# Asset Loader

## Current state

TGA loading is implemented in `game/src/assets.rs`. `Image::from_tga(path)` reads the file,
parses the 18-byte header, skips the colormap block, and returns an `Image` — supporting
type 1 (uncompressed) and type 9 (RLE) via the private `decode_rle()` function in the same
module. `game.rs` uses it directly: `Image::from_tga("assets/tilesets/overworld.tga")`.

`Image` also provides `to_tileset() -> Vec<[u8; 64]>`, which splits the image into 8×8
tiles row-major. Every tile is emitted; tile ID is the flat row-major index into the Vec,
so tiles are never skipped or reordered. (Transparency is a per-pixel concern handled at
blit time by `blit_tile`, not by the splitter.)

`AssetStore` (a named registry) is **not yet implemented**. Assets are currently loaded
inline in `Game::start()`.

## Goal

Add an `AssetStore` so that game code can ask for an asset by name rather than loading
files directly at the call site.

## Design notes

- `Image` struct: `width: u32`, `height: u32`, `pixels: Vec<u8>` — done.
- A simple `AssetStore` could be a `HashMap<&'static str, Image>` loaded at startup.
- No streaming needed — the whole game is small enough to load everything upfront in `start()`.
- Palette index 0 is transparent when blitting sprites. This convention is enforced by
  `blit_tile()` in `pixelhelper.rs`; the loader itself does not need to handle it.
- Pixel assets are stored as flat `Vec<u8>` of palette indices, row-major, width × height bytes.
- Future: consider embedding assets with `include_bytes!` to produce a single binary.

## Open questions

- Should `AssetStore` hold pre-split tilesets too, or just raw `Image` values?