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, gp.rot, gp.pivot );
234 // Initialize velocity field.
235 sgdSetVec3( gp.vel, 0.0, 0.0, 0.0 );
236 sgdSetVec3( gp.rot, 0.0, 0.0, 0.0 );
237 sgdSetVec3( gp.pivot, 0.0, 0.0, 0.0 );
240 // Get the texture name and decide what ground type we have.
241 ssgState *st = l->getState();
242 if (st != NULL && st->isAKindOf(ssgTypeSimpleState())) {
243 ssgSimpleState *ss = (ssgSimpleState*)st;
244 SGPath fullPath( ss->getTextureFilename() ? ss->getTextureFilename(): "" );
245 string file = fullPath.file();
246 SGPath dirPath(fullPath.dir());
247 string category = dirPath.file();
249 if (category == "Runway")
250 gp.type = FGInterface::Solid;
252 if (file == "asphault.rgb" || file == "airport.rgb")
253 gp.type = FGInterface::Solid;
254 else if (file == "water.rgb" || file == "water-lake.rgb")
255 gp.type = FGInterface::Water;
256 else if (file == "forest.rgb" || file == "cropwood.rgb")
257 gp.type = FGInterface::Forest;
265 FGGroundCache::putLineLeafIntoCache(const sgdSphere *wsp, const sgdMat4 xform,
268 GroundProperty gp = extractGroundProperty(l);
270 // Lines must have special meanings.
271 // Wires and catapults are done with lines.
272 int nl = l->getNumLines();
273 for (int i = 0; i < nl; ++i) {
278 l->getLine(i, v, v+1 );
279 for (int k=0; k<2; ++k) {
280 sgdSetVec3(ends[k], l->getVertex(v[k]));
281 sgdXformPnt3(ends[k], xform);
282 sphere.extend(ends[k]);
285 if (wsp->intersects( &sphere )) {
286 if (gp.type == FGInterface::Wire) {
288 sgdCopyVec3(wire.ends[0], ends[0]);
289 sgdCopyVec3(wire.ends[1], ends[1]);
290 sgdCopyVec3(wire.velocity, gp.vel);
291 sgdCopyVec3(wire.rotation, gp.rot);
292 sgdSubVec3(wire.rotation_pivot, gp.pivot, cache_center);
293 wire.wire_id = gp.wire_id;
295 wires.push_back(wire);
297 if (gp.type == FGInterface::Catapult) {
299 sgdCopyVec3(cat.start, ends[0]);
300 sgdCopyVec3(cat.end, ends[1]);
301 sgdCopyVec3(cat.velocity, gp.vel);
302 sgdCopyVec3(cat.rotation, gp.rot);
303 sgdSubVec3(cat.rotation_pivot, gp.pivot, cache_center);
305 catapults.push_back(cat);
312 FGGroundCache::putSurfaceLeafIntoCache(const sgdSphere *sp,
313 const sgdMat4 xform, bool sphIsec,
314 sgdVec3 down, ssgLeaf *l)
316 GroundProperty gp = extractGroundProperty(l);
318 int nt = l->getNumTriangles();
319 for (int i = 0; i < nt; ++i) {
323 l->getTriangle(i, &v[0], &v[1], &v[2]);
324 for (int k = 0; k < 3; ++k) {
325 sgdSetVec3(t.vertices[k], l->getVertex(v[k]));
326 sgdXformPnt3(t.vertices[k], xform);
327 t.sphere.extend(t.vertices[k]);
330 sgdMakePlane(t.plane, t.vertices[0], t.vertices[1], t.vertices[2]);
331 SGDfloat dot = sgdScalarProductVec3(down, t.plane);
333 if (!l->getCullFace()) {
334 // Surface points downwards, ignore for altitude computations.
337 sgdScaleVec4( t.plane, -1 );
340 // Check if the sphere around the vehicle intersects the sphere
341 // around that triangle. If so, put that triangle into the cache.
342 if (sphIsec && sp->intersects(&t.sphere)) {
343 sgdCopyVec3(t.velocity, gp.vel);
344 sgdCopyVec3(t.rotation, gp.rot);
345 sgdSubVec3(t.rotation_pivot, gp.pivot, cache_center);
347 triangles.push_back(t);
350 // In case the cache is empty, we still provide agl computations.
351 // But then we use the old way of having a fixed elevation value for
352 // the whole lifetime of this cache.
353 if ( fgdIsectSphereInfLine(t.sphere, sp->getCenter(), down) ) {
355 sgdSetVec3(tmp, sp->center[0], sp->center[1], sp->center[2]);
357 if ( sgdIsectInfLinePlane( isectpoint, tmp, down, t.plane ) &&
358 fgdPointInTriangle( isectpoint, t.vertices ) ) {
359 // Compute the offset to the ground cache midpoint
361 sgdSubVec3(off, isectpoint, tmp);
362 // Only accept the altitude if the intersection point is below the
363 // ground cache midpoint
364 if (0 < sgdScalarProductVec3( off, down ) || !found_ground) {
366 sgdAddVec3(isectpoint, cache_center);
367 double this_radius = sgdLengthVec3(isectpoint);
368 if (ground_radius < this_radius)
369 ground_radius = this_radius;
377 FGGroundCache::velocityTransformTriangle(double dt,
378 FGGroundCache::Triangle& dst,
379 const FGGroundCache::Triangle& src)
381 sgdCopyVec3(dst.vertices[0], src.vertices[0]);
382 sgdCopyVec3(dst.vertices[1], src.vertices[1]);
383 sgdCopyVec3(dst.vertices[2], src.vertices[2]);
385 sgdCopyVec4(dst.plane, src.plane);
387 sgdCopyVec3(dst.sphere.center, src.sphere.center);
388 dst.sphere.radius = src.sphere.radius;
390 sgdCopyVec3(dst.velocity, src.velocity);
391 sgdCopyVec3(dst.rotation, src.rotation);
392 sgdCopyVec3(dst.rotation_pivot, src.rotation_pivot);
396 if (dt*sgdLengthSquaredVec3(src.velocity) != 0) {
397 sgdVec3 pivotoff, vel;
398 for (int i = 0; i < 3; ++i) {
399 sgdSubVec3(pivotoff, src.vertices[i], src.rotation_pivot);
400 sgdVectorProductVec3(vel, src.rotation, pivotoff);
401 sgdAddVec3(vel, src.velocity);
402 sgdAddScaledVec3(dst.vertices[i], vel, dt);
405 // Transform the plane equation
406 sgdSubVec3(pivotoff, dst.plane, src.rotation_pivot);
407 sgdVectorProductVec3(vel, src.rotation, pivotoff);
408 sgdAddVec3(vel, src.velocity);
409 dst.plane[3] += dt*sgdScalarProductVec3(dst.plane, vel);
411 sgdAddScaledVec3(dst.sphere.center, src.velocity, dt);
416 FGGroundCache::cache_fill(ssgBranch *branch, sgdMat4 xform,
417 sgdSphere* sp, sgdVec3 down, sgdSphere* wsp)
419 // Travel through all kids.
421 for ( e = branch->getKid(0); e != NULL ; e = branch->getNextKid() ) {
422 if ( !(e->getTraversalMask() & SSGTRAV_HOT) )
424 if ( e->getBSphere()->isEmpty() )
427 // We need to check further if either the sphere around the branch
428 // intersects the sphere around the aircraft or the line downwards from
429 // the aircraft intersects the branchs sphere.
431 sgdSetVec3(esphere.center, e->getBSphere()->center);
432 esphere.radius = e->getBSphere()->radius;
433 esphere.orthoXform(xform);
434 bool wspIsec = wsp->intersects(&esphere);
435 bool downIsec = fgdIsectSphereInfLine(esphere, sp->getCenter(), down);
436 if (!wspIsec && !downIsec)
439 // For branches collect up the transforms to reach that branch and
440 // call cache_fill recursively.
441 if ( e->isAKindOf( ssgTypeBranch() ) ) {
442 ssgBranch *b = (ssgBranch *)e;
443 if ( b->isAKindOf( ssgTypeTransform() ) ) {
444 // Collect up the transfors required to reach that part of
447 sgMakeIdentMat4( xform2 );
448 ssgTransform *t = (ssgTransform*)b;
449 t->getTransform( xform2 );
451 fgMultMat4(xform3, xform, xform2);
452 cache_fill( b, xform3, sp, down, wsp );
454 cache_fill( b, xform, sp, down, wsp );
457 // For leafs, check each triangle for intersection.
458 // This will minimize the number of vertices/triangles in the cache.
459 else if (e->isAKindOf(ssgTypeLeaf())) {
460 // Since we reach that leaf if we have an intersection with the
461 // most propably bigger wire/catapult cache sphere, we need to check
462 // that here, if the smaller cache for the surface has a chance for hits.
463 // Also, if the spheres do not intersect compute a croase agl value
464 // by following the line downwards originating at the aircraft.
465 bool spIsec = sp->intersects(&esphere);
466 putSurfaceLeafIntoCache(sp, xform, spIsec, down, (ssgLeaf *)e);
468 // If we are here, we need to put all special hardware here into
471 putLineLeafIntoCache(wsp, xform, (ssgLeaf *)e);
477 FGGroundCache::prepare_ground_cache(double ref_time, const double pt[3],
482 found_ground = false;
487 // Store the parameters we used to build up that cache.
488 sgdCopyVec3(reference_wgs84_point, pt);
489 reference_vehicle_radius = rad;
490 // Store the time reference used to compute movements of moving triangles.
491 cache_ref_time = ref_time;
493 // Decide where we put the scenery center.
494 Point3D old_cntr = globals->get_scenery()->get_center();
495 Point3D cntr(pt[0], pt[1], pt[2]);
496 // Only move the cache center if it is unaccaptable far away.
497 if (40*40 < old_cntr.distance3Dsquared(cntr))
498 globals->get_scenery()->set_center(cntr);
502 // The center of the cache.
503 sgdSetVec3(cache_center, cntr[0], cntr[1], cntr[2]);
506 sgdSubVec3(ptoff, pt, cache_center);
507 // Prepare sphere around the aircraft.
509 acSphere.setRadius(rad);
510 acSphere.setCenter(ptoff);
512 // Prepare bigger sphere around the aircraft.
513 // This one is required for reliably finding wires we have caught but
514 // have already left the hopefully smaller sphere for the ground reactions.
515 const double max_wire_dist = 300.0;
516 sgdSphere wireSphere;
517 wireSphere.setRadius(max_wire_dist < rad ? rad : max_wire_dist);
518 wireSphere.setCenter(ptoff);
520 // Down vector. Is used for croase agl computations when we are far enough
521 // from ground that we have an empty cache.
523 sgdSetVec3(down, -pt[0], -pt[1], -pt[2]);
524 sgdNormalizeVec3(down);
526 // We collaps all transforms we need to reach a particular leaf.
527 // The leafs itself will be then transformed later.
528 // So our cache is just flat.
529 // For leafs which are moving (carriers surface, etc ...)
530 // we will later store a speed in the GroundType class. We can then apply
531 // some translations to that nodes according to the time which has passed
532 // compared to that snapshot.
534 sgdMakeIdentMat4( xform );
537 // Walk the scene graph and extract solid ground triangles and carrier data.
538 ssgBranch *terrain = globals->get_scenery()->get_scene_graph();
539 cache_fill(terrain, xform, &acSphere, down, &wireSphere);
542 SG_LOG(SG_FLIGHT,SG_DEBUG, "prepare_ground_cache(): ac radius = " << rad
543 << ", # triangles = " << triangles.size()
544 << ", # wires = " << wires.size()
545 << ", # catapults = " << catapults.size()
546 << ", ground_radius = " << ground_radius );
548 // If the ground radius is still below 5e6 meters, then we do not yet have
550 found_ground = found_ground && 5e6 < ground_radius;
552 SG_LOG(SG_FLIGHT, SG_WARN, "prepare_ground_cache(): trying to build cache "
553 "without any scenery below the aircraft" );
555 if (cntr != old_cntr)
556 globals->get_scenery()->set_center(old_cntr);
562 FGGroundCache::is_valid(double *ref_time, double pt[3], double *rad)
564 sgdCopyVec3(pt, reference_wgs84_point);
565 *rad = reference_vehicle_radius;
566 *ref_time = cache_ref_time;
571 FGGroundCache::get_cat(double t, const double dpt[3],
572 double end[2][3], double vel[2][3])
574 // start with a distance of 1e10 meters...
577 // Time difference to the reference time.
580 size_t sz = catapults.size();
581 for (size_t i = 0; i < sz; ++i) {
582 sgdVec3 pivotoff, rvel[2];
584 sgdCopyVec3(ls.a, catapults[i].start);
585 sgdCopyVec3(ls.b, catapults[i].end);
587 sgdSubVec3(pivotoff, ls.a, catapults[i].rotation_pivot);
588 sgdVectorProductVec3(rvel[0], catapults[i].rotation, pivotoff);
589 sgdAddVec3(rvel[0], catapults[i].velocity);
590 sgdSubVec3(pivotoff, ls.b, catapults[i].rotation_pivot);
591 sgdVectorProductVec3(rvel[1], catapults[i].rotation, pivotoff);
592 sgdAddVec3(rvel[1], catapults[i].velocity);
594 sgdAddVec3(ls.a, cache_center);
595 sgdAddVec3(ls.b, cache_center);
597 sgdAddScaledVec3(ls.a, rvel[0], t);
598 sgdAddScaledVec3(ls.b, rvel[1], t);
600 double this_dist = sgdDistSquaredToLineSegmentVec3( ls, dpt );
601 if (this_dist < dist) {
602 SG_LOG(SG_FLIGHT,SG_INFO, "Found catapult "
603 << this_dist << " meters away");
606 // The carrier code takes care of that ordering.
607 sgdCopyVec3( end[0], ls.a );
608 sgdCopyVec3( end[1], ls.b );
609 sgdCopyVec3( vel[0], rvel[0] );
610 sgdCopyVec3( vel[1], rvel[1] );
614 // At the end take the root, we only computed squared distances ...
619 FGGroundCache::get_agl(double t, const double dpt[3], double max_altoff,
620 double contact[3], double normal[3], double vel[3],
621 int *type, double *loadCapacity,
622 double *frictionFactor, double *agl)
626 *type = FGInterface::Unknown;
628 *loadCapacity = DBL_MAX;
629 *frictionFactor = 1.0;
630 sgdSetVec3( vel, 0.0, 0.0, 0.0 );
631 sgdSetVec3( contact, 0.0, 0.0, 0.0 );
632 sgdSetVec3( normal, 0.0, 0.0, 0.0 );
634 // Time difference to th reference time.
637 // The double valued point we start to search for intersection.
639 sgdSubVec3( pt, dpt, cache_center );
641 // The search direction
643 sgdSetVec3( dir, -dpt[0], -dpt[1], -dpt[2] );
644 sgdNormaliseVec3( dir );
646 // Initialize to something sensible
647 double current_radius = 0.0;
649 size_t sz = triangles.size();
650 for (size_t i = 0; i < sz; ++i) {
652 velocityTransformTriangle(t, triangle, triangles[i]);
653 if (!fgdIsectSphereInfLine(triangle.sphere, pt, dir))
656 // Check for intersection.
658 if ( sgdIsectInfLinePlane( isecpoint, pt, dir, triangle.plane ) &&
659 sgdPointInTriangle( isecpoint, triangle.vertices ) ) {
660 // Compute the vector from pt to the intersection point ...
662 sgdSubVec3(off, isecpoint, pt);
663 // ... and check if it is too high or not
664 if (-max_altoff < sgdScalarProductVec3( off, dir )) {
665 // Transform to the wgs system
666 sgdAddVec3( isecpoint, cache_center );
667 // compute the radius, good enough approximation to take the geocentric radius
668 SGDfloat radius = sgdLengthSquaredVec3(isecpoint);
669 if (current_radius < radius) {
670 current_radius = radius;
672 // Save the new potential intersection point.
673 sgdCopyVec3( contact, isecpoint );
674 // The first three values in the vector are the plane normal.
675 sgdCopyVec3( normal, triangle.plane );
676 // The velocity wrt earth.
678 sgdSubVec3(pivotoff, pt, triangle.rotation_pivot);
679 sgdVectorProductVec3(vel, triangle.rotation, pivotoff);
680 sgdAddVec3(vel, triangle.velocity);
681 // Save the ground type.
682 *type = triangle.type;
683 // FIXME: figure out how to get that sign ...
684 // *agl = sqrt(sqdist);
685 *agl = sgdLengthVec3( dpt ) - sgdLengthVec3( contact );
686 // *loadCapacity = DBL_MAX;
687 // *frictionFactor = 1.0;
696 // Whenever we did not have a ground triangle for the requested point,
697 // take the ground level we found during the current cache build.
698 // This is as good as what we had before for agl.
699 double r = sgdLengthVec3( dpt );
700 sgdCopyVec3( contact, dpt );
701 sgdScaleVec3( contact, ground_radius/r );
702 sgdCopyVec3( normal, dpt );
703 sgdNormaliseVec3( normal );
704 sgdSetVec3( vel, 0.0, 0.0, 0.0 );
706 // The altitude is the distance of the requested point from the
708 *agl = sgdLengthVec3( dpt ) - sgdLengthVec3( contact );
709 *type = FGInterface::Unknown;
710 *loadCapacity = DBL_MAX;
711 *frictionFactor = 1.0;
716 bool FGGroundCache::caught_wire(double t, const double pt[4][3])
718 size_t sz = wires.size();
722 // Time difference to the reference time.
725 // Build the two triangles spanning the area where the hook has moved
726 // during the past step.
729 sgdMakePlane( plane[0], pt[0], pt[1], pt[2] );
730 sgdCopyVec3( tri[0][0], pt[0] );
731 sgdCopyVec3( tri[0][1], pt[1] );
732 sgdCopyVec3( tri[0][2], pt[2] );
733 sgdMakePlane( plane[1], pt[0], pt[2], pt[3] );
734 sgdCopyVec3( tri[1][0], pt[0] );
735 sgdCopyVec3( tri[1][1], pt[2] );
736 sgdCopyVec3( tri[1][2], pt[3] );
738 // Intersect the wire lines with each of these triangles.
739 // You have cautght a wire if they intersect.
740 for (size_t i = 0; i < sz; ++i) {
742 for (int k = 0; k < 2; ++k) {
743 sgdVec3 pivotoff, vel;
744 sgdCopyVec3(le[k], wires[i].ends[k]);
745 sgdSubVec3(pivotoff, le[k], wires[i].rotation_pivot);
746 sgdVectorProductVec3(vel, wires[i].rotation, pivotoff);
747 sgdAddVec3(vel, wires[i].velocity);
748 sgdAddScaledVec3(le[k], vel, t);
749 sgdAddVec3(le[k], cache_center);
752 for (int k=0; k<2; ++k) {
754 double isecval = sgdIsectLinesegPlane(isecpoint, le[0], le[1], plane[k]);
755 if ( 0.0 <= isecval && isecval <= 1.0 &&
756 sgdPointInTriangle( isecpoint, tri[k] ) ) {
757 SG_LOG(SG_FLIGHT,SG_INFO, "Caught wire");
758 // Store the wire id.
759 wire_id = wires[i].wire_id;
768 bool FGGroundCache::get_wire_ends(double t, double end[2][3], double vel[2][3])
770 // Fast return if we do not have an active wire.
774 // Time difference to the reference time.
777 // Search for the wire with the matching wire id.
778 size_t sz = wires.size();
779 for (size_t i = 0; i < sz; ++i) {
780 if (wires[i].wire_id == wire_id) {
781 for (size_t k = 0; k < 2; ++k) {
783 sgdCopyVec3(end[k], wires[i].ends[k]);
784 sgdSubVec3(pivotoff, end[k], wires[i].rotation_pivot);
785 sgdVectorProductVec3(vel[k], wires[i].rotation, pivotoff);
786 sgdAddVec3(vel[k], wires[i].velocity);
787 sgdAddScaledVec3(end[k], vel[k], t);
788 sgdAddVec3(end[k], cache_center);
797 void FGGroundCache::release_wire(void)