map.h

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#ifndef ALCHEMY_MAP_H
#define ALCHEMY_MAP_H
 
/// @file
/// Maps: their cells, layers, animations and blend scripts, and the map state.
 
#include "unit/field/field.h"
#include "types.h"
#include "static_assert.h"
 
/// One cell of a map layer: its metatile and flags, its collision code and an
/// attribute indexing the collision table.
struct MapCell {
  /// bits: 15..12 flags (15..14 read by Map_GetCellHighFlags) | 11..0 metatile
  u16 metatileAndFlags;
  /// The step code: 1 to 239 scene events, 240 and 241 encounter ground, 250
  /// hazard, 252 to 254 for Field_RunPushTileEvent, 0xff a wall.
  u8 collisionCode;
  /// Indexes the 4-byte collision entries (gMapCollision): terrain kind in the
  /// first byte's low four bits, then its height samples.
  u8 attributeB;
};
 
/// A map layer's scroll record, seen from its cells.
struct MapLayer {
  struct MapCell *cells; ///< the layer's first cell (MapLayerScroll's cells)
  u8 unk04[0x2c]; ///< the next layer's scroll values; not named by TBS code
};
 
/// The map's running blend script, which sets the blend registers over time.
struct BlendScriptState {
  u16 *script;
  u16 *cursor;
  u16 delay; ///< frames
  u16 paused;
};
 
/// One of the 16 tile animation channels, which copy tiles into VRAM by
/// script.
struct MapAnimation {
  const u16 *start;
  const u16 *cursor;
  u16 timer; ///< frames
  u16 paused;
};
 
/// The map work in heap slot 8 (struct MapScrollWork), seen as its tile
/// animation channels, blend script and layers' cells.
struct MapState {
  u8 unk000[0x14]; ///< MapScrollWork's origin, shake and script
  u16 flags;       ///< REG_DISPCNT bits; Map_SetShownLayers sets BG1 to BG3
  u8 wideTiles;    ///< nonzero: tile animations copy 64-byte tiles
  u8 unk17;        ///< MapScrollWork's footprints; Bilibin Cave sets it
  struct MapAnimation anim[16];
  struct BlendScriptState blend;
  u8 unke4[0x1f]; ///< MapScrollWork's view, bounds and shown layers
  /// The last BLDCNT the blend script wrote; with mode 1 in bits 7..6 its
  /// values go to BLDALPHA, else to BLDY.
  u8 blendControl;
  u8 unk104[0x2c]; ///< the first layer's scroll values; not named by TBS code
  /// Each layer's cells, at MapScrollWork's layers[i].cells; readers mask the
  /// layer with 3, and the fourth entry lies past MapScrollWork's end.
  struct MapLayer layers[4];
};
 
STATIC_ASSERT(sizeof(struct MapAnimation) == 12);
STATIC_ASSERT(offsetof(struct MapState, flags) == 0x14);
STATIC_ASSERT(offsetof(struct MapState, wideTiles) == 0x16);
STATIC_ASSERT(offsetof(struct MapState, anim) == 0x18);
STATIC_ASSERT(offsetof(struct MapState, blend) == 0xd8);
STATIC_ASSERT(offsetof(struct MapState, layers) == 0x130);
 
/// A position on the world map, as its walkability check reads it.
struct WorldPosition {
  s32 x;      ///< 16.16 fixed-point pixels
  s32 height; ///< 16.16 fixed-point pixels
  s32 y;      ///< 16.16 fixed-point pixels
};
 
extern u32 gMapBlocks[];
 
extern u8 gMapLayerData[];
 
extern u8 gMapCollision[];
 
extern u8 gBgTileBuffer[];
 
extern u8 *gMapAnimationPages;
 
#endif