Getting Game Graphics (Good)

[NickH]

Galvanize!

Right, we need to sort out our way of getting graphics into the game. At the moment the little people in the game were made by Darthster by typing a long series of 0's and 1's into an Enigma machine. So we need to at least be able to import stuff from images.

The HAM kit comes with converters that turn your BMPs that you drew in MSPaint/Photoshop, into GBA flavour. However the command lines you have to type are confusing; it changes depending on if you're converting a sprite or a map or a palette.
I'll work it all out and put up something on the Wiki. But hopefully we'll just put some extra stuff in the Makefile, and then if you have the BMPs in the right place it should just make it much easier for everyone to have the right graphics stuff.

So I'll keep you posted on the progress of this.

But you can start drawing art anyway! If you're not sure what we need drawing, then just think of whatever comes into your head, and we'll probably need it!

Does Sam want to butt in with a sketch of Horratio, so that either him or someone else can try to squish him into 16 by 32 pixels? Tar.

[Dan]

Was just looking into drawing something then I realised I had forgotten what size everything was supposed to be. Sam told me some numbers so I wrote them on the wiki graphics page but he wasn't sure so I put question marks next to them.

Can somone help me out with correct numbers so I can get cracking?

I thought I'd start with something fairly simple and do Grass and dirt with transition tiles between them plus a few bushes and flowers.

[NickH]

16x16 as a basic tile or 8x8 for details.

I saw your tiles you made

http://www.warwickgamedesign.co.uk/dev. ... 2FGraphics

and it was good. I don't know if we're going to draw the tiles separately then stitch them together afterwards, or do things another way. We just need all the tile graphics for any one level to be all in one image, so at some point it will need together-making.

It would probably be a good idea if we went as far as mapping out what tiles will go on the tileset we're starting with (which seems to be the generic outdoor one), because if we start making maps with a tileset then move tiles around it'll all go to pot. But if we decide what tiles we need then we'll be sorted. This is the sort of thing we can figure out at meetings!

I'll try and get Dan's graphics into a tileset for now though, so we can play.

Dan mentioned that instead of manualling placing different grass/dirt variations around and doing the transition pieces manually, that the map editor could possibly deal with this. This would be a good idea and would actually be pretty simple to implement, we just need someone to keep working on the map editor Nick hasn't done a lot in a while. I only pretend to understand Visual Basic. I guess I could have a go.

[Dan]

I made dem tiles good.

A further size query, this image that all the tiles at one level have to be part of, how big can that be in pixels? dost there need to be gaps between the tiles? or do they just press up right next to one another?

[NickH]

Yo sup. Well the demo one we had was 256x96, which amounts to 384 mini-tiles of 8x8, or 96 base tiles of 16x16. Which is probably plenty for any one level.

I don't know if 256x96 is some kind of limit or anything, or if we could have larger tilesets. I'll look it up on the HAM docs.

I think it's 256x128, which is 128 base tiles. That's loads. We probably don't need that many, using less is better because it means we're less likely to run out of memory.

In any case, the width of the tileset is 256. So if you stick stuff in there then we can just enlarge it downwards if we do find we need more tiles.

And yeah, they should be exactly next to each other, 8x8 squares without gaps.

We'll use BMPs as the source but you can work in PNG, easy to convert.

Safe!

[NickH]

Another thing about graphics. There are two palettes on the GBA, one for the background tiles and one for sprites. The background isn't really a problem as we'll only have one tileset at any one time.

The sprites thing could be more troublesome though, as all the sprites on screen are sharing the same 256-color palette. I think it might make sense if we get a palette sorted out before we start doing a lot of sprite graphics?

Perhaps the standard web-safe palette would be suitable?


ALSO

I was just reading Darthster's little section in the Graphics wiki page, apparently tiles can be flipped horizontally and vertically, so you can save on tiles by just drawing eg. downward grass->dirt, and for the other way we can flip.

[Mat]

Can we not generate transition tiles on the fly by using a mask and two normal tiles?

[NickH]

I don't knooowwwww. Possibly. I know what you mean. The thing is whatever tiles we have, I'm pretty sure will still have to be within the one tileset object, and so we'd have to generate them inside this, so we'd still have the tile number limit, but then we'd also have the trouble of dynamically allocating spots in this tilespace for the various transitions, which is likely to be a lot.

So yeah, it's a good idea, but the GBA can't do it in tile mode.

I expect games like Golden Sun do their special effects like transitions and overlapping and variable-width text, by just using the bitmap mode and implementing their own tile engine. Which probably involves lots of low level coding to make it work efficiently. We just have to work with what we've got, and this just means we will have to limit the different types of ground we have.

[Mat]

I reckon I could quite easily write code to generate tiles from two others using a mask. It's only a bitmapped C-Array, you could quite easily generate a new tile where there should be a transition on the fly from the one to the left and the one to the right, or whatever, and overlap them... I do reckon I could probably recreate Golden Sun, because I am the hackiest of all hacksor programmer kids.

[Mat]

Same for the text combining, could quite easily do it if someone wants to draw all the letters and combine it into 8x8 tiles on the fly.

[NickH]

I reckon I could quite easily write code to generate tiles from two others using a mask. It's only a bitmapped C-Array, you could quite easily generate a new tile where there should be a transition on the fly from the one to the left and the one to the right, or whatever, and overlap them

I know the creating of the tile would be pretty easy. What I'm saying is that for the tile engine to access it, it has to go into the tileset, which is limited to 128 16x16 tiles. We can't just draw directly onto the map, and we can't just have a bunch of lone tiles in memory, at least not in the GBA tile engine. It's not a matter of generating them on the fly, it's just we'd have nowhere to put them.

Unless you want to start the engine again (again!) using bitmap mode

[NickH]

Having said that... we wouldn't have to start again totally... just the drawing bit... not sure if bitmap mode still has sprites...

ah don't encourage me!

[Dan]

I'm thinking I should hold off on my graphics until we knows what we are doing?

[NickH]

Might be a plan. For the ground tiles at least. You can draw other stuff like rocks and buildings, whatever we end up with we'll still be using tiles of them. Just use magenta or something as the background and we can sort out palettes later.

[Dan]

I updated the wiki again with some more tiley goodness. This time featuring wall, rocks flowers and a bush!

All the fun of christmas but with more graphics.