OpenTTD Source  20241108-master-g80f628063a
tgp.cpp
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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 
10 #include "stdafx.h"
11 #include "clear_map.h"
12 #include "void_map.h"
13 #include "genworld.h"
14 #include "core/random_func.hpp"
15 #include "landscape_type.h"
16 
17 #include "safeguards.h"
18 
19 /*
20  *
21  * Quickie guide to Perlin Noise
22  * Perlin noise is a predictable pseudo random number sequence. By generating
23  * it in 2 dimensions, it becomes a useful random map that, for a given seed
24  * and starting X & Y, is entirely predictable. On the face of it, that may not
25  * be useful. However, it means that if you want to replay a map in a different
26  * terrain, or just vary the sea level, you just re-run the generator with the
27  * same seed. The seed is an int32_t, and is randomised on each run of New Game.
28  * The Scenario Generator does not randomise the value, so that you can
29  * experiment with one terrain until you are happy, or click "Random" for a new
30  * random seed.
31  *
32  * Perlin Noise is a series of "octaves" of random noise added together. By
33  * reducing the amplitude of the noise with each octave, the first octave of
34  * noise defines the main terrain sweep, the next the ripples on that, and the
35  * next the ripples on that. I use 6 octaves, with the amplitude controlled by
36  * a power ratio, usually known as a persistence or p value. This I vary by the
37  * smoothness selection, as can be seen in the table below. The closer to 1,
38  * the more of that octave is added. Each octave is however raised to the power
39  * of its position in the list, so the last entry in the "smooth" row, 0.35, is
40  * raised to the power of 6, so can only add 0.001838... of the amplitude to
41  * the running total.
42  *
43  * In other words; the first p value sets the general shape of the terrain, the
44  * second sets the major variations to that, ... until finally the smallest
45  * bumps are added.
46  *
47  * Usefully, this routine is totally scalable; so when 32bpp comes along, the
48  * terrain can be as bumpy as you like! It is also infinitely expandable; a
49  * single random seed terrain continues in X & Y as far as you care to
50  * calculate. In theory, we could use just one seed value, but randomly select
51  * where in the Perlin XY space we use for the terrain. Personally I prefer
52  * using a simple (0, 0) to (X, Y), with a varying seed.
53  *
54  *
55  * Other things i have had to do: mountainous wasn't mountainous enough, and
56  * since we only have 0..15 heights available, I add a second generated map
57  * (with a modified seed), onto the original. This generally raises the
58  * terrain, which then needs scaling back down. Overall effect is a general
59  * uplift.
60  *
61  * However, the values on the top of mountains are then almost guaranteed to go
62  * too high, so large flat plateaus appeared at height 15. To counter this, I
63  * scale all heights above 12 to proportion up to 15. It still makes the
64  * mountains have flattish tops, rather than craggy peaks, but at least they
65  * aren't smooth as glass.
66  *
67  *
68  * For a full discussion of Perlin Noise, please visit:
69  * http://freespace.virgin.net/hugo.elias/models/m_perlin.htm
70  *
71  *
72  * Evolution II
73  *
74  * The algorithm as described in the above link suggests to compute each tile height
75  * as composition of several noise waves. Some of them are computed directly by
76  * noise(x, y) function, some are calculated using linear approximation. Our
77  * first implementation of perlin_noise_2D() used 4 noise(x, y) calls plus
78  * 3 linear interpolations. It was called 6 times for each tile. This was a bit
79  * CPU expensive.
80  *
81  * The following implementation uses optimized algorithm that should produce
82  * the same quality result with much less computations, but more memory accesses.
83  * The overall speedup should be 300% to 800% depending on CPU and memory speed.
84  *
85  * I will try to explain it on the example below:
86  *
87  * Have a map of 4 x 4 tiles, our simplified noise generator produces only two
88  * values -1 and +1, use 3 octaves with wave length 1, 2 and 4, with amplitudes
89  * 3, 2, 1. Original algorithm produces:
90  *
91  * h00 = lerp(lerp(-3, 3, 0/4), lerp(3, -3, 0/4), 0/4) + lerp(lerp(-2, 2, 0/2), lerp( 2, -2, 0/2), 0/2) + -1 = lerp(-3.0, 3.0, 0/4) + lerp(-2, 2, 0/2) + -1 = -3.0 + -2 + -1 = -6.0
92  * h01 = lerp(lerp(-3, 3, 1/4), lerp(3, -3, 1/4), 0/4) + lerp(lerp(-2, 2, 1/2), lerp( 2, -2, 1/2), 0/2) + 1 = lerp(-1.5, 1.5, 0/4) + lerp( 0, 0, 0/2) + 1 = -1.5 + 0 + 1 = -0.5
93  * h02 = lerp(lerp(-3, 3, 2/4), lerp(3, -3, 2/4), 0/4) + lerp(lerp( 2, -2, 0/2), lerp(-2, 2, 0/2), 0/2) + -1 = lerp( 0, 0, 0/4) + lerp( 2, -2, 0/2) + -1 = 0 + 2 + -1 = 1.0
94  * h03 = lerp(lerp(-3, 3, 3/4), lerp(3, -3, 3/4), 0/4) + lerp(lerp( 2, -2, 1/2), lerp(-2, 2, 1/2), 0/2) + 1 = lerp( 1.5, -1.5, 0/4) + lerp( 0, 0, 0/2) + 1 = 1.5 + 0 + 1 = 2.5
95  *
96  * h10 = lerp(lerp(-3, 3, 0/4), lerp(3, -3, 0/4), 1/4) + lerp(lerp(-2, 2, 0/2), lerp( 2, -2, 0/2), 1/2) + 1 = lerp(-3.0, 3.0, 1/4) + lerp(-2, 2, 1/2) + 1 = -1.5 + 0 + 1 = -0.5
97  * h11 = lerp(lerp(-3, 3, 1/4), lerp(3, -3, 1/4), 1/4) + lerp(lerp(-2, 2, 1/2), lerp( 2, -2, 1/2), 1/2) + -1 = lerp(-1.5, 1.5, 1/4) + lerp( 0, 0, 1/2) + -1 = -0.75 + 0 + -1 = -1.75
98  * h12 = lerp(lerp(-3, 3, 2/4), lerp(3, -3, 2/4), 1/4) + lerp(lerp( 2, -2, 0/2), lerp(-2, 2, 0/2), 1/2) + 1 = lerp( 0, 0, 1/4) + lerp( 2, -2, 1/2) + 1 = 0 + 0 + 1 = 1.0
99  * h13 = lerp(lerp(-3, 3, 3/4), lerp(3, -3, 3/4), 1/4) + lerp(lerp( 2, -2, 1/2), lerp(-2, 2, 1/2), 1/2) + -1 = lerp( 1.5, -1.5, 1/4) + lerp( 0, 0, 1/2) + -1 = 0.75 + 0 + -1 = -0.25
100  *
101  *
102  * Optimization 1:
103  *
104  * 1) we need to allocate a bit more tiles: (size_x + 1) * (size_y + 1) = (5 * 5):
105  *
106  * 2) setup corner values using amplitude 3
107  * { -3.0 X X X 3.0 }
108  * { X X X X X }
109  * { X X X X X }
110  * { X X X X X }
111  * { 3.0 X X X -3.0 }
112  *
113  * 3a) interpolate values in the middle
114  * { -3.0 X 0.0 X 3.0 }
115  * { X X X X X }
116  * { 0.0 X 0.0 X 0.0 }
117  * { X X X X X }
118  * { 3.0 X 0.0 X -3.0 }
119  *
120  * 3b) add patches with amplitude 2 to them
121  * { -5.0 X 2.0 X 1.0 }
122  * { X X X X X }
123  * { 2.0 X -2.0 X 2.0 }
124  * { X X X X X }
125  * { 1.0 X 2.0 X -5.0 }
126  *
127  * 4a) interpolate values in the middle
128  * { -5.0 -1.5 2.0 1.5 1.0 }
129  * { -1.5 -0.75 0.0 0.75 1.5 }
130  * { 2.0 0.0 -2.0 0.0 2.0 }
131  * { 1.5 0.75 0.0 -0.75 -1.5 }
132  * { 1.0 1.5 2.0 -1.5 -5.0 }
133  *
134  * 4b) add patches with amplitude 1 to them
135  * { -6.0 -0.5 1.0 2.5 0.0 }
136  * { -0.5 -1.75 1.0 -0.25 2.5 }
137  * { 1.0 1.0 -3.0 1.0 1.0 }
138  * { 2.5 -0.25 1.0 -1.75 -0.5 }
139  * { 0.0 2.5 1.0 -0.5 -6.0 }
140  *
141  *
142  *
143  * Optimization 2:
144  *
145  * As you can see above, each noise function was called just once. Therefore
146  * we don't need to use noise function that calculates the noise from x, y and
147  * some prime. The same quality result we can obtain using standard Random()
148  * function instead.
149  *
150  */
151 
153 using Height = int16_t;
154 static const int height_decimal_bits = 4;
155 
157 using Amplitude = int;
158 static const int amplitude_decimal_bits = 10;
159 
161 struct HeightMap
162 {
163  std::vector<Height> h; //< array of heights
164  /* Even though the sizes are always positive, there are many cases where
165  * X and Y need to be signed integers due to subtractions. */
166  int dim_x; //< height map size_x Map::SizeX() + 1
167  int size_x; //< Map::SizeX()
168  int size_y; //< Map::SizeY()
169 
176  inline Height &height(uint x, uint y)
177  {
178  return h[x + y * dim_x];
179  }
180 };
181 
183 static HeightMap _height_map = { {}, 0, 0, 0 };
184 
186 #define I2H(i) ((i) << height_decimal_bits)
188 #define H2I(i) ((i) >> height_decimal_bits)
189 
191 #define A2I(i) ((i) >> amplitude_decimal_bits)
192 
194 #define A2H(a) ((a) >> (amplitude_decimal_bits - height_decimal_bits))
195 
197 static const int MAX_TGP_FREQUENCIES = 10;
198 
200 static const Amplitude _water_percent[4] = {70, 170, 270, 420};
201 
209 {
211  /* TGP never reaches this height; this means that if a user inputs "2",
212  * it would create a flat map without the "+ 1". But that would
213  * overflow on "255". So we reduce it by 1 to get back in range. */
215  }
216 
227  static const int max_height[5][MAX_MAP_SIZE_BITS - MIN_MAP_SIZE_BITS + 1] = {
228  /* 64 128 256 512 1024 2048 4096 */
229  { 3, 3, 3, 3, 4, 5, 7 },
230  { 5, 7, 8, 9, 14, 19, 31 },
231  { 8, 9, 10, 15, 23, 37, 61 },
232  { 10, 11, 17, 19, 49, 63, 73 },
233  { 12, 19, 25, 31, 67, 75, 87 },
234  };
235 
236  int map_size_bucket = std::min(Map::LogX(), Map::LogY()) - MIN_MAP_SIZE_BITS;
237  int max_height_from_table = max_height[_settings_game.difficulty.terrain_type][map_size_bucket];
238 
239  /* If there is a manual map height limit, clamp to it. */
241  max_height_from_table = std::min<uint>(max_height_from_table, _settings_game.construction.map_height_limit);
242  }
243 
244  return I2H(max_height_from_table);
245 }
246 
251 {
252  return H2I(TGPGetMaxHeight());
253 }
254 
261 static Amplitude GetAmplitude(int frequency)
262 {
263  /* Base noise amplitudes (multiplied by 1024) and indexed by "smoothness setting" and log2(frequency). */
264  static const Amplitude amplitudes[][7] = {
265  /* lowest frequency ...... highest (every corner) */
266  {16000, 5600, 1968, 688, 240, 16, 16},
267  {24000, 12800, 6400, 2700, 1024, 128, 16},
268  {32000, 19200, 12800, 8000, 3200, 256, 64},
269  {48000, 24000, 19200, 16000, 8000, 512, 320},
270  };
271  /*
272  * Extrapolation factors for ranges before the table.
273  * The extrapolation is needed to account for the higher map heights. They need larger
274  * areas with a particular gradient so that we are able to create maps without too
275  * many steep slopes up to the wanted height level. It's definitely not perfect since
276  * it will bring larger rectangles with similar slopes which makes the rectangular
277  * behaviour of TGP more noticeable. However, these height differentiations cannot
278  * happen over much smaller areas; we basically double the "range" to give a similar
279  * slope for every doubling of map height.
280  */
281  static const double extrapolation_factors[] = { 3.3, 2.8, 2.3, 1.8 };
282 
284 
285  /* Get the table index, and return that value if possible. */
286  int index = frequency - MAX_TGP_FREQUENCIES + static_cast<int>(std::size(amplitudes[smoothness]));
287  Amplitude amplitude = amplitudes[smoothness][std::max(0, index)];
288  if (index >= 0) return amplitude;
289 
290  /* We need to extrapolate the amplitude. */
291  double extrapolation_factor = extrapolation_factors[smoothness];
292  int height_range = I2H(16);
293  do {
294  amplitude = (Amplitude)(extrapolation_factor * (double)amplitude);
295  height_range <<= 1;
296  index++;
297  } while (index < 0);
298 
299  return Clamp((TGPGetMaxHeight() - height_range) / height_range, 0, 1) * amplitude;
300 }
301 
308 static inline bool IsValidXY(int x, int y)
309 {
310  return x >= 0 && x < _height_map.size_x && y >= 0 && y < _height_map.size_y;
311 }
312 
313 
318 static inline bool AllocHeightMap()
319 {
320  assert(_height_map.h.empty());
321 
322  _height_map.size_x = Map::SizeX();
323  _height_map.size_y = Map::SizeY();
324 
325  /* Allocate memory block for height map row pointers */
326  size_t total_size = static_cast<size_t>(_height_map.size_x + 1) * (_height_map.size_y + 1);
327  _height_map.dim_x = _height_map.size_x + 1;
328  _height_map.h.resize(total_size);
329 
330  return true;
331 }
332 
334 static inline void FreeHeightMap()
335 {
336  _height_map.h.clear();
337 }
338 
344 static inline Height RandomHeight(Amplitude rMax)
345 {
346  /* Spread height into range -rMax..+rMax */
347  return A2H(RandomRange(2 * rMax + 1) - rMax);
348 }
349 
357 static void HeightMapGenerate()
358 {
359  /* Trying to apply noise to uninitialized height map */
360  assert(!_height_map.h.empty());
361 
362  int start = std::max(MAX_TGP_FREQUENCIES - (int)std::min(Map::LogX(), Map::LogY()), 0);
363  bool first = true;
364 
365  for (int frequency = start; frequency < MAX_TGP_FREQUENCIES; frequency++) {
366  const Amplitude amplitude = GetAmplitude(frequency);
367 
368  /* Ignore zero amplitudes; it means our map isn't height enough for this
369  * amplitude, so ignore it and continue with the next set of amplitude. */
370  if (amplitude == 0) continue;
371 
372  const int step = 1 << (MAX_TGP_FREQUENCIES - frequency - 1);
373 
374  if (first) {
375  /* This is first round, we need to establish base heights with step = size_min */
376  for (int y = 0; y <= _height_map.size_y; y += step) {
377  for (int x = 0; x <= _height_map.size_x; x += step) {
378  Height height = (amplitude > 0) ? RandomHeight(amplitude) : 0;
379  _height_map.height(x, y) = height;
380  }
381  }
382  first = false;
383  continue;
384  }
385 
386  /* It is regular iteration round.
387  * Interpolate height values at odd x, even y tiles */
388  for (int y = 0; y <= _height_map.size_y; y += 2 * step) {
389  for (int x = 0; x <= _height_map.size_x - 2 * step; x += 2 * step) {
390  Height h00 = _height_map.height(x + 0 * step, y);
391  Height h02 = _height_map.height(x + 2 * step, y);
392  Height h01 = (h00 + h02) / 2;
393  _height_map.height(x + 1 * step, y) = h01;
394  }
395  }
396 
397  /* Interpolate height values at odd y tiles */
398  for (int y = 0; y <= _height_map.size_y - 2 * step; y += 2 * step) {
399  for (int x = 0; x <= _height_map.size_x; x += step) {
400  Height h00 = _height_map.height(x, y + 0 * step);
401  Height h20 = _height_map.height(x, y + 2 * step);
402  Height h10 = (h00 + h20) / 2;
403  _height_map.height(x, y + 1 * step) = h10;
404  }
405  }
406 
407  /* Add noise for next higher frequency (smaller steps) */
408  for (int y = 0; y <= _height_map.size_y; y += step) {
409  for (int x = 0; x <= _height_map.size_x; x += step) {
410  _height_map.height(x, y) += RandomHeight(amplitude);
411  }
412  }
413  }
414 }
415 
417 static void HeightMapGetMinMaxAvg(Height *min_ptr, Height *max_ptr, Height *avg_ptr)
418 {
419  Height h_min, h_max, h_avg;
420  int64_t h_accu = 0;
421  h_min = h_max = _height_map.height(0, 0);
422 
423  /* Get h_min, h_max and accumulate heights into h_accu */
424  for (const Height &h : _height_map.h) {
425  if (h < h_min) h_min = h;
426  if (h > h_max) h_max = h;
427  h_accu += h;
428  }
429 
430  /* Get average height */
431  h_avg = (Height)(h_accu / (_height_map.size_x * _height_map.size_y));
432 
433  /* Return required results */
434  if (min_ptr != nullptr) *min_ptr = h_min;
435  if (max_ptr != nullptr) *max_ptr = h_max;
436  if (avg_ptr != nullptr) *avg_ptr = h_avg;
437 }
438 
440 static int *HeightMapMakeHistogram(Height h_min, [[maybe_unused]] Height h_max, int *hist_buf)
441 {
442  int *hist = hist_buf - h_min;
443 
444  /* Count the heights and fill the histogram */
445  for (const Height &h : _height_map.h) {
446  assert(h >= h_min);
447  assert(h <= h_max);
448  hist[h]++;
449  }
450  return hist;
451 }
452 
454 static void HeightMapSineTransform(Height h_min, Height h_max)
455 {
456  for (Height &h : _height_map.h) {
457  double fheight;
458 
459  if (h < h_min) continue;
460 
461  /* Transform height into 0..1 space */
462  fheight = (double)(h - h_min) / (double)(h_max - h_min);
463  /* Apply sine transform depending on landscape type */
465  case LT_TOYLAND:
466  case LT_TEMPERATE:
467  /* Move and scale 0..1 into -1..+1 */
468  fheight = 2 * fheight - 1;
469  /* Sine transform */
470  fheight = sin(fheight * M_PI_2);
471  /* Transform it back from -1..1 into 0..1 space */
472  fheight = 0.5 * (fheight + 1);
473  break;
474 
475  case LT_ARCTIC:
476  {
477  /* Arctic terrain needs special height distribution.
478  * Redistribute heights to have more tiles at highest (75%..100%) range */
479  double sine_upper_limit = 0.75;
480  double linear_compression = 2;
481  if (fheight >= sine_upper_limit) {
482  /* Over the limit we do linear compression up */
483  fheight = 1.0 - (1.0 - fheight) / linear_compression;
484  } else {
485  double m = 1.0 - (1.0 - sine_upper_limit) / linear_compression;
486  /* Get 0..sine_upper_limit into -1..1 */
487  fheight = 2.0 * fheight / sine_upper_limit - 1.0;
488  /* Sine wave transform */
489  fheight = sin(fheight * M_PI_2);
490  /* Get -1..1 back to 0..(1 - (1 - sine_upper_limit) / linear_compression) == 0.0..m */
491  fheight = 0.5 * (fheight + 1.0) * m;
492  }
493  }
494  break;
495 
496  case LT_TROPIC:
497  {
498  /* Desert terrain needs special height distribution.
499  * Half of tiles should be at lowest (0..25%) heights */
500  double sine_lower_limit = 0.5;
501  double linear_compression = 2;
502  if (fheight <= sine_lower_limit) {
503  /* Under the limit we do linear compression down */
504  fheight = fheight / linear_compression;
505  } else {
506  double m = sine_lower_limit / linear_compression;
507  /* Get sine_lower_limit..1 into -1..1 */
508  fheight = 2.0 * ((fheight - sine_lower_limit) / (1.0 - sine_lower_limit)) - 1.0;
509  /* Sine wave transform */
510  fheight = sin(fheight * M_PI_2);
511  /* Get -1..1 back to (sine_lower_limit / linear_compression)..1.0 */
512  fheight = 0.5 * ((1.0 - m) * fheight + (1.0 + m));
513  }
514  }
515  break;
516 
517  default:
518  NOT_REACHED();
519  break;
520  }
521  /* Transform it back into h_min..h_max space */
522  h = (Height)(fheight * (h_max - h_min) + h_min);
523  if (h < 0) h = I2H(0);
524  if (h >= h_max) h = h_max - 1;
525  }
526 }
527 
544 static void HeightMapCurves(uint level)
545 {
546  Height mh = TGPGetMaxHeight() - I2H(1); // height levels above sea level only
547 
549  struct ControlPoint {
550  Height x;
551  Height y;
552  };
553  /* Scaled curve maps; value is in height_ts. */
554 #define F(fraction) ((Height)(fraction * mh))
555  const ControlPoint curve_map_1[] = { { F(0.0), F(0.0) }, { F(0.8), F(0.13) }, { F(1.0), F(0.4) } };
556  const ControlPoint curve_map_2[] = { { F(0.0), F(0.0) }, { F(0.53), F(0.13) }, { F(0.8), F(0.27) }, { F(1.0), F(0.6) } };
557  const ControlPoint curve_map_3[] = { { F(0.0), F(0.0) }, { F(0.53), F(0.27) }, { F(0.8), F(0.57) }, { F(1.0), F(0.8) } };
558  const ControlPoint curve_map_4[] = { { F(0.0), F(0.0) }, { F(0.4), F(0.3) }, { F(0.7), F(0.8) }, { F(0.92), F(0.99) }, { F(1.0), F(0.99) } };
559 #undef F
560 
561  const std::span<const ControlPoint> curve_maps[] = { curve_map_1, curve_map_2, curve_map_3, curve_map_4 };
562 
563  std::array<Height, std::size(curve_maps)> ht{};
564 
565  /* Set up a grid to choose curve maps based on location; attempt to get a somewhat square grid */
566  float factor = sqrt((float)_height_map.size_x / (float)_height_map.size_y);
567  uint sx = Clamp((int)(((1 << level) * factor) + 0.5), 1, 128);
568  uint sy = Clamp((int)(((1 << level) / factor) + 0.5), 1, 128);
569  std::vector<uint8_t> c(static_cast<size_t>(sx) * sy);
570 
571  for (uint i = 0; i < sx * sy; i++) {
572  c[i] = RandomRange(static_cast<uint32_t>(std::size(curve_maps)));
573  }
574 
575  /* Apply curves */
576  for (int x = 0; x < _height_map.size_x; x++) {
577 
578  /* Get our X grid positions and bi-linear ratio */
579  float fx = (float)(sx * x) / _height_map.size_x + 1.0f;
580  uint x1 = (uint)fx;
581  uint x2 = x1;
582  float xr = 2.0f * (fx - x1) - 1.0f;
583  xr = sin(xr * M_PI_2);
584  xr = sin(xr * M_PI_2);
585  xr = 0.5f * (xr + 1.0f);
586  float xri = 1.0f - xr;
587 
588  if (x1 > 0) {
589  x1--;
590  if (x2 >= sx) x2--;
591  }
592 
593  for (int y = 0; y < _height_map.size_y; y++) {
594 
595  /* Get our Y grid position and bi-linear ratio */
596  float fy = (float)(sy * y) / _height_map.size_y + 1.0f;
597  uint y1 = (uint)fy;
598  uint y2 = y1;
599  float yr = 2.0f * (fy - y1) - 1.0f;
600  yr = sin(yr * M_PI_2);
601  yr = sin(yr * M_PI_2);
602  yr = 0.5f * (yr + 1.0f);
603  float yri = 1.0f - yr;
604 
605  if (y1 > 0) {
606  y1--;
607  if (y2 >= sy) y2--;
608  }
609 
610  uint corner_a = c[x1 + sx * y1];
611  uint corner_b = c[x1 + sx * y2];
612  uint corner_c = c[x2 + sx * y1];
613  uint corner_d = c[x2 + sx * y2];
614 
615  /* Bitmask of which curve maps are chosen, so that we do not bother
616  * calculating a curve which won't be used. */
617  uint corner_bits = 0;
618  corner_bits |= 1 << corner_a;
619  corner_bits |= 1 << corner_b;
620  corner_bits |= 1 << corner_c;
621  corner_bits |= 1 << corner_d;
622 
623  Height *h = &_height_map.height(x, y);
624 
625  /* Do not touch sea level */
626  if (*h < I2H(1)) continue;
627 
628  /* Only scale above sea level */
629  *h -= I2H(1);
630 
631  /* Apply all curve maps that are used on this tile. */
632  for (size_t t = 0; t < std::size(curve_maps); t++) {
633  if (!HasBit(corner_bits, static_cast<uint8_t>(t))) continue;
634 
635  [[maybe_unused]] bool found = false;
636  auto &cm = curve_maps[t];
637  for (size_t i = 0; i < cm.size() - 1; i++) {
638  const ControlPoint &p1 = cm[i];
639  const ControlPoint &p2 = cm[i + 1];
640 
641  if (*h >= p1.x && *h < p2.x) {
642  ht[t] = p1.y + (*h - p1.x) * (p2.y - p1.y) / (p2.x - p1.x);
643 #ifdef WITH_ASSERT
644  found = true;
645 #endif
646  break;
647  }
648  }
649  assert(found);
650  }
651 
652  /* Apply interpolation of curve map results. */
653  *h = (Height)((ht[corner_a] * yri + ht[corner_b] * yr) * xri + (ht[corner_c] * yri + ht[corner_d] * yr) * xr);
654 
655  /* Readd sea level */
656  *h += I2H(1);
657  }
658  }
659 }
660 
662 static void HeightMapAdjustWaterLevel(Amplitude water_percent, Height h_max_new)
663 {
664  Height h_min, h_max, h_avg, h_water_level;
665  int64_t water_tiles, desired_water_tiles;
666  int *hist;
667 
668  HeightMapGetMinMaxAvg(&h_min, &h_max, &h_avg);
669 
670  /* Allocate histogram buffer and clear its cells */
671  std::vector<int> hist_buf(h_max - h_min + 1);
672  /* Fill histogram */
673  hist = HeightMapMakeHistogram(h_min, h_max, hist_buf.data());
674 
675  /* How many water tiles do we want? */
676  desired_water_tiles = A2I(((int64_t)water_percent) * (int64_t)(_height_map.size_x * _height_map.size_y));
677 
678  /* Raise water_level and accumulate values from histogram until we reach required number of water tiles */
679  for (h_water_level = h_min, water_tiles = 0; h_water_level < h_max; h_water_level++) {
680  water_tiles += hist[h_water_level];
681  if (water_tiles >= desired_water_tiles) break;
682  }
683 
684  /* We now have the proper water level value.
685  * Transform the height map into new (normalized) height map:
686  * values from range: h_min..h_water_level will become negative so it will be clamped to 0
687  * values from range: h_water_level..h_max are transformed into 0..h_max_new
688  * where h_max_new is depending on terrain type and map size.
689  */
690  for (Height &h : _height_map.h) {
691  /* Transform height from range h_water_level..h_max into 0..h_max_new range */
692  h = (Height)(((int)h_max_new) * (h - h_water_level) / (h_max - h_water_level)) + I2H(1);
693  /* Make sure all values are in the proper range (0..h_max_new) */
694  if (h < 0) h = I2H(0);
695  if (h >= h_max_new) h = h_max_new - 1;
696  }
697 }
698 
699 static double perlin_coast_noise_2D(const double x, const double y, const double p, const int prime);
700 
721 static void HeightMapCoastLines(uint8_t water_borders)
722 {
723  int smallest_size = std::min(_settings_game.game_creation.map_x, _settings_game.game_creation.map_y);
724  const int margin = 4;
725  int y, x;
726  double max_x;
727  double max_y;
728 
729  /* Lower to sea level */
730  for (y = 0; y <= _height_map.size_y; y++) {
731  if (HasBit(water_borders, BORDER_NE)) {
732  /* Top right */
733  max_x = abs((perlin_coast_noise_2D(_height_map.size_y - y, y, 0.9, 53) + 0.25) * 5 + (perlin_coast_noise_2D(y, y, 0.35, 179) + 1) * 12);
734  max_x = std::max((smallest_size * smallest_size / 64) + max_x, (smallest_size * smallest_size / 64) + margin - max_x);
735  if (smallest_size < 8 && max_x > 5) max_x /= 1.5;
736  for (x = 0; x < max_x; x++) {
737  _height_map.height(x, y) = 0;
738  }
739  }
740 
741  if (HasBit(water_borders, BORDER_SW)) {
742  /* Bottom left */
743  max_x = abs((perlin_coast_noise_2D(_height_map.size_y - y, y, 0.85, 101) + 0.3) * 6 + (perlin_coast_noise_2D(y, y, 0.45, 67) + 0.75) * 8);
744  max_x = std::max((smallest_size * smallest_size / 64) + max_x, (smallest_size * smallest_size / 64) + margin - max_x);
745  if (smallest_size < 8 && max_x > 5) max_x /= 1.5;
746  for (x = _height_map.size_x; x > (_height_map.size_x - 1 - max_x); x--) {
747  _height_map.height(x, y) = 0;
748  }
749  }
750  }
751 
752  /* Lower to sea level */
753  for (x = 0; x <= _height_map.size_x; x++) {
754  if (HasBit(water_borders, BORDER_NW)) {
755  /* Top left */
756  max_y = abs((perlin_coast_noise_2D(x, _height_map.size_y / 2, 0.9, 167) + 0.4) * 5 + (perlin_coast_noise_2D(x, _height_map.size_y / 3, 0.4, 211) + 0.7) * 9);
757  max_y = std::max((smallest_size * smallest_size / 64) + max_y, (smallest_size * smallest_size / 64) + margin - max_y);
758  if (smallest_size < 8 && max_y > 5) max_y /= 1.5;
759  for (y = 0; y < max_y; y++) {
760  _height_map.height(x, y) = 0;
761  }
762  }
763 
764  if (HasBit(water_borders, BORDER_SE)) {
765  /* Bottom right */
766  max_y = abs((perlin_coast_noise_2D(x, _height_map.size_y / 3, 0.85, 71) + 0.25) * 6 + (perlin_coast_noise_2D(x, _height_map.size_y / 3, 0.35, 193) + 0.75) * 12);
767  max_y = std::max((smallest_size * smallest_size / 64) + max_y, (smallest_size * smallest_size / 64) + margin - max_y);
768  if (smallest_size < 8 && max_y > 5) max_y /= 1.5;
769  for (y = _height_map.size_y; y > (_height_map.size_y - 1 - max_y); y--) {
770  _height_map.height(x, y) = 0;
771  }
772  }
773  }
774 }
775 
777 static void HeightMapSmoothCoastInDirection(int org_x, int org_y, int dir_x, int dir_y)
778 {
779  const int max_coast_dist_from_edge = 35;
780  const int max_coast_Smooth_depth = 35;
781 
782  int x, y;
783  int ed; // coast distance from edge
784  int depth;
785 
786  Height h_prev = I2H(1);
787  Height h;
788 
789  assert(IsValidXY(org_x, org_y));
790 
791  /* Search for the coast (first non-water tile) */
792  for (x = org_x, y = org_y, ed = 0; IsValidXY(x, y) && ed < max_coast_dist_from_edge; x += dir_x, y += dir_y, ed++) {
793  /* Coast found? */
794  if (_height_map.height(x, y) >= I2H(1)) break;
795 
796  /* Coast found in the neighborhood? */
797  if (IsValidXY(x + dir_y, y + dir_x) && _height_map.height(x + dir_y, y + dir_x) > 0) break;
798 
799  /* Coast found in the neighborhood on the other side */
800  if (IsValidXY(x - dir_y, y - dir_x) && _height_map.height(x - dir_y, y - dir_x) > 0) break;
801  }
802 
803  /* Coast found or max_coast_dist_from_edge has been reached.
804  * Soften the coast slope */
805  for (depth = 0; IsValidXY(x, y) && depth <= max_coast_Smooth_depth; depth++, x += dir_x, y += dir_y) {
806  h = _height_map.height(x, y);
807  h = static_cast<Height>(std::min<uint>(h, h_prev + (4 + depth))); // coast softening formula
808  _height_map.height(x, y) = h;
809  h_prev = h;
810  }
811 }
812 
814 static void HeightMapSmoothCoasts(uint8_t water_borders)
815 {
816  int x, y;
817  /* First Smooth NW and SE coasts (y close to 0 and y close to size_y) */
818  for (x = 0; x < _height_map.size_x; x++) {
819  if (HasBit(water_borders, BORDER_NW)) HeightMapSmoothCoastInDirection(x, 0, 0, 1);
820  if (HasBit(water_borders, BORDER_SE)) HeightMapSmoothCoastInDirection(x, _height_map.size_y - 1, 0, -1);
821  }
822  /* First Smooth NE and SW coasts (x close to 0 and x close to size_x) */
823  for (y = 0; y < _height_map.size_y; y++) {
824  if (HasBit(water_borders, BORDER_NE)) HeightMapSmoothCoastInDirection(0, y, 1, 0);
825  if (HasBit(water_borders, BORDER_SW)) HeightMapSmoothCoastInDirection(_height_map.size_x - 1, y, -1, 0);
826  }
827 }
828 
836 static void HeightMapSmoothSlopes(Height dh_max)
837 {
838  for (int y = 0; y <= (int)_height_map.size_y; y++) {
839  for (int x = 0; x <= (int)_height_map.size_x; x++) {
840  Height h_max = std::min(_height_map.height(x > 0 ? x - 1 : x, y), _height_map.height(x, y > 0 ? y - 1 : y)) + dh_max;
841  if (_height_map.height(x, y) > h_max) _height_map.height(x, y) = h_max;
842  }
843  }
844  for (int y = _height_map.size_y; y >= 0; y--) {
845  for (int x = _height_map.size_x; x >= 0; x--) {
846  Height h_max = std::min(_height_map.height(x < _height_map.size_x ? x + 1 : x, y), _height_map.height(x, y < _height_map.size_y ? y + 1 : y)) + dh_max;
847  if (_height_map.height(x, y) > h_max) _height_map.height(x, y) = h_max;
848  }
849  }
850 }
851 
859 static void HeightMapNormalize()
860 {
861  int sea_level_setting = _settings_game.difficulty.quantity_sea_lakes;
862  const Amplitude water_percent = sea_level_setting != (int)CUSTOM_SEA_LEVEL_NUMBER_DIFFICULTY ? _water_percent[sea_level_setting] : _settings_game.game_creation.custom_sea_level * 1024 / 100;
863  const Height h_max_new = TGPGetMaxHeight();
864  const Height roughness = 7 + 3 * _settings_game.game_creation.tgen_smoothness;
865 
866  HeightMapAdjustWaterLevel(water_percent, h_max_new);
867 
869  if (water_borders == BORDERS_RANDOM) water_borders = GB(Random(), 0, 4);
870 
871  HeightMapCoastLines(water_borders);
872  HeightMapSmoothSlopes(roughness);
873 
874  HeightMapSmoothCoasts(water_borders);
875  HeightMapSmoothSlopes(roughness);
876 
877  HeightMapSineTransform(I2H(1), h_max_new);
878 
881  }
882 
884 }
885 
893 static double int_noise(const long x, const long y, const int prime)
894 {
895  long n = x + y * prime + _settings_game.game_creation.generation_seed;
896 
897  n = (n << 13) ^ n;
898 
899  /* Pseudo-random number generator, using several large primes */
900  return 1.0 - (double)((n * (n * n * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0;
901 }
902 
903 
907 static inline double linear_interpolate(const double a, const double b, const double x)
908 {
909  return a + x * (b - a);
910 }
911 
912 
917 static double interpolated_noise(const double x, const double y, const int prime)
918 {
919  const int integer_X = (int)x;
920  const int integer_Y = (int)y;
921 
922  const double fractional_X = x - (double)integer_X;
923  const double fractional_Y = y - (double)integer_Y;
924 
925  const double v1 = int_noise(integer_X, integer_Y, prime);
926  const double v2 = int_noise(integer_X + 1, integer_Y, prime);
927  const double v3 = int_noise(integer_X, integer_Y + 1, prime);
928  const double v4 = int_noise(integer_X + 1, integer_Y + 1, prime);
929 
930  const double i1 = linear_interpolate(v1, v2, fractional_X);
931  const double i2 = linear_interpolate(v3, v4, fractional_X);
932 
933  return linear_interpolate(i1, i2, fractional_Y);
934 }
935 
936 
943 static double perlin_coast_noise_2D(const double x, const double y, const double p, const int prime)
944 {
945  double total = 0.0;
946 
947  for (int i = 0; i < 6; i++) {
948  const double frequency = (double)(1 << i);
949  const double amplitude = pow(p, (double)i);
950 
951  total += interpolated_noise((x * frequency) / 64.0, (y * frequency) / 64.0, prime) * amplitude;
952  }
953 
954  return total;
955 }
956 
957 
959 static void TgenSetTileHeight(TileIndex tile, int height)
960 {
961  SetTileHeight(tile, height);
962 
963  /* Only clear the tiles within the map area. */
964  if (IsInnerTile(tile)) {
965  MakeClear(tile, CLEAR_GRASS, 3);
966  }
967 }
968 
977 {
978  if (!AllocHeightMap()) return;
980 
982 
984 
986 
988 
989  /* First make sure the tiles at the north border are void tiles if needed. */
991  for (uint x = 0; x < Map::SizeX(); x++) MakeVoid(TileXY(x, 0));
992  for (uint y = 0; y < Map::SizeY(); y++) MakeVoid(TileXY(0, y));
993  }
994 
995  int max_height = H2I(TGPGetMaxHeight());
996 
997  /* Transfer height map into OTTD map */
998  for (int y = 0; y < _height_map.size_y; y++) {
999  for (int x = 0; x < _height_map.size_x; x++) {
1000  TgenSetTileHeight(TileXY(x, y), Clamp(H2I(_height_map.height(x, y)), 0, max_height));
1001  }
1002  }
1003 
1005 
1006  FreeHeightMap();
1008 }
constexpr debug_inline bool HasBit(const T x, const uint8_t y)
Checks if a bit in a value is set.
constexpr static debug_inline uint GB(const T x, const uint8_t s, const uint8_t n)
Fetch n bits from x, started at bit s.
Map accessors for 'clear' tiles.
@ CLEAR_GRASS
0-3
Definition: clear_map.h:20
void MakeClear(Tile t, ClearGround g, uint density)
Make a clear tile.
Definition: clear_map.h:259
void GenerateWorldSetAbortCallback(GWAbortProc *proc)
Set here the function, if any, that you want to be called when landscape generation is aborted.
Definition: genworld.cpp:244
Functions related to world/map generation.
void IncreaseGeneratingWorldProgress(GenWorldProgress cls)
Increases the current stage of the world generation with one.
static const uint CUSTOM_SEA_LEVEL_NUMBER_DIFFICULTY
Value for custom sea level in difficulty settings.
Definition: genworld.h:47
@ GWP_LANDSCAPE
Create the landscape.
Definition: genworld.h:71
static const uint CUSTOM_TERRAIN_TYPE_NUMBER_DIFFICULTY
Value for custom terrain type in difficulty settings.
Definition: genworld.h:45
Types related to the landscape.
static debug_inline TileIndex TileXY(uint x, uint y)
Returns the TileIndex of a coordinate.
Definition: map_func.h:373
static const uint MIN_MAP_SIZE_BITS
Minimal and maximal map width and height.
Definition: map_type.h:37
static const uint MAX_MAP_SIZE_BITS
Maximal size of map is equal to 2 ^ MAX_MAP_SIZE_BITS.
Definition: map_type.h:38
constexpr T abs(const T a)
Returns the absolute value of (scalar) variable.
Definition: math_func.hpp:23
constexpr T Clamp(const T a, const T min, const T max)
Clamp a value between an interval.
Definition: math_func.hpp:79
Pseudo random number generator.
uint32_t RandomRange(uint32_t limit, const std::source_location location=std::source_location::current())
Pick a random number between 0 and limit - 1, inclusive.
Definition: random_func.hpp:88
A number of safeguards to prevent using unsafe methods.
GameSettings _settings_game
Game settings of a running game or the scenario editor.
Definition: settings.cpp:57
Definition of base types and functions in a cross-platform compatible way.
bool freeform_edges
allow terraforming the tiles at the map edges
uint8_t map_height_limit
the maximum allowed heightlevel
uint8_t terrain_type
the mountainousness of the landscape
uint8_t quantity_sea_lakes
the amount of seas/lakes
uint8_t custom_sea_level
manually entered percentage of water in the map
uint8_t variety
variety level applied to TGP
uint8_t custom_terrain_type
manually entered height for TGP to aim for
uint8_t map_x
X size of map.
uint8_t landscape
the landscape we're currently in
uint8_t tgen_smoothness
how rough is the terrain from 0-3
uint8_t map_y
Y size of map.
uint32_t generation_seed
noise seed for world generation
uint8_t water_borders
bitset of the borders that are water
ConstructionSettings construction
construction of things in-game
DifficultySettings difficulty
settings related to the difficulty
GameCreationSettings game_creation
settings used during the creation of a game (map)
Height map - allocated array of heights (MapSizeX() + 1) x (MapSizeY() + 1)
Definition: tgp.cpp:162
Height & height(uint x, uint y)
Height map accessor.
Definition: tgp.cpp:176
static uint SizeY()
Get the size of the map along the Y.
Definition: map_func.h:279
static debug_inline uint SizeX()
Get the size of the map along the X.
Definition: map_func.h:270
static debug_inline uint LogX()
Logarithm of the map size along the X side.
Definition: map_func.h:251
static uint LogY()
Logarithm of the map size along the y side.
Definition: map_func.h:261
static void HeightMapSmoothCoastInDirection(int org_x, int org_y, int dir_x, int dir_y)
Start at given point, move in given direction, find and Smooth coast in that direction.
Definition: tgp.cpp:777
static void HeightMapSmoothCoasts(uint8_t water_borders)
Smooth coasts by modulating height of tiles close to map edges with cosine of distance from edge.
Definition: tgp.cpp:814
static void HeightMapGenerate()
Base Perlin noise generator - fills height map with raw Perlin noise.
Definition: tgp.cpp:357
static double linear_interpolate(const double a, const double b, const double x)
This routine determines the interpolated value between a and b.
Definition: tgp.cpp:907
static int * HeightMapMakeHistogram(Height h_min, [[maybe_unused]] Height h_max, int *hist_buf)
Dill histogram and return pointer to its base point - to the count of zero heights.
Definition: tgp.cpp:440
static void HeightMapAdjustWaterLevel(Amplitude water_percent, Height h_max_new)
Adjusts heights in height map to contain required amount of water tiles.
Definition: tgp.cpp:662
static Height TGPGetMaxHeight()
Gets the maximum allowed height while generating a map based on mapsize, terraintype,...
Definition: tgp.cpp:208
static bool AllocHeightMap()
Allocate array of (MapSizeX()+1)*(MapSizeY()+1) heights and init the _height_map structure members.
Definition: tgp.cpp:318
#define I2H(i)
Conversion: int to Height.
Definition: tgp.cpp:186
static const Amplitude _water_percent[4]
Desired water percentage (100% == 1024) - indexed by _settings_game.difficulty.quantity_sea_lakes.
Definition: tgp.cpp:200
static void HeightMapGetMinMaxAvg(Height *min_ptr, Height *max_ptr, Height *avg_ptr)
Returns min, max and average height from height map.
Definition: tgp.cpp:417
static void HeightMapCoastLines(uint8_t water_borders)
This routine sculpts in from the edge a random amount, again a Perlin sequence, to avoid the rigid fl...
Definition: tgp.cpp:721
static void HeightMapSmoothSlopes(Height dh_max)
This routine provides the essential cleanup necessary before OTTD can display the terrain.
Definition: tgp.cpp:836
static Height RandomHeight(Amplitude rMax)
Generates new random height in given amplitude (generated numbers will range from - amplitude to + am...
Definition: tgp.cpp:344
int16_t Height
Fixed point type for heights.
Definition: tgp.cpp:153
static Amplitude GetAmplitude(int frequency)
Get the amplitude associated with the currently selected smoothness and maximum height level.
Definition: tgp.cpp:261
static void FreeHeightMap()
Free height map.
Definition: tgp.cpp:334
int Amplitude
Fixed point array for amplitudes (and percent values)
Definition: tgp.cpp:157
uint GetEstimationTGPMapHeight()
Get an overestimation of the highest peak TGP wants to generate.
Definition: tgp.cpp:250
static void HeightMapSineTransform(Height h_min, Height h_max)
Applies sine wave redistribution onto height map.
Definition: tgp.cpp:454
static HeightMap _height_map
Global height map instance.
Definition: tgp.cpp:183
#define A2H(a)
Conversion: Amplitude to Height.
Definition: tgp.cpp:194
static void HeightMapNormalize()
Height map terraform post processing:
Definition: tgp.cpp:859
static bool IsValidXY(int x, int y)
Check if a X/Y set are within the map.
Definition: tgp.cpp:308
static const int MAX_TGP_FREQUENCIES
Maximum number of TGP noise frequencies.
Definition: tgp.cpp:197
static double perlin_coast_noise_2D(const double x, const double y, const double p, const int prime)
This is a similar function to the main perlin noise calculation, but uses the value p passed as a par...
Definition: tgp.cpp:943
static void TgenSetTileHeight(TileIndex tile, int height)
A small helper function to initialize the terrain.
Definition: tgp.cpp:959
void GenerateTerrainPerlin()
The main new land generator using Perlin noise.
Definition: tgp.cpp:976
#define H2I(i)
Conversion: Height to int.
Definition: tgp.cpp:188
static double interpolated_noise(const double x, const double y, const int prime)
This routine returns the smoothed interpolated noise for an x and y, using the values from the surrou...
Definition: tgp.cpp:917
static double int_noise(const long x, const long y, const int prime)
The Perlin Noise calculation using large primes The initial number is adjusted by two values; the gen...
Definition: tgp.cpp:893
#define A2I(i)
Conversion: Amplitude to int.
Definition: tgp.cpp:191
static void HeightMapCurves(uint level)
Additional map variety is provided by applying different curve maps to different parts of the map.
Definition: tgp.cpp:544
bool IsInnerTile(Tile tile)
Check if a tile is within the map (not a border)
Definition: tile_map.h:109
void SetTileHeight(Tile tile, uint height)
Sets the height of a tile.
Definition: tile_map.h:57
Map accessors for void tiles.
void MakeVoid(Tile t)
Make a nice void tile ;)
Definition: void_map.h:19