12. Given the parabola $y^{2}=2 p x(p>0)$, with its focus at $F$, a line passing through $F$ with an inclination angle of $\theta$ intersects the parabola at points $A$ and $B$. The maximum area of $\triangle A B O$ is $\qquad$ (where $O$ is the origin).
12. When $\theta=90^{\circ}, S_{\triangle A O H}=\frac{p^{2}}{2}$. When the rate exists, we can get $S_{\triangle A M B}=\frac{p^{2}}{2 \sin \theta}$, so the maximum area is $\frac{p^{2}}{2}$.