Levels can now be converted to RLE encoded chunk accessors and be re-saved
continuously without any loss of information.
Off-by-one errors resolved:
* The rle.NewGrid() was adding a +1 everywhere making the 2D grids have 129
elements to a side for a 128 chunk size.
* In rle.Decompress() the cursor value and translation to X,Y coordinates is
fixed to avoid a pixel going missing at the end of the first row (128,0)
* The abs.X-- hack in UnmarshalBinary is no longer needed to prevent the
chunks from scooting a pixel to the right on every save.
Doodad tool updates:
* Remove unused CLI flags in `doodad resave` (actors, chunks, script,
attachment, verbose) and add a `--output` flag to save to a different file
name to the original.
* Update `doodad show` to allow debugging of RLE compressed chunks:
* CLI flag `--chunk=1,2` to specify a single chunk coordinate to debug
* CLI flag `--visualize-rle` will Visualize() RLE compressed chunks in
their 2D grid form in your terminal window (VERY noisy for large
levels! Use the --chunk option to narrow to one chunk).
Bug fixes and misc changes:
* Chunk.Usage() to return a better percentage of chunk utilization.
* Chunker.ChunkFromZipfile() was split out into two functions:
* RawChunkFromZipfile retrieves the raw bytes of the chunk as well as the
file extension discovered (.bin or .json) so the caller can interpret
the bytes correctly.
* ChunkFromZipfile calls the former function and then depending on file
extension, unmarshals from binary or json.
* The Raw function enables the `doodad show` command to debug and visualize
the raw contents of the RLE compressed chunks.
* Updated the Visualize() function for the RLE encoder: instead of converting
palette indexes to hex (0-F) which would begin causing problems for palette
indexes above 16 (as they would use two+ characters), indexes are mapped to
a wider range of symbols (0-9A-Z) and roll over if you have more than 36
colors on your level. This at least keeps the Visualize() grid an easy to
read 128x128 characters in your terminal.
Finally add a second option for Chunk MapAccessor implementation besides the
MapAccessor. The RLEAccessor is basically a MapAccessor that will compress
your drawing with Run Length Encoding (RLE) in the on-disk format in the ZIP
file.
This slashes the file sizes of most levels:
* Shapeshifter: 21.8 MB -> 8.1 MB
* Jungle: 10.4 MB -> 4.1 MB
* Zoo: 2.8 MB -> 1.3 MB
Implementation details:
* The RLE binary format for Chunks is a stream of Uvarint pairs storing the
palette index number and the number of pixels to repeat it (along the Y,X
axis of the chunk).
* Null colors are represented by a Uvarint that decodes to 0xFFFF
or 65535 in decimal.
* Gameplay logic currently limits maps to 256 colors.
* The default for newly created chunks in-game will be RLE by default.
* Its in-memory representation is still a MapAccessor (a map of absolute
world coordinates to palette index).
* The game can still open and play legacy MapAccessor maps.
* On save in the editor, the game will upgrade/convert MapAccessor chunks over
to RLEAccessors, improving on your level's file size with a simple re-save.
Current Bugs
* On every re-save to RLE, one pixel is lost in the bottom-right corner of
each chunk. Each subsequent re-save loses one more pixel to the left, so what
starts as a single pixel per chunk slowly evolves into a horizontal line.
* Some pixels smear vertically as well.
* Off-by-negative-one errors when some chunks Iter() their pixels but compute
a relative coordinate of (-1,0)! Some mismatch between the stored world coords
of a pixel inside the chunk vs. the chunk's assigned coordinate by the Chunker:
certain combinations of chunk coord/abs coord.
To Do
* The `doodad touch` command should re-save existing levels to upgrade them.
Noah