src/tile/zoneheight.h

   1 /*
   2  * This file is part of OpenTTD.
   3  * 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.
   4  * 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.
   5  * 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/>.
   6  */
   7
   8 /** @file tile/zoneheight.h Types related to tile zone and height. */
   9
  10 #ifndef TILE_ZONEHEIGHT_H
  11 #define TILE_ZONEHEIGHT_H
  12
  13 #include "../stdafx.h"
  14 #include "../core/bitmath_func.hpp"
  15 #include "../direction_type.h"
  16
  17 static const uint MAX_TILE_HEIGHT     = 255;                   ///< Maximum allowed tile height
  18
  19 static const uint MIN_MAX_HEIGHTLEVEL = 15;                    ///< Lower bound of maximum allowed heightlevel (in the construction settings)
  20 static const uint DEF_MAX_HEIGHTLEVEL = 30;                    ///< Default maximum allowed heightlevel (in the construction settings)
  21 static const uint MAX_MAX_HEIGHTLEVEL = MAX_TILE_HEIGHT;       ///< Upper bound of maximum allowed heightlevel (in the construction settings)
  22
  23 static const uint MIN_SNOWLINE_HEIGHT = 2;                     ///< Minimum snowline height
  24 static const uint DEF_SNOWLINE_HEIGHT = 15;                    ///< Default snowline height
  25 static const uint MAX_SNOWLINE_HEIGHT = (MAX_TILE_HEIGHT - 2); ///< Maximum allowed snowline height
  26
  27 /**
  28  * Tropic zone of a tile (subtropic climate only).
  29  *
  30  * The tropiczone is not modified during gameplay. It mainly affects tree growth (desert tiles are visible though).
  31  *
  32  * In randomly generated maps:
  33  *  TROPICZONE_DESERT: Generated everywhere, if there is neither water nor mountains (TileHeight >= 4) in a certain distance from the tile.
  34  *  TROPICZONE_RAINFOREST: Generated everywhere, if there is no desert in a certain distance from the tile.
  35  *  TROPICZONE_NORMAL: Everywhere else, i.e. between desert and rainforest and on sea (if you clear the water).
  36  *
  37  * In scenarios:
  38  *  TROPICZONE_NORMAL: Default value.
  39  *  TROPICZONE_DESERT: Placed manually.
  40  *  TROPICZONE_RAINFOREST: Placed if you plant certain rainforest-trees.
  41  */
  42 enum TropicZone {
  43         TROPICZONE_NORMAL     = 0,      ///< Normal tropiczone
  44         TROPICZONE_DESERT     = 1,      ///< Tile is desert
  45         TROPICZONE_RAINFOREST = 2,      ///< Rainforest tile
  46 };
  47
  48 /** Zone and height of a tile. */
  49 struct TileZH {
  50         byte height; ///< height of the (northern corner of the) tile
  51         byte zb;     ///< tile zone (2 most significant bits), bridge above (2 least significant bits)
  52 };
  53
  54 /**
  55  * Get the height of a tile
  56  *
  57  * This function returns the height of the northern corner of a tile.
  58  *
  59  * @param t The tile whose height to get
  60  * @return The height of the tile
  61  */
  62 static inline uint tilezh_get_height(const TileZH *t)
  63 {
  64         return t->height;
  65 }
  66
  67 /**
  68  * Set the height of a tile
  69  *
  70  * This function sets the height of the northern corner of a tile.
  71  *
  72  * @param t The tile whose height to set
  73  * @param height The new height value of the tile
  74  * @pre height <= MAX_TILE_HEIGHT
  75  */
  76 static inline void tilezh_set_height(TileZH *t, uint height)
  77 {
  78         assert(height <= MAX_TILE_HEIGHT);
  79         t->height = height;
  80 }
  81
  82 /**
  83  * Get the tropic zone of a tile
  84  * @param t The tile whose zone to get
  85  * @return The zone type of the tile
  86  */
  87 static inline TropicZone tilezh_get_zone(const TileZH *t)
  88 {
  89         return (TropicZone)GB(t->zb, 6, 2);
  90 }
  91
  92 /**
  93  * Set the tropic zone of a tile
  94  * @param t The tile whose zone to set
  95  * @param z The new zone type
  96  * @pre tile < MapSize()
  97  */
  98 static inline void tilezh_set_zone(TileZH *t, TropicZone z)
  99 {
 100         SB(t->zb, 6, 2, z);
 101 }
 102
 103
 104 /**
 105  * Check if this tile has a bridge over it
 106  * @param t The tile to check
 107  * @return Whether there is a bridge above the tile
 108  */
 109 static inline bool tile_has_bridge_above (const TileZH *t)
 110 {
 111         return GB(t->zb, 0, 2) != 0;
 112 }
 113
 114 /**
 115  * Get the axis of the bridge over a tile
 116  * @param t The tile
 117  * @pre tile_has_bridge_above(t)
 118  * @return The axis of the bridge
 119  */
 120 static inline Axis tile_get_bridge_axis (const TileZH *t)
 121 {
 122         assert (tile_has_bridge_above (t));
 123         return (Axis)(GB(t->zb, 0, 2) - 1);
 124 }
 125
 126 /**
 127  * Remove the bridge over a tile
 128  * @param t The tile
 129  */
 130 static inline void tile_clear_bridge_above (TileZH *t)
 131 {
 132         SB(t->zb, 0, 2, 0);
 133 }
 134
 135 /**
 136  * Set a bridge over a tile
 137  * @param t The tile
 138  * @param a Axis of the bridge
 139  * @pre !tile_has_bridge_above(t)
 140  */
 141 static inline void tile_set_bridge_above (TileZH *t, Axis a)
 142 {
 143         assert (!tile_has_bridge_above (t));
 144         SB(t->zb, 0, 2, 1 << a);
 145 }
 146
 147 #endif /* TILE_ZONEHEIGHT_H */