请问bullet游戏物体引擎中的btRaycastVehicle.cpp中resolveSingleBilateral函数问题

Question

在resolveSingleBilateral函数使用雅可比求解车辆与地面的侧向冲量的代码，不清楚其中的原理，希望大神们指导
btScalar normalLenSqr = normal.length2();
btAssert(btFabs(normalLenSqr) < btScalar(1.1));
if (normalLenSqr > btScalar(1.1))
{
impulse = btScalar(0.);
return;
}
btVector3 rel_pos1 = pos1 - body1.getCenterOfMassPosition();
btVector3 rel_pos2 = pos2 - body2.getCenterOfMassPosition();
//this jacobian entry could be re-used for all iterations

btVector3 vel1 = body1.getVelocityInLocalPoint(rel_pos1);
btVector3 vel2 = body2.getVelocityInLocalPoint(rel_pos2);
btVector3 vel = vel1 - vel2;

btJacobianEntry jac(body1.getCenterOfMassTransform().getBasis().transpose(),
body2.getCenterOfMassTransform().getBasis().transpose(),
rel_pos1,rel_pos2,normal,body1.getInvInertiaDiagLocal(),body1.getInvMass(),
body2.getInvInertiaDiagLocal(),body2.getInvMass())

btScalar jacDiagAB = jac.getDiagonal();
btScalar jacDiagABInv = btScalar(1.) / jacDiagAB;

btScalar rel_vel = jac.getRelativeVelocity(
body1.getLinearVelocity(),
body1.getCenterOfMassTransform().getBasis().transpose() * body1.getAngularVelocity(),
body2.gbtScalar rel_vel = jac.getRelativeVelocity(
body1.getLinearVelocity(),
body1.getCenterOfMassTransform().getBasis().transpose() * body1.getAngularVelocity(),
body2.getLinearVelocity(),
body2.getCenterOfMassTransform().getBasis().transpose() * body2.getAngularVelocity()); etLinearVelocity(),
body2.getCenterOfMassTransform().getBasis().transpose() * body2.getAngularVelocity());
btScalar a;
a=jacDiagABInv;
rel_vel = normal.dot(vel);
//todo: move this into proper structure
btScalar contactDamping = btScalar(0.2);
btScalar velocityImpulse = -contactDamping * rel_vel * jacDiagABInv;
impulse = velocityImpulse;

Answer 1

https://blog.csdn.net/mybbs2200/article/details/78748591