How to save / load this data? - delphi

Question

I have a few items I need to save, Its all value for a Map. So each time a user can either load an old map or create and save a new one. But I am unsure how or what process to use to save all the data.
I have
TCube array (1..10000)
Row, Column : integers
NumberOfBlocks : integers
So when a user clicks save it should save the array data ( I am not sure it matters but not all 10,000 cubes are created) , along with the 3 integers.
Full code of the creation of the TCUBE array and integers.
procedure TForm2.createMap(r:integer;c:integer);
var
i : integer;
rows,columns,columnssave : integer;
x,y,z : single;
player : tmodel3d;
begin
columns := r;
rows := c;
i:=1;
x := 0;
y := 0;
z := 0;
NumberOfRows := rows;
NumberOfColumns := columns;
camera1.Position.X := rows/2;
camera1.Position.Y := columns/2;
dummy1.Position.X := rows/2;
dummy1.Position.Y := columns/2;
while rows>0 do
begin
columnssave := columns ;
while columns >0 do
begin
CreateCube[i]:=tcube.Create(self);
CreateCube[i].Visible := true;
CreateCube[i].Position.x := x;
CreateCube[i].Position.Y := y;
CreateCube[i].Position.Z := z;
CreateCube[i].Material.Texture.CreateFromFile(gamedir+'\pics\Grass.bmp');
CreateCube[i].Material.Modulation := TTextureMode.tmReplace;
CreateCube[i].Parent := viewport3d1;
CreateCube[i].OnClick := cubeClick;
CreateCube[i].OnMouseDown := mousedown;
y:= y+1;
i:=i+1;
//z:=z-1;
columns := columns -1;
end;
y:=0;
x:= x+1;
z:=0;
columns := columnssave;
rows:= rows-1;
end;
totalblocks := i;
setblocks := false;
label2.Text := inttostr(totalblocks);
end;
Thanks
Glen

Answer 1

There are lots of ways to save data out to a file. Normally I use NativeXML to read and write XML documents. This probably isn't the best way but it works for me and has been suitable in my projects so far.
It's human readable so you can see what's going on. Great for debugging when something isn't working right.
It's structured. That helps when you need to save data for objects contained by other objects. For example, in your game world, there is a village, the village contains 10 buildings, building 1 contains 7 lamps, building 2 contains 3 swords, etc.
It's a standard and commonly used format. Your game data files can be read and manipulated in other programs.
The XML file can be encrypted as a way to prevent users from modifying the data.
Example of what the save code could look like:
procedure TMyGame.SaveToFile(const FileName: string);
var
XML : TNativeXML;
RootNode : TXmlNode;
CubeNode : TXmlNode;
begin
XML := TNativeXML.CreateName('root');
try
RootNode := XML.Root;
for c1 := 0 to NumberOfCubes-1 do
begin
CubeNode := RootNode.NodeNew('Cube');
CubeNode.NodeNew('XPos').ValueAsInteger := 10;
CubeNode.NodeNew('YPos').ValueAsInteger := 2;
end;
XML.SaveToFile(FileName);
finally
XML.Free;
end;
end;

Answer 2

I strongly advocate for having human-readable data, such as with an XML or .ini file. If you need to block the user from being able to edit/modify the data, you can do that by "signing" the data and adding a validation key. The key can be generated by your program by taking your sensitive data, appending something that only you know, and then generating an MD5 hash or encrypting it. The MD5 result, or the first 100 bytes of the encrypted string, becomes your key which you would store in the .ini or whatever.
ex:
[MAPSTUFF]
SecretCoordinates=1,2,3,PIRATE TREASURE IS HERE
SignedKey=00042055215e2c6c0d751cb5b086e653
The SignedKey is actually an MD5 of the SecretCoordinates string + :XYZZY:
i.e. I ran this through MD5:
1,2,3,PIRATE TREASURE IS HERE:XYZZY:
and got:
00042055215e2c6c0d751cb5b086e653
So to check in the program, you read SecretCoordinates from the .ini file, add :ZYZZY: to it (in the program, so the user can't see (but if they have a debugger they still can)). And see if you get the same MD5. If it's a match, you're good. If it doesn't match, then the SecretCoordinates string has been tampered with, and you reject it. Very simple.

Answer 3

One of the best ways to save this type of data is by createing a record and saving the record. Then its not something human readable either. Sof first create a new type
TCubeSave = record
number : integer;
x : single;
y : single;
z : single;
texture : string[20];
end;
in this case we want to save the number in the array, along with the data x,y,z and texture?
If doing any string make sure its an array or you will get an error.
Next assign your variables and file and make it write ready.
var
myfile : File of TCubeSave;
cube : TcubeSave;
i : integer;
begin
assignfile(myfile, gamedir+'\maps\test.map');
ReWrite(myfile);
i:=0;
Now write each component of the array,
while (i < totalblocks) do
begin
Check if the component exsist, incase you have removed it or it was not created.
if FindComponent('cubename'+inttostr(i)) <> nil then
begin
Write the data to the file cube
cube.number := i;
cube.x := createcube[i].Position.X;
cube.y := createcube[i].Position.Y;
cube.z := createcube[i].Position.Z;
cube.texture := createcube[i].Material.Texture.ToString;
Write(myfile, cube);
end;
i := i+1;
end;
close the file when done.
CloseFile(myfile);
showmessage('Map Saved');
end;
when ready to read in the file..
// Reopen the file in read only mode
FileMode := fmOpenRead;
Reset(myFile);
// Display the file contents
while not Eof(myFile) do
begin
Read(myFile, cube);
i:= cube.number;
CreateCube[i]:=tcube.Create(self);
createCube[i].Position.x := cube.x;
createcube[i].position.y := cube.y;
ect.....
end;
// Close the file
CloseFile(myFile);