Function E_NLD

ogsr_engine/xrGame/Physics.cpp:405–432

body - body case

// body - body case
float E_NLD(dBodyID b1, dBodyID b2, const dReal* norm) // norm - from 2 to 1
{
    dMass m1, m2;
    dBodyGetMass(b1, &m1);
    dBodyGetMass(b2, &m2);
    const dReal* vel1 = dBodyGetLinearVel(b1);
    const dReal* vel2 = dBodyGetLinearVel(b2);

    dReal vel_pr1 = dDOT(vel1, norm);
    dReal vel_pr2 = dDOT(vel2, norm);

    if (vel_pr1 > vel_pr2)
        return 0.f; // exit if the bodies are departing

    dVector3 impuls1 = {vel1[0] * m1.mass, vel1[1] * m1.mass, vel1[2] * m1.mass};
    dVector3 impuls2 = {vel2[0] * m2.mass, vel2[1] * m2.mass, vel2[2] * m2.mass};

    dVector3 c_mas_impuls = {impuls1[0] + impuls2[0], impuls1[1] + impuls2[1], impuls1[2] + impuls2[2]};
    dReal cmass = m1.mass + m2.mass;
    dVector3 c_mass_vel = {c_mas_impuls[0] / cmass, c_mas_impuls[1] / cmass, c_mas_impuls[2] / cmass};

    dReal c_mass_vel_prg = dDOT(c_mass_vel, norm);

    dReal kin_energy_start = vel_pr1 * vel_pr1 * m1.mass / 2.f + vel_pr2 * vel_pr2 * m2.mass / 2.f;
    dReal kin_energy_end = c_mass_vel_prg * c_mass_vel_prg * cmass / 2.f;

    return (kin_energy_start - kin_energy_end);
}
float E_NL(dBodyID b1, dBodyID b2, const dReal* norm)
{
    VERIFY(b1 || b2);