一个旋转的3D箱子(动画)

sp;  c = -35            ; 5x*5y*5z (=125) points
       rept 5
         b = -35
         rept 5
           a = -35
           rept 5
             db a,b,c
             a = a + 20
           endm
           b = b + 20
         endm
         c = c + 20
       endm

Label Palette Byte              ; The palette to use
       db 0,0,0                 ; 63*3 gray-tint
       d = 63
       rept 63
         db d,d,d
         db d,d,d
         db d,d,d
         d = d - 1
       endm

X      DW ?             ; X variable for formula
Y      DW ?
Z      DW ?

Xt     DW ?             ; Temporary variable for x
Yt     DW ?
Zt     DW ?

XAngle DW 0             ; Angle to rotate around x
YAngle DW 0
ZAngle DW 0

DeltaX DW ?             ; Amound Xangle is increased each time
DeltaY DW ?
DeltaZ DW ?

Xoff   DW ?
Yoff   DW ?
Zoff   DW ?             ; Distance from viewer

XSin   DW ?             ; Sine and cosine of angle to rotate around
XCos   DW ?
YSin   DW ?
YCos   DW ?
ZSin   DW ?
ZCos   DW ?

Mx     DW 160            ; Middle of the screen
My     DW 100
        &n