OpenTTD-patches/tile.c

59 lines
1.1 KiB
C

/* $Id$ */
#include "stdafx.h"
#include "tile.h"
/** Converts the heights of 4 corners into a tileh, and returns the minimum height of the tile
* @param n,w,e,s the four corners
* @param h uint pointer to write the height to
* @return the tileh
*/
Slope GetTileh(uint n, uint w, uint e, uint s, uint *h)
{
uint min = n;
Slope r;
if (min >= w) min = w;
if (min >= e) min = e;
if (min >= s) min = s;
r = SLOPE_FLAT;
if ((n -= min) != 0) r += (--n << 4) + SLOPE_N;
if ((e -= min) != 0) r += (--e << 4) + SLOPE_E;
if ((s -= min) != 0) r += (--s << 4) + SLOPE_S;
if ((w -= min) != 0) r += (--w << 4) + SLOPE_W;
if (h != NULL) *h = min * TILE_HEIGHT;
return r;
}
Slope GetTileSlope(TileIndex tile, uint *h)
{
uint a;
uint b;
uint c;
uint d;
assert(tile < MapSize());
if (TileX(tile) == MapMaxX() || TileY(tile) == MapMaxY()) {
if (h != NULL) *h = 0;
return 0;
}
a = TileHeight(tile);
b = TileHeight(tile + TileDiffXY(1, 0));
c = TileHeight(tile + TileDiffXY(0, 1));
d = TileHeight(tile + TileDiffXY(1, 1));
return GetTileh(a, b, c, d, h);
}
uint GetTileZ(TileIndex tile)
{
uint h;
GetTileSlope(tile, &h);
return h;
}