基于分形几何的动态云模拟

云是一种重要的自然景观。对云彩的模拟在视景仿真系统、计算机游戏、三维动画中有着广泛的应用。该文针对目前一些云彩模拟方法中存在的实现复杂、计算耗时、图像分辨力不高且只能生成静态云等问题，提出了一种在分形几何的Diamond—Square算法中采用改良的随机数发生器和顶点扰动、纹理运动结合模拟实现动态云的方法。基本思想是通过运用二次随机法构造改良的随机数发生器，并把它应用到分形几何的Diamond—Square算法中生成逼真的静态云图，然后通过顶点扰动、纹理运动结合模拟实现动态云。最后运用VC＋＋和OpenGL开发工具实现了云的动态模拟。结果表明，该方法实现简单，可获得实时、逼真的动态云效果。

Simulation of Dynamic Cloud Based on Fractal Geometry

Cloud is an important natural phenomenon,which has been widely used in visual simulation system,computer game,3D animation,etc.At present,some cloud simulation methods are confronted with the phenomena such as huge calculation in implementation,time-consume,low resolution in image,and only static clouds produced.This paper presents a method for simulating dynamic cloud based on improved random creator,vertex shaking and texture moving in Diamond-Square algorithm in fractal geometry.The basic idea of the method is to construct an improved random creator based on creating random two times.By using the random creator in Diamond-Square algorithm,it creates vividly static cloud.Combining with vertex shaking and texture moving,it can create dynamic cloud.Moreover,making use of tools such as VC++ and OpenGL,it simulates dynamic cloud.The result of the simulation demonstrates that the method is simple in implementing and can create real-time,vivid dynamic cloud.