@Override
public boolean solvePositionConstraints(final SolverData data) {
final Rot qA = pool.popRot();
final Rot qB = pool.popRot();
final Vec2 rA = pool.popVec2();
final Vec2 rB = pool.popVec2();
final Vec2 uA = pool.popVec2();
final Vec2 uB = pool.popVec2();
final Vec2 temp = pool.popVec2();
final Vec2 PA = pool.popVec2();
final Vec2 PB = pool.popVec2();
Vec2 cA = data.positions[m_indexA].c;
float aA = data.positions[m_indexA].a;
Vec2 cB = data.positions[m_indexB].c;
float aB = data.positions[m_indexB].a;
qA.set(aA);
qB.set(aB);
Rot.mulToOutUnsafe(qA, temp.set(m_localAnchorA).subLocal(m_localCenterA), rA);
Rot.mulToOutUnsafe(qB, temp.set(m_localAnchorB).subLocal(m_localCenterB), rB);
uA.set(cA).addLocal(rA).subLocal(m_groundAnchorA);
uB.set(cB).addLocal(rB).subLocal(m_groundAnchorB);
float lengthA = uA.length();
float lengthB = uB.length();
if (lengthA > 10.0f * Settings.linearSlop) {
uA.mulLocal(1.0f / lengthA);
} else {
uA.setZero();
}
if (lengthB > 10.0f * Settings.linearSlop) {
uB.mulLocal(1.0f / lengthB);
} else {
uB.setZero();
}
// Compute effective mass.
float ruA = Vec2.cross(rA, uA);
float ruB = Vec2.cross(rB, uB);
float mA = m_invMassA + m_invIA * ruA * ruA;
float mB = m_invMassB + m_invIB * ruB * ruB;
float mass = mA + m_ratio * m_ratio * mB;
if (mass > 0.0f) {
mass = 1.0f / mass;
}
float C = m_constant - lengthA - m_ratio * lengthB;
float linearError = MathUtils.abs(C);
float impulse = -mass * C;
PA.set(uA).mulLocal(-impulse);
PB.set(uB).mulLocal(-m_ratio * impulse);
cA.x += m_invMassA * PA.x;
cA.y += m_invMassA * PA.y;
aA += m_invIA * Vec2.cross(rA, PA);
cB.x += m_invMassB * PB.x;
cB.y += m_invMassB * PB.y;
aB += m_invIB * Vec2.cross(rB, PB);
// data.positions[m_indexA].c.set(cA);
data.positions[m_indexA].a = aA;
// data.positions[m_indexB].c.set(cB);
data.positions[m_indexB].a = aB;
pool.pushRot(2);
pool.pushVec2(7);
return linearError < Settings.linearSlop;
}
