Sync fieldmap

include/global.fieldmap.h

@@ -1,13 +1,23 @@
 #ifndef GUARD_GLOBAL_FIELDMAP_H
 #define GUARD_GLOBAL_FIELDMAP_H
 
-#define METATILE_BEHAVIOR_MASK 0x00FF
-#define METATILE_COLLISION_MASK 0x0C00
-#define METATILE_ID_MASK 0x03FF
-#define METATILE_ID_UNDEFINED 0x03FF
-#define METATILE_ELEVATION_SHIFT 12
-#define METATILE_COLLISION_SHIFT 10
-#define METATILE_ELEVATION_MASK 0xF000
+// Masks/shifts for blocks in the map grid
+// Map grid blocks consist of a 10 bit metatile id, a 2 bit collision value, and a 4 bit elevation value
+// This is the data stored in each data/layouts/*/map.bin file
+#define MAPGRID_METATILE_ID_MASK 0x03FF // Bits 0-9
+#define MAPGRID_COLLISION_MASK   0x0C00 // Bits 10-11
+#define MAPGRID_ELEVATION_MASK   0xF000 // Bits 12-15
+#define MAPGRID_COLLISION_SHIFT  10
+#define MAPGRID_ELEVATION_SHIFT  12
+
+// An undefined map grid block has all metatile id bits set and nothing else
+#define MAPGRID_UNDEFINED   MAPGRID_METATILE_ID_MASK
+
+enum {
+    METATILE_LAYER_TYPE_NORMAL,  // Metatile uses middle and top bg layers
+    METATILE_LAYER_TYPE_COVERED, // Metatile uses bottom and middle bg layers
+    METATILE_LAYER_TYPE_SPLIT,   // Metatile uses bottom and top bg layers
+};
 
 #define METATILE_ID(tileset, name) (METATILE_##tileset##_##name)
 
@@ -22,6 +32,7 @@ enum
     METATILE_ATTRIBUTE_LAYER_TYPE,
     METATILE_ATTRIBUTE_7,
     METATILE_ATTRIBUTE_COUNT,
+    METATILE_ATTRIBUTES_ALL = 255  // Special id to get the full attributes value
 };
 
 enum