Fast simulation of lightning for 3d games




Скачать 124.06 Kb.
НазваниеFast simulation of lightning for 3d games
страница1/9
Дата24.09.2012
Размер124.06 Kb.
ТипДокументы
  1   2   3   4   5   6   7   8   9


FAST SIMULATION OF LIGHTNING FOR 3D GAMES


by

Jeremy L. Bryan

B.S, University of Colorado at Colorado Springs, 1997


A thesis submitted to the Graduate Faculty of the

University of Colorado at Colorado Springs

in partial fulfillment of the

requirements for the degree of

Master of Science

Department of Computer Science

2005


This thesis for the Master of Science degree by


Jeremy L. Bryan


has been approved for the


Department of Computer Science


by


____________________________________

Sudhanshu K. Semwal, Chair


____________________________________

C. H. Edward Chow


____________________________________

Tim Chamillard


__________

Date


Bryan, Jeremy L. (M.S., Computer Science)

Fast Simulation of Lightning for 3D Games

Thesis directed by Professor Sudhanshu K. Semwal


Simulating a lightning stroke in computer graphics involves developing a model for the main stroke, and then recursively generating similar models for any branches that may occur. A number of methods have been developed in this field, but most of the research has concentrated on rendering algorithms. This thesis generates volumetric data for a three dimensional lightning stroke through the usage of cellular automata. The goal was to develop a method where realistic lightning strokes could be generated and displayed in real-time. An algorithm, the complex lightning generation model has been designed and implemented in C++. The algorithm uses an automaton with simple rules based on random numbers and probability. Results are presented that compare our results to those created by other researchers in this area.


CONTENTS

INTRODUCTION 1

PREVIOUS WORK 5

MODELING 5

RENDERING 7

CELLULAR AUTOMATA 9

APPLICATIONS 10

CURRENT RESEARCH 10

DESIGN 13

CELLULAR AUTOMATA CHARACTERISTICS 14

COMPLEX LIGHTNING ALGORITHM 14

PSEUDOCODE 17

BENEFITS 19

DISADVANTAGES 19

COMPLEX BRANCH GENERATION 20

PSEUDOCODE 21

IMPLEMENTATION 22

INTRODUCTION 22

TECHNOLOGIES INVESTIGATED 22

SUPPORTING PACKAGES 24

INITIAL PROTOTYPE 25

CLASS STRUCTURES 25

THE LIGHTNING 26

THE CAMERA 27

THE CAR 28

THE TARGET 30

THE EXPLOSION 31

RESULTS 33

SURVEY RESULTS 33

OBSERVATIONS 35

FUTURE WORK 36

INTRODUCTION 36

EFFICIENCY 36

LIGHTING SUPPORT 36

BRANCH MODELING 37

CONCLUSION 39

BIBLIOGRAPHY 41


CHAPTER I

INTRODUCTION



Computer Graphics has experienced a phenomenal growth trend in recent years. It has been used extensively in the advertising, gaming, and motion picture industries, to name just a few. The quality of computer generated images has progressed to the point where synthetic actors and/or objects are practically indistinguishable from their real-world counterparts. With the introduction of dedicated hardware for graphics processing on personal computers, the push to expand the rendered universe has accelerated at an astonishing pace. This thesis focuses on helping to expand our digital world.


Creating realistic models of physical phenomenon has been the topic of many research papers in recent years. Computer scientists have developed algorithms to display plants, mountains, fluids, clouds, and many other naturally occurring subjects. Lightning, nature’s most spectacular display, has proved to be somewhat elusive to capture realistically. Relative to other natural phenomenon, the research in this particular area is fairly sparse.


Generating a lightning model in three-dimensional space could affect a number of applications. Real-time lightning generation could be expanded into the computer gaming industry to enhance future games and effects. In addition, the ability to direct the lightning stroke to any given point could prove beneficial to the visual arts industry. Motion picture film directors could designate some target in a frame of film and our method could be used to create a realistic stroke that would always hit the given target.


The generation of lightning in the real world is a complicated, multi-step process. A lightning stoke cannot happen without the presence of a strong electrical field. This electrical field begins to accelerate free ions in the atmosphere to a very high velocity. These ions create a “stepped leader” which propagates from the cloud towards ground-zero in discrete steps. As the stepped leader approaches the ground, it attracts an “upward positive leader.” As these two electrical occurrences draw closer to one another, the “attachment process” begins. The meeting of the upward and downward leaders triggers the “return stroke” which initiates the lightning flash we see and the thunder we hear. The entire flash lasts about .5 seconds and carries approximately 10,000 amps of current. Once the initial return stroke has been established, there can be as many as four or five subsequent strokes along the main channel. This is where lightning gets its flickering effect. [Reed1994]


Much of the research done in lightning graphics has concentrated on ray-tracing a three-dimensional model in order to produce a two dimensional image. The benefit to creating our three-dimensional model in real-time is being able to move the camera around interactively. This allows the user to view the stroke from any angle and/or direction. The ability to change the view in real-time provides a much clearer understanding of the actual shape and direction of the model. Our final product may not look as polished as some of the previous researcher’s results because they rendered a 2D image using ray-tracing while we will just be displaying the raw model. Until algorithms and/or hardware reach a point where ray-tracing can be done in real-time, our results will not be as aesthetically pleasing due to the difference in rendering.


Our approach uses the concept of cellular automata in order to propagate the lightning strokes through the atmosphere. Cellular automata are dynamic systems where volumes are created using cells that contain values that change based on pre-determined rules and the values of neighboring cells. Using this simple concept, complex global patterns can emerge and amazingly accurate representations are possible. We implement the cellular automata concept by creating a three dimensional lattice to represent the atmospheric space that we want the lightning to propagate through. New algorithms were developed in order to determine the path that the lightning will take. The rules that have to be written for each cell in the automata to perform this path selection are relatively simple and hence easy to update or replace. [Kaushal2004] No control points are needed to generate the stroke and branches.

The algorithm that was developed was implemented in C++ using the OpenGL library as the graphics engine. We wanted the project to have the feel of a 3D game, so we spent time during development on enhancing game-play. The results of our worked turned out very well and are presented in later chapters.

Chapter II goes into more detail on this field and reviews some of the current research. Chapter III describes the design of the propagation algorithm. Chapter IV explains design choices, implementation strategies, and software used. Chapter V presents the results of running the implemented software. Chapter VI suggests some ideas for future work that could enhance the realism of generated lightning models. Chapter VII is the summary of the thesis and conclusion.


CHAPTER II
  1   2   3   4   5   6   7   8   9

Похожие:

Fast simulation of lightning for 3d games iconThe design and use of simulation computer games in education

Fast simulation of lightning for 3d games iconFree team building games ideas, exercises and activities for employee motivation, training and development, children's games and party games

Fast simulation of lightning for 3d games iconТехнические характеристики и анализ производительности Industrial Ethernet
В июне 1995 Fast Ethernet стандарт ieee 802. 3u (100BaseT) был сформирован. Fast Ethernet предоставляет возможность пошагового внедрения...
Fast simulation of lightning for 3d games iconSpirits White as Lightning

Fast simulation of lightning for 3d games iconSpirits White as Lightning by Mercedes Lackey and Rosemary Edghill

Fast simulation of lightning for 3d games iconVolume in drive d is data
Перси Джексон и похититель молний [Percy Jackson & the Olympians The Lightning Thief] [2010]. avi
Fast simulation of lightning for 3d games icon"Healthy" fast food high in salt

Fast simulation of lightning for 3d games iconDiscussion of Ch 3 + some games

Fast simulation of lightning for 3d games iconFast sequence similarity computing with lcs on larpbs

Fast simulation of lightning for 3d games iconGames in the esl class Pg. 6

Разместите кнопку на своём сайте:
Библиотека


База данных защищена авторским правом ©lib.znate.ru 2014
обратиться к администрации
Библиотека
Главная страница