示例#1
0
  @Override
  public int getMaxBalance() {
    int maxBalance = 0;
    for (int i = 0; i < m_nodeCapacity; ++i) {
      final DynamicTreeNode node = m_nodes[i];
      if (node.height <= 1) {
        continue;
      }

      assert (node.child1 == null == false);

      DynamicTreeNode child1 = node.child1;
      DynamicTreeNode child2 = node.child2;
      int balance = org.jbox2d.common.MathUtils.abs(child2.height - child1.height);
      maxBalance = org.jbox2d.common.MathUtils.max(maxBalance, balance);
    }

    return maxBalance;
  }
示例#2
0
  @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;
  }
示例#3
0
  @Override
  public void raycast(
      org.jbox2d.callbacks.TreeRayCastCallback callback, org.jbox2d.collision.RayCastInput input) {
    final Vec2 p1 = input.p1;
    final Vec2 p2 = input.p2;
    float p1x = p1.x, p2x = p2.x, p1y = p1.y, p2y = p2.y;
    float vx, vy;
    float rx, ry;
    float absVx, absVy;
    float cx, cy;
    float hx, hy;
    float tempx, tempy;
    r.x = p2x - p1x;
    r.y = p2y - p1y;
    assert ((r.x * r.x + r.y * r.y) > 0f);
    r.normalize();
    rx = r.x;
    ry = r.y;

    // v is perpendicular to the segment.
    vx = -1f * ry;
    vy = 1f * rx;
    absVx = org.jbox2d.common.MathUtils.abs(vx);
    absVy = org.jbox2d.common.MathUtils.abs(vy);

    // Separating axis for segment (Gino, p80).
    // |dot(v, p1 - c)| > dot(|v|, h)

    float maxFraction = input.maxFraction;

    // Build a bounding box for the segment.
    final org.jbox2d.collision.AABB segAABB = aabb;
    // Vec2 t = p1 + maxFraction * (p2 - p1);
    // before inline
    // temp.set(p2).subLocal(p1).mulLocal(maxFraction).addLocal(p1);
    // Vec2.minToOut(p1, temp, segAABB.lowerBound);
    // Vec2.maxToOut(p1, temp, segAABB.upperBound);
    tempx = (p2x - p1x) * maxFraction + p1x;
    tempy = (p2y - p1y) * maxFraction + p1y;
    segAABB.lowerBound.x = p1x < tempx ? p1x : tempx;
    segAABB.lowerBound.y = p1y < tempy ? p1y : tempy;
    segAABB.upperBound.x = p1x > tempx ? p1x : tempx;
    segAABB.upperBound.y = p1y > tempy ? p1y : tempy;
    // end inline

    nodeStackIndex = 0;
    nodeStack[nodeStackIndex++] = m_root;
    while (nodeStackIndex > 0) {
      final DynamicTreeNode node = nodeStack[--nodeStackIndex];
      if (node == null) {
        continue;
      }

      final org.jbox2d.collision.AABB nodeAABB = node.aabb;
      if (!org.jbox2d.collision.AABB.testOverlap(nodeAABB, segAABB)) {
        continue;
      }

      // Separating axis for segment (Gino, p80).
      // |dot(v, p1 - c)| > dot(|v|, h)
      // node.aabb.getCenterToOut(c);
      // node.aabb.getExtentsToOut(h);
      cx = (nodeAABB.lowerBound.x + nodeAABB.upperBound.x) * .5f;
      cy = (nodeAABB.lowerBound.y + nodeAABB.upperBound.y) * .5f;
      hx = (nodeAABB.upperBound.x - nodeAABB.lowerBound.x) * .5f;
      hy = (nodeAABB.upperBound.y - nodeAABB.lowerBound.y) * .5f;
      tempx = p1x - cx;
      tempy = p1y - cy;
      float separation =
          org.jbox2d.common.MathUtils.abs(vx * tempx + vy * tempy) - (absVx * hx + absVy * hy);
      if (separation > 0.0f) {
        continue;
      }

      if (node.child1 == null) {
        subInput.p1.x = p1x;
        subInput.p1.y = p1y;
        subInput.p2.x = p2x;
        subInput.p2.y = p2y;
        subInput.maxFraction = maxFraction;

        float value = callback.raycastCallback(subInput, node.id);

        if (value == 0.0f) {
          // The client has terminated the ray cast.
          return;
        }

        if (value > 0.0f) {
          // Update segment bounding box.
          maxFraction = value;
          // temp.set(p2).subLocal(p1).mulLocal(maxFraction).addLocal(p1);
          // Vec2.minToOut(p1, temp, segAABB.lowerBound);
          // Vec2.maxToOut(p1, temp, segAABB.upperBound);
          tempx = (p2x - p1x) * maxFraction + p1x;
          tempy = (p2y - p1y) * maxFraction + p1y;
          segAABB.lowerBound.x = p1x < tempx ? p1x : tempx;
          segAABB.lowerBound.y = p1y < tempy ? p1y : tempy;
          segAABB.upperBound.x = p1x > tempx ? p1x : tempx;
          segAABB.upperBound.y = p1y > tempy ? p1y : tempy;
        }
      } else {
        if (nodeStack.length - nodeStackIndex - 2 <= 0) {
          DynamicTreeNode[] newBuffer = new DynamicTreeNode[nodeStack.length * 2];
          System.arraycopy(nodeStack, 0, newBuffer, 0, nodeStack.length);
          nodeStack = newBuffer;
        }
        nodeStack[nodeStackIndex++] = node.child1;
        nodeStack[nodeStackIndex++] = node.child2;
      }
    }
  }
示例#4
0
  @Override
  public void initVelocityConstraints(final org.jbox2d.dynamics.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;

    boolean fixedRotation = (iA + iB == 0.0f);

    m_mass.ex.x = mA + mB + m_rA.y * m_rA.y * iA + m_rB.y * m_rB.y * iB;
    m_mass.ey.x = -m_rA.y * m_rA.x * iA - m_rB.y * m_rB.x * iB;
    m_mass.ez.x = -m_rA.y * iA - m_rB.y * iB;
    m_mass.ex.y = m_mass.ey.x;
    m_mass.ey.y = mA + mB + m_rA.x * m_rA.x * iA + m_rB.x * m_rB.x * iB;
    m_mass.ez.y = m_rA.x * iA + m_rB.x * iB;
    m_mass.ex.z = m_mass.ez.x;
    m_mass.ey.z = m_mass.ez.y;
    m_mass.ez.z = iA + iB;

    m_motorMass = iA + iB;
    if (m_motorMass > 0.0f) {
      m_motorMass = 1.0f / m_motorMass;
    }

    if (m_enableMotor == false || fixedRotation) {
      m_motorImpulse = 0.0f;
    }

    if (m_enableLimit && fixedRotation == false) {
      float jointAngle = aB - aA - m_referenceAngle;
      if (MathUtils.abs(m_upperAngle - m_lowerAngle) < 2.0f * Settings.angularSlop) {
        m_limitState = LimitState.EQUAL;
      } else if (jointAngle <= m_lowerAngle) {
        if (m_limitState != LimitState.AT_LOWER) {
          m_impulse.z = 0.0f;
        }
        m_limitState = LimitState.AT_LOWER;
      } else if (jointAngle >= m_upperAngle) {
        if (m_limitState != LimitState.AT_UPPER) {
          m_impulse.z = 0.0f;
        }
        m_limitState = LimitState.AT_UPPER;
      } else {
        m_limitState = LimitState.INACTIVE;
        m_impulse.z = 0.0f;
      }
    } else {
      m_limitState = LimitState.INACTIVE;
    }

    if (data.step.warmStarting) {
      final Vec2 P = pool.popVec2();
      // Scale impulses to support a variable time step.
      m_impulse.x *= data.step.dtRatio;
      m_impulse.y *= data.step.dtRatio;
      m_motorImpulse *= data.step.dtRatio;

      P.x = m_impulse.x;
      P.y = m_impulse.y;

      vA.x -= mA * P.x;
      vA.y -= mA * P.y;
      wA -= iA * (Vec2.cross(m_rA, P) + m_motorImpulse + m_impulse.z);

      vB.x += mB * P.x;
      vB.y += mB * P.y;
      wB += iB * (Vec2.cross(m_rB, P) + m_motorImpulse + m_impulse.z);
      pool.pushVec2(1);
    } else {
      m_impulse.setZero();
      m_motorImpulse = 0.0f;
    }
    // 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);
  }