@Override
    public void preSolve(Contact contact, Manifold oldManifold) {
        //NOTE: This isn't called for SENSOR bodies
        checkGenericContact(contact.getFixtureA(), contact.getFixtureB(), contact);
        checkGenericContact(contact.getFixtureB(), contact.getFixtureA(), contact);
    }





public void checkGenericContact(Fixture mainFixture, Fixture secondaryFixture, Contact contact){

		short secondaryCategory = secondaryFixture.getFilterData().categoryBits;

		if(mainFixture.getBody().getUserData() != null){
			if(secondaryFixture.getBody().getUserData() != null){
				//Both have userdata
				if(mainFixture.getBody().getUserData() instanceof Character){
					Character characterA = (Character) mainFixture.getBody().getUserData();
					if(secondaryFixture.getBody().getUserData() instanceof Character){
						Character characterB = (Character) secondaryFixture.getBody().getUserData();
						contact.setEnabled(contact.isEnabled() && characterA.collidedWithCharacter(characterB, secondaryCategory, contact));
					} else if(secondaryFixture.getBody().getUserData() instanceof PhysicsEntity){
						PhysicsEntity entityB = (PhysicsEntity) secondaryFixture.getBody().getUserData();
						contact.setEnabled(contact.isEnabled() && characterA.collidedWithEntity(entityB, secondaryCategory, contact));
					}
				} else if(mainFixture.getBody().getUserData() instanceof PhysicsEntity){

					PhysicsEntity entityA = (PhysicsEntity) mainFixture.getBody().getUserData();
					if(secondaryFixture.getBody().getUserData() instanceof Character){
						Character characterB = (Character) secondaryFixture.getBody().getUserData();
						contact.setEnabled(contact.isEnabled() && entityA.collidedWithCharacter(characterB, secondaryCategory, contact));
					} else if(secondaryFixture.getBody().getUserData() instanceof PhysicsEntity){
						PhysicsEntity entityB = (PhysicsEntity) secondaryFixture.getBody().getUserData();
						contact.setEnabled(contact.isEnabled() && entityA.collidedWithEntity(entityB, secondaryCategory, contact));
					}
				}

			} else {
				//Only fixtureA has userdata
				if(mainFixture.getBody().getUserData() instanceof PhysicsEntity){
					PhysicsEntity entityA = (PhysicsEntity) mainFixture.getBody().getUserData();
					contact.setEnabled(contact.isEnabled() && entityA.collidedWithNoUserData(secondaryCategory, contact));
				} else if(mainFixture.getBody().getUserData() instanceof Character){
					Character characterA = (Character) mainFixture.getBody().getUserData();
					contact.setEnabled(contact.isEnabled() && characterA.collidedWithNoUserData(secondaryCategory, contact));
				}
			}
		}


	}