Java MassData类代码示例

import org.jbox2d.collision.shapes.MassData; //导入依赖的package包/类
protected void createFixtures(Body body, PhysicsBodyShape shape, boolean sensor, float friction, float restitution, float density, Float fixedWeight) {
	FixtureDef fd = new FixtureDef();
	fd.shape = createShape(shape, width, height);
	fd.isSensor = sensor || CollisionHandlerType.CLIMBABLE == type;

	fd.friction = friction;
	fd.restitution = restitution;
	
	// calculate the required density to reach the fixed mass 
	if( fixedWeight!=null ) {
		MassData md = new MassData();
		fd.shape.computeMass(md, 1.0f);
		density = fixedWeight/md.mass;
	}
	fd.density = density;
	fd.userData = null;
	
	body.createFixture(fd);
}
 

import org.jbox2d.collision.shapes.MassData; //导入依赖的package包/类
/**
 * Get the mass data of the body. The rotational inertia is relative to the center of mass.
 * 
 * @return a struct containing the mass, inertia and center of the body.
 */
public final void getMassData(MassData data) {
  // data.mass = m_mass;
  // data.I = m_I + m_mass * Vec2.dot(m_sweep.localCenter, m_sweep.localCenter);
  // data.center.set(m_sweep.localCenter);

  data.mass = m_mass;
  data.I =
      m_I
          + m_mass
          * (m_sweep.localCenter.x * m_sweep.localCenter.x + m_sweep.localCenter.y
              * m_sweep.localCenter.y);
  data.center.x = m_sweep.localCenter.x;
  data.center.y = m_sweep.localCenter.y;
}
 

import org.jbox2d.collision.shapes.MassData; //导入依赖的package包/类
/**
 * Get the mass data of the body. The rotational inertia is relative
 * to the center of mass.
 * 
 * @return a struct containing the mass, inertia and center of the body.
 */
public final void getMassData(MassData data) {
	// data.mass = m_mass;
	// data.I = m_I + m_mass * Vec2.dot(m_sweep.localCenter, m_sweep.localCenter);
	// data.center.set(m_sweep.localCenter);
	
	data.mass = m_mass;
	data.I = m_I + m_mass
			* (m_sweep.localCenter.x * m_sweep.localCenter.x + m_sweep.localCenter.y * m_sweep.localCenter.y);
	data.center.x = m_sweep.localCenter.x;
	data.center.y = m_sweep.localCenter.y;
}
 

import org.jbox2d.collision.shapes.MassData; //导入依赖的package包/类
/**
 * Get the mass data of the body. The rotational inertia is relative to the center of mass.
 * 
 * @return a struct containing the mass, inertia and center of the body.
 */
public final void getMassData(MassData data) {
  // data.mass = m_mass;
  // data.I = m_I + m_mass * Vector2.dot(m_sweep.localCenter, m_sweep.localCenter);
  // data.center.set(m_sweep.localCenter);

  data.mass = m_mass;
  data.I =
      m_I
          + m_mass
          * (m_sweep.localCenter.x * m_sweep.localCenter.x + m_sweep.localCenter.y
              * m_sweep.localCenter.y);
  data.center.x = m_sweep.localCenter.x;
  data.center.y = m_sweep.localCenter.y;
}
 

import org.jbox2d.collision.shapes.MassData; //导入依赖的package包/类
/**
 * Get the mass data of the body. The rotational inertia is relative to the
 * center of mass.
 * 
 * @return a struct containing the mass, inertia and center of the body.
 */
public final void getMassData(MassData data) {
	// data.mass = m_mass;
	// data.I = m_I + m_mass * Vec2.dot(m_sweep.localCenter,
	// m_sweep.localCenter);
	// data.center.set(m_sweep.localCenter);

	data.mass = m_mass;
	data.I = m_I
			+ m_mass
			* (m_sweep.localCenter.x * m_sweep.localCenter.x + m_sweep.localCenter.y
					* m_sweep.localCenter.y);
	data.center.x = m_sweep.localCenter.x;
	data.center.y = m_sweep.localCenter.y;
}
 

import org.jbox2d.collision.shapes.MassData; //导入依赖的package包/类
/**
 * Set the mass properties to override the mass properties of the fixtures. Note that this changes
 * the center of mass position. Note that creating or destroying fixtures can also alter the mass.
 * This function has no effect if the body isn't dynamic.
 * 
 * @param massData the mass properties.
 */
public final void setMassData(MassData massData) {
  // TODO_ERIN adjust linear velocity and torque to account for movement of center.
  assert (m_world.isLocked() == false);
  if (m_world.isLocked() == true) {
    return;
  }

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

  m_invMass = 0.0f;
  m_I = 0.0f;
  m_invI = 0.0f;

  m_mass = massData.mass;
  if (m_mass <= 0.0f) {
    m_mass = 1f;
  }

  m_invMass = 1.0f / m_mass;

  if (massData.I > 0.0f && (m_flags & e_fixedRotationFlag) == 0) {
    m_I = massData.I - m_mass * Vec2.dot(massData.center, massData.center);
    assert (m_I > 0.0f);
    m_invI = 1.0f / m_I;
  }

  final Vec2 oldCenter = m_world.getPool().popVec2();
  // Move center of mass.
  oldCenter.set(m_sweep.c);
  m_sweep.localCenter.set(massData.center);
  // m_sweep.c0 = m_sweep.c = Mul(m_xf, m_sweep.localCenter);
  Transform.mulToOutUnsafe(m_xf, m_sweep.localCenter, m_sweep.c0);
  m_sweep.c.set(m_sweep.c0);

  // Update center of mass velocity.
  // m_linearVelocity += Cross(m_angularVelocity, m_sweep.c - oldCenter);
  final Vec2 temp = m_world.getPool().popVec2();
  temp.set(m_sweep.c).subLocal(oldCenter);
  Vec2.crossToOut(m_angularVelocity, temp, temp);
  m_linearVelocity.addLocal(temp);

  m_world.getPool().pushVec2(2);
}
 

import org.jbox2d.collision.shapes.MassData; //导入依赖的package包/类
/**
 * Set the mass properties to override the mass properties of the fixtures.
 * Note that this changes the center of mass position.
 * Note that creating or destroying fixtures can also alter the mass.
 * This function has no effect if the body isn't dynamic.
 * 
 * @param massData
 *            the mass properties.
 */
public final void setMassData(MassData massData) {
	// TODO_ERIN adjust linear velocity and torque to account for movement of center.
	assert (m_world.isLocked() == false);
	if (m_world.isLocked() == true) {
		return;
	}
	
	if (m_type != BodyType.DYNAMIC) {
		return;
	}
	
	m_invMass = 0.0f;
	m_I = 0.0f;
	m_invI = 0.0f;
	
	m_mass = massData.mass;
	if (m_mass <= 0.0f) {
		m_mass = 1f;
	}
	
	m_invMass = 1.0f / m_mass;
	
	if (massData.I > 0.0f && (m_flags & e_fixedRotationFlag) == 0) {
		m_I = massData.I - m_mass * Vec2.dot(massData.center, massData.center);
		assert (m_I > 0.0f);
		m_invI = 1.0f / m_I;
	}
	
	final Vec2 oldCenter = m_world.getPool().popVec2();
	// Move center of mass.
	oldCenter.set(m_sweep.c);
	m_sweep.localCenter.set(massData.center);
	// m_sweep.c0 = m_sweep.c = Mul(m_xf, m_sweep.localCenter);
	Transform.mulToOut(m_xf, m_sweep.localCenter, m_sweep.c0);
	m_sweep.c.set(m_sweep.c0);
	
	// Update center of mass velocity.
	// m_linearVelocity += Cross(m_angularVelocity, m_sweep.c - oldCenter);
	final Vec2 temp = m_world.getPool().popVec2();
	temp.set(m_sweep.c).subLocal(oldCenter);
	Vec2.crossToOut(m_angularVelocity, temp, temp);
	m_linearVelocity.addLocal(temp);
	
	m_world.getPool().pushVec2(2);
}
 

import org.jbox2d.collision.shapes.MassData; //导入依赖的package包/类
/**
 * This resets the mass properties to the sum of the mass properties of the fixtures.
 * This normally does not need to be called unless you called setMassData to override
 * the mass and you later want to reset the mass.
 */
public final void resetMassData() {
	// Compute mass data from shapes. Each shape has its own density.
	m_mass = 0.0f;
	m_invMass = 0.0f;
	m_I = 0.0f;
	m_invI = 0.0f;
	m_sweep.localCenter.setZero();
	
	// Static and kinematic bodies have zero mass.
	if (m_type == BodyType.STATIC || m_type == BodyType.KINEMATIC) {
		// m_sweep.c0 = m_sweep.c = m_xf.position;
		m_sweep.c.set(m_xf.position);
		m_sweep.c0.set(m_xf.position);
		return;
	}
	
	assert (m_type == BodyType.DYNAMIC);
	
	// Accumulate mass over all fixtures.
	final Vec2 center = m_world.getPool().popVec2();
	center.setZero();
	final Vec2 temp = m_world.getPool().popVec2();
	final MassData massData = pmd;
	for (Fixture f = m_fixtureList; f != null; f = f.m_next) {
		if (f.m_density == 0.0f) {
			continue;
		}
		f.getMassData(massData);
		m_mass += massData.mass;
		// center += massData.mass * massData.center;
		temp.set(massData.center).mulLocal(massData.mass);
		center.addLocal(temp);
		m_I += massData.I;
	}
	
	// Compute center of mass.
	if (m_mass > 0.0f) {
		m_invMass = 1.0f / m_mass;
		center.mulLocal(m_invMass);
	}
	else {
		// Force all dynamic bodies to have a positive mass.
		m_mass = 1.0f;
		m_invMass = 1.0f;
	}
	
	if (m_I > 0.0f && (m_flags & e_fixedRotationFlag) == 0) {
		// Center the inertia about the center of mass.
		m_I -= m_mass * Vec2.dot(center, center);
		assert (m_I > 0.0f);
		m_invI = 1.0f / m_I;
	}
	else {
		m_I = 0.0f;
		m_invI = 0.0f;
	}
	
	Vec2 oldCenter = m_world.getPool().popVec2();
	// Move center of mass.
	oldCenter.set(m_sweep.c);
	m_sweep.localCenter.set(center);
	// m_sweep.c0 = m_sweep.c = Mul(m_xf, m_sweep.localCenter);
	Transform.mulToOut(m_xf, m_sweep.localCenter, m_sweep.c0);
	m_sweep.c.set(m_sweep.c0);
	
	// Update center of mass velocity.
	// m_linearVelocity += Cross(m_angularVelocity, m_sweep.c - oldCenter);
	temp.set(m_sweep.c).subLocal(oldCenter);
	Vec2.crossToOut(m_angularVelocity, temp, temp);
	m_linearVelocity.addLocal(temp);
	
	m_world.getPool().pushVec2(3);
}
 

import org.jbox2d.collision.shapes.MassData; //导入依赖的package包/类
private void checkBounds() {
	for (int i=0; i<liquid.length; ++i) {
		if (liquid[i].getWorldCenter().y < -10.0f) {
			m_world.destroyBody(liquid[i]);
			float massPerParticle = totalMass / nParticles;
			
			CircleShape pd = new CircleShape();
			FixtureDef fd = new FixtureDef();
			fd.shape = pd;
			fd.density = 1.0f;
			fd.filter.groupIndex = -10;
			pd.m_radius = .05f;
			fd.restitution = 0.4f;
			fd.friction = 0.0f;
			float cx = 0.0f + MathUtils.randomFloat(-0.6f,0.6f);
			float cy = 15.0f + MathUtils.randomFloat(-2.3f,2.0f);
			BodyDef bd = new BodyDef();
			bd.position = new Vec2( cx, cy );
			bd.fixedRotation = true;
			bd.type = BodyType.DYNAMIC;
			Body b = m_world.createBody(bd);
			b.createFixture(fd).setUserData(LIQUID_INT);
			MassData md = new MassData();
			md.mass = massPerParticle;
			md.I = 1.0f;
			b.setMassData(md);
			b.setSleepingAllowed(false);
			liquid[i] = b;
		}
	}
	
	if (bod.getWorldCenter().y < -15.0f) {
		m_world.destroyBody(bod);
		PolygonShape polyDef = new PolygonShape();
		polyDef.setAsBox(MathUtils.randomFloat(0.3f,0.7f), MathUtils.randomFloat(0.3f,0.7f));
		BodyDef bodyDef = new BodyDef();
		bodyDef.position = new Vec2(0.0f,25.0f);
		bodyDef.type = BodyType.DYNAMIC;
		bod = m_world.createBody(bodyDef);
		bod.createFixture(polyDef, 1f);
	}
}
 

import org.jbox2d.collision.shapes.MassData; //导入依赖的package包/类
/**
 * Set the mass properties to override the mass properties of the fixtures. Note that this changes
 * the center of mass position. Note that creating or destroying fixtures can also alter the mass.
 * This function has no effect if the body isn't dynamic.
 * 
 * @param massData the mass properties.
 */
public final void setMassData(MassData massData) {
  // TODO_ERIN adjust linear velocity and torque to account for movement of center.
  assert (m_world.isLocked() == false);
  if (m_world.isLocked() == true) {
    return;
  }

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

  m_invMass = 0.0f;
  m_I = 0.0f;
  m_invI = 0.0f;

  m_mass = massData.mass;
  if (m_mass <= 0.0f) {
    m_mass = 1f;
  }

  m_invMass = 1.0f / m_mass;

  if (massData.I > 0.0f && (m_flags & e_fixedRotationFlag) == 0) {
    m_I = massData.I - m_mass * Vector2.dot(massData.center, massData.center);
    assert (m_I > 0.0f);
    m_invI = 1.0f / m_I;
  }

  final Vector2 oldCenter = m_world.getPool().popVec2();
  // Move center of mass.
  oldCenter.set(m_sweep.c);
  m_sweep.localCenter.set(massData.center);
  // m_sweep.c0 = m_sweep.c = Mul(m_xf, m_sweep.localCenter);
  Transform.mulToOutUnsafe(m_xf, m_sweep.localCenter, m_sweep.c0);
  m_sweep.c.set(m_sweep.c0);

  // Update center of mass velocity.
  // m_linearVelocity += Cross(m_angularVelocity, m_sweep.c - oldCenter);
  final Vector2 temp = m_world.getPool().popVec2();
  temp.set(m_sweep.c).subLocal(oldCenter);
  Vector2.crossToOut(m_angularVelocity, temp, temp);
  m_linearVelocity.addLocal(temp);

  m_world.getPool().pushVec2(2);
}
 

import org.jbox2d.collision.shapes.MassData; //导入依赖的package包/类
protected MassData initialValue(){
	return new MassData();
}
 

import org.jbox2d.collision.shapes.MassData; //导入依赖的package包/类
private void checkBounds() {
  for (int i = 0; i < liquid.length; ++i) {
    if (liquid[i].getWorldCenter().y < -10.0f) {
      getWorld().destroyBody(liquid[i]);
      float massPerParticle = totalMass / nParticles;

      CircleShape pd = new CircleShape();
      FixtureDef fd = new FixtureDef();
      fd.shape = pd;
      fd.density = 1.0f;
      fd.filter.groupIndex = -10;
      pd.m_radius = .05f;
      fd.restitution = 0.4f;
      fd.friction = 0.0f;
      float cx = 0.0f + MathUtils.randomFloat(-0.6f, 0.6f);
      float cy = 15.0f + MathUtils.randomFloat(-2.3f, 2.0f);
      BodyDef bd = new BodyDef();
      bd.position = new Vec2(cx, cy);
      bd.fixedRotation = true;
      bd.type = BodyType.DYNAMIC;
      Body b = getWorld().createBody(bd);
      b.createFixture(fd).setUserData(LIQUID_INT);
      MassData md = new MassData();
      md.mass = massPerParticle;
      md.I = 1.0f;
      b.setMassData(md);
      b.setSleepingAllowed(false);
      liquid[i] = b;
    }
  }

  if (bod.getWorldCenter().y < -15.0f) {
    getWorld().destroyBody(bod);
    PolygonShape polyDef = new PolygonShape();
    polyDef.setAsBox(MathUtils.randomFloat(0.3f, 0.7f), MathUtils.randomFloat(0.3f, 0.7f));
    BodyDef bodyDef = new BodyDef();
    bodyDef.position = new Vec2(0.0f, 25.0f);
    bodyDef.type = BodyType.DYNAMIC;
    bod = getWorld().createBody(bodyDef);
    bod.createFixture(polyDef, 1f);
  }
}
 

import org.jbox2d.collision.shapes.MassData; //导入依赖的package包/类
@Override
public void computeMass(MassData massData, float density) {
    massData.I = 0f;
    massData.center.setZero();
    massData.mass = (float) mass;
}
 

import org.jbox2d.collision.shapes.MassData; //导入依赖的package包/类
private void createBodyFixture(Node node, Body body) {
    Shape s = NodeShapeBuilder.createShape(node);
    MassData m = new MassData();
    s.computeMass(m, 1);
    body.createFixture(s, (float) layout.getMass(node) / m.mass);
}
 

import org.jbox2d.collision.shapes.MassData; //导入依赖的package包/类
/**
 * Set the mass properties to override the mass properties of the fixtures.
 * Note that this changes the center of mass position. Note that creating or
 * destroying fixtures can also alter the mass. This function has no effect
 * if the body isn't dynamic.
 * 
 * @param massData
 *            the mass properties.
 */
public final void setMassData(MassData massData) {
	// TODO_ERIN adjust linear velocity and torque to account for movement
	// of center.
	assert (m_world.isLocked() == false);
	if (m_world.isLocked() == true) {
		return;
	}

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

	m_invMass = 0.0f;
	m_I = 0.0f;
	m_invI = 0.0f;

	m_mass = massData.mass;
	if (m_mass <= 0.0f) {
		m_mass = 1f;
	}

	m_invMass = 1.0f / m_mass;

	if (massData.I > 0.0f && (m_flags & e_fixedRotationFlag) == 0) {
		m_I = massData.I - m_mass
				* Vec2.dot(massData.center, massData.center);
		assert (m_I > 0.0f);
		m_invI = 1.0f / m_I;
	}

	final Vec2 oldCenter = m_world.getPool().popVec2();
	// Move center of mass.
	oldCenter.set(m_sweep.c);
	m_sweep.localCenter.set(massData.center);
	// m_sweep.c0 = m_sweep.c = Mul(m_xf, m_sweep.localCenter);
	Transform.mulToOut(m_xf, m_sweep.localCenter, m_sweep.c0);
	m_sweep.c.set(m_sweep.c0);

	// Update center of mass velocity.
	// m_linearVelocity += Cross(m_angularVelocity, m_sweep.c - oldCenter);
	final Vec2 temp = m_world.getPool().popVec2();
	temp.set(m_sweep.c).subLocal(oldCenter);
	Vec2.crossToOut(m_angularVelocity, temp, temp);
	m_linearVelocity.addLocal(temp);

	m_world.getPool().pushVec2(2);
}