Research Of Multi-scale Water Body Real-time Simulation Method

Simulation of water is widely used in various fields of human productive activity and life,and gradually becomes an important research subject in the fields of virtual reality,computer graphics,scientific visualization,and computer game.Scholars have been working hard to find realistic and credible modeling and rendering method with low computational cost.This thesis focuses on the reality,real-time and interactivity of multi-scale water body simulation methods.Starting from the principles of various real-time simulation methods,the thesis aims to analyze and solve the problems and difficulties of the existed method to achieve water body modeling and lighting effects on the microscopic mechanism.The proposed methods are willing to make a balance of efficiency,effectiveness and controllability of multi-scale water body simulation methods by means of theoretical derivation,model analysis,algorithm optimization and experimental verification.Firstly,a control scheme based on virtual-particle is proposed to overcome the manipulating difficulties of the mass spring model for small-scale water surface simulation.The accuracy of collision determination is increased by improving existing collision detection algorithms.Momentum distribution algorithm of the collision is optimized to ensure momentum conservation in the process.Various optical phenomena of light and water interaction are accurately demonstrated through the improvement of the lighting model based on the optical laws.The concept of virtual particle set is further introduced and the surface structure of water body is flexibly manipulated,so as to realize the surface model meeting the user's requirement that control simulation result conveniently and quickly.Secondly,a unified particle model is proposed for making up the weakness of the traditional SPH surface and foam simulation method for middle-scale or small-scale water.Weber number is introduced as the criteria for particle states switching between water and foam.An improved algorithm for surface tension based on molecular cohesion is constructed to derive a formula for surface tension under different conditions of curvature.Computational overhead is effectively reduced through a simplified model for simulation scenarios combining Snell's Law.Thirdly,a dynamic threshold method is proposed to truly reproduce the details of the large-scale water surface.The repetitive artifacts caused by the stitching method are suppressed by establishing a dynamic threshold criterion based on global coordinates.A reasonable expression formula of the threshold modulation function is given by analyzing the characteristics of the existing water real-time simulation method.A transparency correction algorithm of inverse modulation function is introduced to deal with the problem of transparency reduction and obvious splicing boundary caused by dynamic threshold criterion.Dynamic threshold criterion is fine-tuned by Perlin noise to solute the problem that the simulation effect is too smooth.The real-time simulation and control of water body is ensured by designing a GPU implementation.Furthermore,a real-time rendering method based on natural images is proposed to overcome the difficulty of color simulation and effect manipulation in real-time simulation of water body scene.An improved color transfer algorithm based on detail retention is selected by evaluating existing color transfer algorithms and analyzing the computational characteristics of water simulation.A calculation distribute and data exchange scheme is proposed by designing a GPU-based optimization method,in combination with the characteristics of the color transfer algorithm.The simulation results are efficiently matched with the referenced natural image colors,which improves the real-time color control of water body scenes simulation intuitively and simplely.Finally,a variety of verification,optimization and evaluation experiments are designed and implemented.The results show that the realistic,real-time and interactive simulations of multi-scale water body have been effectively improved.The corresponding research results have been successfully applied to relevant national-level projects and military projects.