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Fix cushioning when landing on a slope, reduce needed data size

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This commit is contained in:
Alayan 2018-09-20 22:22:23 +02:00
parent 9f3bc471d8
commit 961c4af662
2 changed files with 22 additions and 35 deletions
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48
src/physics/btKart.cpp
View File

@ -51,12 +51,6 @@ btKart::btKart(btRigidBody* chassis, btVehicleRaycaster* raycaster,
Kart *kart)
: m_vehicleRaycaster(raycaster)
{
btScalar height = 0;
for (int i=0;i<stk_config->time2Ticks(HISTORY_TIME);i++)
{
m_ground_height.push_back(height);
}
m_chassisBody = chassis;
m_indexRightAxis = 0;
m_indexUpAxis = 1;
@ -127,10 +121,6 @@ void btKart::reset()
wheel.m_raycastInfo.m_suspensionLength = 0;
updateWheelTransform(i, true);
}
for (int i=0;i<stk_config->time2Ticks(HISTORY_TIME);i++)
{
m_ground_height[i] = 0;
}
m_visual_wheels_touch_ground = false;
m_allow_sliding = false;
m_num_wheels_on_ground = 0;
@ -141,7 +131,8 @@ void btKart::reset()
m_max_speed = -1.0f;
m_min_speed = 0.0f;
m_cushioning_disable_time = 0;
m_new_ground_height = 999.9f;
m_ground_height = 0;
m_ground_height_old = 0;
// Set the brakes so that karts don't slide downhill
setAllBrakes(5.0f);
@ -309,8 +300,8 @@ btScalar btKart::rayCast(unsigned int index, float fraction)
btScalar depth = raylen * rayResults.m_distFraction;
if (depth < m_new_ground_height)
m_new_ground_height = depth;
if (depth < m_ground_height)
m_ground_height = depth;
if (object && depth < max_susp_len)
{
wheel.m_raycastInfo.m_contactNormalWS = rayResults.m_hitNormalInWorld;
@ -551,14 +542,6 @@ void btKart::updateVehicle( btScalar step )
-v_down.getY() + 9.8*step,
step * (-v_down.getY() + 9.8*step)+offset);
#endif
// Update the ground height history
for (int i=stk_config->time2Ticks(HISTORY_TIME)-1;i>0;i--)
{
m_ground_height[i] = m_ground_height[i-1];
}
m_ground_height[0] = m_new_ground_height;
m_new_ground_height = 999.9f;
// 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
@ -568,14 +551,18 @@ void btKart::updateVehicle( btScalar step )
// to the predicted kart movement, which was found experimentally:
btScalar gravity = m_chassisBody->getGravity().length();
btScalar predicted_fall = -v_down.getY() + gravity*step +
(m_ground_height[stk_config->time2Ticks(HISTORY_TIME)-1]
-m_ground_height[0])/stk_config->time2Ticks(HISTORY_TIME);
btScalar predicted_fall = gravity*step*step +
(m_ground_height_old-m_ground_height);
// Limit kart jumping upward brutally if landing just
// after a sudden terrain height change ;
// no jump in STK is so big to normally go over this value
if (predicted_fall > 0.4) predicted_fall = 0.4;
if (v_down.getY()<0 && m_cushioning_disable_time==0 &&
m_ground_height[0] < step*predicted_fall + offset &&
m_ground_height[0] > 0 &&
m_ground_height[stk_config->time2Ticks(HISTORY_TIME)-1] > 0.4)
m_ground_height < predicted_fall + offset &&
m_ground_height > 0 && m_ground_height_old > 0.3 &&
predicted_fall > 0.05)
{
// Disable more cushioning for 1 second. This avoids the problem
// of hovering: a kart gets cushioned on a down-sloping area, still
@ -584,7 +571,7 @@ void btKart::updateVehicle( btScalar step )
m_cushioning_disable_time = stk_config->time2Ticks(1);
needed_cushioning = true;
btVector3 impulse = down * predicted_fall
btVector3 impulse = down * (predicted_fall/step)
/ m_chassisBody->getInvMass();
#ifdef DEBUG_CUSHIONING
float v_old = m_chassisBody->getLinearVelocity().getY();
@ -599,7 +586,7 @@ void btKart::updateVehicle( btScalar step )
-v_down.getY(),
v_old,
m_chassisBody->getLinearVelocity().getY(),
m_ground_height[0],
m_ground_height,
m_wheelInfo[wheel_index].m_raycastInfo.m_isInContact ?
m_wheelInfo[wheel_index].m_raycastInfo.m_contactPointWS.getY()
: -100,
@ -610,6 +597,9 @@ void btKart::updateVehicle( btScalar step )
);
#endif
}
// Update the ground height history
m_ground_height_old = m_ground_height;
m_ground_height = 999.9f;
// Update friction (i.e. forward force)

9
src/physics/btKart.hpp
View File

@ -119,12 +119,9 @@ private:
* physics steps, so need to be set again by the application. */
btScalar m_max_speed;
/** Smallest wheel height to the ground, with a few frames of history */
std::vector<btScalar> m_ground_height;
const float HISTORY_TIME = 0.05f;
/** Used to get the smallest weel height in the current frame */
btScalar m_new_ground_height;
/** Smallest wheel height to the ground */
btScalar m_ground_height;
btScalar m_ground_height_old;
/** True if the visual wheels touch the ground. */
bool m_visual_wheels_touch_ground;