void b2PulleyJoint::InitVelocityConstraints()

in Box2D/Dynamics/Joints/b2PulleyJoint.cpp [73:161]
69 lines of code
5 McCabe index (conditional complexity)

void b2PulleyJoint::InitVelocityConstraints(const b2SolverData& data)
{
	m_indexA = m_bodyA->m_islandIndex;
	m_indexB = m_bodyB->m_islandIndex;
	m_localCenterA = m_bodyA->m_sweep.localCenter;
	m_localCenterB = m_bodyB->m_sweep.localCenter;
	m_invMassA = m_bodyA->m_invMass;
	m_invMassB = m_bodyB->m_invMass;
	m_invIA = m_bodyA->m_invI;
	m_invIB = m_bodyB->m_invI;

	b2Vec2 cA = data.positions[m_indexA].c;
	float32 aA = data.positions[m_indexA].a;
	b2Vec2 vA = data.velocities[m_indexA].v;
	float32 wA = data.velocities[m_indexA].w;

	b2Vec2 cB = data.positions[m_indexB].c;
	float32 aB = data.positions[m_indexB].a;
	b2Vec2 vB = data.velocities[m_indexB].v;
	float32 wB = data.velocities[m_indexB].w;

	b2Rot qA(aA), qB(aB);

	m_rA = b2Mul(qA, m_localAnchorA - m_localCenterA);
	m_rB = b2Mul(qB, m_localAnchorB - m_localCenterB);

	// Get the pulley axes.
	m_uA = cA + m_rA - m_groundAnchorA;
	m_uB = cB + m_rB - m_groundAnchorB;

	float32 lengthA = m_uA.Length();
	float32 lengthB = m_uB.Length();

	if (lengthA > 10.0f * b2_linearSlop)
	{
		m_uA *= 1.0f / lengthA;
	}
	else
	{
		m_uA.SetZero();
	}

	if (lengthB > 10.0f * b2_linearSlop)
	{
		m_uB *= 1.0f / lengthB;
	}
	else
	{
		m_uB.SetZero();
	}

	// Compute effective mass.
	float32 ruA = b2Cross(m_rA, m_uA);
	float32 ruB = b2Cross(m_rB, m_uB);

	float32 mA = m_invMassA + m_invIA * ruA * ruA;
	float32 mB = m_invMassB + m_invIB * ruB * ruB;

	m_mass = mA + m_ratio * m_ratio * mB;

	if (m_mass > 0.0f)
	{
		m_mass = 1.0f / m_mass;
	}

	if (data.step.warmStarting)
	{
		// Scale impulses to support variable time steps.
		m_impulse *= data.step.dtRatio;

		// Warm starting.
		b2Vec2 PA = -(m_impulse) * m_uA;
		b2Vec2 PB = (-m_ratio * m_impulse) * m_uB;

		vA += m_invMassA * PA;
		wA += m_invIA * b2Cross(m_rA, PA);
		vB += m_invMassB * PB;
		wB += m_invIB * b2Cross(m_rB, PB);
	}
	else
	{
		m_impulse = 0.0f;
	}

	data.velocities[m_indexA].v = vA;
	data.velocities[m_indexA].w = wA;
	data.velocities[m_indexB].v = vB;
	data.velocities[m_indexB].w = wB;
}