// this jacobian entry is re-used for all iterations
Matrix3f mat1 = body0.getCenterOfMassTransform(Stack.alloc(Transform.class)).basis;
mat1.transpose();
Matrix3f mat2 = body1.getCenterOfMassTransform(Stack.alloc(Transform.class)).basis;
mat2.transpose();
JacobianEntry jac = jacobiansPool.get();
jac.init(mat1, mat2,
rel_pos1, rel_pos2, cp.normalWorldOnB,
body0.getInvInertiaDiagLocal(Stack.alloc(Vector3f.class)), body0.getInvMass(),