;=============================================================================
; flame.asm - Plasma-Like Flames Demo.
; File created: 11/22/93
; Copyright (c) 1993, Carlos Hasan Last modified: 11/22/93
;
; Description:
; Plasma Like Flames effect based on Vangelis Fire Code.
;
; Portability:
; Requires Turbo Assembler 3.2 or later to be assembled.
; Dependant on the IBM PC 286 or better processor.
;=============================================================================
ideal
model small
jumps
p286
dosseg
stack 1024
ends
global FontFAR:byte ; FLAMES.FNT linked file.
;=========================== VLA Font Header =================================
struc FontHeader
Magic db "VGACH" ; Font Signature
First db ? ; First Char
Width db ? ; Font Width
Height db ? ; Font Height
Total db ? ; Number of Chars
ends FontHeader
;======================== Equates and Data Segment ===========================
TIMEOUT equ 70*50 ; At Least 50 secs
MESGSPEED equ 20 ; Message Speed in VR Ticks
FLSEED equ 4 ; Initial Flames Seed
FLBLANK equ 100 ; Ending Flames Seed (Blank Screen)
XDOTS equ 80 ; VGA Screen Dimensions
YDOTS equ 80
HIDDEN equ 8 ; Number of Hidden Working Lines
dataseg
label Palette byte ; Flames RGB Palette:
I=0 ; black to blue
rept 8
db 0,0,2*I
I=I+1
endm
I=0 ; blue to darkred
rept 8
db 2*I,0,16-2*I
I=I+1
endm
I=0 ; darkred to lightred
rept 24
db 16+47*I/24,0,0
I=I+1
endm
I=0 ; lighred to yellow
rept 32
db 63,31*I/16,0
I=I+1
endm
I=0 ; yellow to white
rept 24
db 63,63,21*I/8
I=I+1
endm
rept 160 ; white
db 63,63,63
endm
Frame dw XDOTS*(YDOTS+HIDDEN) dup(?) ; Flames Frame Buffer
Seed dw 1234h ; Random Seed
FontDataOfs dw ? ; Font Data Address
FontDataSeg dw ?
FontWidths db 256 dup (?) ; Font Char Widths
FontFirst db ? ; Font First Char
FontWidth db ? ; Font Max Width
FontHeight db ? ; Font Height
FontSize dw ? ; Font BitMap Size (=Width*Height)
MesgOff dw offset TheMessage ; Message Offset
TheMessage db " FAKE DEMO CODED BY PELUSA MUSIC BY NECROS"
db " GREETS GO TO ALL THE PC DEMO PEOPLE..."
db " THANKS FOR WATCHING THIS LAME THING..."
db " SEEING YA........ "
db 0
;============================ Code Segment ===================================
codeseg
;-----------------------------------------------------------------------------
; SetModeX - Sets VGA Tweaked Mode 80x80x256.
;-----------------------------------------------------------------------------
proc SetModeX
mov ax,0013h ; Set VGA Linear 320x200x256
int 10h
mov dx,3C4h ; Disable Chain-Four
mov ax,0604h
out dx,ax
mov dx,3C4h ; Enable Write to All Four Planes
mov ax,0F02h
out dx,ax
mov ax,0A000h ; Clear Display Memory
mov es,ax
xor di,di
xor ax,ax
mov cx,8000h
cld
rep stosw
mov dx,3D4h ; Reprogram CRT Controller:
mov ax,00014h ; turn off dword mode
out dx,ax
mov ax,0e317h ; turn on byte mode
out dx,ax
mov ax,00409h ; cell height
out dx,ax
ret
endp SetModeX
;-----------------------------------------------------------------------------
; WaitVR - Waits Vertical Retrace.
;-----------------------------------------------------------------------------
proc WaitVR
mov dx,3DAh
WaitStartVR:
in al,dx
test al,8
je WaitStartVR
WaitEndVR:
in al,dx
test al,8
jne WaitEndVR
ret
endp WaitVR
;-----------------------------------------------------------------------------
; LoadFont - Loads the VLA font.
;-----------------------------------------------------------------------------
proc LoadFont
mov ax,SEG FontFAR ; Load Font File Address
mov es,ax
mov [FontDataSeg],ax
mov [FontDataOfs],Size FontHeader
mov al,[es:FontHeader.First] ; Get Font First Char
mov [FontFirst],al
mov al,[es:FontHeader.Width] ; Get Font Data Size
mov ah,[es:FontHeader.Height]
mov [FontWidth],al
mov [FontHeight],ah
mul ah
mov [FontSize],ax
mov dl,[es:FontHeader.Total]
xor dh,dh
mul dx
add ax,Size FontHeader ; Copy Font Widths.
mov si,ax
xor di,di
mov cl,[es:FontHeader.Total]
xor ch,ch
CopyWidths:
mov al,[es:si]
mov [FontWidths+di],al
inc si
inc di
loop CopyWidths
ret
endp LoadFont
;-----------------------------------------------------------------------------
; DrawChar - Draw a Font Char.
; In:
; AL = Character Code.
; ES:DI = Frame Screen Address.
;-----------------------------------------------------------------------------
proc DrawChar
sub al,[FontFirst] ; Get Char BitMap Offset
xor ah,ah
mov bx,ax
mul [FontSize]
add ax,[FontDataOfs] ; si = char offset
mov si,ax
mov dl,[FontWidths+bx] ; dx = char width
xor dh,dh
mov cl,[FontHeight] ; cx = char height
xor ch,ch
mov al,[FontWidth] ; bp = font max width
xor ah,ah
mov bp,ax
mov ax,XDOTS ; Draw on Screen Center
sub ax,dx
shr ax,1
shl ax,1
add di,XDOTS*(16+YDOTS)
add di,ax
push ds ; ds = font data segment
mov ds,[FontDataSeg]
DrawCharLoop:
push cx
push si
push di
xor ah,ah
DrawPlane1:
mov al,[ds:si]
test al,al
je SkipColor
mov al,0FFh
mov [es:di],ax
SkipColor:
add si,bp
add di,XDOTS*2
loop DrawPlane1
pop di
pop si
pop cx
inc si
add di,2
dec dx
jg DrawCharLoop
pop ds
ret
endp DrawChar
;-----------------------------------------------------------------------------
; DrawMesg - Draws the Next Message on the Screen.
;-----------------------------------------------------------------------------
proc DrawMesg
pusha
push es
mov ax,ds ; Loads Frame Area Address
mov es,ax
lea di,[Frame]
cld
mov si,[MesgOff]
lodsb
test al,al
stc
je DrawMesgExit
mov [MesgOff],si
call DrawChar
clc
DrawMesgExit:
pop es
popa
ret
endp DrawMesg
;-----------------------------------------------------------------------------
; Random - Returns a random number of 16 bits.
;-----------------------------------------------------------------------------
proc Random
mov ax,[Seed]
imul ax,8905h
inc ax
mov [Seed],ax
ret
endp Random
;-----------------------------------------------------------------------------
; Flames - Flames Like Screen Animation.
;-----------------------------------------------------------------------------
proc Flames
pusha
push ds
push es
call SetModeX ; Sets VGA 80x80x256 graphics mode
call LoadFont
mov [MesgOff],offset TheMessage
call WaitVR
lea si,[Palette] ; Sets Color Palette
mov cx,768
mov dx,3C8h
xor al,al
out dx,al
inc dx
cld
rep outsb
mov ax,ds ; Clears Frame Buffer
mov es,ax
lea di,[Frame]
mov cx,XDOTS*(YDOTS+HIDDEN)
xor ax,ax
rep stosw
mov ax,0A000h ; Set Display Memory Segment
mov es,ax
mov bx,FLSEED ; Loads Flames Seed Factor
xor bp,bp ; Start Timer Counter
FlamesLoop:
inc bp ; Increase Timer
call WaitVR ; Wait Vertical Retrace
lea si,[Frame] ; Write Frame to the Screen
xor di,di
mov cx,XDOTS*YDOTS/2
WriteFrameLoop:
lodsw
mov dl,al
lodsw
mov dh,al
mov ax,dx
stosw
loop WriteFrameLoop
cmp bp,TIMEOUT ; Don't Draw Message while
jae DontDrawMesg ; Fading out the Flames.
mov ax,bp
xor dx,dx
mov cx,MESGSPEED
div cx
test dx,dx ; Draws Messages...
jne DontDrawMesg
call DrawMesg
jnc DontDrawMesg ; If no more message text,
mov bp,TIMEOUT ; Start fading out...
DontDrawMesg:
mov cx,XDOTS*(YDOTS+HIDDEN-2) ; Transform Upper Frame Lines
lea si,[Frame+2*XDOTS]
FlamesTransform:
mov ax,[ds:si-2] ; Sets Pixel at (X,Y) like
add ax,[ds:si+0] ; the average of the near four
add ax,[ds:si+2] ; pixels below it:
add ax,[ds:si+2*XDOTS] ; P(X,Y) = (P(X-1,Y+1)+P(X,Y+1)+
sub ax,bx ; P(X+1,Y+1)+P(X,Y+2)-Seed)/4
sar ax,2
jge FlameNotTooLow
xor ax,ax
FlameNotTooLow:
mov [ds:si-2*XDOTS],ax
add si,2
loop FlamesTransform
; Sets New Random Bottom Flames with Colors from 0 to 127.
lea si,[Frame+2*XDOTS*(YDOTS+HIDDEN-2)]
mov cx,XDOTS
xor dx,dx
RandomFlames:
call Random ; Use Random to Create a New
test ax,ax ; Flames Bottom Lines
js NotNewColor
call Random
mov dl,al
and dl,7Fh
NotNewColor:
mov [ds:si],dx
mov [ds:si+2*XDOTS],dx
add si,2
loop RandomFlames
mov ah,1 ; or Any Key Pressed?
int 16h
je CheckTimer
mov ah,0
int 16h
mov bp,TIMEOUT
CheckTimer:
cmp bp,TIMEOUT ; Timeout?
jb FlamesLoop
DecreaseFlames:
inc bx ; Increase Flames Seed
cmp bx,FLBLANK ; (makes flames more low)
jbe FlamesLoop
FlamesExit:
mov ax,0003h ; Set Text Mode 80x25x16
int 10h
pop es
pop ds
popa
ret
endp Flames
;-----------------------------------------------------------------------------
; Start - Startup code called from DOS.
;-----------------------------------------------------------------------------
proc Start
mov ax,@Data ; Set DS Segment
mov ds,ax
mov bx,ss ; Shrink Program Segment
mov ax,es
sub bx,ax
mov ax,sp
shr ax,4
inc ax
add bx,ax
mov ah,4Ah
call Flames ; Do Flames Demo
mov ax,4C00h
int 21h ; Exit to DOS.
endp Start
end Start
