doodle/docs/RLE Encoding for Levels.md

RLE Encoding for Levels

This documents some of the file size savings of the game's built-in levelpacks and doodads once the file format was migrated to use Run Length Encoding (RLE) for drawing chunks.

See Evolution of File Formats for a history of the game's file formats.

Levels

The file sizes of the levels themselves:

First Quest

Filename	Orig Size	New Size	Reduction
Boat.level	4.3M	292K	93%
Castle.level	5.6M	241K	95%
Desert-1of2.level	4.4M	248K	94%
Desert-2of2.level	3.2M	290K	91%
Jungle.level	11M	581K	94%
Shapeshifter.level	22M	263K	98%
Thief 1.level	538K	193K	64%

In raw bytes:

Filename	Orig Size	New Size
Boat.level	4494184	298943
Castle.level	5854222	245872
Desert-1of2.level	4589382	253768
Desert-2of2.level	3310784	296681
Jungle.level	10928779	594601
Shapeshifter.level	22823811	269307
Thief 1.level	550579	196731

The levelpack ZIP:

• Filename: builtin-100-FirstQuest.levelpack
• Original: 50M (52369408)
• New size: 1.8M (1838542) 96%

Tutorial

Filename	Orig Size	New Size	Reduction
Tutorial 1.level	186K	111K	40%
Tutorial 2.level	680K	229K	66%
Tutorial 3.level	409K	148K	64%
Tutorial 4.level	901K	376K	58%
Tutorial 5.level	3M	645K	78%
Zoo.level	2.8M	226K	92%

In raw bytes:

Filename	Orig Size	New Size
Tutorial 1.level	190171	113568
Tutorial 2.level	695936	233880
Tutorial 3.level	418490	150565
Tutorial 4.level	921781	384775
Tutorial 5.level	3059902	659487
Zoo.level	2925633	230712

The levelpack ZIP:

• Filename: builtin-Tutorial.levelpack
• Original: 7.8M (8119658)
• New size: 1.6M (1650381) 79%

Azulian Tag

Filename	Orig Size	New Size	Reduction
AzulianTag-Forest.level	17M	312K	98%
AzulianTag-Night.level	702K	145K	79%
AzulianTag-Tutorial.level	3.4M	185K	94%

In raw bytes:

Filename	Orig Size	New Size
AzulianTag-Forest.level	17662031	318547
AzulianTag-Night.level	718345	147612
AzulianTag-Tutorial.level	3508093	189310

The levelpack ZIP:

• Filename: builtin-200-AzulianTag.levelpack
• Original: 21M (21824441)
• New size: 525K (537345) 97%

Doodads

Spot check of random doodad filesize changes:

Filename	Orig Size	New Size
anvil.doodad	2.7K	1.3K
azu-blu.doodad	8.1K	5.2K
azu-red.doodad	8.1K	5.2K
azu-white.doodad	8.1K	5.2K
box.doodad	29K	4.1K
boy.doodad	30K	8.1K
crumbly-floor.doodad	15K	3.3K
door-blue.doodad	18K	2.7K
electric-trapdoor.doodad	9.5K	2.8K

Total file size of all builtin doodads:

• Original: 576.8 KiB
• New: 153.7 KiB (73% reduction)

Game Binary

• Filename: sketchymaze
• Original: 105M
• New size: 30M, 71% smaller