@Override
public boolean solvePositionConstraints(final org.jbox2d.dynamics.SolverData data) {
final Rot qA = pool.popRot();
final Rot qB = pool.popRot();
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);
float angularError = 0.0f;
float positionError = 0.0f;
boolean fixedRotation = (m_invIA + m_invIB == 0.0f);
// Solve angular limit constraint.
if (m_enableLimit && m_limitState != LimitState.INACTIVE && fixedRotation == false) {
float angle = aB - aA - m_referenceAngle;
float limitImpulse = 0.0f;
if (m_limitState == LimitState.EQUAL) {
// Prevent large angular corrections
float C =
MathUtils.clamp(
angle - m_lowerAngle,
-Settings.maxAngularCorrection,
Settings.maxAngularCorrection);
limitImpulse = -m_motorMass * C;
angularError = MathUtils.abs(C);
} else if (m_limitState == LimitState.AT_LOWER) {
float C = angle - m_lowerAngle;
angularError = -C;
// Prevent large angular corrections and allow some slop.
C = MathUtils.clamp(C + Settings.angularSlop, -Settings.maxAngularCorrection, 0.0f);
limitImpulse = -m_motorMass * C;
} else if (m_limitState == LimitState.AT_UPPER) {
float C = angle - m_upperAngle;
angularError = C;
// Prevent large angular corrections and allow some slop.
C = MathUtils.clamp(C - Settings.angularSlop, 0.0f, Settings.maxAngularCorrection);
limitImpulse = -m_motorMass * C;
}
aA -= m_invIA * limitImpulse;
aB += m_invIB * limitImpulse;
}
// Solve point-to-point constraint.
{
qA.set(aA);
qB.set(aB);
final Vec2 rA = pool.popVec2();
final Vec2 rB = pool.popVec2();
final Vec2 C = pool.popVec2();
final Vec2 impulse = pool.popVec2();
Rot.mulToOutUnsafe(qA, C.set(m_localAnchorA).subLocal(m_localCenterA), rA);
Rot.mulToOutUnsafe(qB, C.set(m_localAnchorB).subLocal(m_localCenterB), rB);
C.set(cB).addLocal(rB).subLocal(cA).subLocal(rA);
positionError = C.length();
float mA = m_invMassA, mB = m_invMassB;
float iA = m_invIA, iB = m_invIB;
final org.jbox2d.common.Mat22 K = pool.popMat22();
K.ex.x = mA + mB + iA * rA.y * rA.y + iB * rB.y * rB.y;
K.ex.y = -iA * rA.x * rA.y - iB * rB.x * rB.y;
K.ey.x = K.ex.y;
K.ey.y = mA + mB + iA * rA.x * rA.x + iB * rB.x * rB.x;
K.solveToOut(C, impulse);
impulse.negateLocal();
cA.x -= mA * impulse.x;
cA.y -= mA * impulse.y;
aA -= iA * Vec2.cross(rA, impulse);
cB.x += mB * impulse.x;
cB.y += mB * impulse.y;
aB += iB * Vec2.cross(rB, impulse);
pool.pushVec2(4);
pool.pushMat22(1);
}
// 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);
return positionError <= Settings.linearSlop && angularError <= Settings.angularSlop;
}
