.dat file loading routine

Question

Okay so i have an old 8-bit game that loads six .dat files for different size lightmaps.

Something along the lines of this:

const
  MAX_LIGHT_COUNT = 5;
  LFiles : array[0..MAX_LIGHT_COUNT] of string = (
    '.\L00.dat',
    '.\L01.dat',
    '.\L02.dat',
    '.\L03.dat',
    '.\L04.dat',
    '.\L05.dat'
   );

type
  TLights = record
    Width  : Integer;
    Height : Integer;
    PDark  : PByte;
  end;

var
  LightArr: array[0..MAX_LIGHT_COUNT] of TLights;   

Procedure InitializeLight();
var
  PreviousSize: Integer;
  i: Integer;
  fHandle: Integer;
  Width, Height: Integer;
begin
  PreviousSize := 0;

  for i := 0 to MAX_LIGHT_COUNT do
  begin
    if FileExists(LFiles[i]) then
    begin
      fHandle := FileOpen(LFiles[i], fmOpenRead or fmShareDenyNone);

      FileRead(fHandle, Width,  SizeOf(Integer));
      FileRead(fHandle, Height, SizeOf(Integer));

      LightArr[i].Width  := Width;
      LightArr[i].Height := Height;
      LightArr[i].PDark  := AllocMem(Width * Height + 8);

      if PreviousSize < Width * Height then
        FileRead(fHandle, LightArr[i].PDark^, Width * Height);
      PreviousSize := Width * Height;

      FileClose(fHandle);
    end;
  end;
end;

Now i need to create an editor for some new .dat files. I had a go basically reversing whats there and using FillChar to populate the array which just ended in a square instead of the lightmaps cirlce look which makes sense, think i am missing something very important with manipulating X, Y.

Something along the lines of:

PDark := @LightArr[i].PDark;
for Y := 0 to Height - 1 do
begin
  for X := 0 to Width - 1 do
  begin
    // Do something with PDark
  end;
end;

Which would then give me that circle look.

Download: LFiles.rar if necessary.

EDIT: Sorry Jerry if it come across that way, i wasn't expecting people to write the code for me just wanted to make sure i was going in the right direction and maybe get a little help and some other stuff to try out.

NOTE: In case people get confused the attached download isn't Source files its the .dat files the game loads. Uploaded in case people wanted to see what my binary files look like compared to theirs. Basically to compare output see if on right track ect.. I dunno lol.

This is what i tried but its missing some kind of manipulation code for the circle:

for i := 0 to MAX_LIGHT_COUNT do
  begin
    if FileExists(LFiles[i]) then
      fHandle := FileOpen(LFiles[i], fmOpenWrite or fmShareDenyNone)
    else fHandle := FileCreate(LFiles[i]);

    if fHandle > 0 then
    begin
      Width  := 196;
      Height := 176;

      FileWrite(fHandle, Width,  SizeOf(Integer));
      FileWrite(fHandle, Height, SizeOf(Integer));

      LightArr[i].Width  := Width;
      LightArr[i].Height := Height;

      LightArr[i].Fog    := AllocMem(Width * Height + 8);
      FillChar(LightArr[i].Fog^, LightArr[i].Width * LightArr[i].Height + 8, Width * Height);

      FileWrite(fHandle, LightArr[i].Fog^, Width * Height);

      FileClose(fHandle);
    end;
  end;

Thanks for reading.