近岛海洋场景海水色彩真实感实时绘制

Real-time Rendering of Realistic Ocean Color Around the Islands

海洋场景仿真一直是计算机虚拟现实研究中一大热点.为更为逼真地表现近岛海洋海水的色彩细节,首先,针对当前大多数海洋模型计算复杂的问题,采用水面网格模型加法线贴图构建大规模海洋表面,由于计算全部由GPU完成,实时性得到大大提高;然后,借助于U3D地形组件,构建了多种岛屿高程地形,通过修正海面的菲涅耳系数,成功地解决了海面与岛屿的边界问题,绘制出逼真的近岛海洋场景;其次,引入海水深浅颜色临界值,以海面和海底的高度变化为控制因子,构建海水颜色变化函数,表现岛屿周围海水丰富的色彩变化;之后,将光强、光源颜色和位置的变化引入海水颜色的计算中,实现一天内不同时刻海水色彩变化;最后,优化菲涅耳反射系数求解方法,依据真实水面反射定理,将反射图和折射图渲染到纹理中,实现真实海水所具有的水面反射与折射效果.

Simulation of Ocean scenes has always been a hot spot in virtual reality.To achieve more realistic ocean color details around the islands,firstly,against the complex computations of most current ocean models,we constructed the large-scale ocean surface by using the surface grid model and the normal map.All the computations were completed in GPU,so the real-time performance was greatly improved.With the help of U3 D terrain component,we built several elevation terrains of the islands.We successfully resolved the obvious borders between the islands and the ocean via correcting the Fresnel coefficient of the ocean,and we got a more realistic ocean scene around the islands.Secondly,to express the rich color performance of the ocean around the island,we introduced a critical depthcolor value of the ocean,and used the depth between the ocean surface and the bottom as a control factor to construct an ocean color changing function.Then we introduced the variations of the light intensity,light color and light position to the calculation of the ocean color,and realized the various colors at different time in a day.Finally,we optimized the method through solving the Fresnel reflection coefficient,and rendered the reflectance map and refraction map to textures based on the true reflection theorem to realize the reflection and refraction effects of the real ocean.