Nghiên cứu kỹ thuật mô phỏng lửa bằng phương pháp Partical và ứng dụng

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

Hà Nội - 2010


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


Ngành : Công nghệ thông tin
Chuyên ngành : Hệ thống thông tin
Mã số : 60.48.05

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. 


  6
 7
 8
 11
 11
 11
 13
CHƢƠNG 2: MÔ PHỎNG LỬA BẰNG PHƢƠNG PHÁP PARTICLE 15
2.1. 















 15
 15
 16
 17
2.1.3.1 18
 19

 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. 




 49
 50
TÀI LIỆU THAM KHẢO 51












3
PHẦN MỞ ĐẦU

 

,   . Mô

 
 







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





 ,  
 
















 .
      
    



 , ph


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
















  








.






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

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

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










 .


Nghiên cƣ
́
u ky
̃
thuâ
̣
t mô pho
̉
ng lƣ
̉
a bă
̀
ng phƣơng pha
́
p Partical v ng
dng”.

4

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




 , 
















Patical, Patical system. C








Particle, Patical system 

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







 














 khi 







 , 

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




 
.








5
CHƢƠNG 1:
KHÁI QUÁT VỀ THỰC TẠI ẢO VÀ MÔ PHỎNG LỬA

 Tổng quan về thực tại ảo v hệ thống thực tại ảo
 Mô phỏng lửa v ý nghĩa
1.1. Tổng quan về thực tại ảo
1.1.1. Định nghĩa
VR- Virtual Reality - 
   



"virtual reality" - - 
 - California, m



 
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





video game.
    
 
 




         

 

 
uy nhiên VR
       
- 

7

nhà phát tr 

- - 
- Immersion- Imagination).
1.1.3. Một số loại hệ thống thực tại ảo


        


 


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

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

 m:
Các thiết bị đầu vào (Input devices): Chúng b

               
- 
-
-gloves).
Các thiết bị đầu ra (Output devices): 
 
-


Bộ giả lập thực tại (reality simulator)



cabin l
Ứng dng (application)


             
(si
phí) Open GL, Open Scene Graph?, Open SG?, C++, Java 3 D?, VRML, X 3

9
D?  World Tool Kit?, People Shop?,Ve
Ga?
 
         


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

10





      

         

Phần cứng của hệ thống thực tại ảo



- 
 Wo W?
IBM, Apple Macintosh
- 

       
nâng cao (Advanced VR - 

- 







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
 

 

 

. 


khai.
C




12



Hình 1: Cháy  Canifornia 2009

Hình 2: Cháy rừng  Nga năm 2010
N 



 nên
   Khi 


 




 











 : 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
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 Mô phỏng lửa bằng Particle

2.1. Cơ sơ
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




              


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. 
         


3.  


            


1.  thành






2. 


 

             

3.             



 





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

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

                


 

            

 
 


18



2.1.3.1. Sự khởi tạo ra các particle

 



1.              
 
f là:
N
f
= Mean
f
+ Rand()


Var
f

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


tích màn hình, Var
saf
ScreenArea là
 
     




Mean
f
= InitialMean

+ DeltaMean

(f – f
0
)
(3)
Hay:

19
Mean
saf
= InitialMean
sa
+ DeltaMean
sa


(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. 

              

           


kính r  tròn bán kính r 
h w



20
Hình. 1. Particle System 
 


             


InitialSpeed = MeanSpeed

+ Rand()

VarSpeed
(5)
 MeanSpeed

  VarSpeed 

       


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


InitialColor
G
= MeanColor
G
+ Rand()

VarColor
G



InitialColor
B
= MeanColor
B
+ Rand()

VarColor

B

(6)

màu RGB.



 

21


2.1.3.3. Chuyển động ca các particle
C







    



2.1.3.4. Render particle




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

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




sáng.

Hình 2-1: Kĩ thuật Anti-Aliased
2.1.3.5. Sự phân cấp ca Particle System
    
              

g


         


            
 
       

23
              
      
Particle Sy

2.1.3.6. Sự chết ca particle
             
             



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

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

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


Partical system, 
 NPartical  Partical system. Hình 2 minh
Partical system 
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