粒子系统在视景仿真中的研究和应用
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摘要
在虚拟仿真场景中,喷泉、火焰、水流、雨、雪等景物具有不规则几何状态、动态性和随机性,这些特殊景观的模型比较复杂,实时播放中的运算量较大。为了保证视景仿真的实时性,对特殊景观的建模一直是视景仿真领域和计算机图形学领域中研究的热点。
粒子系统是实现动态不规则景物模糊效果的有效方法,它使用大量粒子的聚集灵活地构成特效景物,用简单的粒子图元构造出传统计算机图形学难以构造的复杂模糊物体,具有很强的真实感,能够很好地体现景物的动态性和沉浸感。粒子系统是虚拟现实技术中的主要研究内容之一。
鉴于粒子系统建模的灵活性和有效性,本文研究了粒子系统的基本原理及应用,探讨了粒子系统的建模方法以及适用于自然景物动态模拟的粒子属性的通用描述公式,并选取自然景物中的特效景观作为动态模糊物体代表,以OpenGL三维图形函数库作为绘图工具,在VC++的开发环境下对不规则的、模糊的、动态的自然景观进行了模拟,最后利用Vega的回调函数及融合技术,将OpenGL编程实现的特殊景观移植到虚拟现实的Vega环境中,实现了一个基于粒子系统的虚拟自然景观实例。
本文的创新点在于结合牛顿重力学的基本理论,对特效景物提出了简化的粒子系统力学模型,旨在降低粒子系统的计算量,保证特效景物在视景仿真中的实时性能。
视景仿真的实验结果表明,本文建立的粒子系统算法具有较强的有效性和实时性,采用粒子系统算法对特效景观建模,具有灵活性和高效率,其自然景观的模型在虚拟仿真环境下展现了实时逼真的三维效果。
In the virtual simulation scene, the natural sceneries such as fountain, fire, water-stream, rain and snow have anomalistic, dynamic and stochastic features. The special landscape model is more complicated, and needs a large number of computing in real-time player. In order to ensure the real-time characteristic of visual simulation, modeling of special landscape has been a hotspot in the field of visual simulation and computer graphics research.
Particle system is an effective method for representing fuzzy effect of dynamic and anomalistic objects of nature. It gathers a large number of particles to affect a scene flexibly. It structures the complex fuzzy objects which are difficult to construct in traditional computer graphics by simple particle elements. It can also reflect the dynamics and immersion of the sceneries with highly reality. Particle system is one of the main research content in the virtual technology of reality.
In view of the particle system modeling flexibility and effectiveness, the paper studies the basic theories and applications of the particle system,and discusses method of modeling and the common formula of the particle attributes which go for the scene dynamic simulation. Then, the paper chooses the special landscape to simulate the anomalistic, fuzzy and dynamic characteristic under VC++ by the OpenGL function. Finally, the paper transplants the special landscape which realizes by the OpenGL to the virtual reality by the callback function and fusion of Vega. It realizes an example of virtual landscape based on particle system.
In the paper, a new idea is using Newtonian to simplify particle model. It guarantees the real-time characteristics of the special sceneries of better effect during the virtual simulation.
The experimental result of visual simulation shows that the particle system algorithm is more effective, and modeling special landscape produced by the particle system algorithm is more flexible and efficient. The model of the special sceneries of better effect can produce the vivid effect of three-dimensions in virtual simulation.
粒子系统是实现动态不规则景物模糊效果的有效方法,它使用大量粒子的聚集灵活地构成特效景物,用简单的粒子图元构造出传统计算机图形学难以构造的复杂模糊物体,具有很强的真实感,能够很好地体现景物的动态性和沉浸感。粒子系统是虚拟现实技术中的主要研究内容之一。
鉴于粒子系统建模的灵活性和有效性,本文研究了粒子系统的基本原理及应用,探讨了粒子系统的建模方法以及适用于自然景物动态模拟的粒子属性的通用描述公式,并选取自然景物中的特效景观作为动态模糊物体代表,以OpenGL三维图形函数库作为绘图工具,在VC++的开发环境下对不规则的、模糊的、动态的自然景观进行了模拟,最后利用Vega的回调函数及融合技术,将OpenGL编程实现的特殊景观移植到虚拟现实的Vega环境中,实现了一个基于粒子系统的虚拟自然景观实例。
本文的创新点在于结合牛顿重力学的基本理论,对特效景物提出了简化的粒子系统力学模型,旨在降低粒子系统的计算量,保证特效景物在视景仿真中的实时性能。
视景仿真的实验结果表明,本文建立的粒子系统算法具有较强的有效性和实时性,采用粒子系统算法对特效景观建模,具有灵活性和高效率,其自然景观的模型在虚拟仿真环境下展现了实时逼真的三维效果。
In the virtual simulation scene, the natural sceneries such as fountain, fire, water-stream, rain and snow have anomalistic, dynamic and stochastic features. The special landscape model is more complicated, and needs a large number of computing in real-time player. In order to ensure the real-time characteristic of visual simulation, modeling of special landscape has been a hotspot in the field of visual simulation and computer graphics research.
Particle system is an effective method for representing fuzzy effect of dynamic and anomalistic objects of nature. It gathers a large number of particles to affect a scene flexibly. It structures the complex fuzzy objects which are difficult to construct in traditional computer graphics by simple particle elements. It can also reflect the dynamics and immersion of the sceneries with highly reality. Particle system is one of the main research content in the virtual technology of reality.
In view of the particle system modeling flexibility and effectiveness, the paper studies the basic theories and applications of the particle system,and discusses method of modeling and the common formula of the particle attributes which go for the scene dynamic simulation. Then, the paper chooses the special landscape to simulate the anomalistic, fuzzy and dynamic characteristic under VC++ by the OpenGL function. Finally, the paper transplants the special landscape which realizes by the OpenGL to the virtual reality by the callback function and fusion of Vega. It realizes an example of virtual landscape based on particle system.
In the paper, a new idea is using Newtonian to simplify particle model. It guarantees the real-time characteristics of the special sceneries of better effect during the virtual simulation.
The experimental result of visual simulation shows that the particle system algorithm is more effective, and modeling special landscape produced by the particle system algorithm is more flexible and efficient. The model of the special sceneries of better effect can produce the vivid effect of three-dimensions in virtual simulation.
引文
[1] Joshua Schpok, Joseph Simons, David S.Ebert, and Charles Hansen.A Real-Time Cloud Modeling, Rendering, and Animation System[J]. Eurographics/SIGGRAPH Symposium on Computer Animation(2003)
[2]张芹等.火焰、烟、云等不规则物体的建模方法研究综述[J].中国图象图形学报,2000,5(3):186-190
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[4] William T.Reeves. Particle system-a technique for modeling a class of fuzzy objects[C]. Proceedings of the 10th annual conference on Computer graphics and interactive techniques. 1983:359-375
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[6]王静秋,基于粒子系统的动态自然景物模拟的研究[D].南京航空航天大学硕士学位论文,1999,6
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[10] Alex Pang. Sprany rendering. IEEE Computer Graphics and Application,Sept.1994,57-63
[11]谢剑斌,郝建新,蔡宣平,孙茂印.基于粒子系统的雨点和雪花降落模拟生成[J].中国图象图形学报.1999.9
[12] Reeves W T, Blau R. Approximate and Probabilistic Algorithms for Shading and Rending Structured Particle System [A]. Proceedings ofSIGGRAPH85[C],Computer Graphics, 1985,19(3):313-322
[13] Olaf EtzmuB,Bernhard Eberhardt,Michael Hauth. Collision Adaptive Particle System[J].2000 IEEE:338-347
[14]郑晓.虚拟自然环境的研究方法[J].武汉工业学院学报,2002,1:67-70
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[16] Breen D E, House D H, Getto P H. A Physically-based Particle Model of Woven Cloth[J]. The Visual Computer, 1992, 8(5):264-277
[17] Matthias Unbescheiden Andrzej Trembilski.Cloud Simulation in Viriual Environments[A].IEEE Visualization Proeeedings[C],1995,95-104
[18]彭群生,管宇.基于粒子系统的实时瀑布模拟[J].系统仿真学报,2004,11:2471-2474
[19] Geofferey Y.Gardner. Visual Simulation of Clouds. Proceedings of the 12th annual conference on Computer graphics and interactive techniques. 1985:297-304
[20]张从辉,万华根等.基于物理模型的音乐喷泉实时仿真[J].第五届全国虚拟现实与可视化技术及应用学术会议.2005,9
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[23] Olaf Etzmuss, Joachim Gross, Wolfgang Strasser. Deriving a Particle System from Continuum Mechanics for the Animation of Deformable Objects[J]. IEEE Transactions on Visualization and Computer Graphics. Vol 9, No 4,oct-dec 2003:538-550
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[32]赵春霞,张艳,战守义.基于粒子系统方法的三维火焰模拟[J].计算机工程与应用.2004,28:73-75
[33]胡新荣,李德广.三维动态地形中瀑布的设计与实现[J].2004,13(1):38-42
[34]王润杰,田景全,倪政国.基于粒子系统的实时雨雪模拟[J].系统仿真学报,2003,15(4):495-496,501
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[37]罗维佳,都金康,谢顺平.基于粒子系统的三维场地降雨实时模拟[J].中国图象图形学报,2004,9(4):496-500
[38]林夕伟,于海辉.基于粒子系统和纹理绘制的火焰合成[J].计算机应用.2004,24(40):77-79
[39]陈利平,王国才.基于粒子系统的蜡烛火焰实时模拟[J].计算机技术与发展,2006,16(5):186-188
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[2]张芹等.火焰、烟、云等不规则物体的建模方法研究综述[J].中国图象图形学报,2000,5(3):186-190
[3] Frank Losasso, Frederic Gibou, Ron Frekiw. Simulating Water and Smoke with an Octree Data Structure[C]. Proceedings of the 2004 SIGGRAPH Conference,457-462
[4] William T.Reeves. Particle system-a technique for modeling a class of fuzzy objects[C]. Proceedings of the 10th annual conference on Computer graphics and interactive techniques. 1983:359-375
[5]王乘,周均清,李利军.Creator可视化仿真建模技术[M].武汉:华中科技大学出版社,2005,03
[6]王静秋,基于粒子系统的动态自然景物模拟的研究[D].南京航空航天大学硕士学位论文,1999,6
[7]王乘,李利军,周均清.Vega实时三维视景仿真技术[M].武汉:华中科技大学出版社,2005,12
[8]和平鸽工作室.OpenGL三维图形系统开发与实用技术[M].重庆:重庆大学出版社,2003,8
[9] OpenGL体系结构审核委员会,Dave Shreiner,Mason Woo, Jaskie Neider, Tom Davis著.邓郑祥译.OpenGL编程指南[M].第四版,人民邮电出版社,2005
[10] Alex Pang. Sprany rendering. IEEE Computer Graphics and Application,Sept.1994,57-63
[11]谢剑斌,郝建新,蔡宣平,孙茂印.基于粒子系统的雨点和雪花降落模拟生成[J].中国图象图形学报.1999.9
[12] Reeves W T, Blau R. Approximate and Probabilistic Algorithms for Shading and Rending Structured Particle System [A]. Proceedings ofSIGGRAPH85[C],Computer Graphics, 1985,19(3):313-322
[13] Olaf EtzmuB,Bernhard Eberhardt,Michael Hauth. Collision Adaptive Particle System[J].2000 IEEE:338-347
[14]郑晓.虚拟自然环境的研究方法[J].武汉工业学院学报,2002,1:67-70
[15] http://kevinm.blogdriver.com/kevinm/809945.html
[16] Breen D E, House D H, Getto P H. A Physically-based Particle Model of Woven Cloth[J]. The Visual Computer, 1992, 8(5):264-277
[17] Matthias Unbescheiden Andrzej Trembilski.Cloud Simulation in Viriual Environments[A].IEEE Visualization Proeeedings[C],1995,95-104
[18]彭群生,管宇.基于粒子系统的实时瀑布模拟[J].系统仿真学报,2004,11:2471-2474
[19] Geofferey Y.Gardner. Visual Simulation of Clouds. Proceedings of the 12th annual conference on Computer graphics and interactive techniques. 1985:297-304
[20]张从辉,万华根等.基于物理模型的音乐喷泉实时仿真[J].第五届全国虚拟现实与可视化技术及应用学术会议.2005,9
[21] http://www.diybl.com/course/2_picdesign/3DSMax/2007625/69099_13.html
[22]胡泊,吴慧中.虚拟场景中自然景物的真实感与实时性的研究[J].系统工程与电子技术.Vo1. 21第7期,1999
[23] Olaf Etzmuss, Joachim Gross, Wolfgang Strasser. Deriving a Particle System from Continuum Mechanics for the Animation of Deformable Objects[J]. IEEE Transactions on Visualization and Computer Graphics. Vol 9, No 4,oct-dec 2003:538-550
[24] http://www.enet.com.cn/article/2004/0713/A20040713324227.shtml
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[26] http://bbs.vrchina.net/viewthread.php?tid=677&extra=page%3D4
[27] http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=19
[28]刘耀周,张锡恩.基于粒子系统的导弹飞行航迹急烟雾的特效生成[J].计算机工程,2004,30(1):174-176
[29]万华根,彭群生.基于物理模型的实时喷泉水流运动模拟[J].计算机学报,1998,9(21):774-779
[30]王静秋,钱志峰.基于粒子系统的焰火模拟研究[J].南京航空航天大学学报,2001,33(2):166-170
[31]王治刚,陈和平,刘心雄.基于粒子系统和纹理映射的火焰模拟[J].工程图学学报.2002,(4):49-53
[32]赵春霞,张艳,战守义.基于粒子系统方法的三维火焰模拟[J].计算机工程与应用.2004,28:73-75
[33]胡新荣,李德广.三维动态地形中瀑布的设计与实现[J].2004,13(1):38-42
[34]王润杰,田景全,倪政国.基于粒子系统的实时雨雪模拟[J].系统仿真学报,2003,15(4):495-496,501
[35] http://www.bitscn.com/school/3DMax/base/200609/63743.html
[36]郭兆荣,李箐,王彦.Visual C++ OpenGL应用程序开发[M].北京:人民邮电出版社,2006,6
[37]罗维佳,都金康,谢顺平.基于粒子系统的三维场地降雨实时模拟[J].中国图象图形学报,2004,9(4):496-500
[38]林夕伟,于海辉.基于粒子系统和纹理绘制的火焰合成[J].计算机应用.2004,24(40):77-79
[39]陈利平,王国才.基于粒子系统的蜡烛火焰实时模拟[J].计算机技术与发展,2006,16(5):186-188
[40] http://bbs.vrchina.net/index.php
[41] Visual C++ 6.0 MFC类库参考手册[M].北京:人民邮电出版社,2002,11
[42]徐利明,姜星明.基于粒子系统与OpenGL的实时雨雪模拟[J].计算机仿真,2005,7(22):242-245
[43] http://bbs.vrchina.net/viewthread.php?tid=3881&extra=page%3D1