1

/* $Id$ */

     2

     3

#include "stdafx.h"

     4

#include "tile.h"

     5

     6

/** Converts the heights of 4 corners into a tileh, and returns the minimum height of the tile

     7

  * @param n,w,e,s the four corners

     8

  * @param h uint pointer to write the height to

     9

  * @return the tileh

    10

*/

    11

uint GetTileh(uint n, uint w, uint e, uint s, uint *h)

    12

{

    13

	uint min = n;

    14

	uint r;

    15

    16

	if (min >= w) min = w;

    17

	if (min >= e) min = e;

    18

	if (min >= s) min = s;

    19

    20

	r = 0;

    21

	if ((n -= min) != 0) r += (--n << 4) + 8;

    22

	if ((e -= min) != 0) r += (--e << 4) + 4;

    23

	if ((s -= min) != 0) r += (--s << 4) + 2;

    24

	if ((w -= min) != 0) r += (--w << 4) + 1;

    25

    27

    28

	return r;

    29

}

    30

    31

uint GetTileSlope(TileIndex tile, uint *h)

    32

{

    33

	uint a;

    34

	uint b;

    35

	uint c;

    36

	uint d;

    37

    38

	assert(tile < MapSize());

    39

    40

	if (TileX(tile) == MapMaxX() || TileY(tile) == MapMaxY()) {

    41

		if (h != NULL) *h = 0;

    42

		return 0;

    43

	}

    44

    45

	a = TileHeight(tile);

    46

	b = TileHeight(tile + TileDiffXY(1, 0));

    47

	c = TileHeight(tile + TileDiffXY(0, 1));

    48

	d = TileHeight(tile + TileDiffXY(1, 1));

    49

    50

	return GetTileh(a, b, c, d, h);

    51

}

    52

    53

uint GetTileZ(TileIndex tile)

    54

{

    55

	uint h;

    56

	GetTileSlope(tile, &h);

    57

	return h;

    58

}