function p = palka_pohybP(yp,x,y,vx,vy)
% p muze nabyvat hodnot -1 - pohyb dolu, 1 - pohyb nahoru, 0 - stuj
p = 0;
if(vx > 0)
    ypom = y - vy/vx*(x-1);
    n = floor(ypom);
    ypom = mod(ypom,1);
    if(mod(n,2) ~= 0)
        ypom = 1 - ypom;
    end
    if(abs(ypom-yp) > 0.01)
        p = ypom-yp;
    end
else
    if(abs(0.5-yp) > 0.02)
        p = 0.5-yp;
    end
end