Libgdx - Orthographic Camera Pan & Zoom Input processor

PanZoomCameraInput.java

public class PanZoomCameraInput extends InputAdapter {
	OrthographicCamera cam;
	Vector3 lastTouch, tmp;
	
	public PanZoomCameraInput(OrthographicCamera cam){
		this.cam = cam;
		lastTouch = new Vector3();
		tmp = new Vector3();
	}
	
	@Override
	public boolean touchDown(int screenX, int screenY, int pointer, int button) {
		lastTouch.set(screenX, screenY, 0);
	
		return false;
	}
	
	@Override
	public boolean touchDragged(int screenX, int screenY, int pointer) {
		tmp.set(screenX, screenY, 0).sub(lastTouch).scl(-1, 1, 0).scl(cam.zoom);
		cam.translate(tmp);
		lastTouch.set(screenX, screenY, 0);
				
		return false;
	}
	
	@Override
	public boolean scrolled(int amount) {
		cam.zoom *= amount > 0 ? 1.05f : 0.95f;

		return false;
	}
	

		
}