Triangle& src)
461 if (dt*dt*dot(src.velocity, src.velocity) < SGLimitsd::epsilon())
464 SGVec3d baseVert = dst.getBaseVertex();
465 SGVec3d pivotoff = baseVert - src.rotation_pivot;
466 baseVert += dt*(src.velocity + cross(src.rotation, pivotoff));
467 dst.setBaseVertex(baseVert);
468 dst.setEdge(0, dst.getEdge(0) + dt*cross(src.rotation, dst.getEdge(0)));
469 dst.setEdge(1, dst.getEdge(1) + dt*cross(src.rotation, dst.getEdge(1)));
474 FGGroundCache::prepare_ground_cache(double ref_time, const SGVec3d& pt,
479 found_ground = false;
484 // Store the parameters we used to build up that cache.
485 reference_wgs84_point = pt;
486 reference_vehicle_radius = rad;
487 // Store the time reference used to compute movements of moving triangles.
488 cache_ref_time = ref_time;
490 // Get a normalized down vector valid for the whole cache
491 SGQuatd hlToEc = SGQuatd::fromLonLat(SGGeod::fromCart(pt));
492 down = hlToEc.rotate(SGVec3d(0, 0, 1));
494 // Prepare sphere around the aircraft.
495 double cacheRadius = rad;
497 // Prepare bigger sphere around the aircraft.
498 // This one is required for reliably finding wires we have caught but
499 // have already left the hopefully smaller sphere for the ground reactions.
500 const double max_wire_dist = 300.0;
501 double wireCacheRadius = max_wire_dist < rad ? rad : max_wire_dist;
503 // Walk the scene graph and extract solid ground triangles and carrier data.
504 GroundCacheFillVisitor gcfv(this, down, pt, cacheRadius, wireCacheRadius);
505 globals->get_scenery()->get_scene_graph()->accept(gcfv);
508 SG_LOG(SG_FLIGHT,SG_DEBUG, "prepare_ground_cache(): ac radius = " << rad
509 << ", # triangles = " << triangles.size()
510 << ", # wires = " << wires.size()
511 << ", # catapults = " << catapults.size()
512 << ", ground_radius = " << ground_radius );
514 // If the ground radius is still below 5e6 meters, then we do not yet have
516 found_ground = found_ground && 5e6 < ground_radius;
518 SG_LOG(SG_FLIGHT, SG_WARN, "prepare_ground_cache(): trying to build cache "
519 "without any scenery below the aircraft" );
525 FGGroundCache::is_valid(double& ref_time, SGVec3d& pt, double& rad)
527 pt = reference_wgs84_point;
528 rad = reference_vehicle_radius;
529 ref_time = cache_ref_time;
534 FGGroundCache::get_cat(double t, const SGVec3d& dpt,
535 SGVec3d end[2], SGVec3d vel[2])
537 // start with a distance of 1e10 meters...
540 // Time difference to the reference time.
543 size_t sz = catapults.size();
544 for (size_t i = 0; i < sz; ++i) {
545 SGVec3d pivotoff, rvel[2];
546 pivotoff = catapults[i].start - catapults[i].rotation_pivot;
547 rvel[0] = catapults[i].velocity + cross(catapults[i].rotation, pivotoff);
548 pivotoff = catapults[i].end - catapults[i].rotation_pivot;
549 rvel[1] = catapults[i].velocity + cross(catapults[i].rotation, pivotoff);
552 thisEnd[0] = catapults[i].start + t*rvel[0];
553 thisEnd[1] = catapults[i].end + t*rvel[1];
555 double this_dist = distSqr(SGLineSegmentd(thisEnd[0], thisEnd[1]), dpt);
556 if (this_dist < dist) {
557 SG_LOG(SG_FLIGHT,SG_INFO, "Found catapult "
558 << this_dist << " meters away");
568 // At the end take the root, we only computed squared distances ...
573 FGGroundCache::get_agl(double t, const SGVec3d& dpt, double max_altoff,
574 SGVec3d& contact, SGVec3d& normal, SGVec3d& vel,
575 int *type, const SGMaterial** material, double *agl)
579 *type = FGInterface::Unknown;
583 vel = SGVec3d(0, 0, 0);
584 contact = SGVec3d(0, 0, 0);
585 normal = SGVec3d(0, 0, 0);
587 // Time difference to th reference time.
590 // The double valued point we start to search for intersection.
592 // shift the start of our ray by maxaltoff upwards
593 SGRayd ray(pt - max_altoff*down, down);
595 // Initialize to something sensible
596 double current_radius = 0.0;
598 size_t sz = triangles.size();
599 for (size_t i = 0; i < sz; ++i) {
601 SGTriangled triangle;
602 velocityTransformTriangle(t, triangle, sphere, triangles[i]);
603 if (!intersectsInf(ray, sphere))
606 // Check for intersection.
608 if (intersects(isecpoint, triangle, ray, 1e-4)) {
609 // Compute the vector from pt to the intersection point ...
610 SGVec3d off = isecpoint - pt;
611 // ... and check if it is too high or not
613 // compute the radius, good enough approximation to take the geocentric radius
614 double radius = dot(isecpoint, isecpoint);
615 if (current_radius < radius) {
616 current_radius = radius;
618 // Save the new potential intersection point.
620 // The first three values in the vector are the plane normal.
621 normal = triangle.getNormal();
622 // The velocity wrt earth.
623 SGVec3d pivotoff = pt - triangles[i].rotation_pivot;
624 vel = triangles[i].velocity + cross(triangles[i].rotation, pivotoff);
625 // Save the ground type.
626 *type = triangles[i].type;
627 *agl = dot(down, contact - dpt);
629 *material = triangles[i].material;
637 // Whenever we did not have a ground triangle for the requested point,
638 // take the ground level we found during the current cache build.
639 // This is as good as what we had before for agl.
640 double r = length(dpt);
642 contact *= ground_radius/r;
644 vel = SGVec3d(0, 0, 0);
646 // The altitude is the distance of the requested point from the
648 *agl = dot(down, contact - dpt);
651 *material = _material;
656 bool FGGroundCache::caught_wire(double t, const SGVec3d pt[4])
658 size_t sz = wires.size();
662 // Time difference to the reference time.
665 // Build the two triangles spanning the area where the hook has moved
666 // during the past step.
667 SGTriangled triangle[2];
668 triangle[0].set(pt[0], pt[1], pt[2]);
669 triangle[1].set(pt[0], pt[2], pt[3]);
671 // Intersect the wire lines with each of these triangles.
672 // You have caught a wire if they intersect.
673 for (size_t i = 0; i < sz; ++i) {
675 for (int k = 0; k < 2; ++k) {
676 le[k] = wires[i].ends[k];
677 SGVec3d pivotoff = le[k] - wires[i].rotation_pivot;
678 SGVec3d vel = wires[i].velocity + cross(wires[i].rotation, pivotoff);
681 SGLineSegmentd lineSegment(le[0], le[1]);
683 for (int k=0; k<2; ++k) {
684 if (intersects(triangle[k], lineSegment)) {
685 SG_LOG(SG_FLIGHT,SG_INFO, "Caught wire");
686 // Store the wire id.
687 wire_id = wires[i].wire_id;
696 bool FGGroundCache::get_wire_ends(double t, SGVec3d end[2], SGVec3d vel[2])
698 // Fast return if we do not have an active wire.
702 // Time difference to the reference time.
705 // Search for the wire with the matching wire id.
706 size_t sz = wires.size();
707 for (size_t i = 0; i < sz; ++i) {
708 if (wires[i].wire_id == wire_id) {
709 for (size_t k = 0; k < 2; ++k) {
710 SGVec3d pivotoff = wires[i].ends[k] - wires[i].rotation_pivot;
711 vel[k] = wires[i].velocity + cross(wires[i].rotation, pivotoff);
712 end[k] = wires[i].ends[k] + t*vel[k];
721 void FGGroundCache::release_wire(void)