Opening and saving maps

What the editor does with a map file: what it preserves, what Save can strip, revisions, protected and built maps.

This section contains documentation on what scmJS does with a StarCraft map file when it opens and saves one. This is for anyone who wants to know what happens to their file: map makers deciding what to keep in a release copy, and people fixing a broken or protected map. The user guide covers the Save dialog itself; this document explains the file it writes. The format itself, section by section, is in the CHK format reference.

The short version: the editor opens .scm, .scx and bare .chk files, rewrites only the parts of the scenario you changed, and copies everything else through byte for byte, including things it does not understand and things it cannot even name. A map loses nothing by passing through the editor unless you ask for it in the Save dialog.

• The archiveA .scm or .scx file is an MPQ archive, the container format Blizzard used for its games' data.
• The scenarioThe scenario is a flat sequence of sections, each a four-character name, a length and that many bytes of data: MTXM holds the terrain, UNIT the placed units, TRIG the triggers.
• SectionsThe CHK format reference lists every section the editor knows, with a page for each.
• RevisionsThe revision is the VER value.
• New mapsFile ▸ New writes a Brood War map with the section set StarEdit writes for one: the x layouts of the settings tables only, and without IVER, SWNM and CRGB, which StarEdit adds when there …
• Protected and damaged mapsA protected map is one written to be played but not edited: sections repeated, resized or given nonsense names, the archive's file list removed, the scenario member renamed or duplicated,…
• Looking at the bytesThe Section Explorer plugin, installed from Plugins ▸ Browse Plugins…, is a hex editor over the scenario: every section with what the editor knows about it, its bytes coloured by field, e…
• In the sourceFor developers.