MM1 to MM2 Outdoor

MM1 to MM2 Outdoor

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Same world grid

Both games use the same 5×4 overland sector grid (A1–E4). MM1 areaa1…areae4 in MAZEDATA.DTA match MM2 map.dat screens 5–16 and 33–40 (see tools/mm2_gfx_export.py OUTDOOR_SECTOR_BY_SCREEN).

	MM1	MM2
Geometry file	MAZEDATA.DTA (55×512)	map.dat (60×512)
Per-sector script	*.OVR data segment	event.dat + attrib.dat
Cross-sector links	OVR MAP_*_EXIT_ID + section (16-bit id)	attrib.dat +0x05..+0x08 (screen index)

MM1 exit ids (e.g. areaa1 → north 0x0F01 section 2) are map ids, not MAZEDATA indices; the walker remaps via the shared sector → MM2 screen → MM1 index table in tools/mm1_outdoor_codec.py.

Page encoding (why you cannot memcpy)

MM1 overland page 0 is still MapWalls (ScummVM): four 2-bit fields per cell (WALL_NONE…WALL_DOOR), same as dungeons.

MM2 outdoor page 0 uses terrain ids in the low 5 bits (visual & 0x1F → outb.32), with high bits as passability/flags. The indoor wall frustum and the outdoor horizon renderer read the same page differently (-$79E2 outdoor flag).

Direct copy of MM1 areaa* bytes into MM2 map.dat breaks outdoor 3D and cartography (~4% low-nibble match vs MM2 A1 on identical geography).

Page 1 (collision) is largely compatible: (dark<<1)|wall per direction and 0x80 event flag. MM1 desert cells use states dark bit 0x20 similarly.

Conversion strategy (implemented)

tools/mm1_outdoor_codec.py:

1. Load MM2 template visual/collision/attrib per sector from local map.dat + attrib.dat.
2. Read each area*.OVR WALLPIX lane triple (near / mid / far) and map entries 7–14 to biomes (tools/mm1_wallpix.py WALLPIX_BIOME; see 24-mm1-outdoor-wallpix-by-sector.md).
3. For each MM1 area* screen:
   • Open MM1 cell → MM2 terrain id from far-lane biome (e.g. water → id 2 for ocean decor) instead of only the MM2 template nibble.
   • Blocked MM1 cell → template blocked byte, or 0x60 | terrain wall flag.
   • Border (0xFF or all nibbles 3) → template edge tile (e.g. 0xAC).
   • surface / walker biome (desert_32, ocean_32, tundra_32, swamp_32) from lane biomes (water → 0xCC, mountains → 0x99, swamp/thick forest → 0xBB, etc.).
4. Merge MM1 collision event bits (0x80) into template collision.
5. Set walker neighbors from MM2 attrib, remapped to MM1 screen indices 14–33.

Export sets "conversion": "mm1_walls+mm2_template+wallpix_biome" when GOG *.OVR sit beside MAZEDATA.DTA. Without OVR, falls back to template-only mm1_walls+mm2_template.

This preserves MM1 walkable layout while producing bytes the MM2 outdoor walker understands. Horizon/floor art follows MM1 sector biomes, not MM2’s per-sector map.dat paint.

Limits

Topic	Status
Walker outdoor 3D / minimap	Works with converted bytes + MM2 outdoor .32 sheets
Towns / caves / dungeons	MM2 town / cave / castle .32 frustum (all MM1 towns are interior)
MM1 WALLPIX wall art	Not used in walker (labels only drive overland biomes via OVR)
Exact MM2 map.dat round-trip	Not lossless; templates + heuristics
Towns / dungeons on overland	Still separate MM1 screens (not area*)
OVR events on overland	Not wired to MM2 event.dat

Usage

python tools/export_mm1_map_walker.py   # needs GOG MAZEDATA + repo map.dat/attrib.dat

Overland screens export with "outdoor": true, optional "wallLanes" / "wallBiomes" / "biome", and "conversion": "mm1_walls+mm2_template+wallpix_biome". Re-open wiki/mm1-maze-walker/ — areaa1 etc. use MM2 horizon view (ocean/tundra/swamp/desert .32 sheets) and can step to adjacent sectors when neighbors resolve.

See also

• MM1 MAZEDATA
• map.dat format
• attrib.dat format
• 3D view / outdoor branch

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See also

Page	Why
MM1 Outdoor WALLPIX	Per-sector horizon lanes
MM1 Art and Graphics	WALLPIX sheet layout
map dat Format	MM2 outdoor page 0