/**
* Creates a fixture and attach it to this body. Use this function if you need to set some fixture
* parameters, like friction. Otherwise you can create the fixture directly from a shape. If the
* density is non-zero, this function automatically updates the mass of the body. Contacts are not
* created until the next time step.
*
* @param def the fixture definition.
* @warning This function is locked during callbacks.
*/
public final Fixture createFixture(FixtureDef def) {
assert (m_world.isLocked() == false);
if (m_world.isLocked() == true) {
return null;
}
// djm TODO from pool?
Fixture fixture = new Fixture();
fixture.create(this, def);
if ((m_flags & e_activeFlag) == e_activeFlag) {
BroadPhase broadPhase = m_world.m_contactManager.m_broadPhase;
fixture.createProxy(broadPhase, m_xf);
}
fixture.m_next = m_fixtureList;
m_fixtureList = fixture;
++m_fixtureCount;
fixture.m_body = this;
// Adjust mass properties if needed.
if (fixture.m_density > 0.0f) {
resetMassData();
}
// Let the world know we have a new fixture. This will cause new contacts
// to be created at the beginning of the next time step.
m_world.m_flags |= World.NEW_FIXTURE;
return fixture;
}
/**
* 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);
}
/**
* Set the position of the body's origin and rotation. This breaks any contacts and wakes the
* other bodies. Manipulating a body's transform may cause non-physical behavior.
*
* @param position the world position of the body's local origin.
* @param angle the world rotation in radians.
*/
public final void setTransform(Vec2 position, float angle) {
assert (m_world.isLocked() == false);
if (m_world.isLocked() == true) {
return;
}
m_xf.R.set(angle);
m_xf.position.set(position);
// 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);
m_sweep.a0 = m_sweep.a = angle;
BroadPhase broadPhase = m_world.m_contactManager.m_broadPhase;
for (Fixture f = m_fixtureList; f != null; f = f.m_next) {
f.synchronize(broadPhase, m_xf, m_xf);
}
m_world.m_contactManager.findNewContacts();
}
/**
* Destroy a fixture. This removes the fixture from the broad-phase and destroys all contacts
* associated with this fixture. This will automatically adjust the mass of the body if the body
* is dynamic and the fixture has positive density. All fixtures attached to a body are implicitly
* destroyed when the body is destroyed.
*
* @param fixture the fixture to be removed.
* @warning This function is locked during callbacks.
*/
public final void destroyFixture(Fixture fixture) {
assert (m_world.isLocked() == false);
if (m_world.isLocked() == true) {
return;
}
assert (fixture.m_body == this);
// Remove the fixture from this body's singly linked list.
assert (m_fixtureCount > 0);
Fixture node = m_fixtureList;
Fixture last = null; // java change
boolean found = false;
while (node != null) {
if (node == fixture) {
node = fixture.m_next;
found = true;
break;
}
last = node;
node = node.m_next;
}
// You tried to remove a shape that is not attached to this body.
assert (found);
// java change, remove it from the list
if (last == null) {
m_fixtureList = fixture.m_next;
} else {
last.m_next = fixture.m_next;
}
// Destroy any contacts associated with the fixture.
ContactEdge edge = m_contactList;
while (edge != null) {
Contact c = edge.contact;
edge = edge.next;
Fixture fixtureA = c.getFixtureA();
Fixture fixtureB = c.getFixtureB();
if (fixture == fixtureA || fixture == fixtureB) {
// This destroys the contact and removes it from
// this body's contact list.
m_world.m_contactManager.destroy(c);
}
}
if ((m_flags & e_activeFlag) == e_activeFlag) {
assert (fixture.m_proxy != null);
BroadPhase broadPhase = m_world.m_contactManager.m_broadPhase;
fixture.destroyProxy(broadPhase);
} else {
assert (fixture.m_proxy == null);
}
fixture.destroy();
fixture.m_body = null;
fixture.m_next = null;
fixture = null;
--m_fixtureCount;
// Reset the mass data.
resetMassData();
}