ĐẠI HỌC QUỐC GIA HÀ NỘI
TRƯỜNG ĐẠI HỌC CÔNG NGHỆ Vũ Đức Thông Nghiên cứu kỹ thuật mô phỏng lửa
bằng phương pháp Partical và ứng dụng

LUẬN VĂN THẠC SĨ



LUẬN VĂN THẠC SĨ
Người hướng dẫn khoa học: pgs. Ts. Đỗ Năng Toàn

Hà Nội - 2010 1
MỤC LỤC
PHẦN MỞ ĐẦU 3
CHƢƠNG 1: KHÁI QUÁT VỀ THỰC TẠI ẢO VÀ MÔ PHỎNG LỬA 5
 5
 5
1.1.2. 


 21
2.1.3.4. Render particle 21
 22
2.1.3 23
2.1.4. 





 23
icle System 30
 30
 32
 32

2
 33
 34
CHƢƠNG 3: CHƢƠNG TRÌNH THỬ NGHIỆM 36
 36
 45
3.2.1. VRML 45
3.2.2. Billboard 47
PHẦN KẾT LUẬN 49
 49
2. 








mô p










 .
            

  


      . Do
t
 

  














        ,   
  

 


     , 



, 


 


































, 








 . 





























CHƢƠNG 1: KHÁI QUÁT VỀ THỰC TẠI ẢO VÀ MÔ PHỎNG LỬA
         .
 
 



 , 







 

CHƢƠNG 2: MÔ PHỎNG LỬA BẰNG KỸ THUẬT PARTICLE










           




ch 


pháp Particle System.
CHƢƠNG 3: CHƢƠNG TRÌNH THỬ NGHIỆM










 trình bày  


           Particle
system

nên 


 , 


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























 


 , 

 
sau:
VR- Thực Tế Ảo là một hệ thống giao diện cấp cao giữa Người sử dụng và
Máy tính. Hệ thống này mô phỏng các sự vật và hiện tượng theo thời gian thực
có tương tác với người sử dụng qua tổng hợp các kênh cảm giác. Đó là ngũ giác
gồm: thị giác, thính giác, xúc giác, khứu giác, vị giác.[4](approve sites)


thính giác hay các giác qu


 

6
  






1.1.2. Đặc điểm ca một hệ thống thực tại ảo :
 




-time interacti



  


           
Kr


  
-


tro



8



 



1.1.4. Các thnh phần ca một hệ thống thực tại ảo


HW (phần cứng)





ng.
 Không gian trong thế giới ảo (World Space)
             

    

    -các-    

       -các-       

 Cơ sở dữ liệu cho thế giới ảo (World Database)
 
trong vi






            
         






11

 



 SIMNET là


1.1.5. Một số ng dng chính ca VR


- - 
(approve sites)









1.2. Mô phỏng lửa v ý nghĩa
1.2.1. Tầm quan trọng ca lửa v mô phỏng lửa
 

 

 











 : trong h và game
vi tính.  
 





 , trong

13

 

 
1.2.2. Tổng quát về mô phỏng lửa






     


g tin
5]

14


DAS (Dynamic Animations Syste      
            


dùng [6


7].

Hình 3:Wildland Fire Simulation

15

Hình 4: Fire Dynamics Simulator
CHƢƠNG 2:
MÔ PHỎNG LỬA BẰNG PHƢƠNG PHÁP PARTICLE

 Cơ sơ
̉
ly

thuâ
̣
t mô pho
̉
ng lƣ
̉
a





              


2.1.1. Định nghĩa Particle System

Một Particle System là một tập hợp các thành phần hay các hạt (particle)
riêng biệt. Particle System điều khiển tập particle đó, cho phép chúng hoạt
động một cách tự động nhưng với một số thuộc tính chung nhất định. [8]

16
2.1.2. Đặc tính ca Particle System
          

1. 
 

2. 
         


 .  
   

17
 1962, Asteroids  

 

Cosmos, 

       


2.1.3 Mô hình mô phỏng bằng phƣơng pháp Partical
       




1. 
2. 
3. 

4.              

5.              
khung hình (frame buffer).



Var
f

(1)
Rand() 
 -1, 1]; Mean
f
       Var
f
là

2. 




N
f
= (Mean
saf
+ Rand()

Var
saf
)

ScreenArea
(2)
Mean
saf


(f – f
0
)
(4)
f , f
0
InitialMean 
DeltaMean 
 DeltaMean và DeltaMean
sa
là

     

Particle System.

nh rõ f
0

2.1.3.2. Các thuộc tính ca particle


1. 
2. g)
3. 
4. 
5. 
6. 
7. 

   

InitialColor
R
= MeanColor
R
+ Rand()

VarColor
RInitialColor
G
= MeanColor
G
+ Rand()

VarColor
G
InitialColor
B
= MeanColor
B
+ Rand()

VarColor


           
particle khá (

               






            
ình


     

22




                

         











2.1.4. Sƣ
̉
du
̣
ng Partical system cho vu
̣
cháy nổ
 r Trek II: The Wrath of Khan [9

  
      

  





   



B
hành tinh: 
