#include "BodyEnvironment.hpp"
#include "RigidBody.hpp"
+#include <simgear/scene/material/mat.hxx>
+#include <FDM/flight.hxx>
#include "Gear.hpp"
namespace yasim {
+static const float YASIM_PI = 3.14159265358979323846;
+static const float maxGroundBumpAmplitude=0.4;
+ //Amplitude can be positive and negative
Gear::Gear()
{
_dfric = 0.7f;
_brake = 0;
_rot = 0;
+ _initialLoad = 0;
_extension = 1;
_castering = false;
_frac = 0;
+ _ground_frictionFactor = 1;
+ _ground_rollingFriction = 0.02;
+ _ground_loadCapacity = 1e30;
+ _ground_loadResistance = 1e30;
+ _ground_isSolid = 1;
+ _ground_bumpiness = 0;
+ _onWater = 0;
+ _onSolid = 1;
+ _global_x = 0.0;
+ _global_y = 0.0;
+ _reduceFrictionByExtension = 0;
+ _spring_factor_not_planing = 1;
+ _speed_planing = 0;
+ _isContactPoint = 0;
+ _ignoreWhileSolving = 0;
for(i=0; i<3; i++)
_global_ground[i] = _global_vel[i] = 0;
_castering = c;
}
-void Gear::setGlobalGround(double *global_ground, float* global_vel)
+void Gear::setContactPoint(bool c)
+{
+ _isContactPoint=c;
+}
+
+void Gear::setOnWater(bool c)
+{
+ _onWater = c;
+}
+
+void Gear::setOnSolid(bool c)
+{
+ _onSolid = c;
+}
+
+void Gear::setIgnoreWhileSolving(bool c)
+{
+ _ignoreWhileSolving = c;
+}
+
+void Gear::setSpringFactorNotPlaning(float f)
+{
+ _spring_factor_not_planing = f;
+}
+
+void Gear::setSpeedPlaning(float s)
+{
+ _speed_planing = s;
+}
+
+void Gear::setReduceFrictionByExtension(float s)
+{
+ _reduceFrictionByExtension = s;
+}
+
+void Gear::setInitialLoad(float l)
+{
+ _initialLoad = l;
+}
+
+void Gear::setGlobalGround(double *global_ground, float* global_vel,
+ double globalX, double globalY,
+ const SGMaterial *material)
{
int i;
+ double frictionFactor,rollingFriction,loadCapacity,loadResistance,bumpiness;
+ bool isSolid;
+
for(i=0; i<4; i++) _global_ground[i] = global_ground[i];
for(i=0; i<3; i++) _global_vel[i] = global_vel[i];
-}
+
+ if (material) {
+ loadCapacity = (*material).get_load_resistance();
+ frictionFactor =(*material).get_friction_factor();
+ rollingFriction = (*material).get_rolling_friction();
+ loadResistance = (*material).get_load_resistance();
+ bumpiness = (*material).get_bumpiness();
+ isSolid = (*material).get_solid();
+ } else {
+ // no material, assume solid
+ loadCapacity = DBL_MAX;
+ frictionFactor = 1.0;
+ rollingFriction = 0.02;
+ loadResistance = DBL_MAX;
+ bumpiness = 0.0;
+ isSolid = true;
+ }
+ _ground_frictionFactor = frictionFactor;
+ _ground_rollingFriction = rollingFriction;
+ _ground_loadCapacity = loadCapacity;
+ _ground_loadResistance = loadResistance;
+ _ground_bumpiness = bumpiness;
+ _ground_isSolid = isSolid;
+ _global_x = globalX;
+ _global_y = globalY;
+
+ }
void Gear::getPosition(float* out)
{
return _castering;
}
+bool Gear::getGroundIsSolid()
+{
+ return _ground_isSolid;
+}
+
+float Gear::getBumpAltitude()
+{
+ if (_ground_bumpiness<0.001) return 0.0;
+ double x = _global_x*0.1;
+ double y = _global_y*0.1;
+ x -= Math::floor(x);
+ y -= Math::floor(y);
+ x *= 2*YASIM_PI;
+ y *= 2*YASIM_PI;
+ //now x and y are in the range of 0..2pi
+ //we need a function, that is periodically on 2pi and gives some
+ //height. This is not very fast, but for a beginning.
+ //maybe this should be done by interpolating between some precalculated
+ //values
+ float h = Math::sin(x)+Math::sin(7*x)+Math::sin(8*x)+Math::sin(13*x);
+ h += Math::sin(2*y)+Math::sin(5*y)+Math::sin(9*y*x)+Math::sin(17*y);
+
+ return h*(1/8.)*_ground_bumpiness*maxGroundBumpAmplitude;
+}
+
void Gear::calcForce(RigidBody* body, State *s, float* v, float* rot)
{
// Init the return values
if(_extension < 1)
return;
+ // Dont bother if we are in the "wrong" ground
+ if (!((_onWater&&!_ground_isSolid)||(_onSolid&&_ground_isSolid))) {
+ _wow = 0;
+ _frac = 0;
+ _compressDist = 0;
+ _rollSpeed = 0;
+ _casterAngle = 0;
+ return;
+ }
+
// The ground plane transformed to the local frame.
float ground[4];
s->planeGlobalToLocal(_global_ground, ground);
// First off, make sure that the gear "tip" is below the ground.
// If it's not, there's no force.
float a = ground[3] - Math::dot3(_pos, ground);
+ float BumpAltitude=0;
+ if (a<maxGroundBumpAmplitude)
+ {
+ BumpAltitude=getBumpAltitude();
+ a+=BumpAltitude;
+ }
+ _compressDist = -a;
if(a > 0) {
_wow = 0;
_frac = 0;
+ _compressDist = 0;
_rollSpeed = 0;
_casterAngle = 0;
return;
// above ground is negative.
float tmp[3];
Math::add3(_cmpr, _pos, tmp);
- float b = ground[3] - Math::dot3(tmp, ground);
+ float b = ground[3] - Math::dot3(tmp, ground)+BumpAltitude;
// Calculate the point of ground _contact.
_frac = a/(a-b);
// Finally, we can start adding up the forces. First the spring
// compression. (note the clamping of _frac to 1):
_frac = (_frac > 1) ? 1 : _frac;
- float fmag = _frac*clen*_spring;
+ // Add the initial load to frac, but with continous transistion around 0
+ float frac_with_initial_load;
+ if (_frac>0.2 || _initialLoad==0.0)
+ frac_with_initial_load = _frac+_initialLoad;
+ else
+ frac_with_initial_load = (_frac+_initialLoad)
+ *_frac*_frac*3*25-_frac*_frac*_frac*2*125;
+
+ float fmag = frac_with_initial_load*clen*_spring;
+ if (_speed_planing>0)
+ {
+ float v = Math::mag3(cv);
+ if (v < _speed_planing)
+ {
+ float frac = v/_speed_planing;
+ fmag = fmag*_spring_factor_not_planing*(1-frac)+fmag*frac;
+ }
+ }
// Then the damping. Use the only the velocity into the ground
// (projection along "ground") projected along the compression
// axis. So Vdamp = ground*(ground dot cv) dot cmpr
_rollSpeed = vsteer;
_casterAngle = _rot;
}
-
- float fsteer = _brake * calcFriction(wgt, vsteer);
- float fskid = calcFriction(wgt, vskid);
+ float fsteer,fskid;
+ if(_ground_isSolid)
+ {
+ fsteer = (_brake * _ground_frictionFactor
+ +(1-_brake)*_ground_rollingFriction
+ )*calcFriction(wgt, vsteer);
+ fskid = calcFriction(wgt, vskid)*(_ground_frictionFactor);
+ }
+ else
+ {
+ fsteer = calcFrictionFluid(wgt, vsteer)*_ground_frictionFactor;
+ fskid = 10*calcFrictionFluid(wgt, vskid)*_ground_frictionFactor;
+ //factor 10: floats have different drag in x and y.
+ }
if(vsteer > 0) fsteer = -fsteer;
if(vskid > 0) fskid = -fskid;
+
+ //reduce friction if wanted by _reduceFrictionByExtension
+ float factor = (1-_frac)*(1-_reduceFrictionByExtension)+_frac*1;
+ factor = Math::clamp(factor,0,1);
+ fsteer *= factor;
+ fskid *= factor;
// Phoo! All done. Add it up and get out of here.
Math::mul3(fsteer, steer, tmp);
Math::add3(tmp, _force, _force);
}
-float Gear::calcFriction(float wgt, float v)
+float Gear::calcFriction(float wgt, float v) //used on solid ground
{
// How slow is stopped? 10 cm/second?
const float STOP = 0.1f;
else return wgt * _dfric;
}
+float Gear::calcFrictionFluid(float wgt, float v) //used on fluid ground
+{
+ // How slow is stopped? 1 cm/second?
+ const float STOP = 0.01f;
+ const float iSTOP = 1.0f/STOP;
+ v = Math::abs(v);
+ if(v < STOP) return v*iSTOP * wgt * _sfric;
+ else return wgt * _dfric*v*v*0.01;
+ //*0.01: to get _dfric of the same size than _dfric on solid
+}
}; // namespace yasim
projects / flightgear.git / blobdiff