(svn r16138) -Codechange: move GetClosestWaterDistance to map*

1 files changed, 57 insertions, 0 deletions

diff --git a/src/map.cpp b/src/map.cpp
index ba6c82dba..8e7aeffed 100644
--- a/src/map.cpp
+++ b/src/map.cpp
@@ -8,6 +8,7 @@
 #include "core/alloc_func.hpp"
 #include "core/math_func.hpp"
 #include "map_func.h"
+#include "tile_map.h"
 
 #if defined(_MSC_VER)
 /* Why the hell is that not in all MSVC headers?? */
@@ -327,3 +328,59 @@ bool CircularTileSearch(TileIndex *tile, uint radius, uint w, uint h, TestTileOn
 	*tile = INVALID_TILE;
 	return false;
 }
+
+/*!
+ * Finds the distance for the closest tile with water/land given a tile
+ * @param tile  the tile to find the distance too
+ * @param water whether to find water or land
+ * @return distance to nearest water (max 0x7F) / land (max 0x1FF; 0x200 if there is no land)
+ * @note FAILS when an industry should be seen as water
+ */
+uint GetClosestWaterDistance(TileIndex tile, bool water)
+{
+	if (IsTileType(tile, MP_WATER) == water) return 0;
+
+	uint max_dist = water ? 0x7F : 0x200;
+
+	int x = TileX(tile);
+	int y = TileY(tile);
+
+	uint max_x = MapMaxX();
+	uint max_y = MapMaxY();
+	uint min_xy = _settings_game.construction.freeform_edges ? 1 : 0;
+
+	/* go in a 'spiral' with increasing manhattan distance in each iteration */
+	for (uint dist = 1; dist < max_dist; dist++) {
+		/* next 'diameter' */
+		y--;
+
+		/* going counter-clockwise around this square */
+		for (DiagDirection dir = DIAGDIR_BEGIN; dir < DIAGDIR_END; dir++) {
+			static const int8 ddx[DIAGDIR_END] = { -1,  1,  1, -1};
+			static const int8 ddy[DIAGDIR_END] = {  1,  1, -1, -1};
+
+			int dx = ddx[dir];
+			int dy = ddy[dir];
+
+			/* each side of this square has length 'dist' */
+			for (uint a = 0; a < dist; a++) {
+				/* MP_VOID tiles are not checked (interval is [min; max) for IsInsideMM())*/
+				if (IsInsideMM(x, min_xy, max_x) && IsInsideMM(y, min_xy, max_y)) {
+					TileIndex t = TileXY(x, y);
+					if (IsTileType(t, MP_WATER) == water) return dist;
+				}
+				x += dx;
+				y += dy;
+			}
+		}
+	}
+
+	if (!water) {
+		/* no land found - is this a water-only map? */
+		for (TileIndex t = 0; t < MapSize(); t++) {
+			if (!IsTileType(t, MP_VOID) && !IsTileType(t, MP_WATER)) return 0x1FF;
+		}
+	}
+
+	return max_dist;
+}