• Death is natural, there is no afterlife in the way any "holy" book tells us (I try to imagine that there is still some way to maintain consciousness after death, though)
• There is no god in the way people depict him (If anything, the Universe itself is "god" as it is omnipresent and omniscient and omnipotent)
• Religion (or its canonical misinterpretation) is the reason for almost all the wars and conflicts and cruelties
• I support Israel in the Israeli-Palestinian conflict and all other conflicts. It's a democratic and scientifically advanced, small, brave country. I don't support orthodox ultra-anything anyone, be it Jews or Muslims, but Palestinian Muslims are more aggressive and less educated. An influx of those into a country like Israel would mean the end of all democratic and scientific values there. (There are more Palestinians than there are Jews)

^These are not the replies we were looking for.

^I second that. This is gonna be a thing.

Thanks! There was a code/result update again, but still not working as intended. I think it's the frontier behaviour (it's supposed to be a stack, I believe).

Code

And sometimes it returns an access violation error so indexes/lengths aren't always correct. The DeleteArrayItem procedure I got from somewhere on the Internet doesn't help by being so unclear either.

Cross-post from reddit, but man, this was really... strange, and amazing in a way. Good ad, that's for sure.

Here is what I came up with by porting this JavaScript code into Delphi:

unit Unit_Lab;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs;

type
  THindernis = record
    x1, y1, x2, y2: Integer;
  end;

type
  TCell = record
    r, c: Integer;
  end;

type
  TCellArray = Array of TCell;

type
  TForm1 = class(TForm)
    procedure FormPaint(Sender: TObject);
    procedure DeleteArrayItem(var X: TCellArray; const Index: Integer) ;
    procedure MarkFrontiers(row, col: Integer);
    procedure CreateBranch(row, col: Integer);
    procedure AttachCellToTree(row, col, direction: Integer);
    procedure RemoveWall(row, col, direction: Integer);
    procedure RemoveCellFromFrontier(row, col: Integer);
    procedure MazeCreate();
    procedure MazeConvert();
    function CellWithinBorders(row, col: Integer): Boolean;
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  hindernisse: Array [0..3071] of THindernis;
  maze: Array [0..23, 0..23] of Byte;
  frontier: TCellArray;

const
  NO_EXIT  = $00;

  EXIT_EAST  = $01;
  EXIT_NORTH = $02;
  EXIT_WEST  = $04;
  EXIT_SOUTH = $08;

  CELL_INCLUDED = $10;
  CELL_FRONTIER = $20;

  DIR_EAST  = 0;
  DIR_NORTH = 1;
  DIR_WEST  = 2;
  DIR_SOUTH = 3;

  DCOL: Array [0..3] of Integer = (1, 0, -1, 0);
  DROW: Array [0..3] of Integer = (0, -1, 0, 1);

implementation

{$R *.dfm}

procedure TForm1.DeleteArrayItem(var X: TCellArray; const Index: Integer) ;
begin
   if Index > High(X) then Exit;
   if Index < Low(X) then Exit;
   if Index = High(X) then
   begin
     SetLength(X, Length(X) - 1) ;
     Exit;
   end;
   Finalize(X[Index]) ;
   System.Move(X[Index +1], X[Index],(Length(X) - Index -1) * SizeOf(TCell) + 1) ;
   SetLength(X, Length(X) - 1) ;
end;

function TForm1.CellWithinBorders(row, col: Integer): Boolean;
begin
  Result := (row >= 0) and (row < length(maze)) and (col >= 0) and (col < length(maze));
end;

  procedure TForm1.MarkFrontiers(row, col: Integer);
  var k, r, c: Integer;
  begin
    for k := 0 to 3 do begin
      r := row + DROW[k];
      c := col + DCOL[k];

      if CellWithinBorders(r, c)
      and (not ((maze[r, c] and CELL_INCLUDED) = CELL_INCLUDED)
      and not ((maze[r, c] and CELL_FRONTIER) = CELL_FRONTIER))
      then begin
        maze[r, c] := maze[r, c] xor CELL_FRONTIER;
        SetLength(frontier, length(frontier) + 1);
        frontier[length(frontier)].r := r;
        frontier[length(frontier)].c := c;
      end;
    end;
  end;

  procedure TForm1.CreateBranch(row, col: Integer);
  var
    currRow, currCol, randDir, i, d, r, c: Integer;
    bMoved: Boolean;
  begin
    randomize();
    AttachCellToTree(row, col, -1);
    MarkFrontiers(row, col);
    currRow := row;
    currCol := col;

    repeat
      bMoved  := False;
      randDir := random(3);

      for i := 0 to 3 do begin
        d := (randDir + i) mod 3;
        r := currRow + DROW[d];
        c := currCol + DCOL[d];

        if CellWithinBorders(r, c) and ((maze[r, c] and CELL_FRONTIER) = CELL_FRONTIER) then begin
          AttachCellToTree(r, c, (d + 2) mod 3);
          bMoved  := True;
          currRow := r;
          currCol := c;
          Break;
        end;
      end;
    until not bMoved;
  end;

  procedure TForm1.RemoveWall(row, col, direction: Integer);
  begin
    case direction of
      DIR_EAST: begin
          maze[row, col] := maze[row, col] or EXIT_EAST;
          maze[row, col + 1] := maze[row, col + 1] or EXIT_WEST;
        end;
      DIR_NORTH: begin
          maze[row, col] := maze[row, col] or EXIT_NORTH;
          maze[row - 1, col] := maze[row - 1, col] or EXIT_SOUTH;
        end;
      DIR_WEST: begin
          maze[row, col] := maze[row, col] or EXIT_WEST;
          maze[row, col - 1] := maze[row, col - 1] or EXIT_EAST;
        end;
      DIR_SOUTH: begin
          maze[row, col] := maze[row, col] or EXIT_SOUTH;
          maze[row + 1, col] := maze[row + 1, col] or EXIT_NORTH;
        end;
    end;
  end;

  procedure TForm1.RemoveCellFromFrontier(row, col: Integer);
  var i: Integer;
  begin
    maze[row, col] := maze[row, col] xor CELL_FRONTIER;
    for i := 0 to length(frontier) do begin
      if (frontier[i].r = row) and (frontier[i].c = col) then begin
        DeleteArrayItem(frontier, i);
        Break;
      end;
    end;
  end;

  procedure TForm1.AttachCellToTree(row, col, direction: Integer);
  var randDir, i, d, r, c: Integer;
  begin
    randomize();
    RemoveCellFromFrontier(row, col);

    if direction = -1 then begin
      randDir := random(3);

      for i := 0 to 3 do begin
        d := (i + randDir) mod 3;
        r := row + DROW[d];
        c := col + DCOL[d];

        if CellWithinBorders(r, c) and ((maze[r, c] or CELL_INCLUDED) = CELL_INCLUDED) then begin
          RemoveWall(r, c, d);
          Break;
        end;
      end;
    end
    else begin
      RemoveWall(row, col, direction);
    end;
  end;

procedure TForm1.MazeCreate();
var
  i, j, t: Integer;
  startR, startC: Integer;
begin
  randomize();

  for i := 0 to length(maze) do begin
     for j := 0 to length(maze) do begin
        maze[i, j] := NO_EXIT;
     end;
  end;

  startR := random(length(maze)-1);
  startC := random(length(maze)-1);

  maze[startR, startC] := maze[startR, startC] or CELL_INCLUDED;
  MarkFrontiers(startR, startC);

  while (length(frontier) > 0) do begin
    t := random(length(frontier)-1);
    CreateBranch(frontier[t].r, frontier[t].c);
  end;

  MazeConvert();
end;

procedure TForm1.MazeConvert();
var i, j, x0, y0, x1, y1, c: Integer;
begin
  c := 0;
  for i := 0 to length(maze) do begin
    for j := 0 to length(maze) do begin
      x0 := (j + 1) * 10;
      y0 := (i + 1) * 10;
      x1 := x0 + 10;
      y1 := y0 + 10;

      if (maze[i, j] and EXIT_NORTH) = NO_EXIT then begin
         hindernisse[c].x1 := x0;
         hindernisse[c].y1 := y0;
         hindernisse[c].x2 := x1;
         hindernisse[c].y2 := y0;
         c := c + 1;
      end;
      if (maze[i, j] and EXIT_SOUTH) = NO_EXIT then begin
         hindernisse[c].x1 := x0;
         hindernisse[c].y1 := y1;
         hindernisse[c].x2 := x1;
         hindernisse[c].y2 := y1;
         c := c + 1;
      end;
      if (maze[i, j] and EXIT_WEST)  = NO_EXIT then begin
         hindernisse[c].x1 := x0;
         hindernisse[c].y1 := y0;
         hindernisse[c].x2 := x0;
         hindernisse[c].y2 := y1;
         c := c + 1;
      end;
      if (maze[i, j] and EXIT_EAST)  = NO_EXIT then begin
         hindernisse[c].x1 := x1;
         hindernisse[c].y1 := y0;
         hindernisse[c].x2 := x1;
         hindernisse[c].y2 := y1;
         c := c + 1;
      end;
    end;
  end;
  //ShowMessage('N, S, W, E: ' + Format('%d, %d, %d, %d', [n, s, w, e]));
end;

procedure TForm1.FormPaint(Sender: TObject);
var
  i: Integer;
begin
  CANVAS.Brush.Color := RGB(255, 255, 255);
  CANVAS.Rectangle(0, 0, 640, 480);
  CANVAS.Brush.Color := RGB(0, 0, 0);

  MazeCreate();

  for i:= 0 to length(hindernisse) do begin
    CANVAS.MoveTo(hindernisse[i].x1, hindernisse[i].y1);
    CANVAS.LineTo(hindernisse[i].x2, hindernisse[i].y2);
  end;
end;

end.

Unfortunately, I always get this result:

Please help!

Edit: Updated code and result, still not working as intended.

@Jin_sama No no, not because of you. Because of Colorless, mostly.

I made a simple game in which obstacles are saved as TObstacle records with four coordinates x1, y1, x2, y2. The player is a simple rectangle that can move around with the arrow keys. There is collision detection, so the player cannot move over the obstacles.

Now, I need to generate a maze for the level. I googled a lot, I even bugged @halcy, but to no success. I do not understand how to properly implement Depth-First Search in my use-case, most of the code online is for console applications that output that maze as you go using ASCII.

Help, me, Colorless!

@Sutol Thanks!

@PigBoss Originally the prototype for this pig was my best friend from school :3c