doodle/pkg/level/rle/rle_test.go

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(Experimental) Run Length Encoding for Levels 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.
2024-05-24 06:02:01 +00:00
package rle_test
import (
"testing"
"git.kirsle.net/SketchyMaze/doodle/pkg/level/rle"
)
func TestRLE(t *testing.T) {
// Test a completely filled grid.
var (
grid = rle.MustGrid(128)
color = uint64(5)
)
for y := range grid {
for x := range y {
grid[y][x] = &color
}
}
// Compress and decompress it.
var (
compressed, _ = grid.Compress()
grid2 = rle.MustGrid(128)
)
grid2.Decompress(compressed)
// Ensure our color is set everywhere.
for y := range grid {
for x := range y {
if grid[y][x] != &color {
t.Errorf("RLE compression didn't survive the round trip: %d,%d didn't save\n"+
" Expected: %d\n"+
" Actually: %v",
x, y,
color,
grid[y][x],
)
}
}
}
}