add walking and terrain checks to rmmap

2 files changed, 140 insertions, 0 deletions

diff --git a/kon/konrmmap.c b/kon/konrmmap.c
index 0487d84..5e895a3 100644
--- a/kon/konrmmap.c
+++ b/kon/konrmmap.c
@@ -63,3 +63,102 @@ int kon_rmTile(const kon_rmMap_t *map, int layer, int x, int y)
 	if (x < 0 || y < 0 || x >= map->width || y >= map->height) return 0;
 	return map->tiles[((size_t)layer * (size_t)map->height + (size_t)y) * (size_t)map->width + (size_t)x];
 }
+
+/*** walking ***/
+
+int kon_rmFlags(const kon_rmTileset_t *tileset, int tile)
+{
+	if (!tileset || !tileset->flags || tile < 0 || tile >= tileset->flagCount) return 0;
+	return tileset->flags[tile];
+}
+
+int kon_rmRoundX(const kon_rmMap_t *map, int x)
+{
+	if (!map || map->width < 1 || (map->scrollType != 2 && map->scrollType != 3)) return x;
+	return ((x % map->width) + map->width) % map->width;
+}
+
+int kon_rmRoundY(const kon_rmMap_t *map, int y)
+{
+	if (!map || map->height < 1 || (map->scrollType != 1 && map->scrollType != 3)) return y;
+	return ((y % map->height) + map->height) % map->height;
+}
+
+int kon_rmValid(const kon_rmMap_t *map, int x, int y)
+{
+	if (!map) return 0;
+	x = kon_rmRoundX(map, x);
+	y = kon_rmRoundY(map, y);
+	return x >= 0 && y >= 0 && x < map->width && y < map->height;
+}
+
+/* the layers from the top one down, like RPG Maker looks at them */
+int kon_rmPassable(const kon_rmMap_t *map, const kon_rmTileset_t *tileset, int x, int y, int dir)
+{
+	int bit, layer;
+
+	if (!map || dir < 2 || dir > 8 || dir % 2) return 0;
+	x = kon_rmRoundX(map, x);
+	y = kon_rmRoundY(map, y);
+	bit = (1 << (dir / 2 - 1)) & 0x0f;
+	for (layer = 3; layer >= 0; layer--) {
+		int flags = kon_rmFlags(tileset, kon_rmTile(map, layer, x, y));
+
+		if (flags & KON_RM_FLAG_NO_EFFECT) continue;
+		if ((flags & bit) == 0) return 1;
+		if ((flags & bit) == bit) return 0;
+	}
+	return 0;
+}
+
+int kon_rmCanWalk(const kon_rmMap_t *map, const kon_rmTileset_t *tileset, int x, int y, int dir)
+{
+	int dx = 0, dy = 0, x2, y2;
+
+	if (!map) return 0;
+	switch (dir) {
+	case KON_RM_DOWN: dy = 1; break;
+	case KON_RM_LEFT: dx = -1; break;
+	case KON_RM_RIGHT: dx = 1; break;
+	case KON_RM_UP: dy = -1; break;
+	default: return 0;
+	}
+	x2 = kon_rmRoundX(map, x + dx);
+	y2 = kon_rmRoundY(map, y + dy);
+	if (!kon_rmValid(map, x2, y2)) return 0;
+	if (!kon_rmPassable(map, tileset, x, y, dir)) return 0;
+	return kon_rmPassable(map, tileset, x2, y2, 10 - dir);
+}
+
+int kon_rmTerrainTag(const kon_rmMap_t *map, const kon_rmTileset_t *tileset, int x, int y)
+{
+	int layer;
+
+	if (!kon_rmValid(map, x, y)) return 0;
+	x = kon_rmRoundX(map, x);
+	y = kon_rmRoundY(map, y);
+	for (layer = 3; layer >= 0; layer--) {
+		int tag = kon_rmFlags(tileset, kon_rmTile(map, layer, x, y)) >> 12;
+
+		if (tag > 0) return tag;
+	}
+	return 0;
+}
+
+int kon_rmRegion(const kon_rmMap_t *map, int x, int y)
+{
+	return kon_rmTile(map, 5, x, y);
+}
+
+int kon_rmHasFlag(const kon_rmMap_t *map, const kon_rmTileset_t *tileset, int x, int y, int flag)
+{
+	int layer;
+
+	if (!kon_rmValid(map, x, y)) return 0;
+	x = kon_rmRoundX(map, x);
+	y = kon_rmRoundY(map, y);
+	for (layer = 0; layer < 4; layer++) {
+		if (kon_rmFlags(tileset, kon_rmTile(map, layer, x, y)) & flag) return 1;
+	}
+	return 0;
+}
diff --git a/kon/konrmmap.h b/kon/konrmmap.h
index 6274822..27bbe40 100644
--- a/kon/konrmmap.h
+++ b/kon/konrmmap.h
@@ -144,6 +144,47 @@ int kon_rmEventPage(const kon_rmEvent_t *event, int mapId, const kon_rmState_t *
 /* layer is 0 to 5, the four tile layers, the shadows and the regions. 0 outside of the map or for a layer that is not there */
 int kon_rmTile(const kon_rmMap_t *map, int layer, int x, int y);
 
+/*** walking ***/
+
+/* the directions RPG Maker uses, the numbers on a keypad */
+#define KON_RM_DOWN 2
+#define KON_RM_LEFT 4
+#define KON_RM_RIGHT 6
+#define KON_RM_UP 8
+
+/* the flags of a tile in a tileset, the tile layers of the map read from the top one down. a tile past the end of the flags
+   has none. these are RPG Maker's own bits, in kon_rmFlags and below */
+#define KON_RM_FLAG_NO_EFFECT 0x10 /* a star in the editor: this tile does not decide whether you can walk */
+#define KON_RM_FLAG_LADDER 0x20
+#define KON_RM_FLAG_BUSH 0x40
+#define KON_RM_FLAG_COUNTER 0x80
+#define KON_RM_FLAG_DAMAGE 0x100
+
+int kon_rmFlags(const kon_rmTileset_t *tileset, int tile);
+
+/* is x, y inside the map, once a map that loops has wrapped it. loops are the map's scroll type */
+int kon_rmValid(const kon_rmMap_t *map, int x, int y);
+
+/* wraps x or y for a map that loops that way, other positions stay as they are */
+int kon_rmRoundX(const kon_rmMap_t *map, int x);
+int kon_rmRoundY(const kon_rmMap_t *map, int y);
+
+/* can something on x, y leave this tile going dir, as far as the tiles say. no events and no outside of the map here */
+int kon_rmPassable(const kon_rmMap_t *map, const kon_rmTileset_t *tileset, int x, int y, int dir);
+
+/* can it step from x, y to the next tile in dir: the next tile is on the map, and both tiles let it through, the one it is
+   on on the way out and the next on the way in. what an event on the tile would say about it is for the game to ask */
+int kon_rmCanWalk(const kon_rmMap_t *map, const kon_rmTileset_t *tileset, int x, int y, int dir);
+
+/* the terrain tag a tile is marked with in the editor, 0 for none, 0 outside of the map. the top layer that has one wins */
+int kon_rmTerrainTag(const kon_rmMap_t *map, const kon_rmTileset_t *tileset, int x, int y);
+
+/* the region painted on x, y, 0 for none */
+int kon_rmRegion(const kon_rmMap_t *map, int x, int y);
+
+/* 1 when any of the layers of that tile has the flag, 0 outside of the map */
+int kon_rmHasFlag(const kon_rmMap_t *map, const kon_rmTileset_t *tileset, int x, int y, int flag);
+
 #ifdef __cplusplus
 }
 #endif