Examples with Body com.almasb.fxgl.physics.box2d.dynamics.Body used on opensource projects

Example 6 with Body

use of com.almasb.fxgl.physics.box2d.dynamics.Body in project FXGL by AlmasB.

the class ParticleSystem method solvePressure.

private void solvePressure(TimeStep step) {
    // that means dimensionless density
    for (int i = 0; i < m_count; i++) {
        m_accumulationBuffer[i] = 0;
    }
    for (int k = 0; k < m_bodyContactCount; k++) {
        ParticleBodyContact contact = m_bodyContactBuffer[k];
        int a = contact.index;
        float w = contact.weight;
        m_accumulationBuffer[a] += w;
    }
    for (int k = 0; k < m_contactCount; k++) {
        ParticleContact contact = m_contactBuffer[k];
        int a = contact.indexA;
        int b = contact.indexB;
        float w = contact.weight;
        m_accumulationBuffer[a] += w;
        m_accumulationBuffer[b] += w;
    }
    // ignores powder particles
    if ((m_allParticleFlags & k_noPressureFlags) != 0) {
        for (int i = 0; i < m_count; i++) {
            if ((m_flagsBuffer.data[i] & k_noPressureFlags) != 0) {
                m_accumulationBuffer[i] = 0;
            }
        }
    }
    // calculates pressure as a linear function of density
    float pressurePerWeight = m_pressureStrength * getCriticalPressure(step);
    for (int i = 0; i < m_count; i++) {
        float w = m_accumulationBuffer[i];
        float h = pressurePerWeight * Math.max(0.0f, Math.min(w, JBoxSettings.maxParticleWeight) - JBoxSettings.minParticleWeight);
        m_accumulationBuffer[i] = h;
    }
    // applies pressure between each particles in contact
    float velocityPerPressure = step.dt / (m_density * m_particleDiameter);
    for (int k = 0; k < m_bodyContactCount; k++) {
        ParticleBodyContact contact = m_bodyContactBuffer[k];
        int a = contact.index;
        Body b = contact.body;
        float w = contact.weight;
        float m = contact.mass;
        Vec2 n = contact.normal;
        Vec2 p = m_positionBuffer.data[a];
        float h = m_accumulationBuffer[a] + pressurePerWeight * w;
        final Vec2 f = tempVec;
        final float coef = velocityPerPressure * w * m * h;
        f.x = coef * n.x;
        f.y = coef * n.y;
        final Vec2 velData = m_velocityBuffer.data[a];
        final float particleInvMass = getParticleInvMass();
        velData.x -= particleInvMass * f.x;
        velData.y -= particleInvMass * f.y;
        b.applyLinearImpulse(f, p, true);
    }
    for (int k = 0; k < m_contactCount; k++) {
        ParticleContact contact = m_contactBuffer[k];
        int a = contact.indexA;
        int b = contact.indexB;
        float w = contact.weight;
        Vec2 n = contact.normal;
        float h = m_accumulationBuffer[a] + m_accumulationBuffer[b];
        final float fx = velocityPerPressure * w * h * n.x;
        final float fy = velocityPerPressure * w * h * n.y;
        final Vec2 velDataA = m_velocityBuffer.data[a];
        final Vec2 velDataB = m_velocityBuffer.data[b];
        velDataA.x -= fx;
        velDataA.y -= fy;
        velDataB.x += fx;
        velDataB.y += fy;
    }
}

Example 7 with Body

use of com.almasb.fxgl.physics.box2d.dynamics.Body in project FXGL by AlmasB.

the class ContactSolver method init.

public void init(ContactSolverDef def) {
    TimeStep step = def.step;
    m_count = def.count;
    if (m_positionConstraints.length < m_count) {
        ContactPositionConstraint[] old = m_positionConstraints;
        m_positionConstraints = new ContactPositionConstraint[Math.max(old.length * 2, m_count)];
        System.arraycopy(old, 0, m_positionConstraints, 0, old.length);
        for (int i = old.length; i < m_positionConstraints.length; i++) {
            m_positionConstraints[i] = new ContactPositionConstraint();
        }
    }
    if (m_velocityConstraints.length < m_count) {
        ContactVelocityConstraint[] old = m_velocityConstraints;
        m_velocityConstraints = new ContactVelocityConstraint[Math.max(old.length * 2, m_count)];
        System.arraycopy(old, 0, m_velocityConstraints, 0, old.length);
        for (int i = old.length; i < m_velocityConstraints.length; i++) {
            m_velocityConstraints[i] = new ContactVelocityConstraint();
        }
    }
    m_positions = def.positions;
    m_velocities = def.velocities;
    m_contacts = def.contacts;
    for (int i = 0; i < m_count; ++i) {
        final Contact contact = m_contacts[i];
        final Fixture fixtureA = contact.m_fixtureA;
        final Fixture fixtureB = contact.m_fixtureB;
        final Shape shapeA = fixtureA.getShape();
        final Shape shapeB = fixtureB.getShape();
        final float radiusA = shapeA.getRadius();
        final float radiusB = shapeB.getRadius();
        final Body bodyA = fixtureA.getBody();
        final Body bodyB = fixtureB.getBody();
        final Manifold manifold = contact.getManifold();
        int pointCount = manifold.pointCount;
        assert pointCount > 0;
        ContactVelocityConstraint vc = m_velocityConstraints[i];
        vc.friction = contact.getFriction();
        vc.restitution = contact.getRestitution();
        vc.tangentSpeed = contact.getTangentSpeed();
        vc.indexA = bodyA.m_islandIndex;
        vc.indexB = bodyB.m_islandIndex;
        vc.invMassA = bodyA.m_invMass;
        vc.invMassB = bodyB.m_invMass;
        vc.invIA = bodyA.m_invI;
        vc.invIB = bodyB.m_invI;
        vc.contactIndex = i;
        vc.pointCount = pointCount;
        vc.K.setZero();
        vc.normalMass.setZero();
        ContactPositionConstraint pc = m_positionConstraints[i];
        pc.indexA = bodyA.m_islandIndex;
        pc.indexB = bodyB.m_islandIndex;
        pc.invMassA = bodyA.m_invMass;
        pc.invMassB = bodyB.m_invMass;
        pc.localCenterA.set(bodyA.m_sweep.localCenter);
        pc.localCenterB.set(bodyB.m_sweep.localCenter);
        pc.invIA = bodyA.m_invI;
        pc.invIB = bodyB.m_invI;
        pc.localNormal.set(manifold.localNormal);
        pc.localPoint.set(manifold.localPoint);
        pc.pointCount = pointCount;
        pc.radiusA = radiusA;
        pc.radiusB = radiusB;
        pc.type = manifold.type;
        for (int j = 0; j < pointCount; j++) {
            ManifoldPoint cp = manifold.points[j];
            VelocityConstraintPoint vcp = vc.points[j];
            if (step.warmStarting) {
                vcp.normalImpulse = step.dtRatio * cp.normalImpulse;
                vcp.tangentImpulse = step.dtRatio * cp.tangentImpulse;
            } else {
                vcp.normalImpulse = 0;
                vcp.tangentImpulse = 0;
            }
            vcp.rA.setZero();
            vcp.rB.setZero();
            vcp.normalMass = 0;
            vcp.tangentMass = 0;
            vcp.velocityBias = 0;
            pc.localPoints[j].x = cp.localPoint.x;
            pc.localPoints[j].y = cp.localPoint.y;
        }
    }
}

Example 8 with Body

use of com.almasb.fxgl.physics.box2d.dynamics.Body in project FXGL by AlmasB.

the class PrismaticJoint method getJointSpeed.

/**
 * Get the current joint translation, usually in meters.
 */
public float getJointSpeed() {
    Body bA = m_bodyA;
    Body bB = m_bodyB;
    Vec2 temp = pool.popVec2();
    Vec2 rA = pool.popVec2();
    Vec2 rB = pool.popVec2();
    Vec2 p1 = pool.popVec2();
    Vec2 p2 = pool.popVec2();
    Vec2 d = pool.popVec2();
    Vec2 axis = pool.popVec2();
    Vec2 temp2 = pool.popVec2();
    Vec2 temp3 = pool.popVec2();
    temp.set(m_localAnchorA).subLocal(bA.m_sweep.localCenter);
    Rotation.mulToOutUnsafe(bA.m_xf.q, temp, rA);
    temp.set(m_localAnchorB).subLocal(bB.m_sweep.localCenter);
    Rotation.mulToOutUnsafe(bB.m_xf.q, temp, rB);
    p1.set(bA.m_sweep.c).addLocal(rA);
    p2.set(bB.m_sweep.c).addLocal(rB);
    d.set(p2).subLocal(p1);
    Rotation.mulToOutUnsafe(bA.m_xf.q, m_localXAxisA, axis);
    Vec2 vA = bA.getLinearVelocity();
    Vec2 vB = bB.getLinearVelocity();
    float wA = bA.getAngularVelocity();
    float wB = bB.getAngularVelocity();
    Vec2.crossToOutUnsafe(wA, axis, temp);
    Vec2.crossToOutUnsafe(wB, rB, temp2);
    Vec2.crossToOutUnsafe(wA, rA, temp3);
    temp2.addLocal(vB).subLocal(vA).subLocal(temp3);
    float speed = Vec2.dot(d, temp) + Vec2.dot(axis, temp2);
    pool.pushVec2(9);
    return speed;
}

Example 9 with Body

use of com.almasb.fxgl.physics.box2d.dynamics.Body in project FXGL by AlmasB.

the class RevoluteJoint method getJointAngle.

public float getJointAngle() {
    final Body b1 = m_bodyA;
    final Body b2 = m_bodyB;
    return b2.m_sweep.a - b1.m_sweep.a - m_referenceAngle;
}

Example 10 with Body

use of com.almasb.fxgl.physics.box2d.dynamics.Body in project FXGL by AlmasB.

the class RevoluteJoint method getJointSpeed.

public float getJointSpeed() {
    final Body b1 = m_bodyA;
    final Body b2 = m_bodyB;
    return b2.getAngularVelocity() - b1.getAngularVelocity();
}