---------------------------------
Tanky V4 level format description
    (tanky_v4.lev)
---------------------------------

total 243100 bytes (for 11 levels)
total 22100 bytes per level
Can contain any number of levels

Game has 11 levels by default, but you can add more to the file. 
Program will detect it by num_levels=filesize/levelsize.

One level format:
  "T_V4"       4 bytes - magic
  level_description_str 60 bytes - a text description of current level
  x            2 bytes  \                  - xposition of tank (in tiles)
  y            2 bytes   | x6 = 36 bytes   - yposition of tank (in tiles)
  direction    2 bytes  /                  - starting direction of tank
                                             (0-31, 0=0 deg, 1=11.25 deg, ...)
  level_attr   22000 bytes - map (it's 80x55 tiles, 5 bytes per tile attr)

tile attr:
  tile_number     1 byte - number of tile (0-199)
  tile_endurance  1 byte - HP of tile (number of hits needed to break tile,
                           endurance=255 for indestructible tile)
  cycle_min       1 byte
  cycle_max       1 byte
  cycle_init      1 byte - initial value of cycle


Cycle explanation:
  Cycling is new feature in V4.
  When level starts, each tile's actual_cycle starts at cycle_init.
  If actual_cycle==cycle_max, hide the tile, actual_cycle=0
  If actual_cycle==cycle_min, show the tile
  Tile is not cycling if cycle_min==0, it is always visible.
  First the cycling is done, then the logic (tank positions, shots) is updated.
  Hidden tiles don't take any damage, they don't reflect shots.

  For the moment, all tiles are shown in the beginning (it adds a nice look). They
  are erased after the cycle_max value is reached.

  Example
    cycle_min=1; cycle_max=2; cycle_init=0;
    the cycling is : 0,1(hide),2->0(show),0,1(hide),2->0(show)
    tile is shown 1 cycle (cycle_min), hidden 1 cycle (cycle_max-cycle_min)
  Example 2:
    cycle_min=3; cycle_max=5; cycle_init=0;
    the cycling is : 0,1,2,3(hide),4,5->0(show),1,2,...
    tile is shown 3 (cycle_min) cycles, hidden 2 cycles (cycle_max-cycle_min)
    visible cycles are 0,1,2; hidden cycles are 3,4


----------------------------
Tile file format description 
     (tanky_v4.dat)
----------------------------

Tanky V4 has 200 8x8 tiles + 3 big 16x16 tiles.
Tiles have 16 colors.
First 3x(16x16)=768 bytes define 3 big tiles.
Then 200x(8x8)=12800 bytes define 200 normal tiles.
1 byte = 1 color (color is 0-15).
Total : 13568 bytes.

These tiles have special function:
big tile 0 = shield icon
big tile 1 = velocity icon
big tile 2 = ammo icon

normal tile 0 = void tile (shots and players pass thru it).
normal tile 50 = invisible tile (players pass thru it, shots are reflected).
                 Make sure this tile is all black, or you will see it.

