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Added documentation, and properly #ifdef'ed cushioning debug output.

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This commit is contained in:
hiker 2018-06-26 17:21:22 +10:00
parent 12095d6fcd
commit cdfdab7db3
1 changed files with 29 additions and 13 deletions
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42
src/physics/btKart.cpp Executable file → Normal file
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@ -26,6 +26,10 @@
#include "karts/kart.hpp"
#include "karts/kart_model.hpp"
#include "karts/kart_properties.hpp"
#undef DEBUG_CUSHIONING
#ifdef DEBUG_CUSHIONING
#include "modes/world.hpp"
#endif
#include "physics/triangle_mesh.hpp"
#include "tracks/terrain_info.hpp"
#include "tracks/track.hpp"
@ -517,18 +521,20 @@ void btKart::updateVehicle( btScalar step )
}
}
// Cushioning test: if the kart
// Cushioning test: if the kart is falling fast, the suspension might
// not be strong enough to prevent the chassis from hitting the ground.
// Try to detect this upcoming crash, and apply an upward impulse if
// necessary that will slow down the falling speed.
bool needed_cushioning = false;
//const btVector3 &v = m_chassisBody->getLinearVelocity();
btVector3 v =
m_chassisBody->getVelocityInLocalPoint(m_wheelInfo[wheel_index].m_chassisConnectionPointCS);
m_chassisBody->getVelocityInLocalPoint(m_wheelInfo[wheel_index]
.m_chassisConnectionPointCS);
btVector3 down = -m_chassisBody->getGravity();
down.normalize();
btVector3 v_down = (v * down) * down;
btScalar offset=0.1f;
#ifdef DEBUG_CUSHIONING
// If the downward speed is too fast to be caught by the suspension,
// slow down the falling speed by applying an appropriately impulse:)
Log::verbose("physics",
"World %d wheel %d lsuspl %f vdown %f overall speed %f lenght %f",
World::getWorld()->getTimeTicks(),
@ -536,25 +542,34 @@ void btKart::updateVehicle( btScalar step )
m_wheelInfo[wheel_index].m_raycastInfo.m_suspensionLength,
-v_down.getY(),
-v_down.getY() + 9.8*step,
step * (-v_down.getY() + 9.8*step)+0.1f);
step * (-v_down.getY() + 9.8*step)+offset);
#endif
// If the speed should be upwards, don't cushion (which would accelerate
// the kart downward again).
// If the kart is falling, estimate the distance the kart will fall
// in the next time step: the speed gets increased by the gravity*dt.
// This approximation is still not good enough (either because of
// kart rotation that can be changed, or perhaps because of the
// collision threshold used by bullet) - i.e. it would sometimes not
// predict the upcoming collision correcty - so we add an offset
// to the predicted kart movement, which was found experimentally:
btScalar gravity = m_chassisBody->getGravity().length();
if (v_down.getY()<0 &&
m_wheelInfo[wheel_index].m_raycastInfo.m_suspensionLength
< step * (-v_down.getY()+9.8*step)+0.1f)
< step * (-v_down.getY()+gravity*step)+offset)
{
needed_cushioning = true;
btVector3 impulse = down * (-v_down.getY() + 9.8f*step)
btVector3 impulse = down * (-v_down.getY() + gravity*step)
/ m_chassisBody->getInvMass();
#ifdef DEBUG_CUSHIONING
float v_old = m_chassisBody->getLinearVelocity().getY();
#endif
m_chassisBody->applyCentralImpulse(impulse);
#ifdef DEBUG_CUSHIONING
Log::verbose("physics",
"World %d Cushioning imp %f vdown %f max_comp %f from %f m/s to %f m/s contact %f kart %f susp %f relspeed %f",
"World %d Cushioning imp %f vdown %f from %f m/s to %f m/s "
"contact %f kart %f susp %f relspeed %f",
World::getWorld()->getTimeTicks(),
impulse.getY(),
-v_down.getY(), max_compensate_speed,
-v_down.getY(),
v_old,
m_chassisBody->getLinearVelocity().getY(),
m_wheelInfo[wheel_index].m_raycastInfo.m_isInContact ?
@ -562,7 +577,8 @@ void btKart::updateVehicle( btScalar step )
: -100,
m_chassisBody->getWorldTransform().getOrigin().getY(),
m_wheelInfo[wheel_index].m_raycastInfo.m_suspensionLength,
m_chassisBody->getVelocityInLocalPoint(m_wheelInfo[wheel_index].m_chassisConnectionPointCS)
m_chassisBody->getVelocityInLocalPoint(m_wheelInfo[wheel_index]
.m_chassisConnectionPointCS)
);
#endif
}