93 lines
3.2 KiB
C++
93 lines
3.2 KiB
C++
/* $Id$ */
|
|
|
|
/*
|
|
* This file is part of OpenTTD.
|
|
* OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
|
|
* OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
|
|
* See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
/** @file tile_map.cpp Global tile accessors. */
|
|
|
|
#include "stdafx.h"
|
|
#include "tile_map.h"
|
|
#include "core/math_func.hpp"
|
|
|
|
/**
|
|
* Return the slope of a given tile
|
|
* @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 */
|
|
Slope GetTileSlope(TileIndex tile, uint *h)
|
|
{
|
|
assert(tile < MapSize());
|
|
|
|
if (TileX(tile) == MapMaxX() || TileY(tile) == MapMaxY() ||
|
|
(_settings_game.construction.freeform_edges && (TileX(tile) == 0 || TileY(tile) == 0))) {
|
|
if (h != NULL) *h = TileHeight(tile) * TILE_HEIGHT;
|
|
return SLOPE_FLAT;
|
|
}
|
|
|
|
uint a = TileHeight(tile); // Height of the N corner
|
|
uint min = a; // Minimal height of all corners examined so far
|
|
uint b = TileHeight(tile + TileDiffXY(1, 0)); // Height of the W corner
|
|
if (min > b) min = b;
|
|
uint c = TileHeight(tile + TileDiffXY(0, 1)); // Height of the E corner
|
|
if (min > c) min = c;
|
|
uint d = TileHeight(tile + TileDiffXY(1, 1)); // Height of the S corner
|
|
if (min > d) min = d;
|
|
|
|
/* 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 * TILE_HEIGHT;
|
|
|
|
return (Slope)r;
|
|
}
|
|
|
|
/**
|
|
* Get bottom height of the tile
|
|
* @param tile Tile to compute height of
|
|
* @return Minimum height of the tile */
|
|
uint GetTileZ(TileIndex tile)
|
|
{
|
|
if (TileX(tile) == MapMaxX() || TileY(tile) == MapMaxY()) return 0;
|
|
|
|
uint 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
|
|
|
|
return h * TILE_HEIGHT;
|
|
}
|
|
|
|
/**
|
|
* Get top height of the tile
|
|
* @param t Tile to compute height of
|
|
* @return Maximum height of the tile */
|
|
uint GetTileMaxZ(TileIndex t)
|
|
{
|
|
if (TileX(t) == MapMaxX() || TileY(t) == MapMaxY()) return 0;
|
|
|
|
uint h = TileHeight(t); // N corner
|
|
h = max(h, TileHeight(t + TileDiffXY(1, 0))); // W corner
|
|
h = max(h, TileHeight(t + TileDiffXY(0, 1))); // E corner
|
|
h = max(h, TileHeight(t + TileDiffXY(1, 1))); // S corner
|
|
|
|
return h * TILE_HEIGHT;
|
|
}
|