这个程序是巧妙的利用了坐标的不断变化

1、;这个程序是巧妙的利用了坐标的不断变化，从而实现了由星星构成的箱子3D转动！;   Assembler Program By Vulture.                                    

2、60;         ;   3D-system example. Use the following formulas to rotate a point:           ;        Rotate around x-axis       

3、60;                                          ;        YT = Y

4、 * COS(xang) - Z * SIN(xang) / 256                              ;        ZT = Y * SIN(xang) + Z * COS(xang) / 256 &

5、#160;                            ;        Y = YT             

6、0;                                                  ;&#

7、160;       Z = ZT                                          &

8、#160;                     ;                             

9、;                                                 ; 

10、60;      Rotate around y-axis                                         

11、         ;        XT = X * COS(yang) - Z * SIN(yang) / 256                            

12、;  ;        ZT = X * SIN(yang) + Z * COS(yang) / 256                              ;     &#

13、160;  X = XT                                               &

14、#160;                ;        Z = ZT                         

15、0;                                      ;        Rotate around z-axis  

16、;                                                ;  

17、60;     XT = X * COS(zang) - Y * SIN(zang) / 256                              ;        YT = X * SIN(

18、zang) + Y * COS(zang) / 256                              ;        X = XT        

19、                                                  

20、      ;        Y = YT                                    

21、60;                           ;   Divide by 256 coz we have multiplyd our sin values with 256 too.           ;

22、   This example isn't too fast right now but it'll work just fine.            ;       Current Date: 6-9-95         Vulture      

23、;                             ;IDEAL                    

24、0;      ; Ideal modeP386                            ; Allow 80386 instructionsJUMPS         

25、60;                 ; Tasm handles out of range jumps (rulez!:)  SEGMENT CODE                    ; Code segment startsAS

26、SUME cs:code,ds:code          ; Let cs and ds point to code segment ORG 100h                        ; Make a .COM file START: 

27、;                         ; Main program     mov     ax,0013h            ; Init vga&#

28、160;   int     10h    mov     ax,cs    mov     ds,ax               ; ds points to codesegment    mov  

29、60;  ax,0a000h    mov     es,ax               ; es points to vga    lea     si,Palette        ; Set palette  &

30、#160; mov     dx,3c8h    xor     al,al    out     dx,al    mov     dx,3c9h    mov     cx,189*3    repz    outs

31、b; = Set some variables =    mov     DeltaX,1          ; Initial speed of rotation    mov     DeltaY,1          ; Change this and watch what

32、    mov     DeltaZ,1          ; happens. It's fun!    mov     Xoff,256    mov     Yoff,256          ;

33、 Used for calculating vga-pos    mov     Zoff,300          ; Distance from viewerMainLoop:    call    MainProgram         ; Yep. do it all. ;-) &

34、#160;  in      al,60h              ; Scan keyboard    cmp     al,1                ; Test on ESC

35、APE    jne     MainLoop            ; Continue if not keypressed; = Quit to DOS =    mov     ax,0003h            ; Back t

36、o textmode    int     10h    lea     dx,Credits    mov     ah,9    int     21h    mov     ax,4c00h    

37、60;       ; Return control to DOS    int     21h                 ; Call DOS interrupt; = Sub-routines =        

38、0;  PROC WaitVrt                    ; Waits for vertical retrace to reduce "snow"    mov     dx,3dahVrt:    in     

39、 al,dx    test    al,8    jnz     Vrt                 ; Wait until Verticle Retrace startsNoVrt:    in      al,dx&#

40、160;   test    al,8    jz      NoVrt               ; Wait until Verticle Retrace ends    ret         

41、0;               ; Return to main programENDP WaitVrtPROC UpdateAngles; Calculates new x,y,z angles; to rotate around    mov     ax,XAngle         ; Load c

42、urrent angles    mov     bx,YAngle    mov     cx,ZAngle               add     ax,DeltaX         ; Add vel

43、ocity    and     ax,11111111b        ; Range from 0.255    mov     XAngle,ax         ; Update X    add     bx,DeltaY

44、0;        ; Add velocity    and     bx,11111111b        ; Range from 0.255    mov     YAngle,bx         ; Update Y 

45、   add     cx,DeltaZ         ; Add velocity    and     cx,11111111b        ; Range from 0.255    mov     ZAngle,cx  

46、;       ; Update Z    retENDP UpdateAnglesPROC GetSinCos; Needed : bx=angle (0.255); Returns: ax=Sin   bx=Cos    push    bx               &#

47、160;  ; Save angle (use as pointer)    shl     bx,1                ; Grab a word so bx=bx*2    mov     ax,SinCos + bx    ; Get sine

48、0;   pop     bx                  ; Restore pointer into bx    push    ax              

49、;    ; Save sine on stack    add     bx,64               ; Add 64 to get cosine    and     bx,11111111b       

50、 ; Range from 0.255    shl     bx,1                ; *2 coz it's a word    mov     ax,SinCos + bx    ; Get cosine    mov&

51、#160;    bx,ax               ; Save it   bx=Cos    pop     ax                  ; Rest

52、ore   ax=Sin    retENDP GetSinCosPROC SetRotation; Set sine & cosine of x,y,z    mov     bx,XAngle         ; Grab angle    call    GetSinCos    &#

53、160;      ; Get the sine&cosine    mov     Xsin,ax           ; Save sin    mov     Xcos,bx          

54、; Save cos    mov     bx,Yangle    call    GetSinCos    mov     Ysin,ax    mov     Ycos,bx    mov     bx,Zangle   

55、call    GetSinCos    mov     Zsin,ax    mov     Zcos,bx    retENDP SetRotationPROC RotatePoint            ; Rotates the point around x,y,z; Gets

56、original x,y,z values; This can be done elsewhere    movsx   ax,Cube+si    ; si = X        (movsx coz of byte)    mov     X,ax    movsx   ax,Cube+si+1  ; si+1 =

57、 Y    mov     Y,ax    movsx   ax,Cube+si+2  ; si+2 = Z    mov     Z,ax; Rotate around x-axis; YT = Y * COS(xang) - Z * SIN(xang) / 256; ZT = Y * SIN(xang) + Z * COS(xang) / 256; Y = YT; Z = ZT &#

58、160;  mov     ax,Y    mov     bx,XCos    imul    bx               ; ax = Y * Cos(xang)    mov     bp,ax&#

59、160;   mov     ax,Z    mov     bx,XSin    imul    bx               ; ax = Z * Sin(xang)    sub     b

60、p,ax            ; bp = Y * Cos(xang) - Z * Sin(xang)    sar     bp,8             ; bp = Y * Cos(xang) - Z * Sin(xang) / 256    mov 

61、;    Yt,bp    mov     ax,Y    mov     bx,XSin    imul    bx               ; ax = Y * Sin(xang)    mo

62、v     bp,ax    mov     ax,Z    mov     bx,XCos    imul    bx               ; ax = Z * Cos(xang)  

63、60; add     bp,ax            ; bp = Y * SIN(xang) + Z * COS(xang)    sar     bp,8             ; bp = Y * SIN(xang) + Z * COS(xang)

64、 / 256    mov     Zt,bp    mov     ax,Yt          ; Switch values    mov     Y,ax    mov     ax,Zt   

65、; mov     Z,ax; Rotate around y-axis; XT = X * COS(yang) - Z * SIN(yang) / 256; ZT = X * SIN(yang) + Z * COS(yang) / 256; X = XT; Z = ZT    mov     ax,X    mov     bx,YCos    imul  

66、0; bx               ; ax = X * Cos(yang)    mov     bp,ax    mov     ax,Z    mov     bx,YSin    imul 

67、0;  bx               ; ax = Z * Sin(yang)    sub     bp,ax            ; bp = X * Cos(yang) - Z * Sin(yang)    sar &

68、#160;   bp,8             ; bp = X * Cos(yang) - Z * Sin(yang) / 256    mov     Xt,bp    mov     ax,X    mov     bx,YSin 

69、   imul    bx               ; ax = X * Sin(yang)    mov     bp,ax    mov     ax,Z    mov     bx,YCos

70、    imul    bx               ; ax = Z * Cos(yang)    add     bp,ax            ; bp = X * SIN(yang) + Z * COS(y

71、ang)    sar     bp,8             ; bp = X * SIN(yang) + Z * COS(yang) / 256    mov     Zt,bp    mov     ax,Xt    &#

72、160;     ; Switch values    mov     X,ax    mov     ax,Zt    mov     Z,ax; Rotate around z-axis; XT = X * COS(zang) - Y * SIN(zang) / 256; YT = X * SIN(zang) + Y * COS(zang) /

73、 256; X = XT; Y = YT    mov     ax,X    mov     bx,ZCos    imul    bx               ; ax = X * Cos(zang)    mov

74、0;    bp,ax    mov     ax,Y    mov     bx,ZSin    imul    bx               ; ax = Y * Sin(zang)    s

75、ub     bp,ax            ; bp = X * Cos(zang) - Y * Sin(zang)    sar     bp,8             ; bp = X * Cos(zang) - Y * Sin(zang) / 25

76、6    mov     Xt,bp    mov     ax,X    mov     bx,ZSin    imul    bx               ; ax = X * Si

77、n(zang)    mov     bp,ax    mov     ax,Y    mov     bx,ZCos    imul    bx               ; ax =

78、Y * Cos(zang)    add     bp,ax            ; bp = X * SIN(zang) + Y * COS(zang)    sar     bp,8             ; bp = X

79、 * SIN(zang) + Y * COS(zang) / 256    mov     Yt,bp    mov     ax,Xt          ; Switch values    mov     X,ax    mov   &

80、#160; ax,Yt    mov     Y,ax    retENDP RotatePoint           PROC ShowPoint; Calculates screenposition and; plots the point on the screen    mov     ax,Xoff 

81、60;         ; Xoff*X / Z+Zoff = screen x    mov     bx,X    imul    bx    mov     bx,Z    add     bx,Zoff   &#

82、160;       ; Distance    idiv    bx    add     ax,Mx             ; Center on screen    mov     bp,ax 

83、0;  mov     ax,Yoff           ; Yoff*Y / Z+Zoff = screen y    mov     bx,Y    imul    bx    mov     bx,Z    ad

84、d     bx,Zoff           ; Distance    idiv    bx    add     ax,My             ; Center on screen 

85、60;             mov     bx,320    imul    bx    add     ax,bp               ; ax = (y*320)

86、+x    mov     di,ax    mov     ax,Z              ; Get color from Z    add     ax,100d       &#

87、160;     ; (This piece of code could be improved)    mov     byte ptr es:di,al ; Place a dot with color al    mov     Erase+si,di       ; Save position for erase   

88、retENDP ShowPointPROC MainProgram    call    UpdateAngles        ; Calculate new angles    call    SetRotation         ; Find sine & cosine of those angles 

89、   xor     si,si               ; First 3d-point    mov     cx,MaxPointsShowLoop:      call    RotatePoint    &

90、#160;    ; Rotates the point using above formulas    call    ShowPoint           ; Shows the point    add     si,3         &#

91、160;      ; Next 3d-point    loop    ShowLoop    call    WaitVrt             ; Wait for retrace    xor     si,si &#

92、160;             ; Starting with point 0    xor     al,al               ; Color = 0 = black    mov   

93、0; cx,MaxPointsDeletion:    mov     di,Erase+si       ; di = vgapos old point    mov     byte ptr es:di,al ; Delete it    add     si,3     &

94、#160;          ; Next point    loop    Deletion    retENDP MainProgram; = DATA =           Credits   DB   13,10,"Code by Vulture / Outl

95、aw Triad",13,10,"$"Label SinCos Word       ; 256 valuesdw 0,6,13,19,25,31,38,44,50,56dw 62,68,74,80,86,92,98,104,109,115dw 121,126,132,137,142,147,152,157,162,167dw 172,177,181,185,190,194,198,202,206,209dw 213,216,220,223,226,229,231,234,237,239dw 241,24

96、3,245,247,248,250,251,252,253,254dw 255,255,256,256,256,256,256,255,255,254dw 253,252,251,250,248,247,245,243,241,239dw 237,234,231,229,226,223,220,216,213,209dw 206,202,198,194,190,185,181,177,172,167dw 162,157,152,147,142,137,132,126,121,115dw 109,104,98,92,86,80,74,68,62,56dw 50,44,38,31,25,19,13

97、,6,0,-6dw -13,-19,-25,-31,-38,-44,-50,-56,-62,-68dw -74,-80,-86,-92,-98,-104,-109,-115,-121,-126dw -132,-137,-142,-147,-152,-157,-162,-167,-172,-177dw -181,-185,-190,-194,-198,-202,-206,-209,-213,-216dw -220,-223,-226,-229,-231,-234,-237,-239,-241,-243dw -245,-247,-248,-250,-251,-252,-253,-254,-255,

98、-255dw -256,-256,-256,-256,-256,-255,-255,-254,-253,-252dw -251,-250,-248,-247,-245,-243,-241,-239,-237,-234dw -231,-229,-226,-223,-220,-216,-213,-209,-206,-202dw -198,-194,-190,-185,-181,-177,-172,-167,-162,-157dw -152,-147,-142,-137,-132,-126,-121,-115,-109,-104dw -98,-92,-86,-80,-74,-68,-62,-56,-

99、50,-44dw -38,-31,-25,-19,-13,-6Label Cube Byte           ; The 3d points       c = -35            ; 5x*5y*5z (=125) points       rept 5         b = -35         rept 5           a = -35           rept 5    &