Tiles

[Democritus]

Hi

I am new to game programming. I have downloaded Nokia's 2D example. I understand pretty much what is happening. However one thing I can't get my head around is tiles. There is one mbm file, which contains one bmp, level0.mbm. From this the entire background is created. How is that so? The image contains different aspects of the backgound, like mountains and things to jump on. It is only one image though. If anyone has docs on this, I would be grateful.

[ltomuta]

level0.mbm contains 2 bitmaps, each of them holding a set of sprites (I hope I'm not misusing the term here).

Here's how you can have a look inside the mbm file:

F:\Work\Example2D\data>bmconv /v level0.mbm


BMCONV version 112.
level0.mbm is a File store containing 2 bitmaps

Bitmap 1 information:
Pixel size 1224 x 8
Twips size 4337 x 28
12 Bpp Colour
12 bit RLE compression 23%

Bitmap 2 information:
Pixel size 1224 x 8
Twips size 4337 x 28
16 Bpp Colour
16 bit RLE compression 32%


F:\Work\Example2D\data>bmconv /u level0.mbm bm1.bmp bm2.bmp


BMCONV version 112.
Decompiling...
Epoc file: level0.mbm

Bitmap file 1   : bm1.bmp
Bitmap file 2   : bm2.bmp
Success.

F:\Work\Example2D\data>

[Democritus]

Hi

Thanks for the reply. I knew that already. My question was more how are those two bmps used to make an entire game. For example the first sprites in that picture are diamonds. How are they cut from the bmp and placed in the right location.

I think this is the call:

iTileMap = CTileMap::NewL( iBmTile, TSize( KMapW, KMapH ), KLevel0,/* this, */ iSystem );

If you look at ctile.h they are located but I don't know how.

Thanks

[ltomuta]

A bitmap has 8x1224 pixels. With the sprite size being 8x8 that means that the bitmap contains 153 sprites.

In level0.h the defined map has 3x22x255 tiles, for each tile specifying which of the sprite to be loaded (values between 0 and 152).

Each set of 22x255 tiles represents a layer of graphics which overlapped create the graphic environment of the game.

The rest is in the source code ...

[Democritus]

Thanks alot, that's what I was trying to figure out.

I still don't know, how this is mapped to the screen? For example, how are those mountains put there in that order? The diamonds and monsters I can see in code, but not that background stuff.

Thanks for the help.

[ltomuta]

Does this help ?

[Democritus]

Hi,

Ok thanks, I understand the basics of it now. It seems quite a system, just to make a background. If I want to change the 3rd pixle down from the top left, I must count 459 ( 153 x 3 ) elements along the array. I'm guessing there must be a simpler solution.

[ltomuta]

There are many ways of skinning a cat I would assume that those guys who wrote this app had some kind of visual level editor otherwise one would go nuts setting those values.

[olhed]

There is a lot of visual tile map editors out there, do a google on "Tile Editor".

I'd recommend using one of those for creating your maps, only masochists create tile maps by hand

In the "old days", you often made a tile map editor from the same engine you used in your game, specific for the game you were creating.

[anupamamd123]

Hi,
Even I am facing same problem in understanding the code, It seems tile map is defined in 3 layers can u tell how that is and do u know any free tile editor tool....