Examples with Rot org.jbox2d.common.Rot used on opensource projects

Example 36 with Rot

use of org.jbox2d.common.Rot in project libgdx by libgdx.

the class WeldJoint method initVelocityConstraints.

@Override
public void initVelocityConstraints(final SolverData data) {
    m_indexA = m_bodyA.m_islandIndex;
    m_indexB = m_bodyB.m_islandIndex;
    m_localCenterA.set(m_bodyA.m_sweep.localCenter);
    m_localCenterB.set(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;
    // Vec2 cA = data.positions[m_indexA].c;
    float aA = data.positions[m_indexA].a;
    Vec2 vA = data.velocities[m_indexA].v;
    float wA = data.velocities[m_indexA].w;
    // Vec2 cB = data.positions[m_indexB].c;
    float aB = data.positions[m_indexB].a;
    Vec2 vB = data.velocities[m_indexB].v;
    float wB = data.velocities[m_indexB].w;
    final Rot qA = pool.popRot();
    final Rot qB = pool.popRot();
    final Vec2 temp = pool.popVec2();
    qA.set(aA);
    qB.set(aB);
    // Compute the effective masses.
    Rot.mulToOutUnsafe(qA, temp.set(m_localAnchorA).subLocal(m_localCenterA), m_rA);
    Rot.mulToOutUnsafe(qB, temp.set(m_localAnchorB).subLocal(m_localCenterB), m_rB);
    // J = [-I -r1_skew I r2_skew]
    // [ 0 -1 0 1]
    // r_skew = [-ry; rx]
    // Matlab
    // K = [ mA+r1y^2*iA+mB+r2y^2*iB, -r1y*iA*r1x-r2y*iB*r2x, -r1y*iA-r2y*iB]
    // [ -r1y*iA*r1x-r2y*iB*r2x, mA+r1x^2*iA+mB+r2x^2*iB, r1x*iA+r2x*iB]
    // [ -r1y*iA-r2y*iB, r1x*iA+r2x*iB, iA+iB]
    float mA = m_invMassA, mB = m_invMassB;
    float iA = m_invIA, iB = m_invIB;
    final Mat33 K = pool.popMat33();
    K.ex.x = mA + mB + m_rA.y * m_rA.y * iA + m_rB.y * m_rB.y * iB;
    K.ey.x = -m_rA.y * m_rA.x * iA - m_rB.y * m_rB.x * iB;
    K.ez.x = -m_rA.y * iA - m_rB.y * iB;
    K.ex.y = K.ey.x;
    K.ey.y = mA + mB + m_rA.x * m_rA.x * iA + m_rB.x * m_rB.x * iB;
    K.ez.y = m_rA.x * iA + m_rB.x * iB;
    K.ex.z = K.ez.x;
    K.ey.z = K.ez.y;
    K.ez.z = iA + iB;
    if (m_frequencyHz > 0.0f) {
        K.getInverse22(m_mass);
        float invM = iA + iB;
        float m = invM > 0.0f ? 1.0f / invM : 0.0f;
        float C = aB - aA - m_referenceAngle;
        // Frequency
        float omega = 2.0f * MathUtils.PI * m_frequencyHz;
        // Damping coefficient
        float d = 2.0f * m * m_dampingRatio * omega;
        // Spring stiffness
        float k = m * omega * omega;
        // magic formulas
        float h = data.step.dt;
        m_gamma = h * (d + h * k);
        m_gamma = m_gamma != 0.0f ? 1.0f / m_gamma : 0.0f;
        m_bias = C * h * k * m_gamma;
        invM += m_gamma;
        m_mass.ez.z = invM != 0.0f ? 1.0f / invM : 0.0f;
    } else {
        K.getSymInverse33(m_mass);
        m_gamma = 0.0f;
        m_bias = 0.0f;
    }
    if (data.step.warmStarting) {
        final Vec2 P = pool.popVec2();
        // Scale impulses to support a variable time step.
        m_impulse.mulLocal(data.step.dtRatio);
        P.set(m_impulse.x, m_impulse.y);
        vA.x -= mA * P.x;
        vA.y -= mA * P.y;
        wA -= iA * (Vec2.cross(m_rA, P) + m_impulse.z);
        vB.x += mB * P.x;
        vB.y += mB * P.y;
        wB += iB * (Vec2.cross(m_rB, P) + m_impulse.z);
        pool.pushVec2(1);
    } else {
        m_impulse.setZero();
    }
    //    data.velocities[m_indexA].v.set(vA);
    data.velocities[m_indexA].w = wA;
    //    data.velocities[m_indexB].v.set(vB);
    data.velocities[m_indexB].w = wB;
    pool.pushVec2(1);
    pool.pushRot(2);
    pool.pushMat33(1);
}

Example 37 with Rot

use of org.jbox2d.common.Rot in project libgdx by libgdx.

the class DistanceJoint method solvePositionConstraints.

@Override
public boolean solvePositionConstraints(final SolverData data) {
    if (m_frequencyHz > 0.0f) {
        return true;
    }
    final Rot qA = pool.popRot();
    final Rot qB = pool.popRot();
    final Vec2 rA = pool.popVec2();
    final Vec2 rB = pool.popVec2();
    final Vec2 u = 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, u.set(m_localAnchorA).subLocal(m_localCenterA), rA);
    Rot.mulToOutUnsafe(qB, u.set(m_localAnchorB).subLocal(m_localCenterB), rB);
    u.set(cB).addLocal(rB).subLocal(cA).subLocal(rA);
    float length = u.normalize();
    float C = length - m_length;
    C = MathUtils.clamp(C, -Settings.maxLinearCorrection, Settings.maxLinearCorrection);
    float impulse = -m_mass * C;
    float Px = impulse * u.x;
    float Py = impulse * u.y;
    cA.x -= m_invMassA * Px;
    cA.y -= m_invMassA * Py;
    aA -= m_invIA * (rA.x * Py - rA.y * Px);
    cB.x += m_invMassB * Px;
    cB.y += m_invMassB * Py;
    aB += m_invIB * (rB.x * Py - rB.y * Px);
    //    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.pushVec2(3);
    pool.pushRot(2);
    return MathUtils.abs(C) < Settings.linearSlop;
}