void CustomDGRayCastCar::SubmitConstraints (dFloat timestep, int threadIndex)
{
int constraintIndex;
dFloat invTimestep;
dMatrix bodyMatrix;
// get the simulation time
invTimestep = 1.0f / timestep ;
// get the vehicle global matrix, and use it in several calculations
NewtonBodyGetMatrix (m_body0, &bodyMatrix[0][0]);
dMatrix chassisMatrix (m_localFrame * bodyMatrix);
// get the chassis instantaneous linear and angular velocity in the local space of the chassis
dVector bodyOmega;
dVector bodyVelocity;
NewtonBodyGetVelocity (m_body0, &bodyVelocity[0]);
NewtonBodyGetOmega (m_body0, &bodyOmega[0]);
// all tire is on air check
m_vehicleOnAir = 0;
constraintIndex = 0;
for ( int i = 0; i < m_tiresCount; i ++ ) {
Tire& tire = m_tires[i];
tire.m_tireIsOnAir = 1;
tire.m_tireIsConstrained = 0;
tire.m_tireForceAcc = dVector(0.0f, 0.0f, 0.0f, 0.0f);
// calculate all suspension matrices in global space and tire collision
dMatrix suspensionMatrix (CalculateSuspensionMatrix (i, 0.0f) * chassisMatrix);
// calculate the tire collision
CalculateTireCollision (tire, suspensionMatrix, threadIndex);
// calculate the linear velocity of the tire at the ground contact
tire.m_tireAxelPosit = chassisMatrix.TransformVector( tire.m_harpoint - m_localFrame.m_up.Scale (tire.m_posit));
tire.m_tireAxelVeloc = bodyVelocity + bodyOmega * (tire.m_tireAxelPosit - chassisMatrix.m_posit);
tire.m_lateralPin = ( chassisMatrix.RotateVector ( tire.m_localAxis ) );
tire.m_longitudinalPin = ( chassisMatrix.m_up * tire.m_lateralPin );
if (tire.m_posit < tire.m_suspensionLenght ) {
dFloat distance;
dFloat sideSlipCoef;
dFloat slipRatioCoef;
dFloat tireForceMag;
dFloat tireTorqueMag;
dFloat suspensionSpeed;
dFloat axelLinealSpeed;
dFloat tireRotationSpeed;
dFloat frictionCircleMag;
dFloat longitudinalForceMag;
dFloat lateralFrictionForceMag;
tire.m_tireIsOnAir = 0;
tire.m_hitBodyPointVelocity = dVector (0.0f, 0.0f, 0.0f, 1.0f);
if (tire.m_HitBody){
dMatrix matrix;
dVector com;
dVector omega;
NewtonBodyGetOmega (tire.m_HitBody, &omega[0]);
NewtonBodyGetMatrix (tire.m_HitBody, &matrix[0][0]);
NewtonBodyGetCentreOfMass (tire.m_HitBody, &com[0]);
NewtonBodyGetVelocity (tire.m_HitBody, &tire.m_hitBodyPointVelocity[0]);
tire.m_hitBodyPointVelocity += (tire.m_contactPoint - matrix.TransformVector (com)) * omega;
}
// calculate the relative velocity
dVector relVeloc (tire.m_tireAxelVeloc - tire.m_hitBodyPointVelocity);
suspensionSpeed = - (relVeloc % chassisMatrix.m_up);
// now calculate the tire load at the contact point
// Tire suspension distance and hard limit.
distance = tire.m_suspensionLenght - tire.m_posit;
_ASSERTE (distance <= tire.m_suspensionLenght);
tire.m_tireLoad = - NewtonCalculateSpringDamperAcceleration (timestep, tire.m_springConst, distance, tire.m_springDamper, suspensionSpeed );
if ( tire.m_tireLoad < 0.0f ) {
// since the tire is not a body with real mass it can only push the chassis.
tire.m_tireLoad = 0.0f;
}
//this suspension is applying a normalize force to the car chassis, need to scales by the mass of the car
tire.m_tireLoad *= (m_mass * 0.5f);
tire.m_tireIsConstrained = (dAbs (tire.m_torque) < 0.3f);
// convert the tire load force magnitude to a torque and force.
// accumulate the force doe to the suspension spring and damper
tire.m_tireForceAcc += chassisMatrix.m_up.Scale (tire.m_tireLoad);
// calculate relative velocity at the tire center
dVector tireAxelRelativeVelocity (tire.m_tireAxelVeloc - tire.m_hitBodyPointVelocity);
// axle linear speed
axelLinealSpeed = tireAxelRelativeVelocity % chassisMatrix.m_front;
// calculate tire rotation velocity at the tire radio
dVector tireAngularVelocity (tire.m_lateralPin.Scale (tire.m_angularVelocity));
dVector tireRadius (tire.m_contactPoint - tire.m_tireAxelPosit);
dVector tireRotationalVelocityAtContact (tireAngularVelocity * tireRadius);
longitudinalForceMag = 0.0f;
// if (!tire.m_tireIsConstrained) {
// calculate slip ratio and max longitudinal force
tireRotationSpeed = tireRotationalVelocityAtContact % tire.m_longitudinalPin;
slipRatioCoef = (dAbs (axelLinealSpeed) > 1.e-3f) ? ((-tireRotationSpeed - axelLinealSpeed) / dAbs (axelLinealSpeed)) : 0.0f;
// calculate the formal longitudinal force the tire apply to the chassis
longitudinalForceMag = m_normalizedLongitudinalForce.GetValue (slipRatioCoef) * tire.m_tireLoad * tire.m_groundFriction;
// }
// now calculate relative velocity a velocity at contact point
dVector tireContactRelativeVelocity (tireAxelRelativeVelocity + tireRotationalVelocityAtContact);
// calculate the sideslip as the angle between the tire lateral speed and longitudila speed
sideSlipCoef = dAtan2 (dAbs (tireContactRelativeVelocity % tire.m_lateralPin), dAbs (axelLinealSpeed));
lateralFrictionForceMag = m_normalizedLateralForce.GetValue (sideSlipCoef) * tire.m_tireLoad * tire.m_groundFriction;
// Apply brake, need some little fix here.
// The fix is need to generate axial force when the brake is apply when the vehicle turn from the steer or on sliding.
if ( tire.m_breakForce > 1.0e-3f ) {
// row constrained force is save for later determine the dynamic state of this tire
tire.m_isBrakingForceIndex = constraintIndex;
constraintIndex ++;
frictionCircleMag = tire.m_tireLoad * tire.m_groundFriction;
if (tire.m_breakForce > frictionCircleMag) {
tire.m_breakForce = frictionCircleMag;
}
//NewtonUserJointAddLinearRow ( m_joint, &tire.m_tireAxelPosit[0], &tire.m_tireAxelPosit[0], &chassisMatrix.m_front.m_x );
NewtonUserJointAddLinearRow (m_joint, &tire.m_tireAxelPosit[0], &tire.m_tireAxelPosit[0], &tire.m_longitudinalPin.m_x);
NewtonUserJointSetRowMaximumFriction( m_joint, tire.m_breakForce);
NewtonUserJointSetRowMinimumFriction( m_joint, -tire.m_breakForce);
// there is a longitudinal force that will reduce the lateral force, we need to recalculate the lateral force
tireForceMag = lateralFrictionForceMag * lateralFrictionForceMag + tire.m_breakForce * tire.m_breakForce;
if (tireForceMag > (frictionCircleMag * frictionCircleMag)) {
lateralFrictionForceMag *= 0.25f * frictionCircleMag / dSqrt (tireForceMag);
}
}
//project the longitudinal and lateral forces over the circle of friction for this tire;
frictionCircleMag = tire.m_tireLoad * tire.m_groundFriction;
tireForceMag = lateralFrictionForceMag * lateralFrictionForceMag + longitudinalForceMag * longitudinalForceMag;
if (tireForceMag > (frictionCircleMag * frictionCircleMag)) {
dFloat invMag2;
invMag2 = frictionCircleMag / dSqrt (tireForceMag);
longitudinalForceMag *= invMag2;
lateralFrictionForceMag *= invMag2;
}
// submit this constraint for calculation of side slip forces
lateralFrictionForceMag = dAbs (lateralFrictionForceMag);
tire.m_lateralForceIndex = constraintIndex;
constraintIndex ++;
NewtonUserJointAddLinearRow (m_joint, &tire.m_tireAxelPosit[0], &tire.m_tireAxelPosit[0], &tire.m_lateralPin[0]);
NewtonUserJointSetRowMaximumFriction (m_joint, lateralFrictionForceMag);
NewtonUserJointSetRowMinimumFriction (m_joint, -lateralFrictionForceMag);
// accumulate the longitudinal force
dVector tireForce (tire.m_longitudinalPin.Scale (longitudinalForceMag));
tire.m_tireForceAcc += tireForce;
// now we apply the combined tire force generated by this tire, to the car chassis
dVector torque ((tire.m_tireAxelPosit - chassisMatrix.m_posit) * tire.m_tireForceAcc);
NewtonBodyAddForce (m_body0, &tire.m_tireForceAcc[0]);
NewtonBodyAddTorque( m_body0, &torque[0] );
// calculate the net torque on the tire
tireTorqueMag = -((tireRadius * tireForce) % tire.m_lateralPin);
if (dAbs (tireTorqueMag) > dAbs (tire.m_torque)) {
// the tire reaction force can no be larger than the applied engine torque
// when this happens the net torque is zero and the tire is constrained to the vehicle linear motion
tire.m_tireIsConstrained = 1;
tireTorqueMag = tire.m_torque;
}
tire.m_torque -= tireTorqueMag;
}
}
}
void CustomDGRayCastCar::SubmitConstraints (dFloat timestep, int threadIndex)
{
// get the simulation time
// dFloat invTimestep = 1.0f / timestep ;
// get the vehicle global matrix, and use it in several calculations
dMatrix bodyMatrix;
NewtonBodyGetMatrix (m_body0, &bodyMatrix[0][0]);
dMatrix chassisMatrix (m_localFrame * bodyMatrix);
// get the chassis instantaneous linear and angular velocity in the local space of the chassis
dVector bodyForce;
dVector bodyOmega;
dVector bodyVelocity;
NewtonBodyGetVelocity (m_body0, &bodyVelocity[0]);
NewtonBodyGetOmega (m_body0, &bodyOmega[0]);
//static int xxx;
//dTrace (("frame %d veloc(%f %f %f)\n", xxx, bodyVelocity[0], bodyVelocity[1], bodyVelocity[2]));
//xxx ++;
//if (xxx >= 210) {
//xxx *=1;
//bodyVelocity.m_x = 0;
//bodyVelocity.m_z = 10;
//NewtonBodySetVelocity (m_body0, &bodyVelocity[0]);
//}
// dVector normalForces (0.0f, 0.0f, 0.0f, 0.0f);
// all tire is on air check
m_vehicleOnAir = 0;
// int constraintIndex = 0;
for (int i = 0; i < m_tiresCount; i ++) {
// dTrace (("tire: %d ", i));
Tire& tire = m_tires[i];
tire.m_tireIsOnAir = 1;
// tire.m_tireIsConstrained = 0;
tire.m_tireForceAcc = dVector(0.0f, 0.0f, 0.0f, 0.0f);
// calculate all suspension matrices in global space and tire collision
dMatrix suspensionMatrix (CalculateSuspensionMatrix (i, 0.0f) * chassisMatrix);
// calculate the tire collision
CalculateTireCollision (tire, suspensionMatrix, threadIndex);
// calculate the linear velocity of the tire at the ground contact
tire.m_tireAxelPositGlobal = chassisMatrix.TransformVector (tire.m_harpointInJointSpace - m_localFrame.m_up.Scale (tire.m_posit));
tire.m_tireAxelVelocGlobal = bodyVelocity + bodyOmega * (tire.m_tireAxelPositGlobal - chassisMatrix.m_posit);
tire.m_lateralPinGlobal = chassisMatrix.RotateVector (tire.m_localAxisInJointSpace);
tire.m_longitudinalPinGlobal = chassisMatrix.m_up * tire.m_lateralPinGlobal;
if (tire.m_posit < tire.m_suspensionLenght ) {
tire.m_tireIsOnAir = 0;
tire.m_hitBodyPointVelocity = dVector (0.0f, 0.0f, 0.0f, 1.0f);
if (tire.m_HitBody){
dMatrix matrix;
dVector com;
dVector omega;
NewtonBodyGetOmega (tire.m_HitBody, &omega[0]);
NewtonBodyGetMatrix (tire.m_HitBody, &matrix[0][0]);
NewtonBodyGetCentreOfMass (tire.m_HitBody, &com[0]);
NewtonBodyGetVelocity (tire.m_HitBody, &tire.m_hitBodyPointVelocity[0]);
tire.m_hitBodyPointVelocity += (tire.m_contactPoint - matrix.TransformVector (com)) * omega;
}
// calculate the relative velocity
dVector tireHubVeloc (tire.m_tireAxelVelocGlobal - tire.m_hitBodyPointVelocity);
dFloat suspensionSpeed = - (tireHubVeloc % chassisMatrix.m_up);
// now calculate the tire load at the contact point
// Tire suspension distance and hard limit.
dFloat distance = tire.m_suspensionLenght - tire.m_posit;
_ASSERTE (distance <= tire.m_suspensionLenght);
tire.m_tireLoad = - NewtonCalculateSpringDamperAcceleration (timestep, tire.m_springConst, distance, tire.m_springDamper, suspensionSpeed );
if ( tire.m_tireLoad < 0.0f ) {
// since the tire is not a body with real mass it can only push the chassis.
tire.m_tireLoad = 0.0f;
}
//this suspension is applying a normalize force to the car chassis, need to scales by the mass of the car
tire.m_tireLoad *= (m_mass * 0.5f);
// dTrace (("(load = %f) ", tire.m_tireLoad));
//tire.m_tireIsConstrained = (dAbs (tire.m_torque) < 0.3f);
// convert the tire load force magnitude to a torque and force.
// accumulate the force doe to the suspension spring and damper
tire.m_tireForceAcc += chassisMatrix.m_up.Scale (tire.m_tireLoad);
// calculate relative velocity at the tire center
//dVector tireAxelRelativeVelocity (tire.m_tireAxelVeloc - tire.m_hitBodyPointVelocity);
// axle linear speed
//axelLinealSpeed = tireAxelRelativeVelocity % chassisMatrix.m_front;
dFloat axelLinearSpeed = tireHubVeloc % chassisMatrix.m_front;
// calculate tire rotation velocity at the tire radio
//dVector tireAngularVelocity (tire.m_lateralPinGlobal.Scale (tire.m_angularVelocity));
//dVector tireRadius (tire.m_contactPoint - tire.m_tireAxelPositGlobal);
//dVector tireRotationalVelocityAtContact (tireAngularVelocity * tireRadius);
// calculate slip ratio and max longitudinal force
//dFloat tireRotationSpeed = -(tireRotationalVelocityAtContact % tire.m_longitudinalPinGlobal);
//dFloat slipRatioCoef = (dAbs (axelLinearSpeed) > 1.e-3f) ? ((tireRotationSpeed - axelLinearSpeed) / dAbs (axelLinearSpeed)) : 0.0f;
//dTrace (("(slipRatio = %f) ", slipRatioCoef));
// calculate the formal longitudinal force the tire apply to the chassis
//dFloat longitudinalForceMag = m_normalizedLongitudinalForce.GetValue (slipRatioCoef) * tire.m_tireLoad * tire.m_groundFriction;
dFloat longitudinalForceMag = CalculateLongitudinalForce (i, axelLinearSpeed, tire.m_tireLoad * tire.m_groundFriction);
// dTrace (("(longForce = %f) ", longitudinalForceMag));
#if 0
// now calculate relative velocity a velocity at contact point
//dVector tireContactRelativeVelocity (tireAxelRelativeVelocity + tireRotationalVelocityAtContact);
//dVector tireContactAbsoluteVelocity (tireHubVeloc + tireRotationalVelocityAtContact);
// calculate the side slip as the angle between the tire lateral speed and longitudinal speed
//dFloat lateralSpeed = tireContactRelativeVelocity % tire.m_lateralPin;
dFloat lateralSpeed = tireHubVeloc % tire.m_lateralPinGlobal;
dFloat sideSlipCoef = dAtan2 (dAbs (lateralSpeed), dAbs (axelLinearSpeed));
dFloat lateralFrictionForceMag = m_normalizedLateralForce.GetValue (sideSlipCoef) * tire.m_tireLoad * tire.m_groundFriction;
// Apply brake, need some little fix here.
// The fix is need to generate axial force when the brake is apply when the vehicle turn from the steer or on sliding.
if ( tire.m_breakForce > 1.0e-3f ) {
_ASSERTE (0);
/*
// row constrained force is save for later determine the dynamic state of this tire
tire.m_isBrakingForceIndex = constraintIndex;
constraintIndex ++;
frictionCircleMag = tire.m_tireLoad * tire.m_groundFriction;
if (tire.m_breakForce > frictionCircleMag) {
tire.m_breakForce = frictionCircleMag;
}
//NewtonUserJointAddLinearRow ( m_joint, &tire.m_tireAxelPosit[0], &tire.m_tireAxelPosit[0], &chassisMatrix.m_front.m_x );
NewtonUserJointAddLinearRow (m_joint, &tire.m_tireAxelPosit[0], &tire.m_tireAxelPosit[0], &tire.m_longitudinalPin.m_x);
NewtonUserJointSetRowMaximumFriction( m_joint, tire.m_breakForce);
NewtonUserJointSetRowMinimumFriction( m_joint, -tire.m_breakForce);
// there is a longitudinal force that will reduce the lateral force, we need to recalculate the lateral force
tireForceMag = lateralFrictionForceMag * lateralFrictionForceMag + tire.m_breakForce * tire.m_breakForce;
if (tireForceMag > (frictionCircleMag * frictionCircleMag)) {
lateralFrictionForceMag *= 0.25f * frictionCircleMag / dSqrt (tireForceMag);
}
*/
}
//project the longitudinal and lateral forces over the circle of friction for this tire;
dFloat frictionCircleMag = tire.m_tireLoad * tire.m_groundFriction;
dFloat tireForceMag = lateralFrictionForceMag * lateralFrictionForceMag + longitudinalForceMag * longitudinalForceMag;
if (tireForceMag > (frictionCircleMag * frictionCircleMag)) {
dFloat invMag2;
invMag2 = frictionCircleMag / dSqrt (tireForceMag);
longitudinalForceMag *= invMag2;
lateralFrictionForceMag *= invMag2;
}
// submit this constraint for calculation of side slip forces
lateralFrictionForceMag = dAbs (lateralFrictionForceMag);
tire.m_lateralForceIndex = constraintIndex;
constraintIndex ++;
NewtonUserJointAddLinearRow (m_joint, &tire.m_tireAxelPositGlobal[0], &tire.m_tireAxelPositGlobal[0], &tire.m_lateralPinGlobal[0]);
NewtonUserJointSetRowMaximumFriction (m_joint, lateralFrictionForceMag);
NewtonUserJointSetRowMinimumFriction (m_joint, -lateralFrictionForceMag);
#endif
// accumulate the longitudinal force
dVector tireForce (tire.m_longitudinalPinGlobal.Scale (longitudinalForceMag));
tire.m_tireForceAcc += tireForce;
// now we apply the combined tire force generated by this tire, to the car chassis
dVector r (tire.m_tireAxelPositGlobal - chassisMatrix.m_posit);
// add the toque the tire asserts on the car body (principle of action reaction)
dVector torque (r * tire.m_tireForceAcc - tire.m_lateralPinGlobal.Scale (tire.m_torque));
NewtonBodyAddForce (m_body0, &tire.m_tireForceAcc[0]);
NewtonBodyAddTorque( m_body0, &torque[0] );
/*
// calculate the net torque on the tire
dFloat tireTorqueMag = -((tireRadius * tireForce) % tire.m_lateralPinGlobal);
if (dAbs (tireTorqueMag) > dAbs (tire.m_torque)) {
// the tire reaction force cannot be larger than the applied engine torque
// when this happens the net torque is zero and the tire is constrained to the vehicle linear motion
tire.m_tireIsConstrained = 1;
tireTorqueMag = tire.m_torque;
}
tire.m_torque -= tireTorqueMag;
*/
// normalForces += tire.m_tireForceAcc;
} else {
// there is a next torque on the tire
tire.m_torque -= tire.m_angularVelocity * tire.m_Ixx * DG_TIRE_VISCUOS_DAMP;
tire.m_angularVelocity += tire.m_torque * tire.m_IxxInv * timestep;
if (m_tires[i].m_breakForce > dFloat (0.1f)) {
tire.m_angularVelocity = 0.0f;
}
}
// dTrace (("(tireTorque = %f) ", tire.m_torque));
// spin the tire by the angular velocity
tire.m_spinAngle = dMod (tire.m_spinAngle + tire.m_angularVelocity * timestep, 3.14159265f * 2.0f);
// reset the tire torque
tire.m_torque = 0.0f;
tire.m_breakForce = 0.0f;
// dTrace (("\n"));
}
// add a row to simulate the engine rolling resistance
// float bodyWeight = dAbs (normalForces % chassisMatrix.m_up) * m_rollingResistance;
// if (bodyWeight > (1.0e-3f) * m_mass) {
// NewtonUserJointAddLinearRow (m_joint, &chassisMatrix.m_posit[0], &chassisMatrix.m_posit[0], &chassisMatrix.m_front[0]);
// NewtonUserJointSetRowMaximumFriction( m_joint, bodyWeight);
// NewtonUserJointSetRowMinimumFriction( m_joint, -bodyWeight);
// }
}
void dVehicleChassis::CalculateSuspensionForces(dFloat timestep)
{
const int maxSize = 64;
dComplementaritySolver::dJacobianPair m_jt[maxSize];
dComplementaritySolver::dJacobianPair m_jInvMass[maxSize];
dVehicleVirtualTire* tires[maxSize];
dFloat massMatrix[maxSize * maxSize];
dFloat accel[maxSize];
dComplementaritySolver::dBodyState* const chassisBody = m_vehicle->GetBody();
const dMatrix& chassisMatrix = chassisBody->GetMatrix();
const dMatrix& chassisInvInertia = chassisBody->GetInvInertia();
dVector chassisOrigin (chassisMatrix.TransformVector (chassisBody->GetCOM()));
dFloat chassisInvMass = chassisBody->GetInvMass();
int tireCount = 0;
const dList<dVehicleNode*>& children = m_vehicle->GetChildren();
for (dList<dVehicleNode*>::dListNode* tireNode = children.GetFirst(); tireNode; tireNode = tireNode->GetNext()) {
dVehicleVirtualTire* const tire = (dVehicleVirtualTire*) tireNode->GetInfo()->GetAsTire();
if (tire) {
const dVehicleVirtualTire::dTireInfo& info = tire->m_info;
tires[tireCount] = tire;
dFloat x = tire->m_position;
dFloat v = tire->m_speed;
dFloat weight = 1.0f;
/*
switch (tire->m_suspentionType)
{
case m_offroad:
weight = 0.9f;
break;
case m_confort:
weight = 1.0f;
break;
case m_race:
weight = 1.1f;
break;
}
*/
//x = 0.1f;
//v = 10.0f;
dComplementaritySolver::dBodyState* const tireBody = tire->GetBody();
const dFloat invMass = tireBody->GetInvMass();
const dFloat kv = info.m_dampingRatio * invMass;
const dFloat ks = info.m_springStiffness * invMass;
accel[tireCount] = -NewtonCalculateSpringDamperAcceleration(timestep, ks * weight, x, kv, v);
const dMatrix& tireMatrix = tireBody->GetMatrix();
const dMatrix& tireInvInertia = tireBody->GetInvInertia();
dFloat tireMass = tireBody->GetInvMass();
m_jt[tireCount].m_jacobian_J01.m_linear = chassisMatrix.m_up.Scale(-1.0f);
m_jt[tireCount].m_jacobian_J01.m_angular = dVector(0.0f);
m_jt[tireCount].m_jacobian_J10.m_linear = chassisMatrix.m_up;
m_jt[tireCount].m_jacobian_J10.m_angular = (tireMatrix.m_posit - chassisOrigin).CrossProduct(chassisMatrix.m_up);
m_jInvMass[tireCount].m_jacobian_J01.m_linear = m_jt[tireCount].m_jacobian_J01.m_linear.Scale(tireMass);
m_jInvMass[tireCount].m_jacobian_J01.m_angular = tireInvInertia.RotateVector(m_jt[tireCount].m_jacobian_J01.m_angular);
m_jInvMass[tireCount].m_jacobian_J10.m_linear = m_jt[tireCount].m_jacobian_J10.m_linear.Scale(chassisInvMass);
m_jInvMass[tireCount].m_jacobian_J10.m_angular = chassisInvInertia.RotateVector(m_jt[tireCount].m_jacobian_J10.m_angular);
tireCount++;
}
}
for (int i = 0; i < tireCount; i++) {
dFloat* const row = &massMatrix[i * tireCount];
dFloat aii = m_jInvMass[i].m_jacobian_J01.m_linear.DotProduct3(m_jt[i].m_jacobian_J01.m_linear) + m_jInvMass[i].m_jacobian_J01.m_angular.DotProduct3(m_jt[i].m_jacobian_J01.m_angular) +
m_jInvMass[i].m_jacobian_J10.m_linear.DotProduct3(m_jt[i].m_jacobian_J10.m_linear) + m_jInvMass[i].m_jacobian_J10.m_angular.DotProduct3(m_jt[i].m_jacobian_J10.m_angular);
row[i] = aii * 1.0001f;
for (int j = i + 1; j < tireCount; j++) {
dFloat aij = m_jInvMass[i].m_jacobian_J10.m_linear.DotProduct3(m_jt[j].m_jacobian_J10.m_linear) + m_jInvMass[i].m_jacobian_J10.m_angular.DotProduct3(m_jt[j].m_jacobian_J10.m_angular);
row[j] = aij;
massMatrix[j * tireCount + i] = aij;
}
}
dCholeskyFactorization(tireCount, massMatrix);
dCholeskySolve(tireCount, tireCount, massMatrix, accel);
dVector chassisForce(0.0f);
dVector chassisTorque(0.0f);
for (int i = 0; i < tireCount; i++) {
dVehicleVirtualTire* const tire = tires[i];
dComplementaritySolver::dBodyState* const tireBody = tire->GetBody();
tires[i]->m_tireLoad = dMax(dFloat(1.0f), accel[i]);
dVector tireForce(m_jt[i].m_jacobian_J01.m_linear.Scale(accel[i]));
tireBody->SetForce(tireBody->GetForce() + tireForce);
chassisForce += m_jt[i].m_jacobian_J10.m_linear.Scale(accel[i]);
chassisTorque += m_jt[i].m_jacobian_J10.m_angular.Scale(accel[i]);
}
chassisBody->SetForce(chassisBody->GetForce() + chassisForce);
chassisBody->SetTorque(chassisBody->GetTorque() + chassisTorque);
}
void SubmitConstraints (dFloat timestep, int threadIndex)
{
dMatrix tirePivotMatrix;
dMatrix chassisPivotMatrix;
ProjectTireMatrix();
// calculate the position of the pivot point and the Jacobian direction vectors, in global space.
CalculateGlobalMatrix (m_chassisLocalMatrix, m_tireLocalMatrix, chassisPivotMatrix, tirePivotMatrix);
// Restrict the movement on the pivot point along all two orthonormal direction
dVector centerInTire (tirePivotMatrix.m_posit);
dVector centerInChassis (chassisPivotMatrix.m_posit + chassisPivotMatrix.m_up.Scale ((centerInTire - chassisPivotMatrix.m_posit) % chassisPivotMatrix.m_up));
NewtonUserJointAddLinearRow (m_joint, ¢erInChassis[0], ¢erInTire[0], &chassisPivotMatrix.m_front[0]);
NewtonUserJointAddLinearRow (m_joint, ¢erInChassis[0], ¢erInTire[0], &chassisPivotMatrix.m_right[0]);
// get a point along the pin axis at some reasonable large distance from the pivot
dVector pointInPinInTire (centerInChassis + chassisPivotMatrix.m_front.Scale(MIN_JOINT_PIN_LENGTH));
dVector pointInPinInChassis (centerInTire + tirePivotMatrix.m_front.Scale(MIN_JOINT_PIN_LENGTH));
NewtonUserJointAddLinearRow (m_joint, &pointInPinInTire[0], &pointInPinInChassis[0], &chassisPivotMatrix.m_right[0]);
NewtonUserJointAddLinearRow (m_joint, &pointInPinInTire[0], &pointInPinInChassis[0], &chassisPivotMatrix.m_up[0]);
//calculate the suspension spring and damper force
dFloat dist;
dFloat speed;
dFloat force;
dVector tireVeloc;
dVector chassisVeloc;
dVector chassisOmega;
dVector chassisCom;
dMatrix chassisMatrix;
const NewtonBody* tire;
const NewtonBody* chassis;
// calculate the velocity of tire attachments point on the car chassis
tire = GetBody1();
chassis = GetBody0();
NewtonBodyGetVelocity (tire, &tireVeloc[0]);
NewtonBodyGetVelocity (chassis, &chassisVeloc[0]);
NewtonBodyGetOmega (chassis, &chassisOmega[0]);
NewtonBodyGetMatrix (chassis, &chassisMatrix[0][0]);
NewtonBodyGetCentreOfMass (chassis, &chassisCom[0]);
chassisCom = chassisMatrix.TransformVector(chassisCom);
chassisVeloc += chassisOmega * (centerInChassis - chassisCom);
// get the spring damper parameters
speed = (chassisVeloc - tireVeloc) % chassisPivotMatrix.m_up;
dist = (chassisPivotMatrix.m_posit - tirePivotMatrix.m_posit) % chassisPivotMatrix.m_up;
// check if the suspension pass the bumpers limits
if (-dist > m_suspenstionSpan* 0.5f) {
// if it hit the bumpers then speed is zero
speed = 0;
NewtonUserJointAddLinearRow (m_joint, ¢erInChassis[0], ¢erInChassis[0], &chassisPivotMatrix.m_up[0]);
NewtonUserJointSetRowMinimumFriction(m_joint, 0.0f);
} else if (dist > 0.0f) {
// if it hit the bumpers then speed is zero
speed = 0;
NewtonUserJointAddLinearRow (m_joint, ¢erInChassis[0], ¢erInChassis[0], &chassisPivotMatrix.m_up[0]);
NewtonUserJointSetRowMaximumFriction(m_joint, 0.0f);
}
// calculate magnitude of suspension force
force = NewtonCalculateSpringDamperAcceleration (timestep, m_spring, dist, m_damper, speed) * m_effectiveSpringMass;
dVector chassisForce (chassisMatrix.m_up.Scale (force));
dVector chassisTorque ((centerInChassis - chassisCom) * chassisForce);
NewtonBodyAddForce (chassis, &chassisForce[0]);
NewtonBodyAddTorque (chassis, &chassisTorque[0]);
dVector tireForce (chassisForce.Scale (-1.0f));
NewtonBodyAddForce(tire, &tireForce[0]);
// apply the engine torque to tire torque
dFloat relOmega;
dMatrix tireMatrix;
dVector tireOmega;
NewtonBodyGetOmega(tire, &tireOmega[0]);
NewtonBodyGetMatrix (tire, &tireMatrix[0][0]);
relOmega = ((tireOmega - chassisOmega) % tireMatrix.m_front);
// apply engine torque plus some tire angular drag
dVector tireTorque (tireMatrix.m_front.Scale (m_enginetorque - relOmega * m_Ixx * m_angularDragCoef));
NewtonBodyAddTorque (tire, &tireTorque[0]);
dVector chassisReationTorque (chassisMatrix.m_right.Scale (- m_enginetorque));
NewtonBodyAddTorque(chassis, &chassisTorque[0]);
m_enginetorque = 0.0f;
// add the brake torque row
if (dAbs(m_brakeToque) > 1.0e-3f) {
relOmega /= timestep;
NewtonUserJointAddAngularRow (m_joint, 0.0f, &tireMatrix.m_front[0]);
NewtonUserJointSetRowAcceleration(m_joint, relOmega);
NewtonUserJointSetRowMaximumFriction(m_joint, m_brakeToque);
NewtonUserJointSetRowMinimumFriction(m_joint, -m_brakeToque);
}
m_brakeToque = 0.0f;
}