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-rw-r--r--src/tile_map.cpp186
-rw-r--r--src/tile_map.h8
2 files changed, 162 insertions, 32 deletions
diff --git a/src/tile_map.cpp b/src/tile_map.cpp
index 9855484df..17d7d6a39 100644
--- a/src/tile_map.cpp
+++ b/src/tile_map.cpp
@@ -15,7 +15,99 @@
#include "safeguards.h"
/**
- * Return the slope of a given tile
+ * Returns the tile height for a coordinate outside map. Such a height is
+ * needed for painting the area outside map using completely black tiles.
+ * The idea is descending to heightlevel 0 as fast as possible.
+ * @param x The X-coordinate (same unit as TileX).
+ * @param y The Y-coordinate (same unit as TileY).
+ * @return The height in the same unit as TileHeight.
+ */
+uint TileHeightOutsideMap(int x, int y)
+{
+ /* In all cases: Descend to heightlevel 0 as fast as possible.
+ * So: If we are at the 0-side of the map (x<0 or y<0), we must
+ * subtract the distance to coordinate 0 from the heightlevel at
+ * coordinate 0.
+ * In other words: Subtract e.g. -x. If we are at the MapMax
+ * side of the map, we also need to subtract the distance to
+ * the edge of map, e.g. MapMaxX - x.
+ *
+ * NOTE: Assuming constant heightlevel outside map would be
+ * simpler here. However, then we run into painting problems,
+ * since whenever a heightlevel change at the map border occurs,
+ * we would need to repaint anything outside map.
+ * In contrast, by doing it this way, we can localize this change,
+ * which means we may assume constant heightlevel for all tiles
+ * at more than <heightlevel at map border> distance from the
+ * map border.
+ */
+ if (x < 0) {
+ if (y < 0) {
+ return max((int)TileHeight(TileXY(0, 0)) - (-x) - (-y), 0);
+ } else if (y < (int)MapMaxY()) {
+ return max((int)TileHeight(TileXY(0, y)) - (-x), 0);
+ } else {
+ return max((int)TileHeight(TileXY(0, (int)MapMaxY())) - (-x) - (y - (int)MapMaxY()), 0);
+ }
+ } else if (x < (int)MapMaxX()) {
+ if (y < 0) {
+ return max((int)TileHeight(TileXY(x, 0)) - (-y), 0);
+ } else if (y < (int)MapMaxY()) {
+ return TileHeight(TileXY(x, y));
+ } else {
+ return max((int)TileHeight(TileXY(x, (int)MapMaxY())) - (y - (int)MapMaxY()), 0);
+ }
+ } else {
+ if (y < 0) {
+ return max((int)TileHeight(TileXY((int)MapMaxX(), 0)) - (x - (int)MapMaxX()) - (-y), 0);
+ } else if (y < (int)MapMaxY()) {
+ return max((int)TileHeight(TileXY((int)MapMaxX(), y)) - (x - (int)MapMaxX()), 0);
+ } else {
+ return max((int)TileHeight(TileXY((int)MapMaxX(), (int)MapMaxY())) - (x - (int)MapMaxX()) - (y - (int)MapMaxY()), 0);
+ }
+ }
+}
+
+/**
+ * Get a tile's slope given the heigh of its four corners.
+ * @param hnorth The height at the northern corner in the same unit as TileHeight.
+ * @param hwest The height at the western corner in the same unit as TileHeight.
+ * @param heast The height at the eastern corner in the same unit as TileHeight.
+ * @param hsouth The height at the southern corner in the same unit as TileHeight.
+ * @param [out] h The lowest height of the four corners.
+ * @return The slope.
+ */
+static Slope GetTileSlopeGivenHeight(int hnorth, int hwest, int heast, int hsouth, int *h)
+{
+ /* Due to the fact that tiles must connect with each other without leaving gaps, the
+ * biggest difference in height between any corner and 'min' is between 0, 1, or 2.
+ *
+ * Also, there is at most 1 corner with height difference of 2.
+ */
+ int hminnw = min(hnorth, hwest);
+ int hmines = min(heast, hsouth);
+ int hmin = min(hminnw, hmines);
+
+ if (h != NULL) *h = hmin;
+
+ int hmaxnw = max(hnorth, hwest);
+ int hmaxes = max(heast, hsouth);
+ int hmax = max(hmaxnw, hmaxes);
+
+ Slope r = SLOPE_FLAT;
+
+ if (hnorth != hmin) r |= SLOPE_N;
+ if (hwest != hmin) r |= SLOPE_W;
+ if (heast != hmin) r |= SLOPE_E;
+ if (hsouth != hmin) r |= SLOPE_S;
+
+ if (hmax - hmin == 2) r |= SLOPE_STEEP;
+
+ return r;
+}
+
+/**
+ * Return the slope of a given tile inside the map.
* @param tile Tile to compute slope of
* @param h If not \c NULL, pointer to storage of z height
* @return Slope of the tile, except for the HALFTILE part
@@ -29,35 +121,31 @@ Slope GetTileSlope(TileIndex tile, int *h)
return SLOPE_FLAT;
}
- int a = TileHeight(tile); // Height of the N corner
- int min = a; // Minimal height of all corners examined so far
- int b = TileHeight(tile + TileDiffXY(1, 0)); // Height of the W corner
- if (min > b) min = b;
- int c = TileHeight(tile + TileDiffXY(0, 1)); // Height of the E corner
- if (min > c) min = c;
- int d = TileHeight(tile + TileDiffXY(1, 1)); // Height of the S corner
- if (min > d) min = d;
+ int hnorth = TileHeight(tile); // Height of the North corner.
+ int hwest = TileHeight(tile + TileDiffXY(1, 0)); // Height of the West corner.
+ int heast = TileHeight(tile + TileDiffXY(0, 1)); // Height of the East corner.
+ int hsouth = TileHeight(tile + TileDiffXY(1, 1)); // Height of the South corner.
- /* Due to the fact that tiles must connect with each other without leaving gaps, the
- * biggest difference in height between any corner and 'min' is between 0, 1, or 2.
- *
- * Also, there is at most 1 corner with height difference of 2.
- */
-
- uint r = SLOPE_FLAT; // Computed slope of the tile
-
- /* For each corner if not equal to minimum height:
- * - set the SLOPE_STEEP flag if the difference is 2
- * - add the corresponding SLOPE_X constant to the computed slope
- */
- if ((a -= min) != 0) r += (--a << 4) + SLOPE_N;
- if ((c -= min) != 0) r += (--c << 4) + SLOPE_E;
- if ((d -= min) != 0) r += (--d << 4) + SLOPE_S;
- if ((b -= min) != 0) r += (--b << 4) + SLOPE_W;
-
- if (h != NULL) *h = min;
+ return GetTileSlopeGivenHeight(hnorth, hwest, heast, hsouth, h);
+}
- return (Slope)r;
+/**
+ * Return the slope of a given tile outside the map.
+ *
+ * @param tile Tile outside the map to compute slope of.
+ * @param h If not \c NULL, pointer to storage of z height.
+ * @return Slope of the tile outside map, except for the HALFTILE part.
+ */
+Slope GetTilePixelSlopeOutsideMap(int x, int y, int *h)
+{
+ int hnorth = TileHeightOutsideMap(x, y); // N corner.
+ int hwest = TileHeightOutsideMap(x + 1, y); // W corner.
+ int heast = TileHeightOutsideMap(x, y + 1); // E corner.
+ int hsouth = TileHeightOutsideMap(x + 1, y + 1); // S corner.
+
+ Slope s = GetTileSlopeGivenHeight(hnorth, hwest, heast, hsouth, h);
+ if (h != NULL) *h *= TILE_HEIGHT;
+ return s;
}
/**
@@ -93,7 +181,7 @@ int GetTileZ(TileIndex tile)
{
if (TileX(tile) == MapMaxX() || TileY(tile) == MapMaxY()) return 0;
- int h = TileHeight(tile); // N corner
+ int h = TileHeight(tile); // N corner
h = min(h, TileHeight(tile + TileDiffXY(1, 0))); // W corner
h = min(h, TileHeight(tile + TileDiffXY(0, 1))); // E corner
h = min(h, TileHeight(tile + TileDiffXY(1, 1))); // S corner
@@ -102,18 +190,52 @@ int GetTileZ(TileIndex tile)
}
/**
- * Get top height of the tile
+ * Get bottom height of the tile outside map.
+ *
+ * @param tile Tile outside the map to compute height of.
+ * @return Minimum height of the tile outside the map.
+ */
+int GetTilePixelZOutsideMap(int x, int y)
+{
+ uint h = TileHeightOutsideMap(x, y); // N corner.
+ h = min(h, TileHeightOutsideMap(x + 1, y)); // W corner.
+ h = min(h, TileHeightOutsideMap(x, y + 1)); // E corner.
+ h = min(h, TileHeightOutsideMap(x + 1, y + 1)); // S corner
+
+ return h * TILE_HEIGHT;
+}
+
+/**
+ * Get top height of the tile inside the map.
* @param t Tile to compute height of
* @return Maximum height of the tile
*/
int GetTileMaxZ(TileIndex t)
{
- if (TileX(t) == MapMaxX() || TileY(t) == MapMaxY()) return 0;
+ if (TileX(t) == MapMaxX() || TileY(t) == MapMaxY()) return TileHeightOutsideMap(TileX(t), TileY(t));
- int h = TileHeight(t); // N corner
+ int h = TileHeight(t); // N corner
h = max<int>(h, TileHeight(t + TileDiffXY(1, 0))); // W corner
h = max<int>(h, TileHeight(t + TileDiffXY(0, 1))); // E corner
h = max<int>(h, TileHeight(t + TileDiffXY(1, 1))); // S corner
return h;
}
+
+/**
+ * Get top height of the tile outside the map.
+ *
+ * @see Detailed description in header.
+ *
+ * @param tile Tile outside to compute height of.
+ * @return Maximum height of the tile.
+ */
+int GetTileMaxPixelZOutsideMap(int x, int y)
+{
+ uint h = TileHeightOutsideMap(x, y);
+ h = max(h, TileHeightOutsideMap(x + 1, y));
+ h = max(h, TileHeightOutsideMap(x, y + 1));
+ h = max(h, TileHeightOutsideMap(x + 1, y + 1));
+
+ return h * TILE_HEIGHT;
+}
diff --git a/src/tile_map.h b/src/tile_map.h
index 98863eb59..af1cc32dc 100644
--- a/src/tile_map.h
+++ b/src/tile_map.h
@@ -34,6 +34,8 @@ static inline uint TileHeight(TileIndex tile)
return GB(_m[tile].type_height, 0, 4);
}
+uint TileHeightOutsideMap(int x, int y);
+
/**
* Sets the height of a tile.
*
@@ -262,6 +264,8 @@ static inline Slope GetTilePixelSlope(TileIndex tile, int *h)
return s;
}
+Slope GetTilePixelSlopeOutsideMap(int x, int y, int *h);
+
/**
* Get bottom height of the tile
* @param tile Tile to compute height of
@@ -272,6 +276,8 @@ static inline int GetTilePixelZ(TileIndex tile)
return GetTileZ(tile) * TILE_HEIGHT;
}
+int GetTilePixelZOutsideMap(int x, int y);
+
/**
* Get top height of the tile
* @param t Tile to compute height of
@@ -282,6 +288,8 @@ static inline int GetTileMaxPixelZ(TileIndex tile)
return GetTileMaxZ(tile) * TILE_HEIGHT;
}
+int GetTileMaxPixelZOutsideMap(int x, int y);
+
/**
* Calculate a hash value from a tile position