OpenTTD
tilearea.cpp
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1 /* $Id: tilearea.cpp 26482 2014-04-23 20:13:33Z rubidium $ */
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 
12 #include "stdafx.h"
13 
14 #include "tilearea_type.h"
15 
16 #include "safeguards.h"
17 
24 {
25  assert(start < MapSize());
26  assert(end < MapSize());
27 
28  uint sx = TileX(start);
29  uint sy = TileY(start);
30  uint ex = TileX(end);
31  uint ey = TileY(end);
32 
33  if (sx > ex) Swap(sx, ex);
34  if (sy > ey) Swap(sy, ey);
35 
36  this->tile = TileXY(sx, sy);
37  this->w = ex - sx + 1;
38  this->h = ey - sy + 1;
39 }
40 
46 {
47  if (this->tile == INVALID_TILE) {
48  this->tile = to_add;
49  this->w = 1;
50  this->h = 1;
51  return;
52  }
53 
54  uint sx = TileX(this->tile);
55  uint sy = TileY(this->tile);
56  uint ex = sx + this->w - 1;
57  uint ey = sy + this->h - 1;
58 
59  uint ax = TileX(to_add);
60  uint ay = TileY(to_add);
61 
62  sx = min(ax, sx);
63  sy = min(ay, sy);
64  ex = max(ax, ex);
65  ey = max(ay, ey);
66 
67  this->tile = TileXY(sx, sy);
68  this->w = ex - sx + 1;
69  this->h = ey - sy + 1;
70 }
71 
78 {
79  if (ta.w == 0 || this->w == 0) return false;
80 
81  assert(ta.w != 0 && ta.h != 0 && this->w != 0 && this->h != 0);
82 
83  uint left1 = TileX(this->tile);
84  uint top1 = TileY(this->tile);
85  uint right1 = left1 + this->w - 1;
86  uint bottom1 = top1 + this->h - 1;
87 
88  uint left2 = TileX(ta.tile);
89  uint top2 = TileY(ta.tile);
90  uint right2 = left2 + ta.w - 1;
91  uint bottom2 = top2 + ta.h - 1;
92 
93  return !(
94  left2 > right1 ||
95  right2 < left1 ||
96  top2 > bottom1 ||
97  bottom2 < top1
98  );
99 }
100 
107 {
108  if (this->w == 0) return false;
109 
110  assert(this->w != 0 && this->h != 0);
111 
112  uint left = TileX(this->tile);
113  uint top = TileY(this->tile);
114  uint tile_x = TileX(tile);
115  uint tile_y = TileY(tile);
116 
117  return IsInsideBS(tile_x, left, this->w) && IsInsideBS(tile_y, top, this->h);
118 }
119 
124 {
125  assert(this->tile < MapSize());
126  this->w = min(this->w, MapSizeX() - TileX(this->tile));
127  this->h = min(this->h, MapSizeY() - TileY(this->tile));
128 }
129 
136 {
137  assert(start < MapSize());
138  assert(end < MapSize());
139 
140  /* Unfortunately we can't find a new base and make all a and b positive because
141  * the new base might be a "flattened" corner where there actually is no single
142  * tile. If we try anyway the result is either inaccurate ("one off" half of the
143  * time) or the code gets much more complex;
144  *
145  * We also need to increment/decrement a and b here to have one-past-end semantics
146  * for a and b, just the way the orthogonal tile area does it for w and h. */
147 
148  this->a = TileY(end) + TileX(end) - TileY(start) - TileX(start);
149  this->b = TileY(end) - TileX(end) - TileY(start) + TileX(start);
150  if (this->a > 0) {
151  this->a++;
152  } else {
153  this->a--;
154  }
155 
156  if (this->b > 0) {
157  this->b++;
158  } else {
159  this->b--;
160  }
161 }
162 
169 {
170  int a = TileY(tile) + TileX(tile);
171  int b = TileY(tile) - TileX(tile);
172 
173  int start_a = TileY(this->tile) + TileX(this->tile);
174  int start_b = TileY(this->tile) - TileX(this->tile);
175 
176  int end_a = start_a + this->a;
177  int end_b = start_b + this->b;
178 
179  /* Swap if necessary, preserving the "one past end" semantics. */
180  if (start_a > end_a) {
181  int tmp = start_a;
182  start_a = end_a + 1;
183  end_a = tmp + 1;
184  }
185  if (start_b > end_b) {
186  int tmp = start_b;
187  start_b = end_b + 1;
188  end_b = tmp + 1;
189  }
190 
191  return (a >= start_a && a < end_a && b >= start_b && b < end_b);
192 }
193 
198 {
199  assert(this->tile != INVALID_TILE);
200 
201  /* Determine the next tile, while clipping at map borders */
202  bool new_line = false;
203  do {
204  /* Iterate using the rotated coordinates. */
205  if (this->a_max == 1 || this->a_max == -1) {
206  /* Special case: Every second column has zero length, skip them completely */
207  this->a_cur = 0;
208  if (this->b_max > 0) {
209  this->b_cur = min(this->b_cur + 2, this->b_max);
210  } else {
211  this->b_cur = max(this->b_cur - 2, this->b_max);
212  }
213  } else {
214  /* Every column has at least one tile to process */
215  if (this->a_max > 0) {
216  this->a_cur += 2;
217  new_line = this->a_cur >= this->a_max;
218  } else {
219  this->a_cur -= 2;
220  new_line = this->a_cur <= this->a_max;
221  }
222  if (new_line) {
223  /* offset of initial a_cur: one tile in the same direction as a_max
224  * every second line.
225  */
226  this->a_cur = abs(this->a_cur) % 2 ? 0 : (this->a_max > 0 ? 1 : -1);
227 
228  if (this->b_max > 0) {
229  ++this->b_cur;
230  } else {
231  --this->b_cur;
232  }
233  }
234  }
235 
236  /* And convert the coordinates back once we've gone to the next tile. */
237  uint x = this->base_x + (this->a_cur - this->b_cur) / 2;
238  uint y = this->base_y + (this->b_cur + this->a_cur) / 2;
239  /* Prevent wrapping around the map's borders. */
240  this->tile = x >= MapSizeX() || y >= MapSizeY() ? INVALID_TILE : TileXY(x, y);
241  } while (this->tile > MapSize() && this->b_max != this->b_cur);
242 
243  if (this->b_max == this->b_cur) this->tile = INVALID_TILE;
244  return *this;
245 }
TileIndex tile
Base tile of the area.
Definition: tilearea_type.h:66
static void Swap(T &a, T &b)
Type safe swap operation.
Definition: math_func.hpp:277
void ClampToMap()
Clamp the tile area to map borders.
Definition: tilearea.cpp:123
static uint MapSizeX()
Get the size of the map along the X.
Definition: map_func.h:74
bool Contains(TileIndex tile) const
Does this tile area contain a tile?
Definition: tilearea.cpp:106
DiagonalTileArea(TileIndex tile=INVALID_TILE, int8 a=0, int8 b=0)
Construct this tile area with some set values.
Definition: tilearea_type.h:76
static uint MapSizeY()
Get the size of the map along the Y.
Definition: map_func.h:84
static uint TileX(TileIndex tile)
Get the X component of a tile.
Definition: map_func.h:207
static bool IsInsideBS(const T x, const uint base, const uint size)
Checks if a value is between a window started at some base point.
Definition: math_func.hpp:250
int16 a
Extent in diagonal "x" direction (may be negative to signify the area stretches to the left) ...
Definition: tilearea_type.h:67
static T max(const T a, const T b)
Returns the maximum of two values.
Definition: math_func.hpp:26
uint16 w
The width of the area.
Definition: tilearea_type.h:20
OrthogonalTileArea(TileIndex tile=INVALID_TILE, uint8 w=0, uint8 h=0)
Construct this tile area with some set values.
Definition: tilearea_type.h:29
void Add(TileIndex to_add)
Add a single tile to a tile area; enlarge if needed.
Definition: tilearea.cpp:45
bool Intersects(const OrthogonalTileArea &ta) const
Does this tile area intersect with another?
Definition: tilearea.cpp:77
int16 b
Extent in diagonal "y" direction (may be negative to signify the area stretches upwards) ...
Definition: tilearea_type.h:68
Definition of base types and functions in a cross-platform compatible way.
A number of safeguards to prevent using unsafe methods.
Represents the covered area of e.g.
Definition: tilearea_type.h:18
Base class for tile iterators.
Definition: tilearea_type.h:99
static T min(const T a, const T b)
Returns the minimum of two values.
Definition: math_func.hpp:42
TileIterator & operator++()
Move ourselves to the next tile in the rectangle on the map.
Definition: tilearea.cpp:197
TileIndex tile
The base tile of the area.
Definition: tilearea_type.h:19
static uint MapSize()
Get the size of the map.
Definition: map_func.h:94
uint32 TileIndex
The index/ID of a Tile.
Definition: tile_type.h:80
static uint TileY(TileIndex tile)
Get the Y component of a tile.
Definition: map_func.h:217
static T abs(const T a)
Returns the absolute value of (scalar) variable.
Definition: math_func.hpp:83
Type for storing the &#39;area&#39; of something uses on the map.
static const TileIndex INVALID_TILE
The very nice invalid tile marker.
Definition: tile_type.h:85
uint16 h
The height of the area.
Definition: tilearea_type.h:21
static TileIndex TileXY(uint x, uint y)
Returns the TileIndex of a coordinate.
Definition: map_func.h:165
bool Contains(TileIndex tile) const
Does this tile area contain a tile?
Definition: tilearea.cpp:168