anchor.diff:      begin
         fTilesVtx[aI].X := aTX-1;
         fTilesVtx[aI].Y := aTY-1 - Land[aTY, aTX].Height / CELL_HEIGHT_DIV;
  -      fTilesVtx[aI].Z := aTY - 1 - Byte(aIsBottomRow);
  +      fTilesVtx[aI].Z := aTY-1 - Byte(aIsBottomRow);
         fTilesVtx[aI].UTile := aUTile;
         fTilesVtx[aI].VTile := aVTile;
         fTilesVtx[aI].ULit := Land[aTY, aTX].Light;
  
positive.code:   SizeX := Max(fClipRect.Right - fClipRect.Left, 0);
    SizeY := Max(fClipRect.Bottom - fClipRect.Top, 0);
    H := 0;
    SetLength(fTilesVtx, (SizeX + 2) * 4 * (SizeY + 1));
    with gTerrain do
    if (MapX > 0) and (MapY > 0) then
    for I := 0 to SizeY do
    for K := 0 to SizeX+1 do
    begin
      tX := K + fClipRect.Left;
      tY := I + fClipRect.Top;
  
negative.code:   for I := 0 to SizeY do
    for K := 0 to SizeX do
    begin
      Row := I * (SizeX + 1) * 4;
      fTilesInd[H+0] := Row + K * 4;
      fTilesInd[H+1] := Row + K * 4 + 1;
      fTilesInd[H+2] := Row + K * 4 + 2;
  