We present efficient algorithms for real-time rendering of ocean using the newest features of programmable graphics processors (GPU). It differs from previous works in three aspects: adaptive GPU-based ocean surface tessellation, sophisticated optical effects for shallow water, and spray dynamics for oscillating waves. Our tessellation scheme not only offers easier level-of-detail (LOD) control but also avoids the loading of vertex attributes from CPU to GPU at each frame. The object-space wave sampling approach allows us to produce sophisticated optical effects for shallow water and implement a state-preserving particle system for simulating spray motions interactively.