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., 675 Mass Ave, Cambridge, MA 02139, USA.
28 #include <simgear/sg_inlines.h>
29 #include <simgear/constants.h>
30 #include <simgear/debug/logstream.hxx>
31 #include <simgear/math/sg_geodesy.hxx>
33 #include <Main/globals.hxx>
34 #include <Scenery/scenery.hxx>
35 #include <Scenery/tilemgr.hxx>
36 #include <AIModel/AICarrier.hxx>
39 #include "groundcache.hxx"
41 // Specialized version of sgMultMat4 needed because of mixed matrix
43 static inline void fgMultMat4(sgdMat4 dst, sgdMat4 m1, sgMat4 m2) {
44 for ( int j = 0 ; j < 4 ; j++ ) {
45 dst[0][j] = m2[0][0] * m1[0][j] +
50 dst[1][j] = m2[1][0] * m1[0][j] +
55 dst[2][j] = m2[2][0] * m1[0][j] +
60 dst[3][j] = m2[3][0] * m1[0][j] +
67 static inline bool fgdPointInTriangle( sgdVec3 point, sgdVec3 tri[3] )
71 // Some tolerance in meters we accept a point to be outside of the triangle
72 // and still return that it is inside.
75 // punt if outside bouding cube
76 SG_MIN_MAX3 ( min, max, tri[0][0], tri[1][0], tri[2][0] );
77 if( (point[0] < min - eps) || (point[0] > max + eps) )
81 SG_MIN_MAX3 ( min, max, tri[0][1], tri[1][1], tri[2][1] );
82 if( (point[1] < min - eps) || (point[1] > max + eps) )
86 SG_MIN_MAX3 ( min, max, tri[0][2], tri[1][2], tri[2][2] );
87 if( (point[2] < min - eps) || (point[2] > max + eps) )
91 // drop the smallest dimension so we only have to work in 2d.
92 SGDfloat min_dim = SG_MIN3 (dif[0], dif[1], dif[2]);
93 SGDfloat x1, y1, x2, y2, x3, y3, rx, ry;
94 if ( fabs(min_dim-dif[0]) <= DBL_EPSILON ) {
95 // x is the smallest dimension
104 } else if ( fabs(min_dim-dif[1]) <= DBL_EPSILON ) {
105 // y is the smallest dimension
114 } else if ( fabs(min_dim-dif[2]) <= DBL_EPSILON ) {
115 // z is the smallest dimension
125 // all dimensions are really small so lets call it close
126 // enough and return a successful match
130 // check if intersection point is on the same side of p1 <-> p2 as p3
131 SGDfloat tmp = (y2 - y3);
132 SGDfloat tmpn = (x2 - x3);
133 int side1 = SG_SIGN (tmp * (rx - x3) + (y3 - ry) * tmpn);
134 int side2 = SG_SIGN (tmp * (x1 - x3) + (y3 - y1) * tmpn
135 + side1 * eps * fabs(tmpn));
136 if ( side1 != side2 ) {
137 // printf("failed side 1 check\n");
141 // check if intersection point is on correct side of p2 <-> p3 as p1
144 side1 = SG_SIGN (tmp * (x2 - rx) + (ry - y2) * tmpn);
145 side2 = SG_SIGN (tmp * (x1 - rx) + (ry - y1) * tmpn
146 + side1 * eps * fabs(tmpn));
147 if ( side1 != side2 ) {
148 // printf("failed side 2 check\n");
152 // check if intersection point is on correct side of p1 <-> p3 as p2
155 side1 = SG_SIGN (tmp * (x3 - rx) + (ry - y3) * tmpn);
156 side2 = SG_SIGN (tmp * (x1 - rx) + (ry - y1) * tmpn
157 + side1 * eps * fabs(tmpn));
158 if ( side1 != side2 ) {
159 // printf("failed side 3 check\n");
166 // Test if the line given by the point on the line pt_on_line and the
167 // line direction dir intersects the sphere sp.
168 // Adapted from plib.
170 fgdIsectSphereInfLine(const sgdSphere& sp,
171 const sgdVec3 pt_on_line, const sgdVec3 dir)
174 sgdSubVec3( r, sp.getCenter(), pt_on_line ) ;
176 SGDfloat projectedDistance = sgdScalarProductVec3(r, dir);
178 SGDfloat dist = sgdScalarProductVec3 ( r, r ) -
179 projectedDistance * projectedDistance;
181 SGDfloat radius = sp.getRadius();
182 return dist < radius*radius;
185 FGGroundCache::FGGroundCache()
187 sgdSetVec3(cache_center, 0.0, 0.0, 0.0);
189 cache_ref_time = 0.0;
191 sgdSetVec3(reference_wgs84_point, 0.0, 0.0, 0.0);
192 reference_vehicle_radius = 0.0;
193 found_ground = false;
196 FGGroundCache::~FGGroundCache()
200 FGGroundCache::GroundProperty
201 FGGroundCache::extractGroundProperty( ssgLeaf* l )
203 // FIXME: Do more ...
204 // Idea: have a get_globals() function which knows about that stuff.
205 // Or most propably read that from a configuration file,
206 // from property tree or whatever ...
208 // Get ground dependent data.
212 FGAICarrierHardware *ud =
213 dynamic_cast<FGAICarrierHardware*>(l->getUserData());
216 case FGAICarrierHardware::Wire:
217 gp.type = FGInterface::Wire;
220 case FGAICarrierHardware::Catapult:
221 gp.type = FGInterface::Catapult;
224 gp.type = FGInterface::Solid;
228 // Copy the velocity from the carrier class.
229 ud->carrier->getVelocityWrtEarth( gp.vel );
234 // Initialize velocity field.
235 sgSetVec3( gp.vel, 0.0, 0.0, 0.0 );
238 // Get the texture name and decide what ground type we have.
239 ssgState *st = l->getState();
240 if (st != NULL && st->isAKindOf(ssgTypeSimpleState())) {
241 ssgSimpleState *ss = (ssgSimpleState*)st;
242 SGPath fullPath( ss->getTextureFilename() ? ss->getTextureFilename(): "" );
243 string file = fullPath.file();
244 SGPath dirPath(fullPath.dir());
245 string category = dirPath.file();
247 if (category == "Runway")
248 gp.type = FGInterface::Solid;
250 if (file == "asphault.rgb" || file == "airport.rgb")
251 gp.type = FGInterface::Solid;
252 else if (file == "water.rgb" || file == "water-lake.rgb")
253 gp.type = FGInterface::Water;
254 else if (file == "forest.rgb" || file == "cropwood.rgb")
255 gp.type = FGInterface::Forest;
263 FGGroundCache::putLineLeafIntoCache(const sgdSphere *wsp, const sgdMat4 xform,
266 GroundProperty gp = extractGroundProperty(l);
268 // Lines must have special meanings.
269 // Wires and catapults are done with lines.
270 int nl = l->getNumLines();
271 for (int i = 0; i < nl; ++i) {
276 l->getLine(i, v, v+1 );
277 for (int k=0; k<2; ++k) {
278 sgdSetVec3(ends[k], l->getVertex(v[k]));
279 sgdXformPnt3(ends[k], xform);
280 sphere.extend(ends[k]);
283 if (wsp->intersects( &sphere )) {
284 if (gp.type == FGInterface::Wire) {
286 sgdCopyVec3(wire.ends[0], ends[0]);
287 sgdCopyVec3(wire.ends[1], ends[1]);
288 sgdSetVec3(wire.velocity, gp.vel);
289 wire.wire_id = gp.wire_id;
291 wires.push_back(wire);
293 if (gp.type == FGInterface::Catapult) {
295 sgdCopyVec3(cat.start, ends[0]);
296 sgdCopyVec3(cat.end, ends[1]);
297 sgdSetVec3(cat.velocity, gp.vel);
299 catapults.push_back(cat);
306 FGGroundCache::putSurfaceLeafIntoCache(const sgdSphere *sp,
307 const sgdMat4 xform, bool sphIsec,
308 sgdVec3 down, ssgLeaf *l)
310 GroundProperty gp = extractGroundProperty(l);
312 int nt = l->getNumTriangles();
313 for (int i = 0; i < nt; ++i) {
317 l->getTriangle(i, &v[0], &v[1], &v[2]);
318 for (int k = 0; k < 3; ++k) {
319 sgdSetVec3(t.vertices[k], l->getVertex(v[k]));
320 sgdXformPnt3(t.vertices[k], xform);
321 t.sphere.extend(t.vertices[k]);
324 sgdMakePlane(t.plane, t.vertices[0], t.vertices[1], t.vertices[2]);
325 SGDfloat dot = sgdScalarProductVec3(down, t.plane);
327 if (!l->getCullFace()) {
328 // Surface points downwards, ignore for altitude computations.
331 sgdScaleVec4( t.plane, -1 );
334 // Check if the sphere around the vehicle intersects the sphere
335 // around that triangle. If so, put that triangle into the cache.
336 if (sphIsec && sp->intersects(&t.sphere)) {
337 sgdSetVec3(t.velocity, gp.vel);
339 triangles.push_back(t);
342 // In case the cache is empty, we still provide agl computations.
343 // But then we use the old way of having a fixed elevation value for
344 // the whole lifetime of this cache.
345 if ( fgdIsectSphereInfLine(t.sphere, sp->getCenter(), down) ) {
347 sgdSetVec3(tmp, sp->center[0], sp->center[1], sp->center[2]);
349 if ( sgdIsectInfLinePlane( isectpoint, tmp, down, t.plane ) &&
350 fgdPointInTriangle( isectpoint, t.vertices ) ) {
352 sgdAddVec3(isectpoint, cache_center);
353 double this_radius = sgdLengthVec3(isectpoint);
354 if (ground_radius < this_radius)
355 ground_radius = this_radius;
362 FGGroundCache::velocityTransformTriangle(double dt,
363 FGGroundCache::Triangle& dst,
364 const FGGroundCache::Triangle& src)
366 sgdCopyVec3(dst.vertices[0], src.vertices[0]);
367 sgdCopyVec3(dst.vertices[1], src.vertices[1]);
368 sgdCopyVec3(dst.vertices[2], src.vertices[2]);
370 sgdCopyVec4(dst.plane, src.plane);
372 sgdCopyVec3(dst.sphere.center, src.sphere.center);
373 dst.sphere.radius = src.sphere.radius;
375 sgdCopyVec3(dst.velocity, src.velocity);
379 if (dt*sgdLengthSquaredVec3(src.velocity) != 0) {
380 sgdAddScaledVec3(dst.vertices[0], src.velocity, dt);
381 sgdAddScaledVec3(dst.vertices[1], src.velocity, dt);
382 sgdAddScaledVec3(dst.vertices[2], src.velocity, dt);
384 dst.plane[3] += dt*sgdScalarProductVec3(dst.plane, src.velocity);
386 sgdAddScaledVec3(dst.sphere.center, src.velocity, dt);
391 FGGroundCache::cache_fill(ssgBranch *branch, sgdMat4 xform,
392 sgdSphere* sp, sgdVec3 down, sgdSphere* wsp)
394 // Travel through all kids.
396 for ( e = branch->getKid(0); e != NULL ; e = branch->getNextKid() ) {
397 if ( !(e->getTraversalMask() & SSGTRAV_HOT) )
399 if ( e->getBSphere()->isEmpty() )
402 // We need to check further if either the sphere around the branch
403 // intersects the sphere around the aircraft or the line downwards from
404 // the aircraft intersects the branchs sphere.
406 sgdSetVec3(esphere.center, e->getBSphere()->center);
407 esphere.radius = e->getBSphere()->radius;
408 esphere.orthoXform(xform);
409 bool wspIsec = wsp->intersects(&esphere);
410 bool downIsec = fgdIsectSphereInfLine(esphere, sp->getCenter(), down);
411 if (!wspIsec && !downIsec)
414 // For branches collect up the transforms to reach that branch and
415 // call cache_fill recursively.
416 if ( e->isAKindOf( ssgTypeBranch() ) ) {
417 ssgBranch *b = (ssgBranch *)e;
418 if ( b->isAKindOf( ssgTypeTransform() ) ) {
419 // Collect up the transfors required to reach that part of
422 sgMakeIdentMat4( xform2 );
423 ssgTransform *t = (ssgTransform*)b;
424 t->getTransform( xform2 );
426 fgMultMat4(xform3, xform, xform2);
427 cache_fill( b, xform3, sp, down, wsp );
429 cache_fill( b, xform, sp, down, wsp );
432 // For leafs, check each triangle for intersection.
433 // This will minimize the number of vertices/triangles in the cache.
434 else if (e->isAKindOf(ssgTypeLeaf())) {
435 // Since we reach that leaf if we have an intersection with the
436 // most propably bigger wire/catapult cache sphere, we need to check
437 // that here, if the smaller cache for the surface has a chance for hits.
438 // Also, if the spheres do not intersect compute a croase agl value
439 // by following the line downwards originating at the aircraft.
440 bool spIsec = sp->intersects(&esphere);
441 putSurfaceLeafIntoCache(sp, xform, spIsec, down, (ssgLeaf *)e);
443 // If we are here, we need to put all special hardware here into
446 putLineLeafIntoCache(wsp, xform, (ssgLeaf *)e);
452 FGGroundCache::prepare_ground_cache(double ref_time, const double pt[3],
457 found_ground = false;
462 // Store the parameters we used to build up that cache.
463 sgdCopyVec3(reference_wgs84_point, pt);
464 reference_vehicle_radius = rad;
465 // Store the time reference used to compute movements of moving triangles.
466 cache_ref_time = ref_time;
468 // Decide where we put the scenery center.
469 Point3D old_cntr = globals->get_scenery()->get_center();
470 Point3D cntr(pt[0], pt[1], pt[2]);
471 // Only move the cache center if it is unaccaptable far away.
472 if (40*40 < old_cntr.distance3Dsquared(cntr))
473 globals->get_scenery()->set_center(cntr);
477 // The center of the cache.
478 sgdSetVec3(cache_center, cntr[0], cntr[1], cntr[2]);
481 sgdSubVec3(ptoff, pt, cache_center);
482 // Prepare sphere around the aircraft.
484 acSphere.setRadius(rad);
485 acSphere.setCenter(ptoff);
487 // Prepare bigger sphere around the aircraft.
488 // This one is required for reliably finding wires we have caught but
489 // have already left the hopefully smaller sphere for the ground reactions.
490 const double max_wire_dist = 300.0;
491 sgdSphere wireSphere;
492 wireSphere.setRadius(max_wire_dist < rad ? rad : max_wire_dist);
493 wireSphere.setCenter(ptoff);
495 // Down vector. Is used for croase agl computations when we are far enough
496 // from ground that we have an empty cache.
498 sgdSetVec3(down, -pt[0], -pt[1], -pt[2]);
499 sgdNormalizeVec3(down);
501 // We collaps all transforms we need to reach a particular leaf.
502 // The leafs itself will be then transformed later.
503 // So our cache is just flat.
504 // For leafs which are moving (carriers surface, etc ...)
505 // we will later store a speed in the GroundType class. We can then apply
506 // some translations to that nodes according to the time which has passed
507 // compared to that snapshot.
509 sgdMakeIdentMat4( xform );
512 // Walk the scene graph and extract solid ground triangles and carrier data.
513 ssgBranch *terrain = globals->get_scenery()->get_scene_graph();
514 cache_fill(terrain, xform, &acSphere, down, &wireSphere);
517 SG_LOG(SG_FLIGHT,SG_INFO, "prepare_ground_cache(): ac radius = " << rad
518 << ", # triangles = " << triangles.size()
519 << ", # wires = " << wires.size()
520 << ", # catapults = " << catapults.size()
521 << ", ground_radius = " << ground_radius );
523 // If the ground radius is still below 5e6 meters, then we do not yet have
525 found_ground = found_ground && 5e6 < ground_radius;
527 SG_LOG(SG_FLIGHT, SG_WARN, "prepare_ground_cache(): trying to build cache "
528 "without any scenery below the aircraft" );
530 if (cntr != old_cntr)
531 globals->get_scenery()->set_center(old_cntr);
537 FGGroundCache::is_valid(double *ref_time, double pt[3], double *rad)
539 sgdCopyVec3(pt, reference_wgs84_point);
540 *rad = reference_vehicle_radius;
541 *ref_time = cache_ref_time;
546 FGGroundCache::get_cat(double t, const double dpt[3],
547 double end[2][3], double vel[2][3])
549 // start with a distance of 1e10 meters...
552 // Time difference to the reference time.
555 size_t sz = catapults.size();
556 for (size_t i = 0; i < sz; ++i) {
558 sgdCopyVec3(ls.a, catapults[i].start);
559 sgdCopyVec3(ls.b, catapults[i].end);
561 sgdAddVec3(ls.a, cache_center);
562 sgdAddVec3(ls.b, cache_center);
564 sgdAddScaledVec3(ls.a, catapults[i].velocity, t);
565 sgdAddScaledVec3(ls.b, catapults[i].velocity, t);
567 double this_dist = sgdDistSquaredToLineSegmentVec3( ls, dpt );
568 if (this_dist < dist) {
569 SG_LOG(SG_FLIGHT,SG_INFO, "Found catapult "
570 << this_dist << " meters away");
573 // The carrier code takes care of that ordering.
574 sgdCopyVec3( end[0], ls.a );
575 sgdCopyVec3( end[1], ls.b );
576 sgdCopyVec3( vel[0], catapults[i].velocity );
577 sgdCopyVec3( vel[1], catapults[i].velocity );
581 // At the end take the root, we only computed squared distances ...
586 FGGroundCache::get_agl(double t, const double dpt[3], double max_altoff,
587 double contact[3], double normal[3], double vel[3],
588 int *type, double *loadCapacity,
589 double *frictionFactor, double *agl)
593 *type = FGInterface::Unknown;
595 *loadCapacity = DBL_MAX;
596 *frictionFactor = 1.0;
597 sgdSetVec3( vel, 0.0, 0.0, 0.0 );
598 sgdSetVec3( contact, 0.0, 0.0, 0.0 );
599 sgdSetVec3( normal, 0.0, 0.0, 0.0 );
601 // Time difference to th reference time.
604 // The double valued point we start to search for intersection.
606 sgdSubVec3( pt, dpt, cache_center );
608 // The search direction
610 sgdSetVec3( dir, -dpt[0], -dpt[1], -dpt[2] );
611 sgdNormaliseVec3( dir );
613 // Initialize to something sensible
614 double current_radius = 0.0;
616 size_t sz = triangles.size();
617 for (size_t i = 0; i < sz; ++i) {
619 velocityTransformTriangle(t, triangle, triangles[i]);
620 if (!fgdIsectSphereInfLine(triangle.sphere, pt, dir))
623 // Check for intersection.
625 if ( sgdIsectInfLinePlane( isecpoint, pt, dir, triangle.plane ) &&
626 sgdPointInTriangle( isecpoint, triangle.vertices ) ) {
627 // Transform to the wgs system
628 sgdAddVec3( isecpoint, cache_center );
629 // compute the radius, good enough approximation to take the geocentric radius
630 SGDfloat radius = sgdLengthSquaredVec3(isecpoint);
631 if (current_radius < radius) {
632 // Compute the vector from pt to the intersection point ...
634 sgdSubVec3(off, pt, isecpoint);
635 // ... and check if it is too high or not
636 if (-max_altoff < sgdScalarProductVec3( off, dir )) {
637 current_radius = radius;
639 // Save the new potential intersection point.
640 sgdCopyVec3( contact, isecpoint );
641 // The first three values in the vector are the plane normal.
642 sgdCopyVec3( normal, triangle.plane );
643 // The velocity wrt earth.
644 /// FIXME: only true for non rotating objects!!!!
645 sgdCopyVec3( vel, triangle.velocity );
646 // Save the ground type.
647 *type = triangle.type;
648 // FIXME: figure out how to get that sign ...
649 // *agl = sqrt(sqdist);
650 *agl = sgdLengthVec3( dpt ) - sgdLengthVec3( contact );
651 // *loadCapacity = DBL_MAX;
652 // *frictionFactor = 1.0;
661 // Whenever we did not have a ground triangle for the requested point,
662 // take the ground level we found during the current cache build.
663 // This is as good as what we had before for agl.
664 double r = sgdLengthVec3( dpt );
665 sgdCopyVec3( contact, dpt );
666 sgdScaleVec3( contact, ground_radius/r );
667 sgdCopyVec3( normal, dpt );
668 sgdNormaliseVec3( normal );
669 sgdSetVec3( vel, 0.0, 0.0, 0.0 );
671 // The altitude is the distance of the requested point from the
673 *agl = sgdLengthVec3( dpt ) - sgdLengthVec3( contact );
674 *type = FGInterface::Unknown;
675 *loadCapacity = DBL_MAX;
676 *frictionFactor = 1.0;
681 bool FGGroundCache::caught_wire(double t, const double pt[4][3])
683 size_t sz = wires.size();
687 // Time difference to the reference time.
690 // Build the two triangles spanning the area where the hook has moved
691 // during the past step.
694 sgdMakePlane( plane[0], pt[0], pt[1], pt[2] );
695 sgdCopyVec3( tri[0][0], pt[0] );
696 sgdCopyVec3( tri[0][1], pt[1] );
697 sgdCopyVec3( tri[0][2], pt[2] );
698 sgdMakePlane( plane[1], pt[0], pt[2], pt[3] );
699 sgdCopyVec3( tri[1][0], pt[0] );
700 sgdCopyVec3( tri[1][1], pt[2] );
701 sgdCopyVec3( tri[1][2], pt[3] );
703 // Intersect the wire lines with each of these triangles.
704 // You have cautght a wire if they intersect.
705 for (size_t i = 0; i < sz; ++i) {
707 sgdCopyVec3(le[0], wires[i].ends[0]);
708 sgdCopyVec3(le[1], wires[i].ends[1]);
710 sgdAddVec3(le[0], cache_center);
711 sgdAddVec3(le[1], cache_center);
713 sgdAddScaledVec3(le[0], wires[i].velocity, t);
714 sgdAddScaledVec3(le[1], wires[i].velocity, t);
716 for (int k=0; k<2; ++k) {
718 double isecval = sgdIsectLinesegPlane(isecpoint, le[0], le[1], plane[k]);
719 if ( 0.0 <= isecval && isecval <= 1.0 &&
720 sgdPointInTriangle( isecpoint, tri[k] ) ) {
721 SG_LOG(SG_FLIGHT,SG_INFO, "Caught wire");
722 // Store the wire id.
723 wire_id = wires[i].wire_id;
732 bool FGGroundCache::get_wire_ends(double t, double end[2][3], double vel[2][3])
734 // Fast return if we do not have an active wire.
738 // Time difference to the reference time.
741 // Search for the wire with the matching wire id.
742 size_t sz = wires.size();
743 for (size_t i = 0; i < sz; ++i) {
744 if (wires[i].wire_id == wire_id) {
745 sgdCopyVec3(end[0], wires[i].ends[0]);
746 sgdCopyVec3(end[1], wires[i].ends[1]);
748 sgdAddVec3(end[0], cache_center);
749 sgdAddVec3(end[1], cache_center);
751 sgdAddScaledVec3(end[0], wires[i].velocity, t);
752 sgdAddScaledVec3(end[1], wires[i].velocity, t);
754 sgdCopyVec3(vel[0], wires[i].velocity);
755 sgdCopyVec3(vel[1], wires[i].velocity);
763 void FGGroundCache::release_wire(void)