Research On The Real-time Rendering Algorithm Of Multi Scene Elements In Virtual Ocean

The simulation of ocean has always played important roles in virtual 3D games, films, the ocean exploration and other aspects. The present research mostly focused on the ocean surface modeling, or only one ocean optical effect, which has great limitations. There is no method which can realize the multi ocean scene elements in real time. To achieve more realistic simulation of multi ocean scene elements, we focused on the algorithm research of the following two aspects, the two-way interaction between the ocean and the objects and the overall optical effect of the ocean.Firstly, to the problem of the large area of the ocean, and to ensure the authenticity and the real-time requirements, we used a radioactive grid based on the LOD technology and a projective grid to model the ocean grid separately. Combining with the uniform directional spectrum for the long and short waves based on the ocean statistic model, we obtained the surface height field via fast Fourier transform, which realized the large-scale ocean scenes with multiple parameters adjusted and controlled in real time.Secondly, in the aspect of the two-way interaction between the ocean and the objects, especially the less real simulation of the action the ocean to the object, we proposed a finite volume element method to solve the force which the ocean acts on the object based on the physical dynamics of rigid body. The algorithm can correctly calculate the force to a variety of shapes of objects, including the concave polyhedron mesh. In the role of the object of the ocean, we introduced the particle system to simulate the effect of sprays caused by the object dropping into the water.Thirdly, in the interaction between the ocean and the light, we realized the surface reflection and refraction based on the method of rendering to texture, and introduced the Blinn-phong illumination model to achieve the high light reflection. At present, most of the simulation program can't rightly deal with the transition from the island to the ocean boundary, to obtain a soft transition effect between the two different medium, we optimized the Fresnel coefficients solving method, updated the Fresnel coefficients and added foams in the topographic boundary. For the three-dimensional scene effect of the ocean, we introduced the global fog to realize the fuzzy effect under the ocean. And we achieved the underwater caustics based on the caustics map.Finally, we designed and implemented the multi scene elements simulation system of the large-scale ocean using the Unity3 D game engine and the advanced shading language Cg, all the effects were obtained via the real-time calculation and rendering. Experimental results show that the proposed method can effectively simulate multi scene elements of the large-scale virtual ocean, which has a real effect and a high real-time performance.