VGA Trainer Program: part 5
Õ-------------------------------¸
| W E L C O M E |
| To the VGA Trainer Program | |
| By | |
| DENTHOR of ASPHYXIA | | |
Ô-------------------------------¾ | |
--------------------------------Ù |
--------------------------------Ù
--==[ PART 5 ]==--Introduction
Hello! This is Denthor here with the 5 part of the ASPHYXIA VGA Trainer Series : The Scrolling Saga. I have had many requests for information on scrolling, so I decided to make it this weeks topic. Note that I do make reference to my recently released program TEXTER5, which should be available from wherever you get this message. (Note to Sysops : If you put the trainer series up on your boards, please add WORMIE.ZIP and TEXTER5.ZIP as they both supplement this series)
By the way, sorry for the delay in the appearance of this part. Tests, projects and a few wild days of sin at the Wild Coast all conspired against the prompt appearance of this part. Also note I need more input as to what I should do future parts on, so leave me mail.
If you would like to contact me, or the team, there are many ways you can do it :
- Write a message to Grant Smith in private mail here on the Mailbox BBS.
- Write a message here in the Programming conference here on the Mailbox (Preferred if you have a general programming query or problem others would benefit from)
- Write to ASPHYXIA on the ASPHYXIA BBS.
- Write to Denthor, Eze or Livewire on Connectix.
- Write to : Grant Smith P.O.Box 270 Kloof 3640 Natal
- Call me (Grant Smith) at 73 2129 (leave a message if you call during varsity)
NB : If you are a representative of a company or BBS, and want ASPHYXIA to do you a demo, leave mail to me; we can discuss it.
NNB : If you have done/attempted a demo, SEND IT TO ME! We are feeling quite lonely and want to meet/help out/exchange code with other demo groups. What do you have to lose? Leave a message here and we can work out how to transfer it. We really want to hear from you!
What is scrolling?
If you have ever seen a demo, you have probably seen some form of scrolling. Our SILKYDEMO has quite a nice example of scrolling. What it is is a long row of text moving across your screen, usually from right to left, eg :
H : Step 1
He : Step 2
Hel : Step 3
Hell : Step 4
Hello : Step 5
Hello : Step 6etc. etc. See the program attached for an example of scrolling.
What do we scroll?
Usually, letters. Most groups put greetings and information in their 'scrollies', as they are termed. You can also scroll and entire screen using the scrolling technique. Scrolling your text is a hell of a lot less boring then just having it appear on your screen. Unfortunately, 'scrollies' have been used so many times in demos they are wearing a bit thin, so usually they are accompanied by a cool picture or some nice routine happening at the same time (In our SILKYDEMO we had a moving checkerboard and colour bars going at the same time).
How do we scroll from side to side?
The theory behind scrolling is quite easy. Let us imagine that we are scrolling a 16x16 font grabbed by TEXTER (;-)) across the top of the screen (ie. 320 pixels) As we know, the VGA screen starts at zero at the top left hand part of the screen, then counts up to the right to 319, then goes back to the left hand side one pixel down at 320. (See Tut 1) This means that a 16*320 scroller takes up the space 0 to 5119 on the screen. In ascii this looks like this :
(0) . . (319)
(320) . . (639)
" " "
(4800) . . (5119)Simple enough. Now what we do is we put down the first Y-line of the first character onto the very right hand side of the screen , like so :
For loop1:=1 to 16 do
Putpixel (319,loop1-1,font['A',1,loop1],vga);This will draw some stuff on the very right hand side. Your screen should now look like this :
(0) . X. (319)
(320) . X. (639)
" " "
(4800) . X. (5119)Next, we move each line one to the left, ie :
For loop1:=0 to 15 do
Move (mem[VGA:loop1*320+1],mem[VGA:loop1*320],320);This scrolls the screen from right to left, which is the easiest to read. To scroll the screen from left to right, swap the +1 onto the other side of the command. Also, to increase the size of the portion scrolled, increase the 15 to however many lines from the top you wish to scroll-1.
After this move, your screen will look like this :
(0) . X . (319)
(320) . X . (639)
" " "
(4800) . X . (5119)
^
Note this spaceWhat you then do is draw in the next line on the right hand side, move it, draw the next line, move it etc. etc. Tah-Dah! You have a scrolly! Fairly simple, isn't it?
How do we scroll up or down?
To scroll up or down is also fairly simple. This can be used for 'movie credit' endings (I once wrote a little game with a desert scrolling down with you being a little robot on the bottom of the screen). The theory is this : Draw the top line (or bottom line) then move the entire screen :
Move (mem[vga:0],mem[vga:320],63680);
{ 64000 - 320 = 63680 }For scrolling down, or :
Move (mem[vga:320],mem[vga:0],63680);For scrolling up. You then draw the next line and repeat.
Because of the simplicity of coding in a scrolly, most demos have one. It is usually best to have something extra happening on the screen so that the viewer doesn't get too bored, even, as I say, if it is only a really nice picture.
In closing
The University of Natal, Durban, Science Dept., now has 10 new 486's! This is a great boon, as now I can program nice routines during frees (even though I am a Commerce Student (Shhhhh) ;-) ). I can now use those previously wasted hours that I spent socialising and making friends coding instead ;-)
I suggest you get a copy of TEXTER, for coding demos with fonts, or in fact almost any graphics application, it is an amazing help, and we have used it for *ALL* our demos. (P.S. We have written many demos, but many have been written for companies and have not been released for the general public) NOTE : For TEXTER's test program TEST.PAS, add {$X+} {$R-} if you have range checking on (I code with it off.)
[ "I'm from the Computer Inspection Agency, sir, I'm here to check your computer. Here is my identification."
"Certainly. Have a look, I'm clean. I don't have any pirated software."
The C-man pushes past him and sits in front of the computer. He notes the fact that the computer is currently off with a look of disdain. He makes a note on his clipboard. He boots up.
"What is this?" he asks, pointing at the screen.
"It's MasterMenu" stutters the man. "I wrote it myself!"
"Do you know what the penalty is for using junk like this on a private machine?" The C-man smiles.
"This is a two-month sentance in itself!"
"I'm sorry sir! It won't happen again!"
"I know. I'll make sure of that." He smiles again.
The C-man runs through the hard drive, checking for illeagal software, bad programs and anti-government propaganda. He notes with satisfaction that he has enough to put this weenie away for ten years, not that it mattered. He usually could just make something up.
He comes to the last entry on the aphebetised menu tree. His hands jerk away from the keyboard. Then, tentatively, he types in the three letters of doom. He looks at the man, who is backing away with wide eyes and his hands outstretched in front of him, as if to ward off a blow.
The C-man smiles, his lips a thin, hard line.
"Windows!"]- Grant Smith
1:55pm
16/9/93
Cheers,
- Denthor
TUTPROG5.PAS
{$X+} {$R-}
Uses Crt;
CONST VGA = $a000;
XSize = 16;
YSize = 16;
TYPE
Letter = Array[1..xsize,1..ysize] of Byte;
Letters = Array[' '..']'] of Letter;
VAR Font : ^Letters;
{--------------------------------------------------------------------------}
Procedure SetMCGA; { This procedure gets you into 320x200x256 mode. }
BEGIN
asm
mov ax,0013h
int 10h
end;
END;
{--------------------------------------------------------------------------}
Procedure SetText; { This procedure returns you to text mode. }
BEGIN
asm
mov ax,0003h
int 10h
end;
END;
{--------------------------------------------------------------------------}
procedure WaitRetrace; assembler;
{ This waits until you are in a Verticle Retrace }
label
l1, l2;
asm
mov dx,3DAh
l1:
in al,dx
and al,08h
jnz l1
l2:
in al,dx
and al,08h
jz l2
end;
{--------------------------------------------------------------------------}
Procedure Pal(ColorNo : Byte; R,G,B : Byte);
{ This sets the Red, Green and Blue values of a certain color }
Begin
Port[$3c8] := ColorNo;
Port[$3c9] := R;
Port[$3c9] := G;
Port[$3c9] := B;
End;
{--------------------------------------------------------------------------}
Procedure PutPixel (X,Y : Integer; Col : Byte; Where : Word);
{ This puts a pixel at X,Y using color col, on VGA or the Virtual Screen}
BEGIN
Mem [Where:X+(Y*320)]:=col;
END;
{--------------------------------------------------------------------------}
procedure LoadPal (FileName : string);
{ This loads the Pallette file and puts it on screen }
type DACType = array [0..255] of record
R, G, B : byte;
end;
var DAC : DACType;
Fil : file of DACType;
I : integer;
BEGIN
assign (Fil, FileName);
reset (Fil);
read (Fil, DAC);
close (Fil);
for I := 0 to 255 do Pal(I,Dac[I].R,Dac[I].G,Dac[I].B);
end;
{--------------------------------------------------------------------------}
function Exist(FileName: string): Boolean;
{ Checks to see if filename exits or not }
var f: file;
begin
{$I-}
Assign(f, FileName);
Reset(f);
Close(f);
{$I+}
Exist := (IOResult = 0) and
(FileName <> '');
end;
{--------------------------------------------------------------------------}
Procedure Setup;
{ This loads the font and the pallette }
VAR f:file;
loop1:char;
loop2,loop3:integer;
BEGIN
getmem (font,sizeof (font^));
If exist ('softrock.fnt') then BEGIN
Assign (f,'softrock.fnt');
reset (f,1);
blockread (f,font^,sizeof (font^));
close (f);
Writeln ('SoftRock.FNT from TEXTER5 found in current directory. Using.');
END
ELSE BEGIN
Writeln ('SoftRock.FNT from TEXTER5 not found in current directory.');
For loop1:=' ' to ']' do
For loop2:=1 to 16 do
for loop3:=1 to 16 do
font^[loop1,loop2,loop3]:=loop2;
END;
If exist ('pallette.col') then
Writeln ('Pallette.COL from TEXTER5 found in current directory. Using.')
ELSE
Writeln ('Pallette.COL from TEXTER5 not found in current directory.');
Writeln;
Writeln;
Write ('Hit any key to continue ...');
readkey;
setmcga;
If exist ('pallette.col') then loadpal ('pallette.col');
END;
{--------------------------------------------------------------------------}
Procedure ScrollMsg (Msg : String);
{ This scrolls the string in MSG across the screen }
Var Loop1,loop2,loop3 : Integer;
Begin
For loop1:=1 to length (msg) do BEGIN
For loop2:=1 to xsize do BEGIN
{ This bit scrolls the screen by one then puts in the new row of
letters }
waitretrace;
For Loop3 := 100 to 99+ysize do
move (mem[vga:1+(loop3*320)],mem[vga:(loop3*320)],319);
for loop3:=100 to 99+ysize do
putpixel (319,loop3,font^[msg[loop1],loop2,loop3-99],vga);
{ Change the -99 above to the minimum of loop3-1, which you
will change in order to move the position of the scrolly }
END;
{This next bit scrolls by one pixel after each letter so that there
are gaps between the letters }
waitretrace;
For Loop3 := 100 to 99+ysize do
move (mem[vga:1+(loop3*320)],mem[vga:(loop3*320)],319);
for loop3:=100 to 99+ysize do
putpixel (319,loop3,0,vga);
END;
End;
BEGIN
ClrScr;
Writeln ('This program will give you an example of a scrolly. If the file');
Writeln ('SOFTROCK.FNT is in the current directory, this program will scroll');
Writeln ('letters, otherwise it will only scroll bars. It also searches for');
Writeln ('PALLETTE.COL, which it uses for it''s pallette. Both SOFTROCK.FNT');
Writeln ('and PALLETTE.COL come with TEXTER5.ZIP, at a BBS near you.');
Writeln;
Writeln ('You will note that you can change what the scrolly says merely by');
Writeln ('changing the string in the program.');
Writeln;
Setup;
repeat
ScrollMsg ('ASPHYXIA RULZ!!! ');
until keypressed;
Settext;
freemem (font, sizeof (font^));
Writeln ('All done. This concludes the fifth sample program in the ASPHYXIA');
Writeln ('Training series. You may reach DENTHOR under the name of GRANT');
Writeln ('SMITH on the MailBox BBS, or leave a message to ASPHYXIA on the');
Writeln ('ASPHYXIA BBS. Get the numbers from Roblist, or write to :');
Writeln (' Grant Smith');
Writeln (' P.O. Box 270');
Writeln (' Kloof');
Writeln (' 3640');
Writeln ('I hope to hear from you soon!');
Writeln; Writeln;
Write ('Hit any key to exit ...');
Readkey;
END.WORMIE.PAS
{$R-}
{$X+}
Program T_holic;
USES
Crt;
CONST
Vga : Word = $a000;
Block : Array[1..40,1..40] of Byte = (
(0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0),
(0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0),
(0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0),
(0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0),
(0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0),
(0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0),
(0,0,0,0,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,0,0,0,0),
(0,0,0,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,0,0,0),
(0,0,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,0,0),
(0,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,0),
(1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1),
(1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1),
(1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1),
(1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1),
(1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1),
(1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1),
(1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1),
(1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1),
(1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1),
(1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1),
(1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1),
(1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1),
(1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1),
(1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1),
(1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1),
(1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1),
(1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1),
(1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1),
(1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1),
(1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1),
(0,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,0),
(0,0,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,0,0),
(0,0,0,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,0,0,0),
(0,0,0,0,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,0,0,0,0),
(0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0),
(0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0),
(0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0),
(0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0),
(0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0),
(0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0)
);
VAR
WholePal : Array[1..256,1..3] of Byte;
CurX,CurY,CurCol : Word;
right,down:Boolean;
{--------------------------------------------------------------------------}
Procedure SetMCGA; { This procedure gets you into 320x200x256 mode. }
BEGIN
asm
mov ax,0013h
int 10h
end;
END;
{--------------------------------------------------------------------------}
Procedure SetText; { This procedure returns you to text mode. }
BEGIN
asm
mov ax,0003h
int 10h
end;
END;
{--------------------------------------------------------------------------}
procedure WaitRetrace; assembler;
label
l1, l2;
asm
mov dx,3DAh
l1:
in al,dx
and al,08h
jnz l1
l2:
in al,dx
and al,08h
jz l2
end;
{--------------------------------------------------------------------------}
Procedure GetPal(ColorNo : Byte; Var R,G,B : Byte);
{ This reads the values of the Red, Green and Blue values of a certain
color and returns them to you. }
Begin
Port[$3c7] := ColorNo;
R := Port[$3c9];
G := Port[$3c9];
B := Port[$3c9];
End;
{--------------------------------------------------------------------------}
Procedure Pal(ColorNo : Byte; R,G,B : Byte);
{ This sets the Red, Green and Blue values of a certain color }
Begin
Port[$3c8] := ColorNo;
Port[$3c9] := R;
Port[$3c9] := G;
Port[$3c9] := B;
End;
{--------------------------------------------------------------------------}
Procedure FadeDown;
{ This procedure fades the screen out to black. }
VAR loop1,loop2:integer;
Tmp : Array [1..3] of byte;
{ This is temporary storage for the values of a color }
BEGIN
For loop1:=1 to 64 do BEGIN
WaitRetrace;
For loop2:=1 to 255 do BEGIN
Getpal (loop2,Tmp[1],Tmp[2],Tmp[3]);
If Tmp[1]>0 then dec (Tmp[1]);
If Tmp[2]>0 then dec (Tmp[2]);
If Tmp[3]>0 then dec (Tmp[3]);
{ If the Red, Green or Blue values of color loop2 are not yet zero,
then, decrease them by one. }
Pal (loop2,Tmp[1],Tmp[2],Tmp[3]);
{ Set the new, altered pallette color. }
END;
END;
END;
{--------------------------------------------------------------------------}
Procedure Putpixel (X,Y : Integer; Col : Byte);
{ This puts a pixel on the screen by writing directly to memory. }
BEGIN
Mem [VGA:X+(Y*320)]:=Col;
END;
{--------------------------------------------------------------------------}
Procedure CunninglyManipulatePalette;
{ This moves up the pallette by one so that the color of the block
being put down is always the same }
Var
Tmp : Array[1..3] of byte;
loop : Byte;
Begin
Move(WholePal[210],Tmp[1],3); { Save Last Colour }
Move(WholePal[1],WholePal[2],209*3); { Move Rest Up one }
Move(Tmp,WholePal[1],3); { Put Last Colour to First pos }
For Loop := 1 to 210 do
Pal(Loop,WholePal[Loop,1],WholePal[Loop,2],WholePal[Loop,3]);
End;
{--------------------------------------------------------------------------}
Procedure PreparePalette;
{ This sets up the palette to have pretty gradients in it for our use }
Var
Loop : Byte;
Begin
For loop := 1 to 30 do BEGIN
Wholepal [loop,1]:=loop*2;
Wholepal [loop,2]:=0;
Wholepal [loop,3]:=0;
END;
For loop := 31 to 60 do BEGIN
Wholepal [loop,1]:=0;
Wholepal [loop,2]:=loop*2-30;
Wholepal [loop,3]:=0;
END;
For loop := 61 to 90 do BEGIN
Wholepal [loop,1]:=0;
Wholepal [loop,2]:=0;
Wholepal [loop,3]:=loop*2-30;
END;
For loop := 91 to 120 do BEGIN
Wholepal [loop,1]:=loop*2-30;
Wholepal [loop,2]:=loop*2-30;
Wholepal [loop,3]:=loop*2-30;
END;
For loop := 121 to 150 do BEGIN
Wholepal [loop,1]:=loop*2-30;
Wholepal [loop,2]:=loop*2-30;
Wholepal [loop,3]:=0;
END;
For loop := 151 to 180 do BEGIN
Wholepal [loop,1]:=0;
Wholepal [loop,2]:=loop*2-30;
Wholepal [loop,3]:=loop*2-30;
END;
For loop := 181 to 210 do BEGIN
Wholepal [loop,1]:=loop*2-30;
Wholepal [loop,2]:=0;
Wholepal [loop,3]:=loop*2-30;
END;
End;
{--------------------------------------------------------------------------}
Procedure IngeniouslyMoveCurPos;
{ This moves the position of the block to put down around the screen }
Begin
CurCol := (CurCol) mod 210 + 1; { This Does Work }
if right then CurX := CurX + 4 else CurX := CurX - 3;
if down then CurY := CurY + 3 else CurY := CurY - 2;
If CurX > 250 then right:= FALSE;
If CurY > 150 then down := FALSE;
If CurX < 10 then right := TRUE;
If CurY < 10 then down := TRUE;
End;
{--------------------------------------------------------------------------}
Procedure DrawBlock;
{ This draws the block onto the VGA screen }
Var
Xloop,Yloop : Integer;
Begin
For XLoop := 1 to 40 do
For Yloop := 1 to 40 do
If block[Yloop,Xloop] = 1 then
PutPixel(CurX+Xloop,CurY+Yloop,CurCol);
End;
{--------------------------------------------------------------------------}
Procedure StartSnakiepoo;
{ This is the proc where we set things up & set em in motion! ;-) }
Begin
CurX := 100;
CurY := 100;
CurCol := 1;
PreparePalette;
Repeat
DrawBlock;
CunninglyManipulatePalette;
IngeniouslyMoveCurPos;
Until Keypressed;
fadedown;
Readkey;
End;
Begin
ClrScr;
Writeln ('Hi there! This is a small little routine that Livewire');
Writeln ('and Denthor of ASPHYXIA threw together during lunch break');
Writeln ('at varsity. We first saw this routine in the T-Holic demo');
Writeln ('by Extreme a few months back, and decided to write it as');
Writeln ('a supliment to the ASPHYXIA VGA Demo Trainer Series on the');
Writeln ('MailBox BBS here in Durban. ');
Writeln;
Writeln ('The routine consists of a wormy type thing bouncing around');
Writeln ('the screen, and looks quite effective. The code is');
Writeln ('documented, and the concept behind it is so easy everyone');
Writeln ('should be able to understand it. ');
Writeln;
Writeln ('The Pal routines, setmcga, waitretrace etc. are taken');
Writeln ('directly from the ASPHYXIA Trainer Series, and you should');
Writeln ('read those to understand how they work.');
Writeln;
Writeln ('See the Trainer Series for how to get into contact with us.');
Writeln; Writeln;
Writeln ('Hit any key to continue .... ');
Readkey;
SetMCGA;
StartSnakiepoo;
SetText;
Writeln ('All done. This was a sample routine written by ASPHYXIA.');
Writeln ('Please read the ASPHYXIA Demo Trainer Series on the MailBox BBS,');
Writeln ('written by Denthor. You may reach DENTHOR under the name of GRANT');
Writeln ('SMITH on the MailBox BBS, or leave a message to ASPHYXIA on the');
Writeln ('ASPHYXIA BBS. Get the numbers from Roblist, or write to :');
Writeln (' Grant Smith');
Writeln (' P.O. Box 270');
Writeln (' Kloof');
Writeln (' 3640');
Writeln ('We hope to hear from you soon!');
Writeln; Writeln;
Write ('Hit any key to exit ...');
Readkey;
End.
