基于Direct3D与粒子系统实现喷泉效果

【作者】 常志伟；

【导师】 谭同德；

【作者基本信息】 郑州大学 ， 计算机应用技术， 2007， 硕士

【摘要】 虚拟场景中，自然景物的模拟一直是计算机图形学领域中研究的内容。喷泉、瀑布、火焰、水流、雨、雪等具有不规则性、动态性和随机性，这些自然景物的模拟十分复杂困难，具有一定的挑战性。模拟自然景物的方法有两种：一种是基于物理建模技术的方法；另一种是采用粒子系统建模的方法。本论文采用后一种方法对喷泉的三维效果进行研究。喷泉效果可以大大增强虚拟现实系统的沉浸感，粒子系统是实现喷泉效果的有效方法。粒子系统是虚拟场景中研究的主要内容之一，一些研究人员利用粒子系统技术对模糊的、不规则的物体或景物进行了模拟，如对流云、闪电、雨、雪、树木、瀑布等景物。大多数研究者使用的绘图工具是OpenGL三维图形函数库，本文则是尝试以Direct3D三维图形函数库为绘图工具，对不规则的、“模糊”的自然景物进行模拟。主要从以下几个方面进行研究：●探讨Microsoft公司三维图形函数库Direct3D的技术与功能以及Direct3D的核心设备；运用Direct3D中的点精灵作为粒子图元，对粒子的属性能灵活的设置。●介绍粒子系统的基本原理，粒子系统的实现步骤，并运用粒子系统分析自然景物。●分析流体动力学及流体粘度，基于流体动力学中的流体粘度和牛顿粘性定律与粒子系统相结合，提出伪粒子粘度方法。由牛顿粘性定律得出粒子流体的内摩擦力，使多个粒子“粘”在一起形成不同大小的水珠粒子，以此模拟喷泉的真实效果。●利用粒子系统技术对喷泉体进行分析，运用流体动力学原理分析现实生活中喷泉水体的运动，应用粒子系统的建模方法，构建出喷泉粒子系统模型；对喷泉水珠粒子的产生、运动和消亡进行研究，并应用伪粒子粘度方法，在Direct3D开发平台下绘制出喷泉的效果。更多还原

【Abstract】 The simulation of nature sceneries in virtual scene is an important research branch in the field of computer graphics. The nature sceneries, such as fountain、waterfall、fire、water-stream、rain、and snow, possess anomalistic、dynamic and stochastic character. It is extremely challenging to simulate these nature sceneries, since it is quite complex and difficult to model these. There are two methods to simulate these: one is based on physics modeling; another is founded on particle system modeling. The thesis adopts the latter method to research fountain effect.The effect of fountain can boost up the immersion feeling of virtual reality system, and particle system is the impactful means to implement fountain effect. Particle system is one of the main research contents in virtual scene. Some researchers simulate fuzzy and anomalistic objects by the means of particle system. Since most of the researchers make use of 3-D graphics function lib—OpenGL as drawing tool, the thesis attempts to adopt 3-D graphics function lib—Direct3D as drawing tool to simulate these anomalistic> fuzzy nature objects. And the article begins the research from several aspects:The paper discusses the technique and function of 3-D graphics function lib—Direct3D of Microsoft and probes into core device of Direct3D. We apply the point-sprite of Direct3D as particle primitive and set up the attributes of particle neatly.The paper introduces the basic principle and the implementation steps. Then we analyze nature sceneries by use of particle system.The article analyzes the hydrokinetics principle and the viscosity of fluid body. Then we bring forward the method of fake-particle-viscosity, which is based on liquid viscosity of hydrokinetics and the combination of Newton Viscosity Law and particle system. The inner friction which is calculated by Newton Viscosity Law make several particle to conglutinate up of differently big and small water-beads, which can simulate the true effect of fountain. We analyze the fountain body by making use of the technique of particle system, then analyze the motion of true-life fountain by bringing to bear hydrokinetics principle. And we construct the model of fountain particle system by the means of particle system modeling, then do some research about the generation、the motion and the death of water-bead particle of the fountain. Finally, we implement the 3-D effect of fountain in the platform of Direct3D by adopting the method of fake-particle-viscosity and the modeling of fountain particle system.更多还原