src/tilematrix_type.hpp

   1 /* $Id$ */
   2
   3 /*
   4  * This file is part of OpenTTD.
   5  * 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.
   6  * 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.
   7  * 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/>.
   8  */
   9
  10 /** @file tilematrix_type.hpp Template for storing a value per area of the map. */
  11
  12 #ifndef TILEMATRIX_TYPE_HPP
  13 #define TILEMATRIX_TYPE_HPP
  14
  15 #include "core/alloc_func.hpp"
  16 #include "map/tilearea.h"
  17
  18 /**
  19  * A simple matrix that stores one value per N*N square of the map.
  20  * Storage is only allocated for the part of the map that has values
  21  * assigned.
  22  *
  23  * @note No constructor is called for newly allocated values, you
  24  *       have to do this yourself if needed.
  25  * @tparam T The type of the stored items.
  26  * @tparam N Grid size.
  27  */
  28 template <typename T, uint N>
  29 class TileMatrix {
  30
  31         /** Allocates space for a new tile in the matrix.
  32          * @param tile Tile to add.
  33          */
  34         void AllocateStorage(TileIndex tile)
  35         {
  36                 uint old_left = TileX(this->area.tile) / N;
  37                 uint old_top  = TileY(this->area.tile) / N;
  38                 uint old_w    = this->area.w / N;
  39                 uint old_h    = this->area.h / N;
  40
  41                 /* Add the square the tile is in to the tile area. We do this
  42                  * by adding top-left and bottom-right of the square. */
  43                 uint grid_x = (TileX(tile) / N) * N;
  44                 uint grid_y = (TileY(tile) / N) * N;
  45                 this->area.Add(TileXY(grid_x, grid_y));
  46                 this->area.Add(TileXY(grid_x + N - 1, grid_y + N - 1));
  47
  48                 /* Allocate new storage. */
  49                 T *new_data = xcalloct<T>(this->area.w / N * this->area.h / N);
  50
  51                 if (old_w > 0) {
  52                         /* Copy old data if present. */
  53                         uint offs_x = old_left - TileX(this->area.tile) / N;
  54                         uint offs_y = old_top  - TileY(this->area.tile) / N;
  55
  56                         for (uint row = 0; row < old_h; row++) {
  57                                 MemCpyT(&new_data[(row + offs_y) * this->area.w / N + offs_x], &this->data[row * old_w], old_w);
  58                         }
  59                 }
  60
  61                 free(this->data);
  62                 this->data = new_data;
  63         }
  64
  65 public:
  66         static const uint GRID = N;
  67
  68         TileArea area; ///< Area covered by the matrix.
  69
  70         T *data; ///< Pointer to data array.
  71
  72         TileMatrix() : area(INVALID_TILE, 0, 0), data(NULL) {}
  73
  74         ~TileMatrix()
  75         {
  76                 free(this->data);
  77         }
  78
  79         /**
  80          * Get the total covered area.
  81          * @return The area covered by the matrix.
  82          */
  83         const TileArea& GetArea() const
  84         {
  85                 return this->area;
  86         }
  87
  88         /**
  89          * Get the area of the matrix square that contains a specific tile.
  90          * @param The tile to get the map area for.
  91          * @param extend Extend the area by this many squares on all sides.
  92          * @return Tile area containing the tile.
  93          */
  94         static TileArea GetAreaForTile(TileIndex tile, uint extend = 0)
  95         {
  96                 uint tile_x = (TileX(tile) / N) * N;
  97                 uint tile_y = (TileY(tile) / N) * N;
  98                 uint w = N, h = N;
  99
 100                 w += min(extend * N, tile_x);
 101                 h += min(extend * N, tile_y);
 102
 103                 tile_x -= min(extend * N, tile_x);
 104                 tile_y -= min(extend * N, tile_y);
 105
 106                 w += min(extend * N, MapSizeX() - tile_x - w);
 107                 h += min(extend * N, MapSizeY() - tile_y - h);
 108
 109                 return TileArea(TileXY(tile_x, tile_y), w, h);
 110         }
 111
 112         /**
 113          * Extend the coverage area to include a tile.
 114          * @param tile The tile to include.
 115          */
 116         void Add(TileIndex tile)
 117         {
 118                 if (!this->area.Contains(tile)) {
 119                         this->AllocateStorage(tile);
 120                 }
 121         }
 122
 123         /**
 124          * Get the value associated to a tile index.
 125          * @param tile The tile to get the value for.
 126          * @return Pointer to the value.
 127          */
 128         T *Get(TileIndex tile)
 129         {
 130                 this->Add(tile);
 131
 132                 tile -= this->area.tile;
 133                 uint x = TileX(tile) / N;
 134                 uint y = TileY(tile) / N;
 135
 136                 return &this->data[y * this->area.w / N + x];
 137         }
 138
 139         /** Array access operator, see #Get. */
 140         inline T &operator[](TileIndex tile)
 141         {
 142                 return *this->Get(tile);
 143         }
 144 };
 145
 146 #endif /* TILEMATRIX_TYPE_HPP */