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godot/scene/3d/vehicle_body.cpp

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/*************************************************************************/
/* vehicle_body.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md) */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/*************************************************************************/
#include "vehicle_body.h"
#define ROLLING_INFLUENCE_FIX
class btVehicleJacobianEntry {
public:
Vector3 m_linearJointAxis;
Vector3 m_aJ;
Vector3 m_bJ;
Vector3 m_0MinvJt;
Vector3 m_1MinvJt;
//Optimization: can be stored in the w/last component of one of the vectors
real_t m_Adiag;
real_t getDiagonal() const { return m_Adiag; }
btVehicleJacobianEntry(){};
//constraint between two different rigidbodies
btVehicleJacobianEntry(
const Basis &world2A,
const Basis &world2B,
const Vector3 &rel_pos1,
const Vector3 &rel_pos2,
const Vector3 &jointAxis,
const Vector3 &inertiaInvA,
const real_t massInvA,
const Vector3 &inertiaInvB,
const real_t massInvB) :
m_linearJointAxis(jointAxis) {
m_aJ = world2A.xform(rel_pos1.cross(m_linearJointAxis));
m_bJ = world2B.xform(rel_pos2.cross(-m_linearJointAxis));
m_0MinvJt = inertiaInvA * m_aJ;
m_1MinvJt = inertiaInvB * m_bJ;
m_Adiag = massInvA + m_0MinvJt.dot(m_aJ) + massInvB + m_1MinvJt.dot(m_bJ);
//btAssert(m_Adiag > real_t(0.0));
}
real_t getRelativeVelocity(const Vector3 &linvelA, const Vector3 &angvelA, const Vector3 &linvelB, const Vector3 &angvelB) {
Vector3 linrel = linvelA - linvelB;
Vector3 angvela = angvelA * m_aJ;
Vector3 angvelb = angvelB * m_bJ;
linrel *= m_linearJointAxis;
angvela += angvelb;
angvela += linrel;
real_t rel_vel2 = angvela[0] + angvela[1] + angvela[2];
return rel_vel2 + CMP_EPSILON;
}
};
void VehicleWheel::_notification(int p_what) {
if (p_what == NOTIFICATION_ENTER_TREE) {
VehicleBody *cb = Object::cast_to<VehicleBody>(get_parent());
if (!cb)
return;
body = cb;
local_xform = get_transform();
cb->wheels.push_back(this);
m_chassisConnectionPointCS = get_transform().origin;
m_wheelDirectionCS = -get_transform().basis.get_axis(Vector3::AXIS_Y).normalized();
m_wheelAxleCS = get_transform().basis.get_axis(Vector3::AXIS_X).normalized();
}
if (p_what == NOTIFICATION_EXIT_TREE) {
VehicleBody *cb = Object::cast_to<VehicleBody>(get_parent());
if (!cb)
return;
cb->wheels.erase(this);
body = NULL;
}
}
String VehicleWheel::get_configuration_warning() const {
if (!Object::cast_to<VehicleBody>(get_parent())) {
return TTR("VehicleWheel serves to provide a wheel system to a VehicleBody. Please use it as a child of a VehicleBody.");
}
return String();
}
void VehicleWheel::_update(PhysicsDirectBodyState *s) {
if (m_raycastInfo.m_isInContact)
{
real_t project = m_raycastInfo.m_contactNormalWS.dot(m_raycastInfo.m_wheelDirectionWS);
Vector3 chassis_velocity_at_contactPoint;
Vector3 relpos = m_raycastInfo.m_contactPointWS - s->get_transform().origin;
chassis_velocity_at_contactPoint = s->get_linear_velocity() +
(s->get_angular_velocity()).cross(relpos); // * mPos);
real_t projVel = m_raycastInfo.m_contactNormalWS.dot(chassis_velocity_at_contactPoint);
if (project >= real_t(-0.1)) {
m_suspensionRelativeVelocity = real_t(0.0);
m_clippedInvContactDotSuspension = real_t(1.0) / real_t(0.1);
} else {
real_t inv = real_t(-1.) / project;
m_suspensionRelativeVelocity = projVel * inv;
m_clippedInvContactDotSuspension = inv;
}
}
else // Not in contact : position wheel in a nice (rest length) position
{
m_raycastInfo.m_suspensionLength = m_suspensionRestLength;
m_suspensionRelativeVelocity = real_t(0.0);
m_raycastInfo.m_contactNormalWS = -m_raycastInfo.m_wheelDirectionWS;
m_clippedInvContactDotSuspension = real_t(1.0);
}
}
void VehicleWheel::set_radius(float p_radius) {
m_wheelRadius = p_radius;
update_gizmo();
}
float VehicleWheel::get_radius() const {
return m_wheelRadius;
}
void VehicleWheel::set_suspension_rest_length(float p_length) {
m_suspensionRestLength = p_length;
update_gizmo();
}
float VehicleWheel::get_suspension_rest_length() const {
return m_suspensionRestLength;
}
void VehicleWheel::set_suspension_travel(float p_length) {
m_maxSuspensionTravelCm = p_length / 0.01;
}
float VehicleWheel::get_suspension_travel() const {
return m_maxSuspensionTravelCm * 0.01;
}
void VehicleWheel::set_suspension_stiffness(float p_value) {
m_suspensionStiffness = p_value;
}
float VehicleWheel::get_suspension_stiffness() const {
return m_suspensionStiffness;
}
void VehicleWheel::set_suspension_max_force(float p_value) {
m_maxSuspensionForce = p_value;
}
float VehicleWheel::get_suspension_max_force() const {
return m_maxSuspensionForce;
}
void VehicleWheel::set_damping_compression(float p_value) {
m_wheelsDampingCompression = p_value;
}
float VehicleWheel::get_damping_compression() const {
return m_wheelsDampingCompression;
}
void VehicleWheel::set_damping_relaxation(float p_value) {
m_wheelsDampingRelaxation = p_value;
}
float VehicleWheel::get_damping_relaxation() const {
return m_wheelsDampingRelaxation;
}
void VehicleWheel::set_friction_slip(float p_value) {
m_frictionSlip = p_value;
}
float VehicleWheel::get_friction_slip() const {
return m_frictionSlip;
}
void VehicleWheel::set_roll_influence(float p_value) {
m_rollInfluence = p_value;
}
float VehicleWheel::get_roll_influence() const {
return m_rollInfluence;
}
bool VehicleWheel::is_in_contact() const {
return m_raycastInfo.m_isInContact;
}
void VehicleWheel::_bind_methods() {
ClassDB::bind_method(D_METHOD("set_radius", "length"), &VehicleWheel::set_radius);
ClassDB::bind_method(D_METHOD("get_radius"), &VehicleWheel::get_radius);
ClassDB::bind_method(D_METHOD("set_suspension_rest_length", "length"), &VehicleWheel::set_suspension_rest_length);
ClassDB::bind_method(D_METHOD("get_suspension_rest_length"), &VehicleWheel::get_suspension_rest_length);
ClassDB::bind_method(D_METHOD("set_suspension_travel", "length"), &VehicleWheel::set_suspension_travel);
ClassDB::bind_method(D_METHOD("get_suspension_travel"), &VehicleWheel::get_suspension_travel);
ClassDB::bind_method(D_METHOD("set_suspension_stiffness", "length"), &VehicleWheel::set_suspension_stiffness);
ClassDB::bind_method(D_METHOD("get_suspension_stiffness"), &VehicleWheel::get_suspension_stiffness);
ClassDB::bind_method(D_METHOD("set_suspension_max_force", "length"), &VehicleWheel::set_suspension_max_force);
ClassDB::bind_method(D_METHOD("get_suspension_max_force"), &VehicleWheel::get_suspension_max_force);
ClassDB::bind_method(D_METHOD("set_damping_compression", "length"), &VehicleWheel::set_damping_compression);
ClassDB::bind_method(D_METHOD("get_damping_compression"), &VehicleWheel::get_damping_compression);
ClassDB::bind_method(D_METHOD("set_damping_relaxation", "length"), &VehicleWheel::set_damping_relaxation);
ClassDB::bind_method(D_METHOD("get_damping_relaxation"), &VehicleWheel::get_damping_relaxation);
ClassDB::bind_method(D_METHOD("set_use_as_traction", "enable"), &VehicleWheel::set_use_as_traction);
ClassDB::bind_method(D_METHOD("is_used_as_traction"), &VehicleWheel::is_used_as_traction);
ClassDB::bind_method(D_METHOD("set_use_as_steering", "enable"), &VehicleWheel::set_use_as_steering);
ClassDB::bind_method(D_METHOD("is_used_as_steering"), &VehicleWheel::is_used_as_steering);
ClassDB::bind_method(D_METHOD("set_friction_slip", "length"), &VehicleWheel::set_friction_slip);
ClassDB::bind_method(D_METHOD("get_friction_slip"), &VehicleWheel::get_friction_slip);
ClassDB::bind_method(D_METHOD("is_in_contact"), &VehicleWheel::is_in_contact);
ClassDB::bind_method(D_METHOD("set_roll_influence", "roll_influence"), &VehicleWheel::set_roll_influence);
ClassDB::bind_method(D_METHOD("get_roll_influence"), &VehicleWheel::get_roll_influence);
ClassDB::bind_method(D_METHOD("get_skidinfo"), &VehicleWheel::get_skidinfo);
ADD_PROPERTY(PropertyInfo(Variant::BOOL, "use_as_traction"), "set_use_as_traction", "is_used_as_traction");
ADD_PROPERTY(PropertyInfo(Variant::BOOL, "use_as_steering"), "set_use_as_steering", "is_used_as_steering");
ADD_GROUP("Wheel", "wheel_");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "wheel_roll_influence"), "set_roll_influence", "get_roll_influence");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "wheel_radius"), "set_radius", "get_radius");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "wheel_rest_length"), "set_suspension_rest_length", "get_suspension_rest_length");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "wheel_friction_slip"), "set_friction_slip", "get_friction_slip");
ADD_GROUP("Suspension", "suspension_");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "suspension_travel"), "set_suspension_travel", "get_suspension_travel");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "suspension_stiffness"), "set_suspension_stiffness", "get_suspension_stiffness");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "suspension_max_force"), "set_suspension_max_force", "get_suspension_max_force");
ADD_GROUP("Damping", "damping_");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "damping_compression"), "set_damping_compression", "get_damping_compression");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "damping_relaxation"), "set_damping_relaxation", "get_damping_relaxation");
}
void VehicleWheel::set_use_as_traction(bool p_enable) {
engine_traction = p_enable;
}
bool VehicleWheel::is_used_as_traction() const {
return engine_traction;
}
void VehicleWheel::set_use_as_steering(bool p_enabled) {
steers = p_enabled;
}
bool VehicleWheel::is_used_as_steering() const {
return steers;
}
float VehicleWheel::get_skidinfo() const {
return m_skidInfo;
}
VehicleWheel::VehicleWheel() {
steers = false;
engine_traction = false;
m_steering = real_t(0.);
//m_engineForce = real_t(0.);
m_rotation = real_t(0.);
m_deltaRotation = real_t(0.);
m_brake = real_t(0.);
m_rollInfluence = real_t(0.1);
m_suspensionRestLength = 0.15;
m_wheelRadius = 0.5; //0.28;
m_suspensionStiffness = 5.88;
m_wheelsDampingCompression = 0.83;
m_wheelsDampingRelaxation = 0.88;
m_frictionSlip = 10.5;
m_bIsFrontWheel = false;
m_maxSuspensionTravelCm = 500;
m_maxSuspensionForce = 6000;
m_suspensionRelativeVelocity = 0;
m_clippedInvContactDotSuspension = 1.0;
m_raycastInfo.m_isInContact = false;
body = NULL;
}
void VehicleBody::_update_wheel_transform(VehicleWheel &wheel, PhysicsDirectBodyState *s) {
wheel.m_raycastInfo.m_isInContact = false;
Transform chassisTrans = s->get_transform();
/*
if (interpolatedTransform && (getRigidBody()->getMotionState())) {
getRigidBody()->getMotionState()->getWorldTransform(chassisTrans);
}
*/
wheel.m_raycastInfo.m_hardPointWS = chassisTrans.xform(wheel.m_chassisConnectionPointCS);
//wheel.m_raycastInfo.m_hardPointWS+=s->get_linear_velocity()*s->get_step();
wheel.m_raycastInfo.m_wheelDirectionWS = chassisTrans.get_basis().xform(wheel.m_wheelDirectionCS).normalized();
wheel.m_raycastInfo.m_wheelAxleWS = chassisTrans.get_basis().xform(wheel.m_wheelAxleCS).normalized();
}
void VehicleBody::_update_wheel(int p_idx, PhysicsDirectBodyState *s) {
VehicleWheel &wheel = *wheels[p_idx];
_update_wheel_transform(wheel, s);
Vector3 up = -wheel.m_raycastInfo.m_wheelDirectionWS;
const Vector3 &right = wheel.m_raycastInfo.m_wheelAxleWS;
Vector3 fwd = up.cross(right);
fwd = fwd.normalized();
//rotate around steering over de wheelAxleWS
real_t steering = wheel.steers ? m_steeringValue : 0.0;
Basis steeringMat(up, steering);
Basis rotatingMat(right, wheel.m_rotation);
Basis basis2(
right[0], up[0], fwd[0],
right[1], up[1], fwd[1],
right[2], up[2], fwd[2]);
wheel.m_worldTransform.set_basis(steeringMat * rotatingMat * basis2);
//wheel.m_worldTransform.set_basis(basis2 * (steeringMat * rotatingMat));
wheel.m_worldTransform.set_origin(
wheel.m_raycastInfo.m_hardPointWS + wheel.m_raycastInfo.m_wheelDirectionWS * wheel.m_raycastInfo.m_suspensionLength);
}
real_t VehicleBody::_ray_cast(int p_idx, PhysicsDirectBodyState *s) {
VehicleWheel &wheel = *wheels[p_idx];
_update_wheel_transform(wheel, s);
real_t depth = -1;
real_t raylen = wheel.m_suspensionRestLength + wheel.m_wheelRadius;
Vector3 rayvector = wheel.m_raycastInfo.m_wheelDirectionWS * (raylen);
Vector3 source = wheel.m_raycastInfo.m_hardPointWS;
wheel.m_raycastInfo.m_contactPointWS = source + rayvector;
const Vector3 &target = wheel.m_raycastInfo.m_contactPointWS;
source -= wheel.m_wheelRadius * wheel.m_raycastInfo.m_wheelDirectionWS;
real_t param = real_t(0.);
PhysicsDirectSpaceState::RayResult rr;
PhysicsDirectSpaceState *ss = s->get_space_state();
bool col = ss->intersect_ray(source, target, rr, exclude);
wheel.m_raycastInfo.m_groundObject = 0;
if (col) {
param = source.distance_to(rr.position) / source.distance_to(target);
depth = raylen * param;
wheel.m_raycastInfo.m_contactNormalWS = rr.normal;
wheel.m_raycastInfo.m_isInContact = true;
if (rr.collider)
wheel.m_raycastInfo.m_groundObject = Object::cast_to<PhysicsBody>(rr.collider);
real_t hitDistance = param * raylen;
wheel.m_raycastInfo.m_suspensionLength = hitDistance - wheel.m_wheelRadius;
//clamp on max suspension travel
real_t minSuspensionLength = wheel.m_suspensionRestLength - wheel.m_maxSuspensionTravelCm * real_t(0.01);
real_t maxSuspensionLength = wheel.m_suspensionRestLength + wheel.m_maxSuspensionTravelCm * real_t(0.01);
if (wheel.m_raycastInfo.m_suspensionLength < minSuspensionLength) {
wheel.m_raycastInfo.m_suspensionLength = minSuspensionLength;
}
if (wheel.m_raycastInfo.m_suspensionLength > maxSuspensionLength) {
wheel.m_raycastInfo.m_suspensionLength = maxSuspensionLength;
}
wheel.m_raycastInfo.m_contactPointWS = rr.position;
real_t denominator = wheel.m_raycastInfo.m_contactNormalWS.dot(wheel.m_raycastInfo.m_wheelDirectionWS);
Vector3 chassis_velocity_at_contactPoint;
//Vector3 relpos = wheel.m_raycastInfo.m_contactPointWS-getRigidBody()->getCenterOfMassPosition();
//chassis_velocity_at_contactPoint = getRigidBody()->getVelocityInLocalPoint(relpos);
chassis_velocity_at_contactPoint = s->get_linear_velocity() +
(s->get_angular_velocity()).cross(wheel.m_raycastInfo.m_contactPointWS - s->get_transform().origin); // * mPos);
real_t projVel = wheel.m_raycastInfo.m_contactNormalWS.dot(chassis_velocity_at_contactPoint);
if (denominator >= real_t(-0.1)) {
wheel.m_suspensionRelativeVelocity = real_t(0.0);
wheel.m_clippedInvContactDotSuspension = real_t(1.0) / real_t(0.1);
} else {
real_t inv = real_t(-1.) / denominator;
wheel.m_suspensionRelativeVelocity = projVel * inv;
wheel.m_clippedInvContactDotSuspension = inv;
}
} else {
wheel.m_raycastInfo.m_isInContact = false;
//put wheel info as in rest position
wheel.m_raycastInfo.m_suspensionLength = wheel.m_suspensionRestLength;
wheel.m_suspensionRelativeVelocity = real_t(0.0);
wheel.m_raycastInfo.m_contactNormalWS = -wheel.m_raycastInfo.m_wheelDirectionWS;
wheel.m_clippedInvContactDotSuspension = real_t(1.0);
}
return depth;
}
void VehicleBody::_update_suspension(PhysicsDirectBodyState *s) {
real_t chassisMass = mass;
for (int w_it = 0; w_it < wheels.size(); w_it++) {
VehicleWheel &wheel_info = *wheels[w_it];
if (wheel_info.m_raycastInfo.m_isInContact) {
real_t force;
//Spring
{
real_t susp_length = wheel_info.m_suspensionRestLength;
real_t current_length = wheel_info.m_raycastInfo.m_suspensionLength;
real_t length_diff = (susp_length - current_length);
force = wheel_info.m_suspensionStiffness * length_diff * wheel_info.m_clippedInvContactDotSuspension;
}
// Damper
{
real_t projected_rel_vel = wheel_info.m_suspensionRelativeVelocity;
{
real_t susp_damping;
if (projected_rel_vel < real_t(0.0)) {
susp_damping = wheel_info.m_wheelsDampingCompression;
} else {
susp_damping = wheel_info.m_wheelsDampingRelaxation;
}
force -= susp_damping * projected_rel_vel;
}
}
// RESULT
wheel_info.m_wheelsSuspensionForce = force * chassisMass;
if (wheel_info.m_wheelsSuspensionForce < real_t(0.)) {
wheel_info.m_wheelsSuspensionForce = real_t(0.);
}
} else {
wheel_info.m_wheelsSuspensionForce = real_t(0.0);
}
}
}
//bilateral constraint between two dynamic objects
void VehicleBody::_resolve_single_bilateral(PhysicsDirectBodyState *s, const Vector3 &pos1,
PhysicsBody *body2, const Vector3 &pos2, const Vector3 &normal, real_t &impulse, const real_t p_rollInfluence) {
real_t normalLenSqr = normal.length_squared();
//ERR_FAIL_COND( normalLenSqr < real_t(1.1));
if (normalLenSqr > real_t(1.1)) {
impulse = real_t(0.);
return;
}
Vector3 rel_pos1 = pos1 - s->get_transform().origin;
Vector3 rel_pos2;
if (body2)
rel_pos2 = pos2 - body2->get_global_transform().origin;
//this jacobian entry could be re-used for all iterations
Vector3 vel1 = s->get_linear_velocity() + (s->get_angular_velocity()).cross(rel_pos1); // * mPos);
Vector3 vel2;
if (body2)
vel2 = body2->get_linear_velocity() + body2->get_angular_velocity().cross(rel_pos2);
Vector3 vel = vel1 - vel2;
Basis b2trans;
float b2invmass = 0;
Vector3 b2lv;
Vector3 b2av;
Vector3 b2invinertia; //todo
if (body2) {
b2trans = body2->get_global_transform().basis.transposed();
b2invmass = body2->get_inverse_mass();
b2lv = body2->get_linear_velocity();
b2av = body2->get_angular_velocity();
}
btVehicleJacobianEntry jac(s->get_transform().basis.transposed(),
b2trans,
rel_pos1,
rel_pos2,
normal,
s->get_inverse_inertia_tensor().get_main_diagonal(),
1.0 / mass,
b2invinertia,
b2invmass);
// FIXME: rel_vel assignment here is overwritten by the following assignment.
// What seems to be intended in the next next assignment is: rel_vel = normal.dot(rel_vel);
// Investigate why.
real_t rel_vel = jac.getRelativeVelocity(
s->get_linear_velocity(),
s->get_transform().basis.transposed().xform(s->get_angular_velocity()),
b2lv,
b2trans.xform(b2av));
rel_vel = normal.dot(vel);
// !BAS! We had this set to 0.4, in bullet its 0.2
real_t contactDamping = real_t(0.2);
if (p_rollInfluence > 0.0) {
// !BAS! But seeing we apply this frame by frame, makes more sense to me to make this time based
// keeping in mind our anti roll factor if it is set
contactDamping = s->get_step() / p_rollInfluence;
}
#define ONLY_USE_LINEAR_MASS
#ifdef ONLY_USE_LINEAR_MASS
real_t massTerm = real_t(1.) / ((1.0 / mass) + b2invmass);
impulse = -contactDamping * rel_vel * massTerm;
#else
real_t velocityImpulse = -contactDamping * rel_vel * jacDiagABInv;
impulse = velocityImpulse;
#endif
}
VehicleBody::btVehicleWheelContactPoint::btVehicleWheelContactPoint(PhysicsDirectBodyState *s, PhysicsBody *body1, const Vector3 &frictionPosWorld, const Vector3 &frictionDirectionWorld, real_t maxImpulse) :
m_s(s),
m_body1(body1),
m_frictionPositionWorld(frictionPosWorld),
m_frictionDirectionWorld(frictionDirectionWorld),
m_maxImpulse(maxImpulse) {
float denom0 = 0;
float denom1 = 0;
{
Vector3 r0 = frictionPosWorld - s->get_transform().origin;
Vector3 c0 = (r0).cross(frictionDirectionWorld);
Vector3 vec = s->get_inverse_inertia_tensor().xform_inv(c0).cross(r0);
denom0 = s->get_inverse_mass() + frictionDirectionWorld.dot(vec);
}
/* TODO: Why is this code unused?
if (body1) {
Vector3 r0 = frictionPosWorld - body1->get_global_transform().origin;
Vector3 c0 = (r0).cross(frictionDirectionWorld);
Vector3 vec = s->get_inverse_inertia_tensor().xform_inv(c0).cross(r0);
//denom1= body1->get_inverse_mass() + frictionDirectionWorld.dot(vec);
}
*/
real_t relaxation = 1.f;
m_jacDiagABInv = relaxation / (denom0 + denom1);
}
real_t VehicleBody::_calc_rolling_friction(btVehicleWheelContactPoint &contactPoint) {
real_t j1 = 0.f;
const Vector3 &contactPosWorld = contactPoint.m_frictionPositionWorld;
Vector3 rel_pos1 = contactPosWorld - contactPoint.m_s->get_transform().origin;
Vector3 rel_pos2;
if (contactPoint.m_body1)
rel_pos2 = contactPosWorld - contactPoint.m_body1->get_global_transform().origin;
real_t maxImpulse = contactPoint.m_maxImpulse;
Vector3 vel1 = contactPoint.m_s->get_linear_velocity() + (contactPoint.m_s->get_angular_velocity()).cross(rel_pos1); // * mPos);
Vector3 vel2;
if (contactPoint.m_body1) {
vel2 = contactPoint.m_body1->get_linear_velocity() + contactPoint.m_body1->get_angular_velocity().cross(rel_pos2);
}
Vector3 vel = vel1 - vel2;
real_t vrel = contactPoint.m_frictionDirectionWorld.dot(vel);
// calculate j that moves us to zero relative velocity
j1 = -vrel * contactPoint.m_jacDiagABInv;
return CLAMP(j1, -maxImpulse, maxImpulse);
}
static const real_t sideFrictionStiffness2 = real_t(1.0);
void VehicleBody::_update_friction(PhysicsDirectBodyState *s) {
//calculate the impulse, so that the wheels don't move sidewards
int numWheel = wheels.size();
if (!numWheel)
return;
m_forwardWS.resize(numWheel);
m_axle.resize(numWheel);
m_forwardImpulse.resize(numWheel);
m_sideImpulse.resize(numWheel);
//collapse all those loops into one!
for (int i = 0; i < wheels.size(); i++) {
m_sideImpulse.write[i] = real_t(0.);
m_forwardImpulse.write[i] = real_t(0.);
}
{
for (int i = 0; i < wheels.size(); i++) {
VehicleWheel &wheelInfo = *wheels[i];
if (wheelInfo.m_raycastInfo.m_isInContact) {
//const btTransform& wheelTrans = getWheelTransformWS( i );
Basis wheelBasis0 = wheelInfo.m_worldTransform.basis; //get_global_transform().basis;
m_axle.write[i] = wheelBasis0.get_axis(Vector3::AXIS_X);
//m_axle[i] = wheelInfo.m_raycastInfo.m_wheelAxleWS;
const Vector3 &surfNormalWS = wheelInfo.m_raycastInfo.m_contactNormalWS;
real_t proj = m_axle[i].dot(surfNormalWS);
m_axle.write[i] -= surfNormalWS * proj;
m_axle.write[i] = m_axle[i].normalized();
m_forwardWS.write[i] = surfNormalWS.cross(m_axle[i]);
m_forwardWS.write[i].normalize();
_resolve_single_bilateral(s, wheelInfo.m_raycastInfo.m_contactPointWS,
wheelInfo.m_raycastInfo.m_groundObject, wheelInfo.m_raycastInfo.m_contactPointWS,
m_axle[i], m_sideImpulse.write[i], wheelInfo.m_rollInfluence);
m_sideImpulse.write[i] *= sideFrictionStiffness2;
}
}
}
real_t sideFactor = real_t(1.);
real_t fwdFactor = 0.5;
bool sliding = false;
{
for (int wheel = 0; wheel < wheels.size(); wheel++) {
VehicleWheel &wheelInfo = *wheels[wheel];
//class btRigidBody* groundObject = (class btRigidBody*) wheelInfo.m_raycastInfo.m_groundObject;
real_t rollingFriction = 0.f;
if (wheelInfo.m_raycastInfo.m_isInContact) {
if (engine_force != 0.f && wheelInfo.engine_traction != false) {
rollingFriction = -engine_force * s->get_step();
} else {
real_t defaultRollingFrictionImpulse = 0.f;
float cbrake = MAX(wheelInfo.m_brake, brake);
real_t maxImpulse = cbrake ? cbrake : defaultRollingFrictionImpulse;
btVehicleWheelContactPoint contactPt(s, wheelInfo.m_raycastInfo.m_groundObject, wheelInfo.m_raycastInfo.m_contactPointWS, m_forwardWS[wheel], maxImpulse);
rollingFriction = _calc_rolling_friction(contactPt);
}
}
//switch between active rolling (throttle), braking and non-active rolling friction (no throttle/break)
m_forwardImpulse.write[wheel] = real_t(0.);
wheelInfo.m_skidInfo = real_t(1.);
if (wheelInfo.m_raycastInfo.m_isInContact) {
wheelInfo.m_skidInfo = real_t(1.);
real_t maximp = wheelInfo.m_wheelsSuspensionForce * s->get_step() * wheelInfo.m_frictionSlip;
real_t maximpSide = maximp;
real_t maximpSquared = maximp * maximpSide;
m_forwardImpulse.write[wheel] = rollingFriction; //wheelInfo.m_engineForce* timeStep;
real_t x = (m_forwardImpulse[wheel]) * fwdFactor;
real_t y = (m_sideImpulse[wheel]) * sideFactor;
real_t impulseSquared = (x * x + y * y);
if (impulseSquared > maximpSquared) {
sliding = true;
real_t factor = maximp / Math::sqrt(impulseSquared);
wheelInfo.m_skidInfo *= factor;
}
}
}
}
if (sliding) {
for (int wheel = 0; wheel < wheels.size(); wheel++) {
if (m_sideImpulse[wheel] != real_t(0.)) {
if (wheels[wheel]->m_skidInfo < real_t(1.)) {
m_forwardImpulse.write[wheel] *= wheels[wheel]->m_skidInfo;
m_sideImpulse.write[wheel] *= wheels[wheel]->m_skidInfo;
}
}
}
}
// apply the impulses
{
for (int wheel = 0; wheel < wheels.size(); wheel++) {
VehicleWheel &wheelInfo = *wheels[wheel];
Vector3 rel_pos = wheelInfo.m_raycastInfo.m_contactPointWS -
s->get_transform().origin;
if (m_forwardImpulse[wheel] != real_t(0.)) {
s->apply_impulse(rel_pos, m_forwardWS[wheel] * (m_forwardImpulse[wheel]));
}
if (m_sideImpulse[wheel] != real_t(0.)) {
PhysicsBody *groundObject = wheelInfo.m_raycastInfo.m_groundObject;
Vector3 rel_pos2;
if (groundObject) {
rel_pos2 = wheelInfo.m_raycastInfo.m_contactPointWS - groundObject->get_global_transform().origin;
}
Vector3 sideImp = m_axle[wheel] * m_sideImpulse[wheel];
#if defined ROLLING_INFLUENCE_FIX // fix. It only worked if car's up was along Y - VT.
Vector3 vChassisWorldUp = s->get_transform().basis.transposed()[1]; //getRigidBody()->getCenterOfMassTransform().getBasis().getColumn(m_indexUpAxis);
rel_pos -= vChassisWorldUp * (vChassisWorldUp.dot(rel_pos) * (1.f - wheelInfo.m_rollInfluence));
#else
rel_pos[1] *= wheelInfo.m_rollInfluence; //?
#endif
s->apply_impulse(rel_pos, sideImp);
//apply friction impulse on the ground
//todo
//groundObject->applyImpulse(-sideImp,rel_pos2);
}
}
}
}
void VehicleBody::_direct_state_changed(Object *p_state) {
RigidBody::_direct_state_changed(p_state);
state = Object::cast_to<PhysicsDirectBodyState>(p_state);
float step = state->get_step();
for (int i = 0; i < wheels.size(); i++) {
_update_wheel(i, state);
}
for (int i = 0; i < wheels.size(); i++) {
_ray_cast(i, state);
wheels[i]->set_transform(state->get_transform().inverse() * wheels[i]->m_worldTransform);
}
_update_suspension(state);
for (int i = 0; i < wheels.size(); i++) {
//apply suspension force
VehicleWheel &wheel = *wheels[i];
real_t suspensionForce = wheel.m_wheelsSuspensionForce;
if (suspensionForce > wheel.m_maxSuspensionForce) {
suspensionForce = wheel.m_maxSuspensionForce;
}
Vector3 impulse = wheel.m_raycastInfo.m_contactNormalWS * suspensionForce * step;
Vector3 relpos = wheel.m_raycastInfo.m_contactPointWS - state->get_transform().origin;
state->apply_impulse(relpos, impulse);
//getRigidBody()->applyImpulse(impulse, relpos);
}
_update_friction(state);
for (int i = 0; i < wheels.size(); i++) {
VehicleWheel &wheel = *wheels[i];
Vector3 relpos = wheel.m_raycastInfo.m_hardPointWS - state->get_transform().origin;
Vector3 vel = state->get_linear_velocity() + (state->get_angular_velocity()).cross(relpos); // * mPos);
if (wheel.m_raycastInfo.m_isInContact) {
const Transform &chassisWorldTransform = state->get_transform();
Vector3 fwd(
chassisWorldTransform.basis[0][Vector3::AXIS_Z],
chassisWorldTransform.basis[1][Vector3::AXIS_Z],
chassisWorldTransform.basis[2][Vector3::AXIS_Z]);
real_t proj = fwd.dot(wheel.m_raycastInfo.m_contactNormalWS);
fwd -= wheel.m_raycastInfo.m_contactNormalWS * proj;
real_t proj2 = fwd.dot(vel);
wheel.m_deltaRotation = (proj2 * step) / (wheel.m_wheelRadius);
wheel.m_rotation += wheel.m_deltaRotation;
} else {
wheel.m_rotation += wheel.m_deltaRotation;
}
wheel.m_deltaRotation *= real_t(0.99); //damping of rotation when not in contact
}
state = NULL;
}
void VehicleBody::set_engine_force(float p_engine_force) {
engine_force = p_engine_force;
}
float VehicleBody::get_engine_force() const {
return engine_force;
}
void VehicleBody::set_brake(float p_brake) {
brake = p_brake;
}
float VehicleBody::get_brake() const {
return brake;
}
void VehicleBody::set_steering(float p_steering) {
m_steeringValue = p_steering;
}
float VehicleBody::get_steering() const {
return m_steeringValue;
}
void VehicleBody::_bind_methods() {
ClassDB::bind_method(D_METHOD("set_engine_force", "engine_force"), &VehicleBody::set_engine_force);
ClassDB::bind_method(D_METHOD("get_engine_force"), &VehicleBody::get_engine_force);
ClassDB::bind_method(D_METHOD("set_brake", "brake"), &VehicleBody::set_brake);
ClassDB::bind_method(D_METHOD("get_brake"), &VehicleBody::get_brake);
ClassDB::bind_method(D_METHOD("set_steering", "steering"), &VehicleBody::set_steering);
ClassDB::bind_method(D_METHOD("get_steering"), &VehicleBody::get_steering);
ADD_GROUP("Motion", "");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "engine_force", PROPERTY_HINT_RANGE, "0.00,1024.0,0.01,or_greater"), "set_engine_force", "get_engine_force");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "brake", PROPERTY_HINT_RANGE, "0.0,1.0,0.01"), "set_brake", "get_brake");
ADD_PROPERTY(PropertyInfo(Variant::REAL, "steering", PROPERTY_HINT_RANGE, "-180,180.0,0.01"), "set_steering", "get_steering");
}
VehicleBody::VehicleBody() :
RigidBody() {
m_pitchControl = 0;
m_currentVehicleSpeedKmHour = real_t(0.);
m_steeringValue = real_t(0.);
engine_force = 0;
brake = 0;
state = NULL;
ccd = false;
exclude.insert(get_rid());
//PhysicsServer::get_singleton()->body_set_force_integration_callback(get_rid(), this, "_direct_state_changed");
set_mass(40);
}
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