Realistic Scene Rendering Of Ocean Based On GPU In Marine Simulator

With the continuous updating of high performance computer,the great improvement of GPU programmability and the rapid development of the computer graphics technology,users have higher requirements on simulation function and it's virtual operating environment of marine simulator.To improve the real-time capability and realism of visual system,the dissertation mainly studies GPU technology,realistic rendering of ocean wave and 3D visualization of marine oil spill.The mainly contributions of this dissertation are:1.Developing 3D visual system for simulation system based on GPU has gradually become a focus in computer graphics.In the dissertation,the key technologies and high-level rendering languages of GPU are discussed,the advantages and features of GPU program are analyzed,and the applications of GPU in computer graphics are reviewed.2.To render ocean wave scientifically,rapidly and realistically is an important aspect in marine simulator.According to the actual demand of marine simulator,the spectrum method is studied aider analyzing the wave theory.A new realistic scene rendering algorithm of large-scale ocean wave is proposed based on GPU.To guarantee the real-time capability of rendering,a grid of concentric circles is proposed to represent ocean surface.The fast Fourier transform based on GPU is used to generate the height map of ocean surface,the height of grid vertex can be obtained through sampling the tiled height map with the technology of vertex texture fetch,and the ocean wave geometry is modeled with the grid form.Then the choppy wave is simulated,the repeating tile of ocean is not apparent,and the relative motion between ocean and ship is achieved.Moreover,the reflection and refraction of ocean surface are added and the spray is simulated. 3.On the basis of the realistic rendering algorithm of ocean wave,a method of 3D visualization of marine oil spill is proposed after analyzing the related theory and technology.Firstly,the early process of instantaneous oil spill is divided into two phases:oil spread,oil drift and dispersion,and the track of each stage is calculated using the respective mathematical model.Then the particle system is adopted to implement the oil particle model.Using the technique of planar refraction map,the track of oil spill is generated to a texture which is projected to ocean surface in fragment shader.4.The modeling and manageing of scene database will directly affect the rendering efficiency of scene.The tree structure and the rendering process of scene database are analyzed.A structure combining logic and space is developed to organize the database. Several key technologies are discussed to improve the rendering efficiency of scene, including the number and size of node,the LOD structure,the state change,etc. Furthermore,the scene graph of OSG is emphatically analyzed,and the scene of marine simulator is managed and displayed with the powerful functions of OSG.