Exemplo n.º 1
0
 protected final void advance(float t) {
   // Advance to the new safe time.
   m_sweep.advance(t);
   m_sweep.c.set(m_sweep.c0);
   m_sweep.a = m_sweep.a0;
   synchronizeTransform();
 }
Exemplo n.º 2
0
  private void solveTOI(final TimeStep step) {

    final Island island = toiIsland;
    island.init(
        2 * Settings.maxTOIContacts,
        Settings.maxTOIContacts,
        0,
        m_contactManager.m_contactListener);
    if (m_stepComplete) {
      for (Body b = m_bodyList; b != null; b = b.m_next) {
        b.m_flags &= ~Body.e_islandFlag;
        b.m_sweep.alpha0 = 0.0f;
      }

      for (Contact c = m_contactManager.m_contactList; c != null; c = c.m_next) {
        // Invalidate TOI
        c.m_flags &= ~(Contact.TOI_FLAG | Contact.ISLAND_FLAG);
        c.m_toiCount = 0;
        c.m_toi = 1.0f;
      }
    }

    // Find TOI events and solve them.
    for (; ; ) {
      // Find the first TOI.
      Contact minContact = null;
      float minAlpha = 1.0f;

      for (Contact c = m_contactManager.m_contactList; c != null; c = c.m_next) {
        // Is this contact disabled?
        if (c.isEnabled() == false) {
          continue;
        }

        // Prevent excessive sub-stepping.
        if (c.m_toiCount > Settings.maxSubSteps) {
          continue;
        }

        float alpha = 1.0f;
        if ((c.m_flags & Contact.TOI_FLAG) != 0) {
          // This contact has a valid cached TOI.
          alpha = c.m_toi;
        } else {
          Fixture fA = c.getFixtureA();
          Fixture fB = c.getFixtureB();

          // Is there a sensor?
          if (fA.isSensor() || fB.isSensor()) {
            continue;
          }

          Body bA = fA.getBody();
          Body bB = fB.getBody();

          BodyType typeA = bA.m_type;
          BodyType typeB = bB.m_type;
          assert (typeA == BodyType.DYNAMIC || typeB == BodyType.DYNAMIC);

          boolean activeA = bA.isAwake() && typeA != BodyType.STATIC;
          boolean activeB = bB.isAwake() && typeB != BodyType.STATIC;

          // Is at least one body active (awake and dynamic or kinematic)?
          if (activeA == false && activeB == false) {
            continue;
          }

          boolean collideA = bA.isBullet() || typeA != BodyType.DYNAMIC;
          boolean collideB = bB.isBullet() || typeB != BodyType.DYNAMIC;

          // Are these two non-bullet dynamic bodies?
          if (collideA == false && collideB == false) {
            continue;
          }

          // Compute the TOI for this contact.
          // Put the sweeps onto the same time interval.
          float alpha0 = bA.m_sweep.alpha0;

          if (bA.m_sweep.alpha0 < bB.m_sweep.alpha0) {
            alpha0 = bB.m_sweep.alpha0;
            bA.m_sweep.advance(alpha0);
          } else if (bB.m_sweep.alpha0 < bA.m_sweep.alpha0) {
            alpha0 = bA.m_sweep.alpha0;
            bB.m_sweep.advance(alpha0);
          }

          assert (alpha0 < 1.0f);

          int indexA = c.getChildIndexA();
          int indexB = c.getChildIndexB();

          // Compute the time of impact in interval [0, minTOI]
          final TOIInput input = toiInput;
          input.proxyA.set(fA.getShape(), indexA);
          input.proxyB.set(fB.getShape(), indexB);
          input.sweepA.set(bA.m_sweep);
          input.sweepB.set(bB.m_sweep);
          input.tMax = 1.0f;

          pool.getTimeOfImpact().timeOfImpact(toiOutput, input);

          // Beta is the fraction of the remaining portion of the .
          float beta = toiOutput.t;
          if (toiOutput.state == TOIOutputState.TOUCHING) {
            alpha = MathUtils.min(alpha0 + (1.0f - alpha0) * beta, 1.0f);
          } else {
            alpha = 1.0f;
          }

          c.m_toi = alpha;
          c.m_flags |= Contact.TOI_FLAG;
        }

        if (alpha < minAlpha) {
          // This is the minimum TOI found so far.
          minContact = c;
          minAlpha = alpha;
        }
      }

      if (minContact == null || 1.0f - 10.0f * Settings.EPSILON < minAlpha) {
        // No more TOI events. Done!
        m_stepComplete = true;
        break;
      }

      // Advance the bodies to the TOI.
      Fixture fA = minContact.getFixtureA();
      Fixture fB = minContact.getFixtureB();
      Body bA = fA.getBody();
      Body bB = fB.getBody();

      backup1.set(bA.m_sweep);
      backup2.set(bB.m_sweep);

      bA.advance(minAlpha);
      bB.advance(minAlpha);

      // The TOI contact likely has some new contact points.
      minContact.update(m_contactManager.m_contactListener);
      minContact.m_flags &= ~Contact.TOI_FLAG;
      ++minContact.m_toiCount;

      // Is the contact solid?
      if (minContact.isEnabled() == false || minContact.isTouching() == false) {
        // Restore the sweeps.
        minContact.setEnabled(false);
        bA.m_sweep.set(backup1);
        bB.m_sweep.set(backup2);
        bA.synchronizeTransform();
        bB.synchronizeTransform();
        continue;
      }

      bA.setAwake(true);
      bB.setAwake(true);

      // Build the island
      island.clear();
      island.add(bA);
      island.add(bB);
      island.add(minContact);

      bA.m_flags |= Body.e_islandFlag;
      bB.m_flags |= Body.e_islandFlag;
      minContact.m_flags |= Contact.ISLAND_FLAG;

      // Get contacts on bodyA and bodyB.
      tempBodies[0] = bA;
      tempBodies[1] = bB;
      for (int i = 0; i < 2; ++i) {
        Body body = tempBodies[i];
        if (body.m_type == BodyType.DYNAMIC) {
          for (ContactEdge ce = body.m_contactList; ce != null; ce = ce.next) {
            if (island.m_bodyCount == island.m_bodyCapacity) {
              break;
            }

            if (island.m_contactCount == island.m_contactCapacity) {
              break;
            }

            Contact contact = ce.contact;

            // Has this contact already been added to the island?
            if ((contact.m_flags & Contact.ISLAND_FLAG) != 0) {
              continue;
            }

            // Only add static, kinematic, or bullet bodies.
            Body other = ce.other;
            if (other.m_type == BodyType.DYNAMIC
                && body.isBullet() == false
                && other.isBullet() == false) {
              continue;
            }

            // Skip sensors.
            boolean sensorA = contact.m_fixtureA.m_isSensor;
            boolean sensorB = contact.m_fixtureB.m_isSensor;
            if (sensorA || sensorB) {
              continue;
            }

            // Tentatively advance the body to the TOI.
            backup1.set(other.m_sweep);
            if ((other.m_flags & Body.e_islandFlag) == 0) {
              other.advance(minAlpha);
            }

            // Update the contact points
            contact.update(m_contactManager.m_contactListener);

            // Was the contact disabled by the user?
            if (contact.isEnabled() == false) {
              other.m_sweep.set(backup1);
              other.synchronizeTransform();
              continue;
            }

            // Are there contact points?
            if (contact.isTouching() == false) {
              other.m_sweep.set(backup1);
              other.synchronizeTransform();
              continue;
            }

            // Add the contact to the island
            contact.m_flags |= Contact.ISLAND_FLAG;
            island.add(contact);

            // Has the other body already been added to the island?
            if ((other.m_flags & Body.e_islandFlag) != 0) {
              continue;
            }

            // Add the other body to the island.
            other.m_flags |= Body.e_islandFlag;

            if (other.m_type != BodyType.STATIC) {
              other.setAwake(true);
            }

            island.add(other);
          }
        }
      }

      subStep.dt = (1.0f - minAlpha) * step.dt;
      subStep.inv_dt = 1.0f / subStep.dt;
      subStep.dtRatio = 1.0f;
      subStep.positionIterations = 20;
      subStep.velocityIterations = step.velocityIterations;
      subStep.warmStarting = false;
      island.solveTOI(subStep, bA.m_islandIndex, bB.m_islandIndex);

      // Reset island flags and synchronize broad-phase proxies.
      for (int i = 0; i < island.m_bodyCount; ++i) {
        Body body = island.m_bodies[i];
        body.m_flags &= ~Body.e_islandFlag;

        if (body.m_type != BodyType.DYNAMIC) {
          continue;
        }

        body.synchronizeFixtures();

        // Invalidate all contact TOIs on this displaced body.
        for (ContactEdge ce = body.m_contactList; ce != null; ce = ce.next) {
          ce.contact.m_flags &= ~(Contact.TOI_FLAG | Contact.ISLAND_FLAG);
        }
      }

      // Commit fixture proxy movements to the broad-phase so that new contacts are created.
      // Also, some contacts can be destroyed.
      m_contactManager.findNewContacts();

      if (m_subStepping) {
        m_stepComplete = false;
        break;
      }
    }
  }