fly/flightgear
1
0
Fork 0
Code Activity

Modified Files:

Browse source 
groundcache.hxx groundcache.cxx: Make use of the collision
	library now available in simgear
This commit is contained in:
frohlich 2007-01-30 20:13:32 +00:00
parent 3dd9e4ca5e
commit 64b9f93589
2 changed files with 87 additions and 294 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

364
src/FDM/groundcache.cxx
View file

@ -26,7 +26,6 @@
#include <float.h>
#include <plib/sg.h>
#include <osg/CullFace>
#include <osg/Drawable>
#include <osg/Geode>
@ -49,180 +48,15 @@
#include "flight.hxx"
#include "groundcache.hxx"
/// Ok, variant that uses a infinite line istead of the ray.
/// also not that this only works if the ray direction is normalized.
static inline bool
fgdRayTriangle(SGVec3d& x, const SGVec3d& point, const SGVec3d& dir,
const SGVec3d v[3])
intersectsInf(const SGRayd& ray, const SGSphered& sphere)
{
double eps = 1e-4;
// Method based on the observation that we are looking for a
// point x that can be expressed in terms of the triangle points
// x = p_0 + \mu_1*(p_1 - p_0) + \mu_2*(p_2 - p_0)
// with 0 <= \mu_1, \mu_2 and \mu_1 + \mu_2 <= 1.
// OTOH it could be expressed in terms of the ray
// x = point + \lambda*dir
// Now we can compute \mu_i and \lambda.
// define
SGVec3d d1 = v[1] - v[0];
SGVec3d d2 = v[2] - v[0];
SGVec3d b = point - v[0];
// the vector in normal direction, but not normalized
SGVec3d d1crossd2 = cross(d1, d2);
double denom = -dot(dir, d1crossd2);
double signDenom = copysign(1, denom);
// return if paralell ??? FIXME what if paralell and in plane?
// may be we are ok below than anyway??
// if (SGMiscd::abs(denom) <= SGLimitsd::min())
// return false;
// Now \lambda would read
// lambda = 1/denom*dot(b, d1crossd2);
// To avoid an expensive division we multiply by |denom|
double lambdaDenom = signDenom*dot(b, d1crossd2);
if (lambdaDenom < 0)
return false;
// For line segment we would test against
// if (1 < lambda)
// return false;
// with the original lambda. The multiplied test would read
// if (absDenom < lambdaDenom)
// return false;
double absDenom = fabs(denom);
double absDenomEps = absDenom*eps;
SGVec3d bcrossr = cross(b, dir);
// double mu1 = 1/denom*dot(d2, bcrossr);
double mu1 = signDenom*dot(d2, bcrossr);
if (mu1 < -absDenomEps)
return false;
// double mu2 = -1/denom*dot(d1, bcrossr);
// if (mu2 < -eps)
// return false;
double mmu2 = signDenom*dot(d1, bcrossr);
if (mmu2 > absDenomEps)
return false;
if (mu1 - mmu2 > absDenom + absDenomEps)
return false;
x = point;
// if we have survived here it could only happen with denom == 0
// that the point is already in plane. Then return the origin ...
if (SGLimitsd::min() < absDenom)
x += (lambdaDenom/absDenom)*dir;
return true;
}
static inline bool
fgdPointInTriangle( const SGVec3d& point, const SGVec3d tri[3] )
{
SGVec3d dif;
// Some tolerance in meters we accept a point to be outside of the triangle
// and still return that it is inside.
SGDfloat min, max;
// punt if outside bouding cube
SG_MIN_MAX3 ( min, max, tri[0][0], tri[1][0], tri[2][0] );
if( (point[0] < min) || (point[0] > max) )
return false;
dif[0] = max - min;
SG_MIN_MAX3 ( min, max, tri[0][1], tri[1][1], tri[2][1] );
if( (point[1] < min) || (point[1] > max) )
return false;
dif[1] = max - min;
SG_MIN_MAX3 ( min, max, tri[0][2], tri[1][2], tri[2][2] );
if( (point[2] < min) || (point[2] > max) )
return false;
dif[2] = max - min;
// drop the smallest dimension so we only have to work in 2d.
SGDfloat min_dim = SG_MIN3 (dif[0], dif[1], dif[2]);
SGDfloat x1, y1, x2, y2, x3, y3, rx, ry;
if ( fabs(min_dim-dif[0]) <= DBL_EPSILON ) {
// x is the smallest dimension
x1 = point[1];
y1 = point[2];
x2 = tri[0][1];
y2 = tri[0][2];
x3 = tri[1][1];
y3 = tri[1][2];
rx = tri[2][1];
ry = tri[2][2];
} else if ( fabs(min_dim-dif[1]) <= DBL_EPSILON ) {
// y is the smallest dimension
x1 = point[0];
y1 = point[2];
x2 = tri[0][0];
y2 = tri[0][2];
x3 = tri[1][0];
y3 = tri[1][2];
rx = tri[2][0];
ry = tri[2][2];
} else if ( fabs(min_dim-dif[2]) <= DBL_EPSILON ) {
// z is the smallest dimension
x1 = point[0];
y1 = point[1];
x2 = tri[0][0];
y2 = tri[0][1];
x3 = tri[1][0];
y3 = tri[1][1];
rx = tri[2][0];
ry = tri[2][1];
} else {
// all dimensions are really small so lets call it close
// enough and return a successful match
return true;
}
// check if intersection point is on the same side of p1 <-> p2 as p3
SGDfloat tmp = (y2 - y3);
SGDfloat tmpn = (x2 - x3);
int side1 = SG_SIGN (tmp * (rx - x3) + (y3 - ry) * tmpn);
int side2 = SG_SIGN (tmp * (x1 - x3) + (y3 - y1) * tmpn);
if ( side1 != side2 ) {
// printf("failed side 1 check\n");
return false;
}
// check if intersection point is on correct side of p2 <-> p3 as p1
tmp = (y3 - ry);
tmpn = (x3 - rx);
side1 = SG_SIGN (tmp * (x2 - rx) + (ry - y2) * tmpn);
side2 = SG_SIGN (tmp * (x1 - rx) + (ry - y1) * tmpn);
if ( side1 != side2 ) {
// printf("failed side 2 check\n");
return false;
}
// check if intersection point is on correct side of p1 <-> p3 as p2
tmp = (y2 - ry);
tmpn = (x2 - rx);
side1 = SG_SIGN (tmp * (x3 - rx) + (ry - y3) * tmpn);
side2 = SG_SIGN (tmp * (x1 - rx) + (ry - y1) * tmpn);
if ( side1 != side2 ) {
// printf("failed side 3 check\n");
return false;
}
return true;
}
// Test if the line given by the point on the line pt_on_line and the
// line direction dir intersects the sphere sp.
// Adapted from plib.
static inline bool
fgdIsectSphereInfLine(const SGVec3d& sphereCenter, double radius,
const SGVec3d& pt_on_line, const SGVec3d& dir)
{
SGVec3d r = sphereCenter - pt_on_line;
double projectedDistance = dot(r, dir);
SGVec3d r = sphere.getCenter() - ray.getOrigin();
double projectedDistance = dot(r, ray.getDirection());
double dist = dot(r, r) - projectedDistance * projectedDistance;
return dist < radius*radius;
return dist < sphere.getRadius2();
}
template<typename T>
@ -311,6 +145,12 @@ public:
mGroundProperty.pivot = SGVec3d(0, 0, 0);
}
void setSceneryCenter(const SGVec3d& cntr)
{
mLocalToGlobal.makeTranslate(cntr.osg());
mGlobalToLocal.makeTranslate(-cntr.osg());
}
void updateCullMode(osg::StateSet* stateSet)
{
if (!stateSet)
@ -342,7 +182,8 @@ public:
// cats or wires
double rw = bs.radius() + mWireCacheRadius;
if (rw*rw < centerDist2 &&
!fgdIsectSphereInfLine(cntr, bs.radius(), mCacheReference, mDown))
!intersectsInf(SGRayd(mCacheReference, mDown),
SGSphered(cntr, bs.radius())))
return false;
sphIsec = false;
}
@ -476,73 +317,64 @@ public:
// a bounding sphere in the node local system
SGVec3d boundCenter = (1.0/3)*(v[0] + v[1] + v[2]);
#if 0
double boundRadius = std::max(norm1(v[0] - boundCenter),
norm1(v[1] - boundCenter));
boundRadius = std::max(boundRadius, norm1(v[2] - boundCenter));
// Ok, we take the 1-norm instead of the expensive 2 norm.
// Therefore we need that scaling factor - roughly sqrt(3)
boundRadius = 1.733*boundRadius;
#else
double boundRadius = std::max(distSqr(v[0], boundCenter),
distSqr(v[1], boundCenter));
boundRadius = std::max(boundRadius, distSqr(v[2], boundCenter));
boundRadius = sqrt(boundRadius);
#endif
SGRayd ray(mLocalCacheReference, mLocalDown);
// if we are not in the downward cylinder bail out
if (!fgdIsectSphereInfLine(boundCenter, boundRadius + mCacheRadius,
mLocalCacheReference, mLocalDown))
if (!intersectsInf(ray, SGSphered(boundCenter, boundRadius + mCacheRadius)))
return;
SGTriangled triangle(v);
// The normal and plane in the node local coordinate system
SGVec3d n = normalize(cross(v[1] - v[0], v[2] - v[0]));
SGVec3d n = cross(triangle.getEdge(0), triangle.getEdge(1));
if (0 < dot(mLocalDown, n)) {
if (mBackfaceCulling) {
// Surface points downwards, ignore for altitude computations.
return;
} else {
n = -n;
std::swap(v[1], v[2]);
triangle.flip();
}
}
// Only check if the triangle is in the cache sphere if the plane
// containing the triangle is near enough
if (sphIsec && fabs(dot(n, v[0] - mLocalCacheReference)) < mCacheRadius) {
// Check if the sphere around the vehicle intersects the sphere
// around that triangle. If so, put that triangle into the cache.
double r2 = boundRadius + mCacheRadius;
if (distSqr(boundCenter, mLocalCacheReference) < r2*r2) {
FGGroundCache::Triangle t;
for (unsigned i = 0; i < 3; ++i)
t.vertices[i].osg() = v[i].osg()*mLocalToGlobal;
t.boundCenter.osg() = boundCenter.osg()*mLocalToGlobal;
t.boundRadius = boundRadius;
SGVec3d tmp;
tmp.osg() = osg::Matrixd::transform3x3(n.osg(), mLocalToGlobal);
t.plane = SGVec4d(tmp[0], tmp[1], tmp[2], -dot(tmp, t.vertices[0]));
t.velocity = mGroundProperty.vel;
t.rotation = mGroundProperty.rot;
t.rotation_pivot = mGroundProperty.pivot - mGroundCache->cache_center;
t.type = mGroundProperty.type;
t.material = mGroundProperty.material;
mGroundCache->triangles.push_back(t);
if (sphIsec) {
double d = dot(n, v[0] - mLocalCacheReference);
if (d*d < mCacheRadius*dot(n, n)) {
// Check if the sphere around the vehicle intersects the sphere
// around that triangle. If so, put that triangle into the cache.
double r2 = boundRadius + mCacheRadius;
if (distSqr(boundCenter, mLocalCacheReference) < r2*r2) {
FGGroundCache::Triangle t;
t.triangle.setBaseVertex(SGVec3d(v[0].osg()*mLocalToGlobal));
t.triangle.setEdge(0, SGVec3d(osg::Matrixd::transform3x3(triangle.getEdge(0).osg(), mLocalToGlobal)));
t.triangle.setEdge(1, SGVec3d(osg::Matrixd::transform3x3(triangle.getEdge(1).osg(), mLocalToGlobal)));
t.sphere.setCenter(SGVec3d(boundCenter.osg()*mLocalToGlobal));
t.sphere.setRadius(boundRadius);
t.velocity = mGroundProperty.vel;
t.rotation = mGroundProperty.rot;
t.rotation_pivot = mGroundProperty.pivot;
t.type = mGroundProperty.type;
t.material = mGroundProperty.material;
mGroundCache->triangles.push_back(t);
}
}
}
// In case the cache is empty, we still provide agl computations.
// But then we use the old way of having a fixed elevation value for
// the whole lifetime of this cache.
SGVec4d plane = SGVec4d(n[0], n[1], n[2], -dot(n, v[0]));
SGVec3d isectpoint;
if (fgdRayTriangle(isectpoint, mLocalCacheReference, mLocalDown, v)) {
if (intersects(isectpoint, triangle, ray, 1e-4)) {
mGroundCache->found_ground = true;
isectpoint.osg() = isectpoint.osg()*mLocalToGlobal;
isectpoint += mGroundCache->cache_center;
double this_radius = length(isectpoint);
if (mGroundCache->ground_radius < this_radius) {
mGroundCache->ground_radius = this_radius;
@ -568,7 +400,7 @@ public:
wire.ends[1] = gv2;
wire.velocity = mGroundProperty.vel;
wire.rotation = mGroundProperty.rot;
wire.rotation_pivot = mGroundProperty.pivot - mGroundCache->cache_center;
wire.rotation_pivot = mGroundProperty.pivot;
wire.wire_id = mGroundProperty.wire_id;
mGroundCache->wires.push_back(wire);
@ -587,7 +419,7 @@ public:
}
cat.velocity = mGroundProperty.vel;
cat.rotation = mGroundProperty.rot;
cat.rotation_pivot = mGroundProperty.pivot - mGroundCache->cache_center;
cat.rotation_pivot = mGroundProperty.pivot;
mGroundCache->catapults.push_back(cat);
}
@ -611,7 +443,6 @@ public:
FGGroundCache::FGGroundCache()
{
cache_center = SGVec3d(0, 0, 0);
ground_radius = 0.0;
cache_ref_time = 0.0;
wire_id = 0;
@ -626,28 +457,24 @@ FGGroundCache::~FGGroundCache()
inline void
FGGroundCache::velocityTransformTriangle(double dt,
FGGroundCache::Triangle& dst,
SGTriangled& dst, SGSphered& sdst,
const FGGroundCache::Triangle& src)
{
dst = src;
dst = src.triangle;
sdst = src.sphere;
if (fabs(dt*dot(src.velocity, src.velocity)) < SGLimitsd::epsilon())
if (dt*dt*dot(src.velocity, src.velocity) < SGLimitsd::epsilon())
return;
for (int i = 0; i < 3; ++i) {
SGVec3d pivotoff = src.vertices[i] - src.rotation_pivot;
dst.vertices[i] += dt*(src.velocity + cross(src.rotation, pivotoff));
}
// Transform the plane equation
SGVec3d pivotoff, vel;
sgdSubVec3(pivotoff.sg(), dst.plane.sg(), src.rotation_pivot.sg());
vel = src.velocity + cross(src.rotation, pivotoff);
dst.plane[3] += dt*sgdScalarProductVec3(dst.plane.sg(), vel.sg());
dst.boundCenter += dt*src.velocity;
SGVec3d baseVert = dst.getBaseVertex();
SGVec3d pivotoff = baseVert - src.rotation_pivot;
baseVert += dt*(src.velocity + cross(src.rotation, pivotoff));
dst.setBaseVertex(baseVert);
dst.setEdge(0, dst.getEdge(0) + dt*cross(src.rotation, dst.getEdge(0)));
dst.setEdge(1, dst.getEdge(1) + dt*cross(src.rotation, dst.getEdge(1)));
}
bool
FGGroundCache::prepare_ground_cache(double ref_time, const SGVec3d& pt,
double rad)
@ -669,20 +496,7 @@ FGGroundCache::prepare_ground_cache(double ref_time, const SGVec3d& pt,
SGQuatd hlToEc = SGQuatd::fromLonLat(SGGeod::fromCart(pt));
down = hlToEc.rotate(SGVec3d(0, 0, 1));
// Decide where we put the scenery center.
SGVec3d old_cntr = globals->get_scenery()->get_center();
SGVec3d cntr(pt);
// Only move the cache center if it is unacceptable far away.
if (40*40 < distSqr(old_cntr, cntr))
globals->get_scenery()->set_center(cntr);
else
cntr = old_cntr;
// The center of the cache.
cache_center = cntr;
// Prepare sphere around the aircraft.
SGVec3d ptoff = pt - cache_center;
double cacheRadius = rad;
// Prepare bigger sphere around the aircraft.
@ -692,7 +506,8 @@ FGGroundCache::prepare_ground_cache(double ref_time, const SGVec3d& pt,
double wireCacheRadius = max_wire_dist < rad ? rad : max_wire_dist;
// Walk the scene graph and extract solid ground triangles and carrier data.
GroundCacheFillVisitor gcfv(this, down, ptoff, cacheRadius, wireCacheRadius);
GroundCacheFillVisitor gcfv(this, down, pt, cacheRadius, wireCacheRadius);
gcfv.setSceneryCenter(globals->get_scenery()->get_center());
globals->get_scenery()->get_scene_graph()->accept(gcfv);
// some stats
@ -709,9 +524,6 @@ FGGroundCache::prepare_ground_cache(double ref_time, const SGVec3d& pt,
SG_LOG(SG_FLIGHT, SG_WARN, "prepare_ground_cache(): trying to build cache "
"without any scenery below the aircraft" );
if (cntr != old_cntr)
globals->get_scenery()->set_center(old_cntr);
return found_ground;
}
@ -743,14 +555,10 @@ FGGroundCache::get_cat(double t, const SGVec3d& dpt,
rvel[1] = catapults[i].velocity + cross(catapults[i].rotation, pivotoff);
SGVec3d thisEnd[2];
thisEnd[0] = cache_center + catapults[i].start + t*rvel[0];
thisEnd[1] = cache_center + catapults[i].end + t*rvel[1];
sgdLineSegment3 ls;
sgdCopyVec3(ls.a, thisEnd[0].sg());
sgdCopyVec3(ls.b, thisEnd[1].sg());
double this_dist = sgdDistSquaredToLineSegmentVec3( ls, dpt.sg() );
thisEnd[0] = catapults[i].start + t*rvel[0];
thisEnd[1] = catapults[i].end + t*rvel[1];
double this_dist = distSqr(SGLineSegmentd(thisEnd[0], thisEnd[1]), dpt);
if (this_dist < dist) {
SG_LOG(SG_FLIGHT,SG_INFO, "Found catapult "
<< this_dist << " meters away");
@ -786,28 +594,28 @@ FGGroundCache::get_agl(double t, const SGVec3d& dpt, double max_altoff,
t -= cache_ref_time;
// The double valued point we start to search for intersection.
SGVec3d pt = dpt - cache_center;
SGVec3d pt = dpt;
// shift the start of our ray by maxaltoff upwards
SGVec3d raystart = pt - max_altoff*down;
SGRayd ray(pt - max_altoff*down, down);
// Initialize to something sensible
double current_radius = 0.0;
size_t sz = triangles.size();
for (size_t i = 0; i < sz; ++i) {
Triangle triangle;
velocityTransformTriangle(t, triangle, triangles[i]);
if (!fgdIsectSphereInfLine(triangle.boundCenter, triangle.boundRadius, pt, down))
SGSphered sphere;
SGTriangled triangle;
velocityTransformTriangle(t, triangle, sphere, triangles[i]);
if (!intersectsInf(ray, sphere))
continue;
// Check for intersection.
SGVec3d isecpoint;
if (fgdRayTriangle(isecpoint, raystart, down, triangle.vertices)) {
if (intersects(isecpoint, triangle, ray, 1e-4)) {
// Compute the vector from pt to the intersection point ...
SGVec3d off = isecpoint - pt;
// ... and check if it is too high or not
// Transform to the wgs system
isecpoint += cache_center;
// compute the radius, good enough approximation to take the geocentric radius
double radius = dot(isecpoint, isecpoint);
if (current_radius < radius) {
@ -816,15 +624,15 @@ FGGroundCache::get_agl(double t, const SGVec3d& dpt, double max_altoff,
// Save the new potential intersection point.
contact = isecpoint;
// The first three values in the vector are the plane normal.
sgdCopyVec3( normal.sg(), triangle.plane.sg() );
normal = triangle.getNormal();
// The velocity wrt earth.
SGVec3d pivotoff = pt - triangle.rotation_pivot;
vel = triangle.velocity + cross(triangle.rotation, pivotoff);
SGVec3d pivotoff = pt - triangles[i].rotation_pivot;
vel = triangles[i].velocity + cross(triangles[i].rotation, pivotoff);
// Save the ground type.
*type = triangle.type;
*type = triangles[i].type;
*agl = dot(down, contact - dpt);
if (material)
*material = triangle.material;
*material = triangles[i].material;
}
}
}
@ -862,16 +670,9 @@ bool FGGroundCache::caught_wire(double t, const SGVec3d pt[4])
// Build the two triangles spanning the area where the hook has moved
// during the past step.
SGVec4d plane[2];
SGVec3d tri[2][3];
sgdMakePlane( plane[0].sg(), pt[0].sg(), pt[1].sg(), pt[2].sg() );
tri[0][0] = pt[0];
tri[0][1] = pt[1];
tri[0][2] = pt[2];
sgdMakePlane( plane[1].sg(), pt[0].sg(), pt[2].sg(), pt[3].sg() );
tri[1][0] = pt[0];
tri[1][1] = pt[2];
tri[1][2] = pt[3];
SGTriangled triangle[2];
triangle[0].set(pt[0], pt[1], pt[2]);
triangle[1].set(pt[0], pt[2], pt[3]);
// Intersect the wire lines with each of these triangles.
// You have caught a wire if they intersect.
@ -881,15 +682,12 @@ bool FGGroundCache::caught_wire(double t, const SGVec3d pt[4])
le[k] = wires[i].ends[k];
SGVec3d pivotoff = le[k] - wires[i].rotation_pivot;
SGVec3d vel = wires[i].velocity + cross(wires[i].rotation, pivotoff);
le[k] += t*vel + cache_center;
le[k] += t*vel;
}
SGLineSegmentd lineSegment(le[0], le[1]);
for (int k=0; k<2; ++k) {
SGVec3d isecpoint;
double isecval = sgdIsectLinesegPlane(isecpoint.sg(), le[0].sg(),
le[1].sg(), plane[k].sg());
if ( 0.0 <= isecval && isecval <= 1.0 &&
fgdPointInTriangle( isecpoint, tri[k] ) ) {
if (intersects(triangle[k], lineSegment)) {
SG_LOG(SG_FLIGHT,SG_INFO, "Caught wire");
// Store the wire id.
wire_id = wires[i].wire_id;
@ -917,7 +715,7 @@ bool FGGroundCache::get_wire_ends(double t, SGVec3d end[2], SGVec3d vel[2])
for (size_t k = 0; k < 2; ++k) {
SGVec3d pivotoff = end[k] - wires[i].rotation_pivot;
vel[k] = wires[i].velocity + cross(wires[i].rotation, pivotoff);
end[k] = cache_center + wires[i].ends[k] + t*vel[k];
end[k] = wires[i].ends[k] + t*vel[k];
}
return true;
}

17
src/FDM/groundcache.hxx
View file

@ -26,6 +26,7 @@
#include <simgear/compiler.h>
#include <simgear/constants.h>
#include <simgear/math/SGMath.hxx>
#include <simgear/math/SGGeometry.hxx>
class SGMaterial;
class GroundCacheFillVisitor;
@ -85,13 +86,9 @@ private:
struct Triangle {
Triangle() : material(0) {}
// The edge vertices.
SGVec3d vertices[3];
// The surface normal.
SGVec4d plane;
// The bounding shpere.
SGVec3d boundCenter;
double boundRadius;
// The triangle we represent
SGTriangled triangle;
SGSphered sphere;
// The linear and angular velocity.
SGVec3d velocity;
SGVec3d rotation;
@ -117,8 +114,6 @@ private:
};
// The center of the cache.
SGVec3d cache_center;
// Approximate ground radius.
// In case the aircraft is too high above ground.
double ground_radius;
@ -156,8 +151,8 @@ private:
const SGMaterial* material;
};
static void velocityTransformTriangle(double dt, Triangle& dst,
const Triangle& src);
static void velocityTransformTriangle(double dt, SGTriangled& dst,
SGSphered& sdst, const Triangle& src);
};
#endif