{> Cut here. FileName= PAL_RAD.SRC }
const PalConst:Real=0;

procedure SetPalette;

function f(x:real):real;
begin
  x := x+palconst;
  x := (x - round(x));
  f:=x*x*4;
end;

var   N, C : Integer;
      r,g,b,i: real;

begin
  Port[$3C8] := 0;
  for N := 0 to 255 do begin
    R := F(N/256-1/3);
    G := F(N/256);
    B := F(N/256+1/3);
    i :=r; if g>i then i:= g; if b>i then i:=b;
    Port[$3C9] := round(r*63/1);
    Port[$3C9] := round(g*63/1);
    Port[$3C9] := round(b*63/1);
  end;
end; {of SetPalette}

{> Cut here. FileName= PIC1.PAS }
{$R-,Q-,S-,Q-}
uses crt;
{$i pal_rad.src}

type TScr = array[0..199,0..319] of byte;
var Scr: TScr absolute $A000:$0000;
type TScr2 = array[0..63999] of byte;
var Scr2: TScr2 absolute $A000:$0000;
var Scr3, Scr4: ^TScr;

const color:byte=255;

function longmul(X, Y: Integer): Longint;
inline($5A/$58/$f7/$EA);

function LongDiv(X: Longint; Y: Integer): Integer;
inline($59/$58/$5A/$F7/$F9);

procedure line(x1,y1,x2,y2:integer);
var i,j:integer;
begin
  i := abs(x2-x1);
  j := abs(y2-y1);
  if i<j then i:=j;
  if i=0 then exit;

  for j := 0 to i do begin
{    inc(scr[y1+longdiv(longmul(y2-y1,j), i),
            x1+longdiv(longmul(x2-x1,j), i)], color);{}
  scr[y1+longdiv(longmul(y2-y1,j), i),
      x1+longdiv(longmul(x2-x1,j), i)] :=
      (y1+longdiv(longmul(y2-y1,j), i)) or
      (1+(x1+longdiv(longmul(x2-x1,j), i)) div 2);
  end;
end;

procedure drop(x,y,r:integer); {капля}
var i,j,L:integer;
    x1,y1:integer;
begin
  for i := -r to +r do begin
    L := round(sqrt(sqr(r+0.5)-sqr(i)));
    for j := -L to +L do begin
      x1 := x+ ((j*7) div 8); y1 := y+ ((i*7) div 8);
      scr3^[y+i,x+j] := scr4^[y1, x1];{}
{      scr3^[y+i,x+j] := (scr4^[y1, x1]+scr4^[y1, x1+1]+
       scr4^[y1, x1-1]+scr4^[y1+1, x1]+scr4^[y1-1, x1]) div 5;{}
    end;
  end;
  for i := y-r to y+r do
    for j := x-r to x+r do begin
      scr4^[i,j] := scr3^[i,j];{}
      scr[i,j] := scr3^[i,j];
    end;
end;

Procedure vidMode(mode : byte);assembler;
  asm mov ah,$00;  mov al,mode; int 10h; end;

var x,y,x1,y1:integer;
    i:word;
begin
  vidMode($13);                       { 320x200x256 graphics mode }
  SetPalette;
  GetMem(Scr3,65535);
  GetMem(Scr4,65535);
  y := random(200);
  x := random(320);
  i :=0;
  for i:=0 to 65535 do begin
    y := (i + (i shl 5) xor i shl 3 ) div 320;
    x := (i + (i shl 5) xor i shl 3 ) mod 320;
    y1:=y; x1:=x;
  scr[y, x] :={y xor x}random(255);
  end;
  scr4^:=scr;
  scr3^:=scr;
  repeat
{   palconst:=palconst+0.01; setpalette;{}
    y := random(200);
    x := random(320);
    drop(x,y,4);
  until keypressed; readkey;
  vidMode($03);                       { return to 80x25 textmode }
  writeln('i=',i);
end.