void steerParticleUsingMouse(int dx, int dy) {
		UserField uf = null;
		int n = getModel().getNumberOfParticles();
		for (int i = 0; i < n; i++) {
			uf = getModel().getParticle(i).getUserField();
			if (uf != null) {
				double r = 1.0 / Math.hypot(dx, dy);
				uf.setAngle(dx * r, dy * r);
				switch (uf.getMode()) {
				case UserField.FORCE_MODE:
					uf.setIntensity(UserField.INCREMENT * uf.getGear());
					break;
				case UserField.IMPULSE1_MODE:
					uf.increaseGear(0.1f);
					break;
				}
			}
		}
	}