From df013784fcefb208a23c8e339e099ab2795a4f91 Mon Sep 17 00:00:00 2001
From: Martin Michelsen <fuzziqersoftware+g@gmail.com>
Date: Mon, 11 Sep 2023 11:24:35 -0700
Subject: [PATCH] document map_category field in MapDefinition

---
 src/Episode3/DataIndexes.cc |  6 +++---
 src/Episode3/DataIndexes.hh | 18 +++++++++++++-----
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/src/Episode3/DataIndexes.cc b/src/Episode3/DataIndexes.cc
index 8c786431..60ba0fc7 100644
--- a/src/Episode3/DataIndexes.cc
+++ b/src/Episode3/DataIndexes.cc
@@ -1521,7 +1521,7 @@ string MapDefinition::str(const CardIndex* card_index) const {
   lines.emplace_back(string_printf("  level_overrides=[win=%" PRId32 ", loss=%" PRId32 "]",
       this->win_level_override.load(), this->loss_level_override.load()));
   lines.emplace_back(string_printf("  a9=[%04hX %04hX]", this->unknown_a9_c.load(), this->unknown_a9_d.load()));
-  lines.emplace_back(string_printf("  a10=%02hhX", this->unknown_a10));
+  lines.emplace_back(string_printf("  map_category=%02hhX", this->map_category));
   lines.emplace_back(string_printf("  cyber_block_type=%02hhX", this->cyber_block_type));
   lines.emplace_back(string_printf("  a11=%02hhX%02hhX", this->unknown_a11[0], this->unknown_a11[1]));
   static const array<const char*, 0x18> sc_card_entry_names = {
@@ -1647,7 +1647,7 @@ MapDefinitionTrial::MapDefinitionTrial(const MapDefinition& map)
       loss_level_override(map.loss_level_override),
       unknown_a9_c(map.unknown_a9_c),
       unknown_a9_d(map.unknown_a9_d),
-      unknown_a10(map.unknown_a10),
+      map_category(map.map_category),
       cyber_block_type(map.cyber_block_type),
       unknown_a11(map.unknown_a11),
       unknown_t12(0xFF) {
@@ -2075,7 +2075,7 @@ const string& MapIndex::get_compressed_list(size_t num_players) const {
       strings_w.write(map.description.data(), map.description.len());
       strings_w.put_u8(0);
 
-      e.unknown_a1 = map_it.second->is_quest ? 0x00 : 0xFF;
+      e.map_category = map_it.second->is_quest ? 0x00 : 0xFF;
 
       entries_w.put(e);
       num_maps++;
diff --git a/src/Episode3/DataIndexes.hh b/src/Episode3/DataIndexes.hh
index b66ffbd1..e704e4e9 100644
--- a/src/Episode3/DataIndexes.hh
+++ b/src/Episode3/DataIndexes.hh
@@ -803,6 +803,8 @@ struct MapList {
   be_uint32_t total_size; // Including header, entries, and strings
 
   struct Entry {
+    // The fields in this structure have the same meanings as the corresponding
+    // fields in MapDefinition.
     /* 0000 */ be_uint16_t map_x;
     /* 0002 */ be_uint16_t map_y;
     /* 0004 */ be_uint16_t environment_number;
@@ -817,9 +819,7 @@ struct MapList {
     /* 001A */ be_uint16_t height;
     /* 001C */ parray<parray<uint8_t, 0x10>, 0x10> map_tiles;
     /* 011C */ parray<parray<uint8_t, 0x10>, 0x10> modification_tiles;
-    // This appears to be 0xFF for free battle maps, and 0 for quests.
-    // TODO: Figure out what this field's meaning actually is
-    /* 021C */ uint8_t unknown_a1;
+    /* 021C */ uint8_t map_category;
     /* 021D */ parray<uint8_t, 3> unused;
     /* 0220 */
   } __attribute__((packed));
@@ -984,7 +984,15 @@ struct MapDefinition { // .mnmd format; also the format of (decompressed) quests
 
   /* 59D8 */ be_uint16_t unknown_a9_c;
   /* 59DA */ be_uint16_t unknown_a9_d;
-  /* 59DC */ uint8_t unknown_a10;
+
+  // map_category appears to specify where in the menu the map should appear in
+  // offline mode. (In online mode, this is ignored, and the map's location in
+  // the menu is determined by the corresponding field in the compressed map
+  // list instead.) If this is FF, the map appears in the Free Battle section;
+  // if it's a small positive number (usually 0 or 2), the map appears in the
+  // Quest section instead. It's not known if this controls anything else; the
+  // values 0, 1, and 2 appear to all do the same thing here.
+  /* 59DC */ uint8_t map_category;
 
   // This field determines block graphics to be used in the Cyber environment.
   // There are 10 block types (0-9); if this value is > 9, type 0 is used.
@@ -1082,7 +1090,7 @@ struct MapDefinitionTrial {
   /* 416C */ be_uint32_t loss_level_override;
   /* 4170 */ be_uint16_t unknown_a9_c;
   /* 4172 */ be_uint16_t unknown_a9_d;
-  /* 4174 */ uint8_t unknown_a10;
+  /* 4174 */ uint8_t map_category;
   /* 4175 */ uint8_t cyber_block_type;
   /* 4176 */ parray<uint8_t, 2> unknown_a11;
   // TODO: This field may contain some version of unavailable_sc_cards and/or