ilikecats/stk-code_catmod
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separate zipper velocity change from suspension/turning impulses

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git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/branches/irrlicht@3874 178a84e3-b1eb-0310-8ba1-8eac791a3b58
This commit is contained in:
davemk 2009-08-17 07:19:14 +00:00
parent 284599bb38
commit b35ec4b31f
3 changed files with 46 additions and 37 deletions
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13
src/karts/kart.cpp
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@ -681,18 +681,13 @@ void Kart::handleZipper()
// Ignore a zipper that's activated while braking
if(m_controls.m_brake) return;
m_zipper_time_left = stk_config->m_zipper_time;
btVector3 v = m_body->getLinearVelocity();
float current_speed = v.length();
float speed = std::min(current_speed+stk_config->m_zipper_speed_gain,
getMaxSpeedOnTerrain());
// If the speed is too low, very minor components of the velocity vector
// can become too big. E.g. each kart has a z component (to offset gravity
// I assume, around 0.16) --> if the karts are (nearly) at standstill,
// the z component is exaggerated, resulting in a jump. Even if Z
// is set to 0, minor left/right movements are then too strong.
// Therefore a zipper only adds the speed if the speed is at least 1
// (experimentally found valud). It also avoids NAN problems (if v=0).
if(current_speed>1.0f) m_body->setLinearVelocity(v*(speed/current_speed));
m_vehicle->activateZipper(speed);
} // handleZipper
//-----------------------------------------------------------------------------
@ -1067,6 +1062,8 @@ void Kart::endRescue()
m_body->setLinearVelocity (btVector3(0.0f,0.0f,0.0f));
m_body->setAngularVelocity(btVector3(0.0f,0.0f,0.0f));
m_vehicle->deactivateZipper();
// let the mode decide where to put the kart
RaceManager::getWorld()->moveKartAfterRescue(this, m_body);

66
src/physics/btKart.cpp
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@ -32,6 +32,9 @@ btKart::btKart(const btVehicleTuning& tuning,btRigidBody* chassis,
: btRaycastVehicle(tuning, chassis, raycaster)
{
m_track_connect_accel = track_connect_accel;
m_zipper_active = false;
m_zipper_velocity = btScalar(0);
}
// ----------------------------------------------------------------------------
@ -414,42 +417,47 @@ void btKart::updateFriction(btScalar timeStep)
btScalar rollingFriction = 0.f;
if (groundObject)
{
if (wheelInfo.m_engineForce != 0.f)
{
rollingFriction = wheelInfo.m_engineForce* timeStep;
} else
{
btScalar defaultRollingFrictionImpulse = 0.f;
btScalar maxImpulse = wheelInfo.m_brake ? wheelInfo.m_brake : defaultRollingFrictionImpulse;
btWheelContactPoint contactPt(m_chassisBody,groundObject,wheelInfo.m_raycastInfo.m_contactPointWS,m_forwardWS[wheel],maxImpulse);
rollingFriction = calcRollingFriction(contactPt);
// This is a work around for the problem that a kart shakes
// if it is braking: we get a minor impulse forward, which
// bullet then tries to offset by applying a backward
// impulse - which is a bit too big, causing a impulse
// backwards, ... till the kart is shaking backwards and
// forwards
if(wheelInfo.m_brake && fabsf(rollingFriction)<10)
rollingFriction=0;
}
}
//switch between active rolling (throttle), braking and non-active rolling friction (no throttle/break)
m_forwardImpulse[wheel] = btScalar(0.);
m_wheelInfo[wheel].m_skidInfo= btScalar(1.);
if (groundObject)
{
m_forwardImpulse[wheel] = rollingFriction;//wheelInfo.m_engineForce* timeStep;
}
if (m_zipper_active)
{
if (wheel==2 || wheel==3)
{
m_forwardImpulse[wheel] = 0.5*(m_zipper_velocity - getRigidBody()->getLinearVelocity().length()) / m_chassisBody->getInvMass();
}
}
else
{
if (wheelInfo.m_engineForce != 0.f)
{
rollingFriction = wheelInfo.m_engineForce* timeStep;
} else
{
//switch between active rolling (throttle), braking and non-active rolling friction (no throttle/break)
btScalar defaultRollingFrictionImpulse = 0.f;
btScalar maxImpulse = wheelInfo.m_brake ? wheelInfo.m_brake : defaultRollingFrictionImpulse;
btWheelContactPoint contactPt(m_chassisBody,groundObject,wheelInfo.m_raycastInfo.m_contactPointWS,m_forwardWS[wheel],maxImpulse);
rollingFriction = calcRollingFriction(contactPt);
// This is a work around for the problem that a kart shakes
// if it is braking: we get a minor impulse forward, which
// bullet then tries to offset by applying a backward
// impulse - which is a bit too big, causing a impulse
// backwards, ... till the kart is shaking backwards and
// forwards
if(wheelInfo.m_brake && fabsf(rollingFriction)<10)
rollingFriction=0;
}
m_forwardImpulse[wheel] = rollingFriction;//wheelInfo.m_engineForce* timeStep;
}
}
}
m_zipper_active = false;
}

4
src/physics/btKart.hpp
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@ -24,6 +24,8 @@ class btKart : public btRaycastVehicle
void defaultInit(const btVehicleTuning& tuning);
btScalar m_track_connect_accel;
btScalar m_skidding_factor;
bool m_zipper_active;
btScalar m_zipper_velocity;
public:
btKart(const btVehicleTuning& tuning,btRigidBody* chassis,
btVehicleRaycaster* raycaster, float track_connect_accel );
@ -36,6 +38,8 @@ public:
const btVector3& hitPoint,
const btVector3& hitNormal,btScalar depth);
void setPitchControl(btScalar pitch) { m_pitchControl = pitch; }
void activateZipper(btScalar vel) { m_zipper_active = true; m_zipper_velocity = vel; }
void deactivateZipper() { m_zipper_active = false; }
void updateSuspension(btScalar deltaTime);
virtual void updateFriction(btScalar timeStep);
};