Simulation Of Virtual Scene Of Rain And Pond Based On The Particle System

Natural phenomena simulation is one hot research direction of computer simulation field, and it includes waves, rain, snow, fire and so on. It has been widely used in lots of fields, such as games, movie special effects, virtual reality and many other industries. However, as its mock objects are always vague irregular objects, the traditional methods are not applicable for it. Thus, people have to develop new methods for modeling them. The particle system is an effective method in simulating fuzzy irregular object. Use particle system, we can not only get good effect but also keep the real-time capability.This article is based on particle systems, and it uses OpenGL and VS2010to simulate pond rain scene which is one of natural phenomena. The simulation work has the following three parts:Firstly, as this paper’s key object is to simulate rain scene pond, the realization of raining scene is the primary work. From the view of application, the particle system can be divided into three categories:the direction of particle systems, structured particle systems and random particle system. The particle system needs to consider the interaction effect between particles, and it is used to simulate objects and rigid body which can be deformed or the like as usual; the structured particle system is typically used to simulate an object with a fixed structure, such as clouds, trees, grass and so on; the stochastic particle system changes the properties of the particles through a random process, and it’s mostly used to simulate smoke, fire, explosions and other scenes. Given the simulation of rain phenomenon in this article does not need to consider the interaction between the particles, and raindrop has no fixed structure, thus a random particle system is used to simulate rainfall.Secondly, when raindrop falls into the pond, it produces some circle concentric ripples in the local surface shape around the impact point. The reason is that a vibration source is produced as raindrops hit the surface, thus the height of the water surface nearby will be fluctuated, and the magnitude of the fluctuations is called amplitude. In order to simulate the generation and diffusion effect of the water ripples, we added two ripple parameters in the properties of the raindrops:amplitude and radii, which represent the amplitude and the range of the initial vibration source which are produced when the raindrops hit water surface. After generating the vibration source, we perform some relative algorithms to diffuse the vibration source to achieve the effect of ripple.Finally, when it rains, the raindrops are often affected by the wind, and the rain will change. In order to make the simulation effect closer to the real world, we also joined the wind and the rain variable wind in the designation. The values of these variables are manipulated by the user. The former changes the displacement in the horizontal direction to achieve the effect of wind and rain, and the raindrops will be presented in inclined rain line according to the value of the wind line. The rain variable controls the interval between each raindrop. The larger its value is, the longer the interval is, and the smaller the corresponding rain is; the smaller its value is, the shorter the interval is, and the greater the rain is.