;-------------------------------------------------------------------------
;XXXXXXXXXXXXXX||:::===----     KDE    ----====::::|||||XXXXXXXXXXXXXXXXXX
;XXXXXXXXXXXXXX|:=-    by Wessko's Melodyes  -=:|XXXXXXXXXXXXXXXXXXXXXXXXX
;-------------------------------------------------------------------------
;/* SORRY, LINUX FANS! IT WOULD BE GREAT-A DESKTOP ENVIRONMENT IN 256 BYTEs
;BUT IT'S STILL IMPOSSIBLE */
;
; Credits:
;WESSKO'S MELODYES:
;  DUKE NUKEM - CODE,GFX,GRX,3DENGINEERING....
;
; JUST IN TWO SENTENCES:
;i just saw an awfully slow intro, concerning about the same effect, written
;by Ufix of DSK!...i just wanna unblame myself - i really did not copied
;*ANYTHING*. Also my one is better because of the following:
;1: mine is 7-8 times faster (uses SQRT precalculated table, as the Ufix's
;   does not - relies on the slow FPU)
;2: runs until keypress (ufix's runs until keypress *OR* generated 600 frames)
;   The problem is that the most beautiful color effects are exactly after
;   700-800 frames-so i recommend you to wait mine until you see the nice
;   thing:)
;
;   Hope i convinced you i'm not a pirate (at least i don't steal in silence
;   and also steal for good purposes only:) (i have a version of Ufix's intro
;   *WITH* SQRT table and i can give it if ya want to see the differences:)
;   (if ya notice them :)))
;
;       here's the source;i put some comments:)

        IDEAL
        MODEL TINY
        P386n           ;system requirements:386DX
        P387            ;with FPU

DATASEG
x1      DW      -300    ;xcoord of "flare" no.1 (it's not a flare if fact, )
x2      dw      620     ;xcoord of "flare" no.2 (but i can't name it)
y1      dw      -100    ;....
y2      dw      300
cbx     dw      ?
res     db      ?
SQRTabl db 65000 DUP (?) ;the praised sqrt table (increases da speed 7 times)

CODESEG
        org 100h
Start:                          ;now we'll perform a cycle to initialise
        mov cx,65000            ;the table
        mov di,offset SQRTabl
        xor bx,bx
@initloop:
        mov [cbx],bx
        fild [cbx]
        fsqrt                   ;this is 65000 fsqrts (!!)
;        mov [cbx],10           ;(but without them they'll be about
 ;       fild [cbx]             ;12000000 (65000 per frame) )
  ;      fdiv                   ;the trick is that we calculate one
        fistp   [cbx]           ;full frame only once, and the other
        mov ax,[cbx]            ;choice is to do it every frame
        stosb
        inc bx                  ;bx is the main variable here
        loop  @initloop

        mov ax,13h              ;set videomode 320x200x8bit
        int 10h                 ;use BIOS
        push 0a000h             ;load the video segment
        pop es                  ;in es
@mainloop:
        xor     di,     di
        xor bx,bx                ;bx=linenumber
@lineloop:
        xor ax,ax               ;ax=colonumber
@hhe:

; putpix

        push ax
        push bx                  ;save all registers
        sub ax,[x1]            ;get in ax the vertical distance
        sub bx,[y1]
        push bx                ;bx is needed later
        mov bx,ax              ;ax=ax*ax
        imul bx                
        mov si,ax              ;si=axý
        pop ax                 ;ax=bx
        mov bx,ax              ;bx=bx
        imul bx                ;ax=bxý
        add si,ax              ;si=axý+bxý (pithagor theorem)
        shr si,6               ;si=(axý+bxý)/64 (Duke nukem's Theorem :))
        add si,offset sqrtabl  ;for example si=6; we'll get in ax sqrt(6)
        ;xor ax,ax              ;[ds:si+offset sqrtabl] is sqrt (si)
        lodsb                  ; load the value
        mov [res],al           ;save it
        pop bx                 ; now the absolute same procedure for the
        pop ax                 ; other "flare"...
        push ax
        push bx
        sub ax,[x2]
        sub bx,[y2]
        push bx
        mov bx,ax
        imul bx
        mov si,ax
        pop ax
        mov bx,ax
        imul bx
        add si,ax
        shr si,6
        add si,offset sqrtabl
;        xor ax,ax
        lodsb                   ;ax=sqrt((vdistý+hdistý)/64)
;        mov al, [ds:si]
   ;     pop bx
    ;    pop ax
     ;   sub ax,[x3]
      ;  sub bx,[y3]
       ; call absregs
;        push bx
 ;       mov bx,ax
  ;      imul bx
   ;     mov si,ax
    ;    pop ax
     ;   mov bx,ax
      ;  imul bx
       ; add si,ax
        ;add si,offset sqrtabl
;        xor ax,ax
 ;       lodsb
        add al,[res]            ;ax=ax+the_saved_value (from flare no 1)
        add al,32               ;min color=32 (colors >32 are much prettier
        stosb                   ;at last-store the calculated thing in VRAM
        pop bx                    ;pop all registers
        pop ax


;endp putpix


        inc ax                  ;next pixel
        cmp ax,320              ;have we reached the end if the line?
        jb @hhe                ;no? -next pixel
        inc bx                  ;yes? -next line
        cmp bl ,200             ;have we reached the last line?
        jb @lineloop           ;no? -next line
        inc [x1]                ;flare no1 moves right...
        dec [x2]                ;flare no2 moves left---
        dec [y2]                ;...and up
        inc [y1]                ;---and down
;        dec [y3]
        mov ah,0bh              ;0bh dos function - check keyboard
        int 21h                 ;call DOS/WinDOS/whatever
        or al,al                ;is key pressed?
        je @mainloop            ;no? then next frame
        mov ah,7                ;yes? -select DOS function: read key
        int 21h                 ;read it
        mov ax,3                ;back to textmode 80x25x4bitcol...
        int 10h                 
        mov ax,4c00h            ;and terminate program
        int 21h

virus   db      0,0,"(r)ViruS",0,0
END     Start                   ;end/entry point