room_default_entrance.h

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#ifndef YAZE_ZELDA3_DUNGEON_ROOM_DEFAULT_ENTRANCE_H
#define YAZE_ZELDA3_DUNGEON_ROOM_DEFAULT_ENTRANCE_H
 
#include <cstdint>
#include <vector>
 
namespace yaze {
 
class Rom;
 
namespace zelda3 {
 
// How a room's default entrance was chosen.
enum class RoomEntranceSource : uint8_t {
  kNone,        // No entrance could be associated with the room.
  kDirect,      // An entrance leads straight into the room.
  kDungeonMap,  // The room is on a dungeon's pause-menu map.
  kNeighbour,   // Inherited from an adjacent room in the 16-wide room grid.
};
 
// The entrance the game would most plausibly load a room through, and the
// main graphics set that entrance selects.
//
// The game's main blockset ($0AA1) comes only from the entrance
// (Underworld_LoadEntrance: EntranceData.main_GFX -> $0AA1); moving between
// rooms never changes it. The room header's blockset byte is the secondary
// set ($0AA2). A room entered through a door therefore uses the main graphics
// of the dungeon it belongs to, which yaze recovers here.
struct RoomDefaultEntrance {
  int entrance_id = -1;          // Regular entrance index, or -1.
  uint8_t main_blockset = 0xFF;  // EntranceData.main_GFX, or 0xFF.
  RoomEntranceSource source = RoomEntranceSource::kNone;
  int via_room = -1;  // For kNeighbour: the room inherited from.
};
 
struct GameData;
 
// The source selected by the same main-blockset precedence as
// Room::LoadRoomGraphics. A default is direct only when the default entrance
// actually leads into this room; map and neighbour defaults are inferred.
enum class RoomMainBlocksetSource : uint8_t {
  kExplicitPreview,
  kDirectDefault,
  kInferredDefault,
  kHeaderFallback,
  kZeroFallback,
};
 
struct RoomMainBlocksetResolution {
  uint8_t main_blockset = 0;
  RoomMainBlocksetSource source = RoomMainBlocksetSource::kZeroFallback;
};
 
RoomMainBlocksetResolution ResolveRoomMainBlockset(
    int room_id, uint8_t header_blockset, uint8_t requested_main_blockset,
    const GameData& game_data);
 
// Palette half for a destination background slot (tile ID / 64). The game's
// runtime upload slot runs in the opposite direction. Index zero remains
// transparent; apply this offset only to nonzero 3bpp pixel indices.
int DungeonBackgroundPaletteOffset(uint8_t main_blockset, int destination_slot);
 
// One entry per dungeon room (kNumberOfRooms), in order:
//  1. an entrance whose room is this room;
//  2. an entrance of the dungeon whose pause-menu map lists the room (map
//     index to dungeon ID by majority over that map's direct entrances);
//  3. the choice of a neighbouring room (+-1 in the same row, +-16).
std::vector<RoomDefaultEntrance> ComputeRoomDefaultEntrances(Rom& rom);
 
}  // namespace zelda3
}  // namespace yaze
 
#endif  // YAZE_ZELDA3_DUNGEON_ROOM_DEFAULT_ENTRANCE_H